Design of Rectangular Waveguide to Microstrip Power Dividers and Their Application as Compact Rectangular Matching Terminations

In this article, a vertical four-way rectangular waveguide to microstrip power divider is proposed. The power divider achieves perfect power division from 10.1 to 11 GHz with a 20-dB return loss and a short longitudinal length. Based on the four-way power divider, two microstrip ports are added, and a compact improved four-way rectangular waveguide to microstrip power divider is constructed. The 20-dB return loss bandwidth of the power divider can be extended from 9.9 to 12.4 GHz. If all the output microstrip ports are connected to resistive loads, the power dividers become rectangular matching terminations. Thus, the four-way power divider can achieve a rectangular matching load with an 8% bandwidth and a 2-mm matching length. The improved four-way power divider can achieve a rectangular matching load with a 22.4% bandwidth and a 2.5-mm matching length. The measurements agree well with the simulations. The proposed designs of the rectangular loads are superior in their compact volume, high power capacity, and ease of fabrication.