Adaptable Electrically Steerable Antenna Array with Diverse Switchable Polarization

Abstract

Adaptability is essential for antenna systems, especially those operating in harsh or unpredictable environments. Adaptable electrically steerable antennas (AESA) provide this flexibility. AESA use in radar systems is expanding due to new technologies that enable higher power and more miniaturized implementations. Polarization diversity is another way of adding adaptability to radar systems.System-level analysis of a typical radar system was performed to determine the specifications for a series of 4x4 switchable polarization AESA arrays meant to operate from 9.4 to 9.5 GHz. These arrays were designed on a multilayer Rogers Duroid PCB.Sub-components such as a microstrip feeding network, patch antennas, switches and hybrid couplers were integrated on the same PCB utilizing both sides of the board.Simple 4x4 linear and 4x4 circular polarized arrays were designed and fabricated on this chosen package. These single-polarization arrays were compacted into a single lowprofile PCB that measures 2.5x2.5 inches. The measurements of both single-polarization arrays closely matched the simulated results, which helped correct issues with the design process before adding more polarization states. Measurements show that these modularly scalable 2.5x2.5-inch PCBs can achieve a gain of between 12 and 21 dB depending on how many boards are tiled together.A technique for increasing the bandwidth of a single patch antenna through resistive loading was also explored. Using commercially packaged resistors to load a single patch resulted in a bandwidth increase of 400 MHz.Once simple single-polarization arrays were verified, two switchable polarization arrays, one linear and one circular, were designed and simulated. These switchable