A 5 bit Low Loss Compact Switched Delay Line Phase Shifter for Phased Array Radar Applications

Phase Shifters are employed in phased array radars to induce phase shift within transmitted power which results in steering of transmitted beam. This paper encompasses design of a compact, 5-bit switched delay line phase shifter, capable of handling up-to 10W RF power. Switched delay line phase shifter works on the principle of inducing phase shift through comparative passage of RF waves through reference and delay arms. Initial design of phase shifter was completed on Agilent's Advanced Design Simulation (ADS) Schematic window with center frequency of 1.3 GHz. Final version from Schematic window was then drawn in ADS Layout window which was further simulated for computation of S parameters. Design was optimized for best possible values of insertion and return losses with minimum phase error. Fabrication of final design is accomplished on low loss Rogers RT Duroid 6006 substrate. Solid state SPDT switches provided selection of reference or delay arm to achieve desired phase shift. Fabricated model was tested on Vector Network Analyzer (VNA) for all 32 combinations of phase states. 5-bit phase shifter designed in this work is realized on a low loss substrate coupled with a highly efficient switched delay line phase shifting technique.