Substrate Integrated Waveguide Horn Antenna on Thin Substrate With Back-Lobe Suppression and Its Application to Arrays

A substrate integrated waveguide H-plane horn antenna on thin substrate with low back-lobe radiation is presented, and its application to arrays demonstrated. To suppress the back lobe, a pair of slots is employed in the top and bottom metallization. After size and position of the pair of slots are investigated, low back-lobe radiation is achieved. Moreover, the size of the horn aperture is approximately one wavelength, which is suitable for array applications. To highlight this point, the proposed horn antenna is used in a 1 × 4 planar array on a substrate as thin as one tenth of the wavelength. The array is designed, fabricated, and measured. Measurements show good agreement with simulations and suppressed back-lobe radiation with a 24 dB front-to-back ratio.