A Millimeter-Wave Scanning Array with Fine and Coarse Phase Shifters Realized by Using U-Section Meander Feed Lines and Varactor Diodes

It is well known that conventional microwave phase shifters become both lossy and expensive when we attempt to scale them to operate at millimeter wavelengths. The objective of this paper is to present a scanning-array design which realizes the requisite phase shifts in both discrete as well as fine steps to scan the array. The discrete phase shifts are achieved by using meander lines with switches for the feed networks of the radiating elements, while varactor diodes are employed to realize phase shifts in a continuous manner by varying the bias voltages of the varactors, and to enhance the range of the realizable phase shifts. A Ka-band array of rectangular microstrip patches has been designed to demonstrate the scan capability of the designed array, which is expected to find potential applications in portable millimeter wave devices for 5G systems.