Leaky wave antenna loaded complementary elements with dual-stopband suppression

Abstract

In this paper, a periodic leaky wave antenna (PLWA) using complementary elements is proposed. The complementary elements of the transverse slot (horizontal magnetic current) and the monopole pairs (vertical electric current) in the substrate integrated waveguide (SIW) is employed as the radiation element, which can simultaneously suppress closed stopband β0p=π and open stopband (OSB) β-1p=0 to enhance the forward scanning of the LWA. Additionally, the gain and cross-polarization of the element are improved due to the loading of the monopole pairs. The LWA achieves forward and backward scanning from -73° to 10° when operating at the n=-1 spatial harmonic (SH), with corresponding gains of 11.5 to 15.4 dBi. When operating at the n=0 SH, it achieves forward scanning from 58° to 72°, with corresponding gains of 5.2 to 7.5 dBi. Moreovere, due to the element and its symmetrical structure, the cross-polarization within the entire operating frequency range is less than -35 dB. The design concept is validated through processed, fabricated, and tested.