7-Bit Multilayer True-Time Delay up to 1016ps for Wideband Phased Array Antenna

We present a seven-bit multilayer true-time delay (TTD) circuit operating from 1 to 7GHz for wideband phased array antennas. By stacking advanced substrates with low dielectric loss, the TTD with PCB process is miniaturized and has low insertion loss. The signal vias with surrounding ground vias are designed to provide impedance matching throughout the band, allowing the overall group delay to be flat. The standard deviation of the TTD for all states is below 19ps, which is 1.87% of the maximum group delay. The maximum delay is 1016ps with resolution of 8ps. The implemented TTD is 36.6×19.4mm2 and consumes 0.65mW at 3.3V supply for all the delay states. The measured input/output return loss is better than 12.1dB for the band of 1-7GHz.