Use Integrated RF Modules to Improve Performance and Cut SWaP in X-Band AESA Radar

Airborne threats have evolved rapidly in recent years. Drones, low-cost missiles, and similar systems are small and inexpensive enough to deploy in large numbers, increasing demand for detection platforms with longer range, improved target discrimination, and reduced size, weight, and power (SWaP).

X-band active electronically scanned array (AESA) radar is central to meeting these requirements. Operating at 8 to 12 gigahertz (GHz), X-band’s short wavelengths are ideal for resolving small targets from a compact aperture. This pairing works well with electronic beam steering, which can track many targets without relying on moving parts.

The catch is that tightly integrated AESA architectures must fit the transmit/receive circuitry for each element or group of elements within a limited array space, so compactness matters more than ever. Plus, designers still face traditional tradeoffs, such as power versus sensitivity.

To meet these demands, designers need sophisticated radio frequency (RF) components based on technologies used in Qorvo’s X-band radar solutions (Figure 1). These products are part of Qorvo’s broader defense and aerospace technologies portfolio, which also includes S-band radar, electronic warfare, and other RF and microwave applications.

Figure 1: X-band radar requires sophisticated RF solutions based on modern technologies, some of which are shown here in blue. (Image source: Qorvo)

Integrated front-ends for X-band radar

Qorvo front-end modules (FEMs) integrate multiple RF functions into compact packages. In the QPF5012 module, the power amplifier (PA) and transmit/receive (T/R) switch use gallium nitride on silicon carbide (GaN-on-SiC), while the limiter and low-noise amplifier (LNA) use gallium arsenide (GaAs), optimizing the technology for each functional block. Packaging the dies together also reduces the number of discrete components, improving SWaP and simplifying RF layout and matching.

The QPF5012 comes in a QFN package, measures 7 × 5 millimeters (mm), and delivers 10 watts of saturated transmit power across 8.5 to 10.5 GHz. The module provides consistent performance under varying load conditions, making it suitable for phased-array systems.

Historically, FEM selection has involved tradeoffs among output power, prime power, and sensitivity. The QPF5012 addresses this balancing act by combining a typical power-added efficiency (PAE) of 40% at an input power of 20 decibels referenced to 1 milliwatt (dBm) under pulsed operation (Figure 2), with a receive noise figure of 2.1 decibels (dB) and 23 dB of receive gain. The low noise figure supports receive sensitivity, while the high PAE helps reduce prime power consumption and thermal load.

Figure 2: The QPF5012 maintains high PAE across its 8.5 to 10.5 GHz operating range under the specified temperature conditions. (Image source: Qorvo)

X-band frequency conversion has its own challenges

The transition from RF to intermediate frequency (IF) is another common source of design challenges. On dense cards typical of modern X-band radar, local oscillator (LO) leakage can produce unwanted responses, and inadequate image rejection can allow an image-frequency signal to appear at the same IF as the desired signal.

Qorvo’s double-balanced mixers (DBMs) and in-phase/quadrature (I/Q) mixers address this issue by delivering strong LO-to-RF isolation and low conversion loss. This portfolio supports both image-reject and single-sideband approaches while keeping surrounding routing and filtering simple. 

The CMD183C4 is a good example. This 7.5 to 13 GHz I/Q mixer can be configured as an image-reject mixer or a single-sideband upconverter. It integrates two double-balanced mixer cells and a 90° hybrid, while an external IF hybrid is required to complete the image rejection function. Offered in a compact 3.9 × 3.9 mm, 24-lead surface-mount package, this monolithic microwave integrated circuit (MMIC) provides a smaller alternative to the hybrid assemblies traditionally used for these functions.

Key characteristics of the CMD183C4 include low conversion loss, high isolation, and 20 dB or better image rejection across the X-band, with minimal variation over temperature (Figure 3). These features enable clean frequency conversion while preserving the information needed for target discrimination.

Figure 3: The CMD183C4 provides 20 dB or better image rejection across the X-band, with minimal variation over temperature. (Image source: Qorvo)

Evaluation boards for next-gen X-band radar designs

If you’re looking to take advantage of the latest X-band technology, you can explore the possibilities with Qorvo’s extensive lineup of evaluation boards. A typical example is the CMD183C4-EVB (Figure 4). This board places the CMD183C4 on a printed circuit board (pc board) with four subminiature version A (SMA) end-launch connectors and vias to connect the top and bottom ground planes.

Figure 4: The CMD183C4-EVB integrates the CMD183C4 with four end-launch SMA connectors on a single board. (Image source: Qorvo)

The use of SMA end-launch connectors demonstrates close attention to detail. Unlike traditional right-angle pc board connectors that force signals to turn 90°, end-launch types align directly with the board trace to help minimize reflections.

Conclusion

Rapidly evolving airborne threats are driving demand for capable X-band radar systems that can be developed and deployed efficiently. Qorvo’s broad portfolio of defense and aerospace solutions can help designers meet these requirements by improving performance and SWaP while simplifying RF integration.