Half-mode substrate integrated waveguide six-port front-end circuits for direct-conversion transceiver design

Two six-port junction circuits based on the half-mode substrate integrated waveguide (HMSIW) technique are proposed and implemented in this paper. The first six-port junction consists of four directional couplers, which can work as a reflection-type I/Q modulator in a direct-conversion transmitter. The other six-port junction involves one T-junction and three directional couplers, and it can work as a demodulator in a direct-conversion receiver. One T-junction, two couplers and a 50Ohm matching load are independently simulated and designed by using the recently proposed HMSIW technique. Two six-port junction circuits are designed and integrated on the basis of the developed basic building components. Measurements of the proposed two six-port junctions are presented over a frequency band from 22GHz to 26GHz.