Rectangular to Parallel Plate Waveguide Transition and Its Tapering Effect for Microwave Devices Characterization

Abstract

The experimental characterization in exploiting the property of microwave devices is an essential complement to theoretical and/or simulation works. Thus, the need of instrument for the characterization is becoming unavoidable thing to be established. This paper reports the development of test-fixture in form of a parallel plate waveguide (PPW) to characterize the reflectivity and/or transmittivity of microwave device whereby the property of reflection and/or transmission can be achieved under normal incidence. Since the PPW is excited using a rectangular waveguide, a transition section which connects the rectangular waveguide and the PPW needs to be investigated to have an optimum performance required for microwave devices characterization. The tapering effect of transition section is examined and analyzed numerically in yielding the influences to the test-fixture performance. Here, a WR248 type rectangular waveguide which has working frequency of 2.60GHz to 3.95GHz for TE10 mode is used as coaxial-to-waveguide transducer for exciting the PPW. The result shows that the linear-tapered transition has better performance in term of bandwidth compared to the step-tapered one. In addition, the discussions of taper length and number of step-tapered transition related to the performance of test-fixture as well as the experimental characterization for linear-tapered transition are also presented.