Miniaturized Coplanar Waveguide to Rectangular Waveguide Transition Using Inductance-Compensated Slotline

In this paper, a miniaturized coplanar waveguide (CPW) to rectangular waveguide transition using an inductance-compensated slotline is proposed. The proposed transition has 38.06% 15-dB fractional bandwidth, which almost covers the whole X-band (8.2-12.4 GHz). As compared with the CPW to rectangular waveguide transition, which uses the quarter-wavelength slotline, our design has 18% reduction in the transition size, with only 2.72% reduction in the 15-dB fractional bandwidth as a tradeoff. In order to verify our design, we fabricate and measure back-to-back CPW to rectangular waveguide transitions of which the measurement results are in good agreement with the simulation results.