A 18-40 GHz Substrate Integrated Waveguide H-Plane Horn Antenna

A 18-40 GHz wideband substrate integrated waveguide (SIW) H-plane horn antenna is proposed for applications on both the K-and Ka-bands. By employing a grating transition in front of the horn aperture, the impedance bandwidth (IBW) of the proposed antenna is broadened considerably. A broadband double-ridge waveguide (DRW)-to-SIW transition is also developed as the feeding structure for the proposed SIW H-plane horn antenna. The DRW is adopted to support a wider IBW as compared to that of a rectangular waveguide. A prototype of the proposed antenna is experimentally verified. The measured results show that the IBW for vertical bar S-11 vertical bar <= -10 dB ranges from 18 GHz to more than 40 GHz, covering the entire K-and Ka-bands. The measured gain varies from 7.52 to 15.37 dBi with an average gain of 11.58 dBi. In addition, the endfire radiation patterns are observed and maintained within the IBW.