Design of Low-Profile Metamaterial-Loaded Substrate Integrated Waveguide Horn Antenna and Its Array Applications

Abstract

A metamaterial-loaded substrate integrated waveguide (SIW) horn antenna and its array application are researched in this communication. The mushroom-type metamaterial is placed in front of SIW horn aperture, and much improvement in impedance matching is achieved on a 1/20 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> -thickness substrate. Due to the backward wave generated by the metamaterial, backward endfire radiation pattern is observed for the proposed antenna. Experimental results indicate that a fractional impedance bandwidth of 10.6% is obtained for a fabricated prototype. Furthermore, a shunt four-element array and a monopulse four-element array are designed based on the novel SIW horn element to further enhance the radiation performance. Results show that performances of wide operating bandwidth, low profile, and backward endfire radiation pattern are maintained for the designed two arrays.