Microwave sampling beamformer--prototype verification and switch design

In this study, a four-element prototype of the microwave sampling beamformer structure is constructed and tested. The prototype is composed of the microwave hardware and control hardware. A new compact switch is designed and utilized in the structure. The control circuitry is a four-branch time delay and pulse width control circuits along with p-i-n diode drivers. The beamforming structure is designed to have 8-bit phase shifter resolution and 12-bit attenuation resolution. For each antenna element the phase shift and attenuation are controlled through the time delay and pulse width of the corresponding pulse train. Different beamforming examples such as beam steering, sidelobe level (SLL) control and null forming are examined with the prototype. It is observed that the structure scans the beams to the proper steering angles. SLL close to--30 dB and nulls deeper than--30 dB are measured. Index Terms--Amplitude-phase control, beam steering, microwave beamforming (MBF), microwave sampling beamformer (MSBF).