2D beam scanning focal plane array using microfluidic reconfiguration techniques

Novel microfluidic based focal plane arrays (FPAs) have been recently introduced as a low cost alternative to realize mm-wave beam-scanning arrays. These FPAs consist of a proximity-fed patch antenna within a microfluidic channel filled with a low loss dielectric solution. Elevation plane scanning is obtained by placing the channel at the focal plane of a microwave lens and repositioning the antenna using micropumps. This paper, for the first time, realizes the antenna element of these FPAs from a metalized plate (instead of liquid metal) to improve the implementation reliability. In addition, a circuit model is presented for the all-passive feed network of the arrays to conveniently model their bandwidth and impedance matching performance for various element numbers. Also, the array is combined with a stepper motor to provide beam-scanning in the azimuth plane. Due to the microfluidic reconfiguration enabled all-passive feed network, the beam-scanning is realized without employing any RF switches or phase shifters. As a result, the feed network design is simplified and cost is notably reduced. The proposed design is verified by designing and evaluating a 1×8 microfluidic enabled 30GHz FPA. Specifically, the array exhibits a beam scanning range of ±25° with > 20dB measured realized gain.