Millimeter-wave Low-Loss Integrated Waveguide on Liquid Crystal Polymer Substrate

In this paper, low loss integrated waveguides implemented in Liquid Crystal Polymer (LCP) substrate are investigated for the first time as a candidate of choice for millimeter-wave packaging. The proposed Integrated Waveguide (IWG) can be used as a low loss millimeter-wave feed-through transition between the MMIC and the module. As the top face of the integrated waveguide does not have any electro-magnetic effects, a package lid can be attached to provide a hermetic sealing. The measured insertion loss of the integrated waveguide is -0.12 dB/mm and the measured insertion loss of the microstrip line-to-integrated waveguide transition is -0.28 dB. This low loss integrated waveguide on liquid crystal polymer can easily be used in many millimeter-wave packaging applications.