Compact Microstrip Line to Gap Waveguide Transition suitable for Beam Steering Antenna Applications at K-band

This paper presents an innovative microstrip-to-waveguide transition specifically designed for beam steering antenna applications, ensuring efficient signal transmission in the K-band frequency range. Smooth transitions between microstrip and waveguide technologies are essential for optimizing signal integrity in high-frequency systems, where minimizing loss and maintaining impedance matching are critical for overall performance. By using gap waveguide technology, the proposed design achieves seamless integration between the substrate and the metallic waveguide, enhancing the efficiency of the system while reducing complexity. A bone-shaped coupling slot enables effective energy coupling between the microstrip section and groove gap waveguide section, minimizing reflection loss between the substrate and waveguide sections. Additionally, a “bed-of-nails” structure is employed behind the microstrip to suppress unwanted radiation, ensuring system stability and reduction in cross-talk among neighbouring channels. This design meets the demand for compact, high-efficiency transitions in modern communication systems, providing a robust platform for future beam steering technologies. Simulation results demonstrate excellent performance, with S<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf>below -10 dB and insertion loss less than 0.45 dB over the 17.4 to 19.75 GHz range.