Types of Quantum Computing Technology

With the increased use of quantum computing comes the rise in related technologies.

Silicon

Silicon-based technology relies on quantum dots carved out of silicon. This can achieve high-density qubits which can scale up to large numbers and tackle practical quantum computing problems. This uses traditional silicon wafer fabing techniques for development. The goal is to spin qubits on silicon at the atomic scale.

Ionic

Ionic-based technology uses charged atomic particles, which can be confined and suspended in free space using electromagnetic fields. Qubits are stored in the stable electronic states of each ion. Lasers are used to induce coupling between qubits. With ion-based technology there is the potential for scalable trapped ion quantum computers.

Carbon

Carbon-based technology is a suspended carbon nanotube coupled to a quantum dot, making a mechanical oscillator that serves as a qubit. This technology is based on grown carbon nano tubes that combine spins to ensure long coherence times and high frequency microwave components to enable fast operations. Carbon technology might be a way to reduce error rates and therefore would be useful in “noisy” quantum environments.

Photonic

Photonic-based technology consists of superpositions of multiple photons in a light pulse. Qubits consist of so-called “squeeze states” consisting of superpositions of multiple photons in a light pulse. The squeezed light and optical gates use silicon design techniques. Photonic technology can help scale quantum computers to millions of qubits. Qubits can be made with photons or single particles of quantum computing platforms.

Superconducting

Superconducting-based technology is photons and/or exotic states of matter trapped in magnetic fields. When temperatures drop, the laws of physics change, and the particles allow for faster computation. Superconduction occurs in cryogenic applications; this places extreme demand on interconnect materials, which means custom materials are needed, as standard coax will not survive.

Hybrid

Hybrid technology is a combination of classical computing and quantum computing. It combines elements of quantum computing, especially the use of quantum bits or qubits for processing, and classical computers as we already know them.

The Difference Between Classical and Quantum Computing

Both classical and quantum computing process data. The difference lies in the methods and the speed of each type of computing. Although quantum computing is becoming more widely used, it will not replace classical computing; it can, however, do some things that classical computing cannot. Getting the computing power that many industries need is increasingly less possible with classical computing, which is where quantum computing comes in.

Classical Computing

A classical computer uses bits to represent data for binary processing, which has states of either 0 or 1. This eliminates any ambiguity and makes data easily predicable and replicable. A classical CPU is silicon based with transistor logic and requires external memory. Classical computing power increases linearly as a function of computing power, based on the number of transistors and bits; this allows classical computers to have good speed with parallel processing and algorithms.

Quantum Computing

Quantum computing works using the quantum properties of atomic and subatomic particles. The primary element for computations is called a quantum bit or qubit. A quantum computer CPU is atomic, ionic, or photonic. They can be incredibly powerful while using a fraction of the energy of a classical computer. Quantum computing power also increases exponentially with each additional qubit.

Quantum computing uses two main properties from quantum physics: superposition and entanglement. Qubit processing with a quantum computer allows for multiple superposition states where a qubit can either be a 0, a 1, or both simultaneously. This property enables a quantum computer to process information significantly faster and more efficiently than a classical computer. Quantum computing also uses the principle of entanglement, where one qubit can be in a state and when coupled with another qubit, their states mimic each other without physical contact. Entanglement allows for true parallel processing.

What is Quantum Computing?

First theorized in the 1980s, quantum computing is the next frontier of computation, representing a significant shift in computing performance capabilities. As quantum becomes more prevalent in research, this type of computing will save years of development time and a substantial amount of money in engineering design.

The main use cases for quantum computing are applications with complex problems and complicated operations involving thousands of inputs. These types of applications can include:

• Global Shipping Logistics
• Cybersecurity
• Financial and Economic Modeling
• Aerodynamic and Thermodynamic Modeling
• Cosmology Simulation

To keep quantum computers stable, they need to be exceptionally cold—typically colder than the vacuum of space. The performance capabilities inherent in quantum computing require robust RF interconnects and cable assemblies to transport data (qubits) to and from the computer reliably.

Quantum Computing and Times Microwave Systems

Quantum computers require specialized cabling solutions such as rugged, low-loss, and phase stable coaxial assemblies. The RF cable assemblies these systems rely on must be custom built to customer specifications, with specific bend radii and lengths. Quantum computing also requires signal access points close to processors and non-magnetic cables to eliminate potential interference with applied magnetic fields.

At Times Microwave Systems, we build cabling products for the most challenging environments on the planet, including the extreme temperatures of the cryo-chamber, which can reach zero degrees Kelvin. Our hermetically sealed custom coaxial cabling assemblies address the need for reliable performance in grueling environments by utilizing advanced manufacturing techniques that ensure zero electric field distortion.

Frequency Matters Podcast: Quantum Computing with Dave Slack

Summary

Gary Lerude of Microwave Journal recently spoke with Dave Slack, Engineering Director at Times Microwave Systems, on quantum computing. Watch the complete video or read the session notes below.

Session Notes

What is quantum computing?

Quantum computing has been in development for a couple of decades now but it’s really starting to heat up for several reasons. I compare it to classical computing. With classical computing we’re all familiar with we use ones and zeros and binary data. Quantum computing works using the quantum properties of atomic and subatomic matter. It uses those very strange quantum properties and it’s pretty interesting technology.

I tend to look at new technologies like this in a historical context because I find you can look at what has happened and play that forward and get a pretty good understanding of how things are going to play out in the upcoming years. If you look back at the development of classing computing right in 1951, the U.S. Census Bureau took delivery of a machine called Univac. This Univac was room sized, it was sixty thousand pounds, 5,000 vacuum tubes, and it could perform calculation at a massive 1,000 calculations per second. We processed that as a kilohertz. Today we have hundreds of megahertz computing power in our pockets that we’re just carrying around with us so quite a gap has been covered in that period. From 1951 with the vacuum tubes, in the late 50s transistors were introduced; in the 60s and 70s those transistors were integrated into integrated circuits. 1980s microprocessors came along and computers got more and more powerful and they got smaller and smaller and smaller. 1965 a gentleman named Gordon Moore put out Moore’s law, that the transistor density of chips would double every year and that has that has been true from 1965 until about 2010.

In 2010 Moore’s Law started to trail off, meaning that the technology behind classical computing is starting to reach it’s the limits of physics and the limits of economics. To get the computing power that you know many industries need is going to be increasingly less possible with classical computing. Classical computing, as we mentioned earlier, uses very discrete ones and zeros. No ambiguity. It’s either/or, nowhere in the middle. It’s very predictable, it’s very reproducible. Quantum physics uses the properties of quantum, of quantum mechanics, which is the mechanics of matter very, very microscopic scales.

The basic element for computations is called a quantum bit or qubit. Qubit can be it can be a one or a zero, but it actually shouldn’t be thought of as a one and a zero because it can be both which is kind of which is kind of weird when you think about it. And quantum mechanics also use the principle of entanglement, where one qubit can be in a state and it will be coupled with another qubit their states will kind of mimic each other without any physical connection, which is super weird.

When I try to get my head around how can a bit of data be a one and a zero that’s really hard for me to grasp, so I think of it, being a microwave guy, I think of it in terms of noise. I think about that spectrum analyzer with no inputs and you set your filters up and you get noise for down 130, 140 dbm, and you see the randomness, you just see random noise. And you could park a market at any frequency you want to and you’re going to get this range of noise values. You know, they’re going to be all over the place. So you cannot say that if I put a marker at five gigahertz, I am going to measure power X. it’s just not that deterministic like you would expect in a classical computing world. Being a one or a zero, what you’re going to see is a range of numbers and if you capture those numbers over time you can describe them statistically. You will have X probability of measuring Y value every time you sample. It’s about the best you can do. And that’s the way I think of a quantum bit or qubit being a one and a zero. If you’re controlling it and it should be in the one state you know statistically it’s going to tend to be in the one state but it could be in a zero or anywhere in between. It’s only what it is when I measure it is what matters. Quantum computing takes advantage of both of those properties, the superposition properties of the one and the zero and the entanglement properties. The entanglement kind of gives you true parallel processing, so whereas classical computing power increases linearly as a function of computing power, the number of transistors and number of bits, quantum computing increases exponentially with the number of qubits so they can be massively more powerful with every time you add on another bit. They have the ability to be super powerful with a fraction of the energy usage.

So I’m with you so far, that makes sense. I like your analogy of the kind of noise floor on a spectrum analyzer to try to understand the probabilistic nature. If we think about more practical terms, you talked about the power of quantum computing, but what would a quantum computer be able to do?

First of all what they will not do is replace classical computing. We’re always going to have that. That’s always going to be the best tool for many, many calculations. What quantum computing will do is it allows the use of different bits. It uses different algorithms and works totally differently and what it will allow you to do is take problems that have a massive number of inputs and where these inputs are not always discreetly defined they’re more statistical inputs, and it will allow you to process problems like that because that’s the way the machines thinks and works.

The use cases that are seen for this is anything where a large number of complex numbers are involved, like cybersecurity, security, banking security, financial and economic modeling. If you try to get two economists to agree on what the economy is going to do their models are limited in what they can do so the quantum computer is really geared towards that kind of a complex problem with thousands and thousands of inputs into it. Predicting the weather, you can never get two weathermen to agree on what the weather is going to do. It’s super complicated modeling climate change. All these super complex models are where I think quantum computing has a fit.

I think artificial intelligence is just going to explode when it has access to this tool. And the other thing is you know aerodynamic and thermodynamic modeling, especially with hypersonic weapons, that modeling of those thermodynamics and the aerodynamics at those speeds and velocities aren’t well known, so today they’re doing a lot of physical testing to kind of understand. They run models that takes weeks to complete. Having a quantum computer to run those models would be way less physical testing and they could run more models much more quickly would be super valuable.

That makes sense, a lot of power involved there particularly with very complex problems. Now, we hear that there’s a connection between quantum computing and microwave engineering. How is microwave engineering involved in quantum computing?

That’s the question for this audience, I’m sure. So how do we play in this? The qubits, you can think of the qubits as a microwave resonator like an LC tank or something, and you can drive these qubits from a zero state to a one state, to one energy level zero or a one, by driving it with a microwave signal. It’s a resonant and you drive it with a signal at that frequency of resonance and you’re going to change the energy level within that resonator. Under this driven condition the probabilities of being a one or a zero vary sinusoidally with time and it could be controlled too much the way other signal can be controlled. It’s important to know that like other signals, the qubits have magnitude and a phase relationship. They’re complex signals, so it’s very familiar to the microwave community these concepts.

One of the limiting factors in quantum computing is when you have this resonator under this driven condition, it’s kind of predictable and controlled and is only able to be maintained for a certain period of time because with any resonator there’s losses and there’s things affect it that cause it to lose energy and stop resonating. And that’s the limiters here. That is called the correlation of the qubit. When these things become de-correlated they’re no longer predictable, they’re no longer controlled, and that’s analogous to bit errors in data, so you’d have computational issues. The correlation and the control of the qubits is one of the real driving issues behind the technology development. What it really boils down to is the noise comes from thermal noise, it comes from magnetic noise, and it can come from mechanical noise, vibrations, things like that. Microwave hardware that can feed these resonators and minimize these contaminations. In fact, one of the prime limitations is super low noise driving signals for the qubits, especially low phase noise, so a lot of work is going on to ultra low phase noise oscillators and things like that.

The way to have a computer, you need more than one bit so you have two bits or multiple bits; when you have two of these bits they can be coupled together and they can be controlled by this driving signal which is at a microwave frequency, and it can be amplitude and phase modulated to give it certain properties. Both qubits can be modulated separately, and then using the wave properties of the two you can get it to perform in certain ways and the wave properties actually interfere. It’s very analogous to interferometry that antenna and radar people do.

I think of it again in terms of that classic high school demonstration of the two slits and the laser beam and you get the interferometry pattern, you get areas where the two wave patterns can interfere constructively and then others where they interfere destructively. You get kind of high-density probabilities and low density probabilities. You get essentially the ones and zeros and those can be controlled. All of the hardware that’s used to control these qubits and this coupling, I’ll introduce these noises, the thermal, the magnetic, the vibrational noise, so aside from the low noise sources of these driving signals in precise modulation schemes it’s hardware that minimizes that contamination. This is where I think a lot of the microwave community can support.

I think one of the requirements to maintain low noise is to have very low temperatures. Is that correct?

Absolutely. The resonators, the lump constant model is an inductor in parallel with a capacitor. And if you have that you have this perpetual motion machine that just the magnetic flux collapses drives the capacitor which then charges and then discharges and repeat. That would go on forever on paper but in reality there’s losses, these resistive losses, so you get kind of a damp sine wave unless you feedback some of that energy with this driving signal. Being at cryogenic temperatures, below 4 miliKelvin, which is really close to absolute zero, which also astounds me that we can get things that cold, but you minimize resistive losses. It’s virtually zero so you don’t have those losses. The noise floor is less so thermal noise is less. The quantum computing actually wants to happen in a really hard vacuum at super cold temperatures and totally shielded from the Earth’s magnetic field. It’s a very pristine place that these computations want to take place.

You’ve convinced me that there’s a lot of potential here. What’s the actual state of the technology and capability today? I know there’s a lot of research going on, but where are we?

The way I see it, we are in the period before Univac was delivered to its customer. We don’t quite have that Univac machine, that big room-sized monster. The first time commercial quantum computers are going to be quite analogous to that and I think over time they’re going to do what classic computers have done, they’re going to get smaller and faster and more accurate very quickly. I think in the decades that have spanned between then and now, I think that development time frame is going to be a fraction of what it was. I think the next five years are going to be astounding. Next year is going to be a big year and the next ten years is just going to be amazing at where the development is.

Google is spending billions of dollars on this and they have recently just claimed supremacy; they’ve proclaimed there’s a computer problem that Google’s quantum computer has solved in 200 seconds that they claim that IBM Summit machine would take 10,000 years to solve which is an astounding claim. IBM of course disputes this. IBM says that now it would take our Summit computer two and a half days to solve this problem, so by IBM’s own numbers it’s taken a two and a half day solution can now be done in 200 seconds which a thousand to one improvement. And this is on that pre, this is on that lab level computer. So if we can get a thousand time improvement of our quantum Univac , the next five or ten years I mean only the imagination is our limits. I think ti’s going to be a really interesting ride and I’m really looking forward to seeing it unfold.

by Dave Murray, Technical Fellow

Originally published in Microwave Product Digest

Hypersonic missiles represent the most significant advancement in defense weaponry since the 1960s. However, they also present substantial challenges. The term “hypersonic” describes any speed faster than five times the speed of sound (above Mach 5). In fact, these missiles are so fast that, as they travel, their speed can alter the adjacent air molecules. Compared to ballistic missiles, which are fast but travel along a predictable trajectory, and cruise missiles, which are accurate but slower, hypersonic weapons combine speed and accuracy. In addition, they are low-flying and maneuverable, designed to be nimble enough that traditional missile defense systems cannot detect and react in time.

There are two types: hypersonic glide vehicles (HGVs), also known as boost-glide vehicles, are typically launched from a ballistic missile and released at a specific altitude, speed, and with the flight path tailored to reaching its target without being powered. A small propulsion system could be added to speed arrival at the target and provide directional control.

In contrast, hypersonic cruise missiles (HCMs) are powered all the way to their targets, flying high altitudes but lower than those of HGVs and launched from a rocket or jet aircraft. Power is delivered by air-breathing scramjet engines. Scramjets have been in development since the 1950s and they’ve proven to be extremely difficult to perfect, with the most successful results produced only since the 2000s. The trajectories of both types of weapons are shown in Figure 1.

Figure 1: Hypersonic glide vehicles (also known as boost-glide vehicles) are typically launched from a ballistic missile and released at a specific altitude, speed, and with the flight path tailored to reaching its target without being powered. Hypersonic cruise missiles are powered all the way to their targets, flying high altitudes but lower than those of HGVs and launched from a rocket or jet aircraft.

RF technology is key to powering many advanced electronics applications in hypersonic missiles. However, designing a crucial RF interconnect system that will perform well and withstand the extraordinary environmental and technical conditions presented by hypersonic missiles requires unique, highly customized coaxial cable solutions to prevent failure.

For example, a hypersonic missile utilizes multiple antennas and sensors with phase-matched or time-matched cables. These elements must survive at speeds that can exceed Mach 5, at times topping 5,000 mph. At such speeds, the temperature on the surface and in the boundary layer of the missile may exceed 1,800° F (1000° C).

During its journey, hypersonic missile guidance will reach temperatures ranging from 200° C to as high as 1000° C. This creates a unique material challenge as extreme temperatures will melt the plastics and polymers typically used in coaxial cables.

High-performance dielectrics and phase-matched systems are essential to meet phase versus temperature requirements. A hypersonic missile will go through the top of the atmosphere, generating vast amounts of heat, like a space capsule during re-entry. As the cable moves from cold to very hot temperatures, the phase matching between cables needs to track.

Hence, phase is a crucial parameter for detection and measurement in RF systems that rely on high accuracy continuous transmission and reception of RF signals. RF signals must travel through coaxial cables at consistent speeds regardless of environmental factors. Temperature variations degrade the electrical match between coaxial cable assemblies. That small amount of degradation, known as phase tracking characteristic, can adversely affect system performance.

For example, the electronically steered antenna used in many RF applications employs an array of radiating elements to steer antenna beams rather than physically moving an antenna. Beam steering for transmission or reception is performed by adjusting the phase of the individual antenna elements in the array. High-frequency transmission lines feed each antenna array element. The accuracy of the signal phase presented to each array element depends on the phase accuracy and stability of the cable assemblies. Therefore, cable assemblies optimized for phase performance usually exhibit minimal changes in phase with temperature.

Modern missile systems also utilize extensive communications equipment packed within a highly confined space. This creates a demand for novel solutions that combine a small form factor with reduced weight and rugged construction to withstand the high impact and vibration conditions from deployment to target.

Polytetrafluoroethylene (PTFE) has traditionally been the dielectric material of choice for many high-frequency cables, as it provides excellent flexibility and low loss. However, at +19°C, PTFE exhibits a well-known deviation, commonly referred to as the “knee,” in its phase versus temperature characteristics due to a change in its crystalline state. This abrupt change in phase length at +19° C can generate inaccuracies in systems that use phase as a measurement parameter.

These inaccuracies, though slight, can lead to much larger, crucial issues; any variations in the electrical behavior of RF/microwave coaxial cable assemblies can introduce amplitude and phase variations that degrade the performance of a phased-array radar system overall.

Silicon Dioxide Coaxial Cables

Hypersonic missile systems cannot tolerate phase errors, so cable designers must consider other materials that do not present the same shortcomings as PTFE. Times Microwave Systems developed a proprietary silicon dioxide dielectric (SiO2) to address these unique challenges (Figure 2). Silicon dioxide is well known in the microelectronics industry for its excellent insulating properties.

Figure 2: Times Microwave Systems SiO2 cable, designed to meet the challenges of hypersonic missiles and other demanding spaceflight systems

The SiO2 construction starts with a solid oxygen-free copper center conductor, a silicon dioxide insulating dielectric, and a stainless steel jacket with copper cladding to act as the outer conductor. Low loss, high-velocity silicon dioxide dielectrics excel in extreme environments as they provide excellent phase stability and can perform at extreme temperatures ranging from just above absolute zero to 1000° C. In addition, compared to other cable types, SiO2 cables provide exceptionally low hysteresis, with phase and loss returning to the same values at a given temperature even after extreme excursions.

The metal and silicon dioxide dielectric construction make the cable resist radiation naturally, up to 100 Mrads. All connectors for Times’ SiO2 cable assemblies employ a crack-free, fired glass seal to provide the optimum microwave performance. The stainless steel jacket is welded to the connectors with laser beam technology to create a hermetic seal.

Between the silicon dioxide dielectric and the tight tolerances of each cable assembly, SiO2 has an EMI shielding of better than 110 dB. The 50 ohm cables are available with outer diameters of 0.090, 0.141, and 0.270 in. with cutoff frequencies of 64, 36, and 18.5 GHz, respectively.

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Frequency Matters Podcast: Hypersonic Weapons with Dave Slack

Summary

Gary Lerude of Microwave Journal recently spoke with Dave Slack, Engineering Director at Times Microwave Systems, on hypersonic weapons. Watch the complete video or read the session notes below.

Session Notes

Hypersonic weapons have been a hot topic in the news lately. Please give us some background on hypersonics and what all the buzz is about.

A really quick definition of hypersonic is that it describes any speed faster than five times the speed of sound (above Mach 5). The hypersonic weapon systems creating all the buzz today will go faster—about 10, 15, 20, or even 25 times the speed of sound.

Hypersonic technologies are not new; however, they have been around for 70 years or so since the end of World War II. Examples include Sputnik, the Apollo missions, SpaceX rockets, etc. What they all had in common is that they have a ballistic path, a parabolic arc set by the force of gravity and launch velocity. The path is very predictable, and it is easy to determine where the vehicle came from, where it’s going to land, etc., so it’s easy to defend against and countermeasure.

The difference today is that the new generation of hypersonic vehicles is steerable. This makes it challenging to determine precisely where it came from, which is a game changer. The weapon system that is getting the most attention right now is hypersonic glide vehicles. These are initially launched on a parabolic or ballistic arc but can drop down much lower in altitude mid-course and “glide” at a relatively low atmosphere at hypersonic speeds. As a result, they are much more challenging to detect.

Not only are these missiles traveling at hypersonic speeds, but they are also maneuverable. As a result, the time to react could be as little as two-three minutes compared to 45 minutes or an hour with other missile types, so they are very difficult to defend against. Additionally, there are hypersonic cruise missiles, powered vehicles with a scramjet or a supersonic ram jet. That is another game changer because it can travel at much lower altitudes at much longer ranges and is powered, so it’s not just gliding.

Given the physics associated with hypersonic speeds and the extreme environmental conditions, what kind of challenges or emerging technologies have hypersonics created?

The maneuverability factor is the primary issue when it comes to electronics. Every time the missile maneuvers, it loses energy, which is then dissipated as heat. This is in addition to the heat caused by the friction of slipping through the air stream. Dealing with that heat is one of the significant technical challenges.

Smart weapons are also precise and accurate, usually requiring someone on the ground to identify a target, communicate with the weapon, and guide it at hypersonic speeds. These vehicles are surrounded by a plasma envelope, which is why space vehicles lose communications for a few seconds on re-entry because the envelope shields them from communications. Penetrating the plasma envelope to communicate with the weapon and steer it creates another big technological hurdle. This drives the need to evaluate smaller, lighter options that can operate at higher temperatures.

RF microwave technology is used on hypersonic weapons in onboard systems for communication, as well as detection and countermeasures. I expect the RF microwave community will play an increasingly important role in countermeasures.

Do you have a sense of the market evolving over the next few years as research and development turn into actual fielded programs?

The armed services and government development agencies rely on industry to develop these weapons, components, and underlying technologies. As a result, a lot of investment will flood into this space because it is the department of defense’s number one development priority right now and will likely continue to be a top priority for at least the next ten years.

New RF Interconnect Solutions Power Mission-Critical 5G Networks

By Kevin Moyher

Originally Published in RadioResource Media Group

5G technologies are being rapidly deployed to deliver increased peak data speeds, ultra-low latency, enhanced reliability, enormous network capacity and increased availability. However, this requires a substantial expansion/upgrade to existing network infrastructure. For example, 5G networks must be densified to get the signal closer to users, which means more cell sites in more locations.

Small cells have emerged as the most practical means of attaining the densification needed to support the speed, coverage and latency requirements of 5G. These 5G small cell applications use multiple input multiple output (MIMO) antennas with multiple in/multiple out feeds, which substantially increases the number of RF ports. Additionally, unlike previous cellular technology generations, which focused on a specific frequency band, 5G deals with a much larger potential frequency range. For example, 4G frequency bands are typically below 3 GHz. 5G, on the other hand, can range from 450 MHz to 3.9 GHz and up to 20 – 56.2 GHz millimeter-wave (mmWave) bands for high-speed operations. 5G also encompasses unlicensed frequency bands, such as the 6 GHz band.

As a result, 5G antennas are shrinking in size as higher frequency bands are used to accommodate more extensive bandwidth requirements, which translates into more antennas and the corresponding RF cables and connectors needed to power them in a much smaller space. This equipment is also packed much closer than traditional telecom towers were years ago; at times, they are only about 100 yards apart. This requires new coaxial cables and connector solutions to deliver high signal integrity and reliability in increasingly dense environments.

The combination of smaller antennas with large numbers of cable connections also creates unique challenges related to installation, torquing, proper weather sealing and more. There are numerous variables to consider: Is it the right cable or the right port? Is that connector properly terminated to that cable? Is the coupling properly torqued down? Is the whole thing properly weather sealed? Are those cables properly captivated? Are they hooked up to the right connector and port? Are they flapping around in the wind? Are they protected from the sun, or if not, do they have the proper UV resistance?

We will discuss these concerns in more depth and provide a strategy for mitigating the challenges through the use of a bundled coaxial cable assembly solution designed for the ultra-demanding 5G small cell environment.

Bundled Cable Assemblies
A bundled cable solution can help create a flexible antenna jumper for applications requiring multiple runs, such as 5G. A spiral configuration of multiple flexible and ultra-flexible jumper cables can be created under a common polyurethane outer jacket to promote easy installation and improved operation. The individual coaxial cable runs are spun together in a way that easily flexes, essentially creating a bundle, which is then run through a large jacket extruder where a ripcord is placed.

This design enables four or five individual cables to be fed into the back of a single connector such as those based on the industry-standard MQ4/MQ5 design that encompasses a four-contact connector and a five-contact connector. The most common bundled cable constructions are built with inner cables that are one quarter of an inch and smaller and can be used on both non-low passive intermodulation (PIM) and low PIM interconnects. Constructions to address low PIM bundled harnesses include corrugated copper outer sheaths as well as ultra-flexible flat braid constructions.

Ensuring connectors are properly and securely tightened and eliminating any nonlinear or poor electrical contacts within the RF interconnect can also help reduce PIM issues. The MQ4 and MQ5 cluster connectors use an outer spring contact so that PIM performance is not tied to how well the tip of the outer contact is making to its mate. The connection between the male and female cluster connectors is sealed to IP67, as are the connector bodies and the transition from the cluster connector to the bundled cable. The solution is also keyed, eliminating the possibility of hooking up the wrong cable to the wrong port as the cables can only be hooked up a certain way; no torque wrenches, know-how or special technique required.

Using the four- or five-conductor solution eliminates the need to create individual weather seals, resulting in tremendous labor savings. Furthermore, it reduces the need to worry about coupling torque. This is critical because all it takes is an error on just one weather seal to create a point of ingress for water that could create a multitude of problems and even potentially shut the system down.

As a result, bundled solutions are optimal for high-density challenges as they permit installation in tight spaces; instead of connecting multiple threaded connectors, just one will do the job. They are faster and easier to install and maintain and provide one firm, reliable connection to support consistent high performance. An example of this type of solution is the TMQ4 and TMQ5 bundled cable assemblies from Times Microwave Systems.

The bundled coaxial cable assembly solution detailed above looks better in terms of appearance and cuts a lot of labor cost, and offers a more rugged solution with better UV resistance and weatherproofing. This helps support the densification needed for the speed, coverage, high frequency and latency requirements of 5G.

When it comes to selecting the right high-density RF cables and connectors, it is best to work with a partner whose engineers can identify the application’s unique needs and design an optimized solution that is ultimately easier to use, creating better electrical, mechanical and environmental performance. Look for a supplier with a long history of building quality cable and connectors, along with the skill, processes, techniques and materials to bring custom solutions for specific application needs to life.

New Multiport Contacts Add High-Frequency Capabilities to UAS Applications

By Times Microwave Systems

Originally published in Unmanned Systems Technology

Today’s unmanned aerial technologies, including intelligence, radar, collision avoidance, electronic guidance, navigation, electronic warfare, and communications, require higher frequencies to provide increased bandwidth for a growing number of complex subsystems. For example, the RF systems in unmanned aerial environments that once operated at frequencies of 12-18 GHz are now extending into the millimeter-wave (mmWave) frequency range of 30 GHz and beyond. As a result, system manufacturers are creating advanced new system designs to meet these evolving needs while accommodating extremely restricted space constraints.

The high-frequency RF interconnections within those systems are essential components—they must perform repeatedly and reliably and meet reduced size, weight, and power (SWaP) requirements. At the same time, the RF coaxial cables and connectors operating in unmanned aerial applications have complex mechanical, electrical, and environmental needs and must remain accessible for maintenance or troubleshooting.

The Multiport Shell Solution

SWaP equipment requirements require coaxial assemblies to maintain reliable electrical and mechanical interconnections in tight spaces and under the most severe operating conditions. However, fitting these complex systems into tight spaces can allow unwanted coupling between RF transmission lines such as coaxial cables.

High-density, modular multiport interconnect systems solve this problem by creating a smaller connector assembly with a higher interconnection density than individual coaxial connections due to integrating multiple coaxial connector contacts into a single housing. By mating a single multiport connector rather than numerous separate coaxial cable assemblies, the single connector interface provided by multiport shells reduces installation time, can ease system maintenance and testing, and increase reliability.

Solutions such as the M8 multiport connection system from Times Microwave Systems are constructed from lightweight aluminum and have advanced Reach/ROHS compliant conductive platings tested to the most severe corrosion resistance requirements. The M8 multiport system features a well-shielded structure to meet the EMI/EMC requirements of densely packed military and civil avionics systems and a design that allows for blind-mating interconnections for ease of installation. They are spring-loaded with sufficient force to ensure full mating engagement under severe vibration.

As the leader in multiport and mini-multiport shells and high-density solutions, Times Microwave Systems has also worked closely with prime contractors to develop plating materials with excellent salt fog resistance (2,000 hours) and Sulfer Dioxide resistance (668 Hours). This plating type is used on the latest, cutting-edge airframes as it is intended for use in harsh airborne and maritime environments requiring shell-to shell-conductivity.

New Contacts Provide Expanded Capabilities Within Existing Infrastructure

Unmanned aerial interconnect systems operate in harsh environments on a wide range of airframes, enduring high-shock and vibration; corrosive effects of hydraulic fluids, fuels, and other chemicals; high altitude conditions; and wide temperature ranges. These unmanned aerial systems must handle these challenging environmental conditions while packing greater functionality into smaller spaces. This requires new connector solutions to deliver high signal integrity and reliability.

The new M8M contact from Times Microwave Systems, based on time-tested multiport connector designs, is ideal for this environment. It was created for high-performance and easily survives harsh environments where high vibration, shock, temperature, and humidity can cause cable and system performance degradation.

The M8M contact is an addition to the Times Microwave Systems trusted high-performance M8 family of multiport interconnects, including the original M8 (18.5 GHz) and M8E contact (23 GHz) and lightweight, low insertion force V8 (18.5 GHz) contact. The new M8M contact works up to 40 GHz to meet the needs of high-frequency applications while using existing multiport shell infrastructure already in place. It is compatible with all M8 shells, and its unique construction makes the M8M contact excellent for use in the high vibration, harsh environments typically found in unmanned aerial applications.

The M8 family of multiport interconnect solutions has been the go-to system for many platforms worldwide throughout its more than 30-year history. Many tens of thousands of these parts are in service on a wide variety of US and allied military aircraft and have logged hundreds of thousands of flight hours. Times Microwave System also has fiber optic and octo contacts to fit into the same shells if multifamily interconnects are needed.

Conclusion

New RF interconnects for unmanned aerial systems must meet higher frequency requirements while retaining their predecessors’ lightweight and small form factors to meet the high-density needs of modern airframes and avionics systems. High-density modular multiport interconnect systems integrate multiple coaxial connector contacts into a single housing to create a higher interconnection density than possible with standard coaxial connectors. Building on the legacy of the trusted, proprietary Times Microwave M8 design, the M8M contact is an example of innovation that brings 40 GHz capability to multiport interconnect systems—using existing shell infrastructure already in place to maximize current investments.

New Connector Design Addresses Significant SMP Shortcomings

Originally Published in Connector Supplier

Making Connections in Ruggedized UAVs

By Dave Murray

Originally Published in Microwaves&RF

Military unmanned aerial vehicles (UAVs) are growing in numbers and complexity, taking on more advanced payloads with multiple sensors. Modern battlefield UAVs do everything that human-piloted air vehicles and their avionics systems once did, including electronic warfare (EW), signal intelligence (SIGINT), and surveillance, often flying at high altitudes and high speeds. Many military UAVs are designed with modular configurations to install different subsystems for each mission to optimize results.

Whether in standard or modular formats, military UAVs rely strongly on their RF/microwave interconnections to keep all systems linked, including from the UAV to the ground through demanding operating conditions. Specifying RF connectors, cables, and cable assemblies for military UAVs, especially as they increase their use of mmWave frequencies, requires an intelligent balance of many factors to keep all systems connected under all conditions.

Military UAVs vary in size and complexity according to application and mission, with larger, fixed-wing vehicles flying at higher speeds and altitudes compared to smaller, fixed- and rotary-wing vehicles used at lower altitudes in commercial and industrial applications. One of the better-known high-altitude UAVs, the RQ-4 Global Hawk, has flown at altitudes of 60,000 ft. and higher.

SWaP Considerations for UAV Components

Military requirements for size, weight, and power (SWaP) offer excellent guidance for component selection in UAVs because component weight and power consumption translate to a UAV’s operating range. In addition, components such as cables and connectors must fit into tight spaces and still be accessible for maintenance and measurement purposes.

UAVs contain many electronic parts and subsystems that must be interconnected, such as antennas, data recorders, radars, receivers, and transmitters. The cables and connectors provide the pathways for routing data, signals, and power throughout these subsystems. Any interruption in the pathways can be mission-critical, even fatal.

In general, space for components and payload in a UAV is limited, whether for military, commercial, or industrial use. The cables, connectors, and cable assemblies that provide interconnections within a UAV must meet tight space requirements while maintaining high performance and reliability. These interconnections have to satisfy challenging mechanical and electrical requirements within a UAV capable of enduring severe environmental conditions.

Choosing Cables and Interconnects: Where to Begin?

A practical starting point for sorting through coaxial cable interconnects is determining if they will even fit within the airframe. Smaller cables may fit where space is limited, adding little to the total weight of the UAV, but they may lack the performance to meet the electrical requirements of its electronic systems, so mechanical and electrical needs must be balanced.

Ideally, once installed, coaxial interconnections can be readily accessed for testing and maintenance purposes. UAVs with modular sensor systems will require access to interconnections for different modules used within the airframe.

Cable selection requires a balance of the mechanical, electrical, and environmental requirements for a UAV’s systems. Maximum cable diameter and weight are practical starting points when sorting through available cable solutions. The coaxial cable should exhibit low loss across a frequency range of interest, which will depend on the length and diameter of the cable.

The cable’s insertion loss and return loss (VSWR) also will be affected by the choice of connectors and how well the cable assembly and connectors are constructed. Low loss is particularly important for cable assemblies used at higher frequencies since signal power is limited at mmWave frequencies.

In addition to cable diameter and weight, the flexibility of a coaxial cable assembly is essential when determining whether a particular assembly can fit the needs of a UAV’s interconnections. Interconnect flexibility can be gauged in terms of its minimum bend radius, which is a function of a cable’s construction. Minimum bend radius effectively defines the space required for the smallest change in a cable’s direction.

Weathering High-Stress Conditions

High-frequency interconnect cable assemblies for military UAVs face severe conditions while in flight due to changing weather and stresses caused by high-speed operation. Some UAVs developed for high-altitude operation include hypersonic capabilities with speeds reaching Mach 5 and above. These speeds result in high-temperature environments for the UAV’s electronic components and systems, which must operate reliably at these higher temperatures.

Because the interconnections are such critical components, cables and connectors for military-grade UAVs are designed for operating temperatures as high as +300°C and total operating temperature ranges as wide as −65 to +300°C. Even the 300°C limit is being challenged; thus, Times Microwave Systems (TMS) has been asked to develop materials for its cables and connectors to handle these new challenges.

RF/microwave interconnections in military UAVs, especially those with phased-array antennas, require high phase stability with temperature. Phase-matched cable assemblies are typically used in antenna systems where phase is used as a beamforming and tuning parameter and in multiple-input/multiple-output (MIMO) antennas that combine the contributions of multiple antennas to send and receive high-frequency signals, often with wide modulation bandwidths.

High-altitude (typically 50,000 ft. or more above sea level) UAVs often operate in conditions that expose their components to near-vacuum environments, resulting in moisture-absorption problems when it returns to sea level. This “water in the cable” affects the interconnect amplitude and phase characteristics of the cable’s conductive metals and dielectric insulators and may result in significant degradation and failure of an electronic systems. As a preventative measure, coaxial cables designed for military UAVs, especially those for high-altitude operation, usually include some form of environmental seal against the effects of vacuum-like environments.

Adding Connectors

The mechanical, electrical, and environmental performance levels achieved by a UAV’s coaxial cables also must include its connectors as they contribute to the SWaP levels. Connectors are typically designed for ease of installation and minimal mechanical and electrical performance degradation. For UAV applications, the high-performance levels must be maintained at high shock and vibration levels.

The quality of a coaxial connector’s machined components, as well as performance and reliability, are impacted by how well the connector is attached to the cable and the effectiveness of its locking mechanism in a mated pair of connectors. Connectors can be soldered or crimped to a cable, with soldering the more labor-intensive approach but providing a robust mechanical attachment with little performance degradation over time. An effective plated finish on a coaxial connector also can contribute to reliable and consistent long-term performance.

Due to the modular architecture of some UAVs, some coaxial connectors must endure many mate-demate cycles for changing of function modules within the UAV. In such cases, a connector’s mate-demate lifetime needs to be evaluated along with its mechanical, electrical, and environmental performance parameters to achieve the best fit within a particular UAV. Oftentimes, high-frequency, high-performance blind-mate connectors are used in UAVs for this purpose.

Seeking Solutions

Practical UAV interconnection solutions are typically available as cables or cable assemblies constructed according to precise lengths and designated connectors. For example, TMS’s MILTECH flexible cable assemblies (Fig. 2) from Times Microwave Systems feature excellent shock and vibration resistance and good phase stability over a wide operating temperature range (−65 to +200°C). They’re manufactured to applicable military standards with tight cable/connector interface control to achieve the hermetic seal needed for high-altitude flight.

The cables are constructed with polytetrafluoroethylene (PTFE) dielectric, a solid silver-plated copper center conductor, and a silver-plated copper shield for protection from electromagnetic interference (EMI). Furthermore, they’re factory-terminated with a variety of coaxial connectors.

To meet the tight space requirements of different UAV systems, MILTECH cables come in various sizes/weights, including 0.130-in. (3.30-mm) diameter cables with 0.650-in. minimum bend radius and 0.175-in. (4.45-mm) diameter cables with 0.875-in. minimum bend radius. The smaller-diameter cables can be terminated with 2.4- or 2.9-mm connectors for use at mmWave frequencies. The cables feature high moisture resistance and vibration resistance according to MIL-STD-202 requirements and high shock resistance per MIL-E-5272 requirements.

For tight UAV fits requiring cables bent close to the connector, TMS’s INSTABEND 047 cable assemblies (Fig. 3) provide low-loss propagation of signals up to 62 GHz in the tightest spaces. To ensure high-quality attachment of connectors to cable, they’re only available as complete assemblies.

An INSTABEND 047 cable assembly with an outside diameter of 0.10 in. (2.67 mm) provides a minimum bend radius of 0.3 in. (6.4 mm). Light in weight for UAVs, these cable assemblies weigh only 0.01 lb./ft. (0.02 kg/m) and are available with several different connectors depending on frequency range. They handle temperatures from −60 to +125°C, are shielded to −90 dBc, and rated for voltages to 100 V.

When phase must be tightly controlled, PhaseTrack cables and cable assemblies developed by Times Microwave Systems are well-suited for that parameter, coming in a variety of diameters with different connectors. A 0.108-in. diameter cable (Fig. 4) features a cutoff frequency of 80 GHz and a minimum bend radius of 0.550 in. The cable is constructed with proprietary TF4 dielectric and doesn’t suffer the phase variations with temperature common to cables with PTFE dielectric.

PhaseTrack cable assemblies fit ground, sea, airborne, and space platforms. They’re available in many versions, including a silicon-dioxide (SiO₂) dielectric for applications with temperatures exceeding +1000°C.

Rugged Connectors

Maintaining connections under high shock and vibration levels common to a UAV while being easy to mate requires a coaxial connector with a simple but effective locking mechanism. The TLMP push-on locking connector from Times Microwave Systems (Fig. 5) was designed with the small form factor of the popular SMP push-on connector but with improved mechanical, electrical, and environmental performance.

The TLMP connector, which is usable to 60 GHz, has a unique mechanical design that supports high-pulsed-power, high-voltage applications. Its latching mechanism achieves improved mating retention compared to an SMP connector even in the high shock and vibration environments of military UAVs. The connector’s slots are entirely covered with its mating part for improved EMI and EMC performance compared to an SMP connector. Connections must maintain high EMI and low levels of signal leakage to prevent an adversary from identifying a military drone in flight.

For UAV interconnect applications that don’t require a hermetic seal or enhanced phase stability, Times Microwave Systems’ LMR and TCA cables and cable assemblies can be practical options. LMR cable assemblies provide flexibility to enable tight fits while LMR LW cables feature an aluminum braid shield for effective shielding in low-weight cable assemblies usable through 8 GHz. TCA cables and connectors have long served commercial avionics systems as flexible interconnect solutions, offering a combination of light weight and durability through 5 GHz and higher.

High-Density RF Solutions

Technology providers are creating advanced new wireless system designs to accommodate extremely restricted space constraints and rising operating frequencies. These solutions need new coaxial cables and connectors to deliver high signal integrity and reliability in increasingly dense environments. Industries requiring high-density RF interconnect systems include 5G, space, and avionics.

5G

Antenna densification is required to deliver increased peak data speeds, ultra-low latency, enhanced reliability, enormous network capacity, and increased availability for 5G. Its specifications are based on MIMO antennas, which are shrinking in size as higher frequency bands are used to accommodate larger bandwidth requirements. This translates into more antennas in a smaller space.

Small cells are a great example of this as they are packed much closer than traditional macro-telecom towers, often only 100 yards or so apart. Demand for high-density cabling solutions to accommodate the necessary connections in smaller, more compact installations will continue to grow. This includes high-density interconnect solutions, such as multiport connectors and coaxial cable bundles.

Bundled coaxial cables use a coaxial feeder cable bundled under a common outer jacket. This innovative design acts as the perfect flexible antenna jumper for applications requiring multiple runs, such as 5G small cells located on towers or building-top sites.

The increasing demand for high coverage antennas has also led to substantial growth in the number of ports on antennas and RF devices. Hooking up the right cables to the correct ports, weather sealing, and torqueing are all concerns in this scenario. Multiport connectors can be used in this instance to reduce the number of connections.

This type of “RF cluster connector” incorporates multiple RF ports in one connector, enabling antennas to provide more ports without the need to increase dimensions. There are standardized designs that encompass a four-contact connector and a five-contact connector including our TMQ4 and TMQ5 multiport connectors. These can significantly reduce the number of cables that have to be hooked up, saving a lot of labor and creating a more rugged solution. They also make the assembly more weatherproof and UV resistant and reduce the need to worry about coupling torque.

Space

Equipment used to power space technology must be lightweight, small, reliable, and resistant to high-shock and vibration, radiation, and harsh/extreme temperatures. RF coaxial cable assemblies must be designed to perform reliably in the smallest possible footprint. The high-frequency cables required for space applications also have a shorter range, requiring a dense network of antennas.

Our new InstaBend™ high-performance microwave assemblies provide a flexible preassembled design for interconnects between RF circuit cards, modules, and enclosure panels, enabling space-efficient implementation for higher frequencies. The cable can be bent around tight corners and very closely behind the connector, minimizing footprint, saving room, and simplifying cable routing in tight spaces.

Aviation

Avionics applications also have limited space as they accommodate more application needs throughout the vehicle. In the past, it may have been common to have 12 antennas on a commercial airframe, but there are now about 50 or more. The increasing number of antennas in aircraft environments also creates the need for more electronic boxes and their connections.

Additionally, minimizing space between the cables and connectors is necessary for the interconnect system to survive the high vibration. InstaBend is also a great fit here. Our Instabend assemblies withstand high vibration and other harsh environmental conditions, ensuring a consistent, long-lasting connection.

Additionally, a new generation of locking miniature push-on connectors, such as our TLMP™, is specifically designed to address the shortcomings of SMP-style connectors. The TLMP connector retains the small form factor of the SMP for highly dense environments but adds improved environmental, shielding, and power capabilities, with a frequency range from DC to 60 GHz. A positive locking feature with visible green (locked) and red (unlocked) color coding prevents de-mating under vibration and shock.