Reliable RF Interconnects for Phased Arrays Radar Systems
Why RF Interconnects Matter in Modern Beamforming Systems
(Source: Dzmitry/stock.adobe.com; generated with AI)
Published July 29, 2026
Radar technology is being asked to do more than ever before. Modern systems must detect small, fast-moving targets reliably in increasingly crowded electromagnetic environments. In defense applications, the growing use of uncrewed aerial vehicles (UAVs) has increased the need to detect and track small targets with very low radar signatures. In the automotive industry, advanced driver assistance systems (ADAS) use radar sensors to detect nearby vehicles, pedestrians, and obstacles with the accuracy needed for advanced safety functions.
To meet these demands, radar systems must achieve higher resolution and faster response times to better distinguish between nearby objects. One way to reach this level of performance is to operate at higher frequencies, where shorter wavelengths provide finer resolution. The tradeoff, however, is that system design becomes more challenging. As frequencies increase, it becomes more difficult to preserve signal integrity and maintain precise phase relationships across the antenna array.
Achieving the performance required for these applications depends on phased-array architectures that precisely control signal timing across the antenna array, along with RF interconnects that maintain signal integrity from one RF module to the next.
This blog explores how phased-array systems achieve high-performance beamforming and why RF interconnects are critical to preserving that performance.
Inside Modern Phased-Array Systems
Electronically steered radar systems are a cornerstone of military surveillance and tracking applications. Unlike traditional radars that physically move to track targets, phased-array systems electronically steer their beams, allowing them to move almost instantly without relying on motors.
Rather than using a single antenna, phased-array radar systems use multiple antenna elements working together. By adjusting the phase of the signal sent to each element, engineers can create constructive and destructive interference patterns that steer the beam electronically without physically moving the antenna. This technique, known as beamforming, allows radar systems to track multiple targets simultaneously. It also allows the beam to shift from one area to another, almost instantly providing faster response times than traditional mechanically scanned radar systems.
Many modern defense systems employ active electronically scanned array (AESA) architectures.[1]In an AESA, each antenna element, or group of elements, is connected to its own transmit/receive (T/R) module. This distributed approach improves reliability and gives the radar greater control over how it forms, steers, and manages its beams.
Modern radar systems achieve much of their performance improvement by operating at higher frequencies. Higher frequencies generally enable greater resolution because they use shorter wavelengths. Many modern target-tracking and drone-detection systems operate in frequency bands such as X-band to improve detection and discrimination of small objects.[2]Automotive radar systems commonly operate between 76GHz and 81GHz, enabling highly accurate object detection and ranging[3]Similar beamforming principles are also used in other high-frequency systems, where phased-array antennas help manage directional links and propagation losses.
As phased-array technology extends beyond its traditional defense origins, engineers are applying beamforming techniques across a wide range of commercial applications. However, realizing the benefits of beamforming requires exceptional control over the RF signal path.
Hardware Challenges Behind Beamforming
Beamforming is most effective when the signals arriving at each antenna element remain tightly synchronized. Even small phase errors can reduce beam accuracy, lower antenna gain, increase sidelobes, and make it harder to distinguish between targets.
How that phase control is achieved depends on the system architecture. Modern AESA radars typically use individual T/R modules, whereas older systems typically relied on central phase shifters. While the hardware may differ, the objective remains the same. Each antenna element must still receive signals with controlled timing and amplitude.
That task becomes more challenging as frequencies increase. At microwave and millimeter-wave frequencies, even minor discontinuities in the signal path can create reflections and impedance mismatches. Those effects may seem insignificant when viewed in isolation, but across a large antenna array, they can introduce errors that affect beamforming performance.
As a result, signal integrity must be considered through the entire RF chain. Cables, printed circuit boards (PCBs), connectors, and board-to-board interconnects all affect how accurately the signals reach their destination.
This challenge is not solely electrical. Modern phased-array systems tend to pack many RF channels into compact footprints. Mobile radar platforms add another layer of complexity as they require engineers to balance performance against size, weight, and power (SWaP) constraints.
Board-to-board interconnects typically provide the RF links between T/R modules and the supporting circuitry in many phased-array designs. They must deliver reliable electrical performance in densely packed assemblies and accommodate factors such as tolerances, vibration, thermal cycling, and mechanical stress. Degradation in the RF signal path can affect beamforming accuracy and radar performance.
Designing Reliable RF Interconnects
As phased-array systems move to higher frequencies and more compact designs, they are changing what engineers need from board-to-board interconnects. These connections must support high-frequency signals while fitting within more compact antenna assembly. In addition to enabling highfrequency performance, they must also minimize insertion loss, reflections, and phase variation so they do not affect overall beamforming performance. Mechanical reliability is especially important in applications such as defense, aerospace, and mobile radar, where systems may encounter harsh environmental conditions.
Amphenol SV Microwave offers a broad portfolio of board-to-board RF interconnect solutions designed to address these challenges. The portfolio includes multiple form factors that support the growing diversity of phased-array architectures across defense, telecommunications, automotive, and satellite communication applications.
Because many phased-array designs require compact RF interconnects that fit within densely packed module assemblies without degrading performance, SMP and SMPM interfaces are commonly used. These spring-loaded and fixed bullet-style interconnects accommodate board-to-board misalignment and mechanical tolerances while maintaining RF reliability. In applications where space is especially limited, pre-tinned board-to-board solutions may be an alternative to traditional cable assemblies.
These options offer designers flexibility to balance RF performance, package density, and mechanical tolerance within the same antenna design. Because board-to-board interconnects are part of the RF signal path, their performance can affect beamforming accuracy. Small variations can be especially noticeable in systems where precise phase relationships determine overall performance, making the quality of every interconnect very important.
Conclusion
Modern phasedarray systems rely on precise phase control and high signal integrity to deliver accurate, highfrequency beamforming performance. As applications such as radar, automotive sensing, and 5G push toward higher frequencies and more compact designs, maintaining clean RF signal paths becomes increasingly challenging. Boardtoboard RF interconnects play a critical role in this process, as even small losses or mismatches can degrade overall system accuracy. By selecting reliable, highperformance interconnect solutions that address both electrical and mechanical demands, engineers can preserve phase coherence, support dense architectures, and ensure consistent performance across advanced beamforming systems.
Sources
[1]https://uk.leonardo.com/en/news-and-stories-detail/-/detail/an-introduction-to-digital-aesa-radars
[2]https://www.northropgrumman.com/what-we-do/mission-solutions/radars/active-electronically-scanned-array-aesa
[3]https://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC-M.2057-1-201801-I%21%21PDF-E.pdf
Author
David Pike is well known across the interconnect industry for his passion and general geekiness. His online name is Connector Geek.