Substrate Integrated Waveguide Leaky-Wave Antenna Featuring Complete Backward Scanning

In this paper, a substrate integrated waveguide (SIW) leaky-wave antenna (LWA) is presented, which has the capability of complete backward scanning with stable backfire radiation. The proposed SIW-based LWA consists of periodic structures, in which each double-layer slotted unit is shaped by duplicating the upper nonidentical slots to the bottom layer with the same offset d
y
with respect to the transversal axis. By properly manipulating the dispersion diagram of the unit cell, continuous frequency scanning characteristic from backfire to broadside is realized. Within the operating band from 12.6 GHz to 18.2 GHz, the antenna works in the fast-wave band, accomplishing beam scanning from −90° to 0° with the average realized gain and radiation efficiency of 10.39 dBi and 84%.