New Approaches to Design Digital Phase Shifters over The Complete Phase Plane

In this theoretical paper, four different circuit configurations are proposed to design 0°-360° wide range, low loss balanced phase shifters. Each configuration utilizes 3 pin diodes. As a consequence of this work, it is straightforward to construct 180° phase shifting cells for multibit phase array antenna systems using 3 pin diodes. Operation of the new circuits is based upon the phase shifting properties of symmetric low/highpass 3-element LC ladders. Assuming the utilization of lossless pin diodes and ideal reactive element, explicit design equations are presented. A numerical method, which includes the diode losses as well as component parasitic, is also described to design practical phase shifters with minimum balanced loss at a given operating frequency. Examples are included to exhibit the use of explicit design formulas and computer simulations are performed to analyze the loss and phase characteristics of the new circuits. It is expected that new configurations will find application in the commercial and especially military large array antenna systems over the EHF band to be implemented as Microwave Monolithic Integrated Circuits (MMIC).