A Quad-Beam Leaky-Wave Antenna Supporting Wide-Scanning Angle for mm-Wave Applications

In this paper, a novel center-fed leaky-wave antenna with four beams for millimeter-wave applications is proposed. The wide-angle beam scanning characteristic is achieved by choosing an appropriate unit cell and utilizing a broadband feeding structure. The unit cell consists of two pairs of identical slots etched on both layers of the substrate integrated waveguide (SIW), and a wideband magic-T is embedded in the middle of SIW to provide an out-of-phase equal amplitude excitation. In such a way, quad-beam radiation is obtained. Each beam can scan from near end-fire to broadside direction, and the forward radiation beams are not used in the proposed design, which further increases the beam-scanning rate. Moreover, with the coexistence of the proposed leaky-wave structure and the two-way SIW power divider, multiple beams can be implemented using only one input port in a low-cost manner. Simulated results illustrate that a wide bandwidth of 27.7% is obtained from 22.5 GHz to 29.75 GHz with vertical bar S-11 vertical bar below -10 dB. Moreover, the proposed antenna can provide an overall beam-scanning range of 284 degrees, with each beam-scanning range of 71 degrees.