Substrate Integrated Waveguide Horn Antennas at Millimeter Waves

Anticipating the potentials and the challenges of the millimeter wave regions, horn antennas in substrate integrated waveguide (SIW) are observed. The antennas are fed by an WR28 rectangular waveguide through a slotted transition to the SIW structure. A parameter study by variating the dimension of the rectangular slot was carried out to get optimal reflection characteristics. Afterwards, several geometry modifications, such as changing the opening of the horn, the flare length and adding some vias, are performed to study the characteristics of the antennas. The antennas have very good reflection characteristics at frequency 38 GHz and a simulated gain of around 7.5 dBi. Measurements with a vector network analyzer confirmed the results.