A Low-Profile Horn Antenna at Ka-Band

In this paper, a compact low-profile horn antenna is proposed at Ka-band. To enhance the impedance matching, the stairs are introduced in the open end of rectangular waveguide. Furthermore, the well-designed choke grooves are positioned beside the broad walls of open waveguide. The operating mechanism of grooves is also studied which can cut off the surface current and improve the radiation performance of the antenna accordingly. The simulated reflection coefficient is below -20dB from 26.8GHz to 33.8GHz. Good radiation patterns are observed within the operating band as well.