A 5-bit RF MEMS switch time delay line shifter

A 5-bit radio frequency micro-electromechanical system (RF MEMS) true-time-delay (TTD) phase shifter operating over frequency ranges 6-12 GHz is designed and fabricated. The TTD phase shifter provides five delay bits: λ, 2λ, 4λ, 8λ, 16λ, the biggest delay-bit time is 1680ps and the total time delay is 3255ps. The circuit uses twenty cantilever RF MEMS switches. The circuit is fabricated on four layers by using microwave multilayer printed circuit board technology (PCB). Measurements show that the return loss of every delay-bit is better than 12dB across the entire band and the insert losses are between -8dB and -10dB for all states. The circuit has high linearity of phase response across the entire band.