Wideband mm-wave compensated 90° bends for Grounded Coplanar Waveguide and microstrip Transmission Lines on flexible LCP substrates

The purpose of this paper is to describe an approach for creating the first truly wideband (10-90 GHz), high performance, compensated 90deg bends for planar transmission lines fabricated on liquid crystal polymer (LCP) for use with mm-wave applications. These bends are very critical components for the miniaturization of high performance packages used for integrated multi-layer millimeter-wave front-ends on low-cost, organic, flexible substrates. In this paper we describe a method for creating ultrawideband, low-cost, high performance bends for microstrip and grounded coplanar waveguide (CPWG) lines. The simulated S-parameters demonstrated a return loss below -30 dB from 10 GHz-90 GHz for the microstrip line bends and below -22 dB for the CPWG bends. These bends are capable of operating for applications ranging from X to W-bands.