Beyond Point-to-Point: RF and Microwave Interconnects as a System-Level Enabler

By Chris Cooper, Director of Engineering at Times Microwave Systems

High fidelity interferometry comes with a strict constraint on system phase error budget. An RF engineer must balance each component within the analog signal processing chain including RF interconnection to accomplish customer requirements regarding direction finding (DF), beam pointing accuracy, and ultimately achieving system array factor. These RF systems designers have come to rely on Times Microwave Systems for their expertise in RF interconnection so that they can focus deeper into the analog signal processing chains.

Times Microwave Systems has spent decades challenging the industry norm that treats cable, connector, and interface as three separate procurement decisions made by three different engineers at different stages of a program. Instead, the company’s engineering team designs the cable, connector, and interface as one electromechanical assembly, a philosophy that is becoming increasingly important as RF architectures become denser and more phase-sensitive.

Designing Cable, Connector, and Transition as One System

Every mechanical joint in an RF path is also an electrical discontinuity. A cable that performs beautifully in isolation can still introduce reflections, loss, or phase drift the moment it meets a connector that was not engineered alongside it. That is the argument for treating the cable-connector-transition combination as a single electromechanical system rather than a set of parts selected independently and assembled downstream.

“When the cable and connector are developed together, you are not just matching a part number to a spec sheet,” said Jerico Sabas, Product Manager at Times Microwave Systems. “You are approaching the dielectric transition, the strain relief geometry, and the termination method as one continuous design problem, so the electrical performance at the interface is as predictable as the performance in the middle of the cable run.”

Qualifying the Assembly, Not the Parts

The benefits of this approach are measurable well beyond a single connector interface. A dielectric that transitions cleanly from cable to connector reduces impedance mismatch and the reflections that come with it, supporting better VSWR control across the assembly. A connector body engineered for a specific cable’s flex characteristics reduces strain at the termination point, which directly affects mechanical reliability under the vibration and shock profiles common to fighter aircraft, rotary-wing platforms, and ground vehicles.

And because the entire assembly is validated as a unit rather than qualified component by component, including hermetic sealing where required, the qualification risk facing a program office drops. MilTech®, Times Microwave Systems’ family of hermetically sealed military RF assemblies, was built around this integrated model specifically because legacy cable-only specifications like MIL-C-17 could not account for how a cable and its connector behave together under altitude cycling, temperature extremes, and decades of service life

This has downstream consequences for how program offices plan qualification testing in the first place. A cable qualified to one specification and a connector qualified to another, then mated in the field or on a bench that neither test program anticipated, leaves a gap in the data an engineer would otherwise rely on. An assembly qualified as a whole, against standards such as MIL-C-87104 or MIL-T-81490, closes that gap by generating test data on the exact configuration that will fly, rather than on two components that happen to be compatible on paper.

PTFE dielectrics, silver-plated conductors, high-temperature jacketing, and FEP vapor barriers all have to work in concert, not just within the cable but across the transition into the connector body. A vapor seal that stops at the edge of the cable and does not carry through the connector interface leaves the exact failure point that hermetic sealing was meant to eliminate. Designing the seal as part of the full assembly, rather than as a cable-level feature, closes that gap.

Supporting Beamforming, EW Agility, and Multi-Channel Synchronization

Phased-array radar and modern electronic warfare systems depend on something the interconnect community sometimes underrates: consistency across dozens or hundreds of nominally identical RF paths. An electronically steered phased array steers its beam by controlling the phase relationship between elements, not by mechanically moving an antenna. If the cable assemblies feeding those elements or portions of the analog signal process chain vary from one to the next, this phase error can degrade array factor and beam-pointing accuracy.

Phase matching ensures that multiple cable assemblies have approximately the same electrical length within a specified tolerance at the same temperature. Phase tracking addresses what happens when those assemblies experience changing or unequal temperatures. Two phase-matched cables must continue to track one another as temperatures shift so that the phase offset between them does not change dramatically.

Times Microwave Systems developed PhaseTrack® cable assemblies to provide enhanced phase stability over temperature. A cable operating at 25°C on the ground may encounter temperatures as low as -40°C at altitude, while different areas of an array can experience temperature gradients of tens of degrees due to nearby heat sources. Compared with conventional PTFE-based designs, PhaseTrack assemblies limit phase change across these temperature variations and help multiple RF paths maintain their relative phase relationships.

“Phase stability is not a spec you hit once at the factory and forget about,” said Jerico Sabas. “A phased array can be flying at altitude one hour and sitting on a hot ramp the next, and every one of those transmit-receive channels has to hold its phase relationship to the others through all of it. That is a system-level requirement, and it must be designed into the cable and connector together, not bolted on afterward.”

Holding Phase Under a Changing Threat Environment

This is where integrated design pays off in ways that isolated component selection cannot replicate. An assembly engineered as a single unit allows tighter control over phase matching across a full set of channels, because the manufacturer is managing electrical length, dielectric consistency, and connector mating repeatability as one process rather than reconciling separately sourced parts after the fact. That level of consistency is directly responsible for beamforming accuracy and tracking performance in radar systems, and it carries equal weight for electronic warfare platforms that rely on precise timing across multiple receive channels to perform direction finding or signal intelligence functions.

The same logic extends to how quickly a platform can respond to a changing threat environment. Electronic warfare agility, the ability to retask a system’s frequency coverage or receive channels as the threat picture shifts, depends on interconnects that behave predictably regardless of which channel is carrying which signal at a given moment.

If the phase for one cable assembly in a bank of receivers drifts away from its neighbors under thermal load, the system must compensate algorithmically for a hardware inconsistency it should never have had to accommodate in the first place. An integrated assembly, built to a single set of phase and loss tolerances across every channel, removes that variable before it ever reaches the software.

Holding Phase Under a Changing Threat EnvironmentSynchronizing Multiple RF Paths

Multi-channel synchronization extends the same logic to communications and SATCOM systems, where several RF paths, sometimes carrying signals at different frequencies, need to maintain a known relationship to one another across long cable runs and temperature swings. An integrated cable-connector assembly gives an engineer a single, testable unit to characterize, rather than a set of independently qualified parts whose combined behavior has to be inferred or discovered after integration testing.

As EW systems push toward higher operating frequencies and platforms add more onboard antennas to cover an expanding set of missions, that predictability becomes harder to achieve with a component-by-component approach and correspondingly more valuable with an integrated one.

Reducing Installation Complexity and Routing VariabilitySynchronizing Multiple RF Paths

System-level design also changes what happens on the platform itself, long after the cable assembly leaves the factory. Military airframes and ground vehicles are congested by nature. Avionics bays were not designed with unlimited routing space in mind, and every additional antenna, sensor, or EW channel added to a modern platform competes for the same limited volume as everything already installed.

High-density multiport interconnects illustrate the payoff directly. Consolidating up to eight RF channels into a single connector interface, rather than routing eight individual cable assemblies with eight individual connectors, does more than save space. It removes seven redundant mechanical interfaces, each of which was a potential source of installation error, torque inconsistency, or long-term vibration loosening. It also removes the lockwire that technicians would otherwise need to secure each of those individual connectors, taking a meaningful source of foreign object debris risk out of the maintenance equation.

“Every connector you eliminate is one less thing that can be installed wrong, one less thing a technician has to torque correctly under time pressure, and one less thing that can loosen over ten thousand flight hours,” said Jerico Sabas. “When we consolidate eight channels into one connector, we are not just making the installer’s job faster, we are removing variability from the system.”

Predictable Routing Over Decades of Service Synchronizing Multiple RF Paths

That variability reduction shows up in routing as well as in the connector count. A cable assembly engineered with a known, repeatable bend radius and a connector interface designed for the space it will occupy gives installation and maintenance crews a predictable path to follow, rather than a generic assembly that has to be routed or field-modified to fit a specific airframe bay.

Replaceable front ends, which allow a damaged connector to be swapped without removing and replacing the entire cable run, extend that same philosophy into the sustainment phase, where military programs routinely operate for decades and field technicians need a fast, low-risk repair path rather than a full assembly replacement.

Routing variability tends to compound the longer a platform stays in service. A UAV or fighter airframe that goes through multiple modernization cycles accumulates cable runs installed by different technicians, at different times, sometimes to different revisions of the same drawing. An integrated assembly with a documented, repeatable installation geometry gives every subsequent installation a common reference point to work from, so a cable installed during a mid-life upgrade behaves the same way, electrically and mechanically, as the one it replaced a decade earlier.

Predictable Routing Over Decades of Service Synchronizing Multiple RF Paths

The cumulative effect reaches beyond any single installation. Programs that run for forty years, a B-52 avionics upgrade or an F-16 service life extension among them, depend on interconnect systems designed from the outset to be maintained, not installed once and left alone. As RF density continues to climb across airframes, UAVs, radar systems, and EW platforms, the interconnect is being asked to do more than connect one point to another. They need to hold phase across dozens of channels, survive decades of vibration and temperature cycling, and fit into ever-tighter spaces.

Engineering the cable, connector, and transition as a single system, rather than treating them as three separate purchasing decisions, meets that expanding set of demands without forcing every other part of the platform to compensate for an interconnect that was never designed to keep up.