Low-cost D-band Waveguide Transition on LCP Substrate
Paper in proceedings, 2018
This work presents a waveguide transition based on a slot radiator implemented on liquid crystal polymer (LCP) substrate. The slot couples the RF signal to a D-band (110–170 GHz) waveguide perpendicular to its plane. The slot is fed using a microstrip line and can be bonded to any monolithic microwave integrated circuit (MMIC). A waveguide split-block that utilizes bed of nails structure is also presented. The structure is used to stop undesired radiation at the interface between the slot and the waveguide opening allowing better coupling between the slot and the waveguide by reducing radiation loss. The transition shows a minimum insertion loss of 2.1 dB and an average of 3.2 dB. The 3-dB bandwidth of the transition covers the frequency range 112 –140 GHz. Another variant of the transition is designed to cover the higher part of the band and shows an average insertion loss of 3.6 dB covering the frequency range 124–154 GHz. The transition presents a simple low-cost technique to interface between standard waveguides and MMICs in millimeter-waves systems.