Realization of Ultra Wideband Bandpass Filter based on LCP Substrate for Wireless Application

Abstract

Liquid crystal polymer (LCP) materials are considered to be promising substrates for RF applications because of the unique combination of features and performance. Although LCP films offer many excellent properties, the poor adhesion between copper and LCP has prevented the use of these materials in flexible microwave circuits. In order to obtain better adhesion between LCP and copper, oxygen plasma pretreatment of the LCP substrate and a thin Ti adhesion layer are introduced before a Cu layer was sputtered on to the substrate. Finally, a novel and compact microstrip ultra wide band (UWB) band pass filter (BPF) is fabricated on LCP substrates using standard processing technology i.e. physical vapor deposition (PVD), lithography and wet etching, which provides LCP substrate the feasibility of the application in RF wireless systems.