MEMS true-time delay circuit for broadband antennas

A monolithic true-time delay (TTD) circuit based on metal-contact RF MEMS microrelays has been successfully fabricated and characterized. The TTD circuit was designed to produce flat delay time over a DC-to-40 GHz bandwidth with full 360-degree phase control at 22.5-degree intervals at 10.8 GHz. Measurements show a close match to the designed delay times for all sixteen delay states with 2.2 to 2.6 dB of insertion loss at 10 GHz. The worst group delay ripple in the DC-to-30 GHz range was 3 ps, well within the single bit delay time of 5.8 ps.