Transmit/Receive (T/R) Modules—Key Elements for Phased Array Antennas

Abstract

Modern active electronically steered antennas (AESA) operate in different platforms and systems. Inside EADS/CASSIDIAN, the focus on X-band antennas today is on airborne and fighter nose radars, in satellite based SAR antennas (synthetic aperture radar) for earth observation, and ground surveillance and security radars. Active antennas are assembled with hundreds or even thousands of transmit/receive modules. This paper will describe an example of a so-called standardized module solution based on LTCC package technology. State-of-the-art modules are assembled with active components such as MMICs realized in GaAs technology, for example, the low noise amplifier (LNA) and the high power amplifier (HPA), silicon based devices, and passives. Assembly technologies are optimized for high yield series production inside CASSIDIAN MicroWave Factory. New semiconductor technologies, such as GaN (gallium nitride) are enablers for a new transmit/receive module generation. GaN/SiC based MMICs with higher power density compared with GaAs-based devices are technological challenges for innovative thermal management solutions and assembly alternatives. GaN power devices are soldered on modern heat sink materials with high thermal conductivity and matched CTE (between the MMIC and the heat sink). The results of thermal simulations comparing different heat sink materials in combination with soldering techniques will be discussed and an optimized solution will be shown. Another type of transmit/receive module technology based on RF-PCB and packaged MMICs will be discussed. Future applications of ground-based security radars, active antenna products with a one-dimensional array, and the need for cost-effective solutions seem to be a good fit for SMD-based products. Different packages, for example, QFN (quad flat pack no lead) and ceramic based (HTCC), mainly for power devices will be shown and compared.