A compact V-band planar wideband bandpass filter based on Liquid Crystal Polymer substrates

The move to higher frequencies has stimulated the development of the materials and integration techniques of the RF/microwave/millimeter (mm)-wave areas. Until now, materials commonly used at high frequency are either expensive or have inadequate performance. Liquid crystal polymers (LCPs), have attracted much more attention as advanced candidates as RF/microwave/mm-wave substrate materials for commercial wireless applications due to their combination of features and performance. In this paper, a compact V-band planar microstrip bandpass filter with sharp-rejection, low insertion-loss and wide-bandwidth based on the dual-mode ring resonator is proposed. The filter is fabricated on a LCP substrate by using standard processing technology. The proposed filter exhibits a return loss level better than 10 dB, an insertion loss of 5 dB, and a 3-dB bandwidth of 30%. The simulated and measured results are compared and agree well, which shows the promising potential of LCP laminates for flexible RF/microwave/mm-wave substrates.