A Quasi-Planar Waveguide Tuner

In this letter, a quasi-planar waveguide tuner is proposed, which is comprised of a main waveguide, three waveguide shorting stubs, and three ridged waveguide shorting stubs. All waveguide stubs are connected to the E-plane of the main waveguide. It can be used to replace the well-known E-H waveguide tuners with a simpler structure, smaller size, and lower fabrication cost. The matching ability is verified by using the quasi-planar tuner to match the discontinuities from an inductive iris and a capacitive iris. The matching results are shown to be the best compared with that of three other conventional tuners, an E-plane tuner, an H-plane tuner, and an E-H tuner. Tested results are also presented.