SIW periodic leaky wave antenna with improved H-plane radiation pattern using baffles

Abstract

A conventional transverse slot substrate integrated waveguide (SIW) periodic leaky wave antenna (LWA) provides a fan beam, usually E-plane beam having narrow beam width and H-plane having wider beamwidth. The main beam direction changes with frequency sweep. In the applications requiring a pencil beam, an array of the antenna is generally used to decrease the H-plane beam width which requires long and tiring optimization steps. In this paper, it is shown that the H-plane beamwidth can be easily decreased by using two baffles with a conventional leaky wave antenna. A prototype periodic leaky wave antenna with baffles is designed and fabricated for X-band applications. The E- and H-plane 3 dB beam widths of the antenna at 10.5GHz are, respectively, 6° and 22°. Over the frequency range 8.2-14 GHz, the antenna scans from θ = -60° to θ = 15°, from backward to forward direction. The use of baffles also improves the gain of the antenna including broadside direction by approximately 4 dB.