Symmetric Lattice 45 degrees, 90 degrees and 180 degrees Digital Phase Shifter at 3-6 GHz for LTE, WIFI, Radar Applications

Abstract

In this paper, we present a novel phase shifter topologies to construct 45 degrees, 90 degrees and 180 degrees phase shifter cells laid out using 180 nm TSMC technology. These phase units provides compact circuit sized with reasonable implementation components. Instead of using pin-diodes in the phase shifter topologies, CMOS switches are used to have advantages of simple control circuit for switching and very low power consumption. Operation of the new circuit is based on the phase shifting properties of the symmetrical all-pass LC lattices. As a consequence of this research, it is straight forward to construct phase shifting cells over a wide frequency band, with various angles for multi bit phase array systems. In this work explicit design equations are presented according to ideal lumped elements and normalized frequency. A numerical method which includes the design model is analyzed in MATLAB. Top level design is simulated in CADENCE. Simulations performed with actual elements from TSMC and inductors are designed in ASITIC tool. A phase shift between 3-6GHz is achieved with less than 4.5 phase error for 45, 90 and 180. Insertion loss for 45, 90 and 180 are between 3.4-5.9 dB, 10.3-11.4 dB and 10.9-18.5dB respectively.