Liquid Crystal Polymer based Tunable Microstrip Filter at Q-Band

In this paper a passive, simple and reliable method for frequency tuning of a planar microstrip band pass filter is presented. A tunable 4-Pole Quasi-Elliptic cross coupled planar microstrip band pass filter is designed and fabricated at Q-band on Liquid Crystal Polymer (LCP) using conventional lithographic process. Tunability of band pass filter transmission response is demonstrated and a 4 % frequency band tuning range is obtained at 48 GHz. Two possible tuning approaches with LCP are proposed and commensurate simulation results are presented. One out of the two suggested approaches has been implemented for the validation and measured results are reported.