A Ka-Band Transition From Integrated-on-Lid Microstrip to Ridge Gap Waveguide

Traditional microstrip line (MSL)-to-ridge gap waveguide (RGW) transition commonly sets the peripheral circuits to the same layer with the MSL for the reason the printed circuit board (PCB) is placed on the metal structure, which causes its inevitable limited integrability and inconvenience controllability. To overcome these demerits, the bottom of the PCB is used to supercede the conventional metal lid of the RGW in this letter. The proposed configuration uses an RGW bifurcated probe (BP) to convert the quasi-TEM mode into the TE101 mode in the resonator built by the plated-blind groove and cavity back. An MSL-modified monopole probe with a pair of irises is inserted in the resonator to couple the electric field (E-field) into the MSL. The methodology and mechanism of the transition are investigated and the manufactured back-to-back module verifies the feasibility of this transition. The transition allows the peripheral circuits to be placed on the flip side of the lid easily, which can significantly attenuate the adverse effects led by peripheral circuits, compact the size, and control the RGW circuits simultaneously.