Compact planar transmission-line transition direct-connecting from a waveguide to four microstrip-lines

摘要

A compact planar transmission-line transition direct-connecting from a waveguide to four microstrip-lines is designed in the submillimeter-wave band. Microstrip array antennas are fed from the back at the center of the antenna for wide frequency bandwidth. To reduce the size of the center feeding circuit, the direct connection of all four microstrip lines into the waveguide is advantageous for radiation performance. For further reduction of the center feeding circuit, the metal pattern under the substrate is extended into the waveguide. Matching characteristics are obtained for compact transitions by optimization of the dimensional parameters in this paper.