Low-loss distributed MEMS phase shifter

This letter presents a one-bit low-loss K/K-a-band phase shifter circuit that employs microelectromechanical systems (MEMS) capacitors. The measured results demonstrate a delay line with a 180 degrees phase shift/1.17 dB loss phase shift at 25 GHz, 270 degrees phase shift/1.69 dB loss at 35 GHz, and a return loss better than 11 dB over a 0-35-GHz band. The state-of-the-art insertion loss performance, 154 degrees/dB at 25 GHz and 160 degrees/dB at 35 GHz, demonstrates the potential for the implementation of a very low-loss multibit digital MEMS phase shifter.