Optimization of distributed MEMS phase shifters

The design and optimization of a 0-60 GHz distributed MEMS true-time delay phase shifter is presented with theory verified by experimental results. The phase shifters are fabricated on 500 mu m quartz with a fixed total CPW width of 300 mu m. Three lines with center conductor widths of 50, 100, and 150 mu m have been fabricated. The line with a 100 mu m center conductor width is shown to be optimal for phase shift per dB loss. The measured results demonstrate 70 degrees/dB at 40 GHz and 900/dB at 60 GHz. The current design, with C-max/C-min - 1.17, is capable of producing 3600 phase shift at 40 GHz with 5.1 dB loss and at 60 GHz with 4 dB loss which is stateof-the-art performance for millimeter-wave phase shifters, Also, it is shown that if a C-max/C-min = 1.3 can be achieved, then the performance increases to 100 degrees/dB at 40 GHz.