Design of True Time Delay Circuit Based on Thin-Film Coplanar Waveguide

This paper presents the design of a true time delay circuit based on thin-film coplanar waveguide. The schematic and the simulation of a 2-bit true time delay circuit are described. The 2-bit true time delay circuit works at X frequency band with a maximum delay of 3 lambda and a delay step of 1 lambda, respectively. The measured total insertion loss is about 5 dB, the delay amplitude variation is less than +/- 0.5 dB and the delay phase variation is less than +/- 5 degrees for all 4 states. The true time delay circuit has a small size, high accuracy and great practical value.