Next-Generation MS-to-RWG Interconnects for Microwave and mm-Wave Communications Using Microstrip Antenna as RF Energy Launcher @ 140 GHz

This work presents the design and development of microstrip-to-rectangular waveguide (MS-to-RWG) transition for next-generation mm-wave communications. Four design variants of MS-to-RWG have been proposed and prepared for the D-band (110–170 GHz) application. The variants are designed using multi-step impedance transformer, reduced three-step impedance transformer, PIN diode ON state, and a resistor, respectively. In each design variant, the RF energy is coupled and launched through microstrip antennas. These antennas are highly directive and have high gain value. Impedance matching and mode matching between the MS line and RWG are achieved by multi-step impedance transformer and inset feeding of antenna. This results in better performance of transitions in terms of insertion loss (IL), return loss (RL), and bandwidth. The designed transitions are simple, compact, and economic since no ridge waveguide, waveguide back short are utilized in WR-7 and microstrip did not contain any via, fence, window, screw, galvanic structure, eWLB process. Hence, the designed interconnects are a better choice for high data rate communications, MMIC circuits, and next-generation mm-wave applications.