The Critical Role of Coaxial Cables in Powering High-Performance Radar Systems

By Ted Prema

Originally published with Microwave Product Digest

Modern radar systems are essential in numerous mission-critical applications, ranging from air traffic control to military surveillance and even weather forecasting. At their core, these radar systems heavily rely on one fundamental element: the consistent and dependable transmission of radio frequency (RF) signals between phased-array antennas and electronic equipment. These signals ultimately enable the detection of objects, their positions, and movements.

A radar system emits an RF signal that travels outward, bouncing off an object in its path. The radar then captures the return signal to determine its location. Coaxial cable assemblies are the vital link between the antenna array and the radar’s transmitter-receiver. The quality and reliability of these RF assemblies is essential to ensure the continuous transmission and reception of high-frequency signals, often over long distances, with high accuracy and minimal loss or interference.

Whether the objective is to guide missiles with pinpoint precision or to maintain aircraft safety through radar warning systems, dependable performance is a non-negotiable requirement in ensuring the dependability of radar systems. For example, in air traffic control radar, precision is everything. Even the slightest signal degradation could hamper the detection of aircraft, potentially compromising safety. Military radar systems demand high-quality coaxial cables that withstand harsh environmental conditions while maintaining signal integrity for precise target detection and tracking. Meteorological radar systems for weather forecasting often require antennas placed in remote, hard-to-access, challenging locations. This requires robust and durable cables that can reliably connect antennas and provide accurate data in all conditions.

In any of these applications, the performance of coaxial cables— that crucial link in accurately deriving an object’s location from a transmitted signal that is bounced off the object back to the receiver—is essential to ensuring the reliability and precision of radar systems. Without an interconnect solution that establishes and preserves this consistency, radar systems cannot position a target object correctly.

Advancements in coaxial cable technology have been instrumental to the evolution of modern radar systems, enabling enhanced detection ranges, higher resolution, and more reliable performance. By ensuring the precise, uninterrupted flow of RF signals, high-performance coaxial cables empower radar systems to achieve their life-saving and operational objectives across sectors.

Meeting Stringent Performance Requirements

Radar applications, including air traffic control, military operations and surveillance, and meteorological monitoring, often have stringent performance requirements due to the critical nature of the information they provide and the often extreme and highly variable environmental conditions in which they operate.

Meeting these stringent performance requirements involves a combination of advanced technology, signal processing, and system design to ensure that radar systems can reliably and accurately fulfill their intended functions in various operational scenarios. These requirements can vary depending on the specific application, but some standard requirements that necessitate high-performance RF coaxial cables include:

Accuracy: Radar systems must provide accurate, precise measurements of an object’s position, velocity, and other relevant parameters. For example, in applications like air traffic control, even minor errors in determining aircraft location can lead to safety risks. High-performance coaxial cables can minimize signal loss and distortion, ensuring that the RF signals carrying radar information maintain their accuracy from the transmitter to the receiver.

Sensitivity: The ability to detect weak signals, such as those from stealthy or distant targets, is crucial, especially in applications such as military radar. Low observability targets are designed to avoid detection, making radar sensitivity a critical requirement. Low-loss coaxial cables help maintain signal strength and sensitivity.

Harsh, Variable, and Demanding Environments: Almost every type of radar is required to operate reliably in demanding conditions, including adverse weather, electromagnetic interference, and harsh environments. For instance, in meteorological monitoring, radar systems must have the ability to continuously operate in rapidly changing weather conditions and differentiate between precipitation types. Downtime can be costly and even life-threatening in some cases. High-quality coaxial cables designed to withstand such environments and are less prone to corrosion and damage, are essential, reducing the risk of signal degradation or system failure.

Resistance to Jamming: In military operations, radar systems must resist electronic countermeasures and jamming attempts. Coaxial cables with shielding and enhanced electromagnetic interference protection help maintain signal integrity.

Low False Alarm Rate: Reducing false alarms is essential to avoid unnecessary responses in applications like air traffic control and missile defense. The signals transmitted and received must be free from interference and noise to reduce false alarms in radar systems. High-performance coaxial cables aid in maintaining signal purity.

Tracking and Update Rate: Radar systems used for tracking purposes, such as air traffic control and missile defense, must provide continuous and accurate tracking data to predict the future positions of targets. The update rate, or how often radar scans its surroundings, is crucial for tracking fast-moving targets. For radar systems that require rapid tracking and high update rates, low-loss coaxial cables are necessary to ensure that the data is transmitted promptly and accurately.

Long Range: Long-range radar systems have the ability to monitor patterns across large areas and detect and track targets at significant distances from the radar antenna. In meteorological radar, long-range capability is necessary to observe weather patterns over a wide area to detect precipitation, storms, and severe weather phenomena at considerable distances and provide timely warnings. Some military radar systems are designed to detect targets at ranges of over a thousand miles. Coaxial cables that minimize signal loss over long distances are crucial for radar systems that must detect targets at extended ranges.

Phase Stability: A Crucial Aspect

Phase is a key parameter in many radar applications. Two primary elements can affect the phase tracking characteristics of a coaxial cable assembly: electrical length and temperature. For example, phased array radars rely on RF interconnects that maintain the same electrical lengths between the antenna and transmitter-receiver. This creates challenges in matching the cables.

After that initial matching, the coaxial cables must also stay matched over varying temperatures. In radar applications, RF signals must travel through the coaxial cables at consistent speeds regardless of these environmental factors. Specialized coaxial cable assemblies ensure that phase and amplitude parameters stay consistent over changing temperatures and maintain phase stability across multi-element arrays.

This includes PhaseTrack^® cables that use a proprietary dielectric, TF4^®, which does not experience the abrupt shift in phase that occurs with solid- or tape-wrapped PTFE-based products under ordinary room ambient temperature conditions. This technology delivers excellent phase versus temperature and loss versus temperature performance and proven repeatability.

Additional Cable Technologies that Meet the Performance Needs of Radar Applications

Beyond phase stability, there are often additional RF interconnect solutions required to empower radar systems to meet their performance benchmarks while addressing the specific challenges posed by each application. Examples include:

LMR^® high-performance flexible, low-loss 50 Ohm broadband coaxial cables: The LMR cable is ideal for lower frequency radars where the phase is not critical, but loss may be. Features include 100% effective shielding and rugged UV, sunlight, and weather resistance.

TCOM^® UV-resistant polyethylene jacketed cables: Common for radars operating in C-band, S-band, and X-band where phase is not critical, T-COM cables are designed for 20-year service outdoor use. They feature bending and handling characteristics that are superior to air-dielectric and corrugated hardline cables.

MaxGain^® ultra-low loss, flexible microwave coaxial cables: MaxGain cables are designed for use in high frequency radars up through the millimeter wave bands where low loss is critical. The lightweight cable is manufactured with the lowest loss materials and unique outer conductor technologies, ensuring a reliable, high-frequency interconnect solution. It also includes a full range of connectors, available as thoroughly tested custom cable assemblies.

Ultra-low loss, flexible microwave coaxial cables: Designed for use in high frequency radars up through the millimeter wave bands where low loss is critical. This type of lightweight cable is with, ensuring a reliable, high-frequency interconnect solution. Top products in this category also include a full range of connectors available as thoroughly tested custom cable assemblies.

Conclusion

In summary, high-performance RF coaxial cables are essential for radar applications that demand accuracy, sensitivity, the ability to operate in demanding environments, resistance to jamming, low false alarm rates, rapid tracking, and long-range detection. High-quality coaxial cables can help ensure that the RF signals maintain their integrity and meet the stringent performance requirements of radar systems in various operational scenarios.

Selecting the right cable partner when designing complex radar applications is crucial, as their expertise in determining the correct mix of coaxial cable technologies to meet the unique needs of each radar type is invaluable. A partner with a long history of creating customized cables trusted across crucial sectors such as military, aerospace, technology, and space is ideal. This is particularly true in rigorous conditions where performance standards are non-negotiable.