A filter synthesis method applied to millimeter-wave distributed switch design

A filter synthesis method based on the image-parameter theory is applied to the design of millimeter-wave distributed switches. The method provides accurate closed-form equations for circuit element calculation. With this set of equations, the required performance can be easily achieved within a close tolerance of required specifications. A distributed SPDT MMIC is implemented with the pHEMT process to confirm the proposed method. The measured insertion loss is less than 3.1 dB and the isolation is better than 40 dB from 15 GHz to 50 GHz, which confirm the proposed method.