Full-Space-Scanning Substrate Integrated Waveguide Antenna With Enhanced Scanning Rate and Efficiency

In this letter, a frequency-controlled substrate integrated waveguide (SIW) leaky-wave antenna (LWA) with enhanced full-space beam scanning from backfire to endfire is proposed. The antenna utilizes a double-layer structure etched with transverse and dumbbell-shaped slots, which can cut off the surface current much more effectively than the single transverse slot. Therefore, the energy leakage rate per unit cell is higher, and the dispersion sensitivity is improved. Based on the equivalent circuit model, the leaky-wave (LW) waveguide is modified to radiate in a single harmonic mode ( n = -1), and the final design has realized the suppression of field cancellation at endfire and open stopband (OSB) at broadside. Simulation results show that the LWA achieves continuous full-space scanning from backfire (-90°) to endfire (+90°) within 21.6-29.4 GHz, with a high average radiation efficiency of 85% and high scanning rate of 5.88°/%. A prototype SIW LWA is fabricated and measured, which agrees well with the simulated one. Experimental results show that this antenna achieves a 180° beam scanning angle and 360° beam coverage range in the band of 22-29.8 GHz with the stable gain varying from 7.8 to 11.6 dBi.