High Power AESAs for 20–60 GHz with Linear and Circular Polarizations

Abstract

An active electronically scanning array (AESA) architecture operating in the range of 20-60 GHz is reported. The transmit/receive (T/R) modules are distributed along parallel printed-circuit-board (PCB) cards, and each PCB card feeds a single column of the array. This architecture potentially provides space for integrating high power T/R modules within a λ/2 element spacing at 60 GHz. Integrating linearly polarized antennas into the array is rather straightforward. More novel designs are also proposed for applications requiring circular polarization. A linear-to-circular polarizer is designed and fabricated that can be stacked onto a linearly polarized array for generating circular polarization. Alternatively, a tile-based antenna with integrated hybrid couplers is designed to directly radiate circular polarization. All arrays here are intended to radiate ~1 W/element. Therefore, thermal management becomes a serious challenge due to poor power amplifier efficiency and tight element spacing at mm-wave frequencies. Methods of integrating liquid cooling into the array are considered at the initial design stage.