High Scanning Rate Asymmetrical Dual-Beam Leaky Wave Antenna Using Sinusoidally Modulated Reactance Superposing Surface

A seamless scanning dual-beam leaky-wave antenna (LWA) suited for multiobject detecting and tracking without blindness exhibits potential applications in wireless communication and radar systems. The beam scanning rate is a key indicator to measure the scanning performance of LWA. However, the high scanning rate dual-beam LWA with continuous scanning is seldom considered in the published literature. Defined first as the sum of the scanning rate of each beam in this communication, a novel asymmetrical dual-beam LWA with a high scanning rate of 12.9 is then proposed based on the combination of a half-mode substrate-integrated waveguide (HMSIW)-surface plasmon polaritons (SPPs) structure and a sinusoidally modulated reactance superposing surface (SMRSS) technique. The high scanning rate is attributed to the dispersion enhancement of the slotted HMSIW-SPP unit, while periodic modulation superposed and uniform slots etched on the top and bottom layers, respectively, contribute to the asymmetrical dual-beam continuous scanning. As an example, an X-band asymmetrical dual-beam LWA is implemented and measured. Over the band of 8.65-9.5 GHz [9.3% fractional bandwidth (BW)], the proposed dual-beam LWA achieves a seamless beam scanning from -65 degrees to -2 degrees and from -6 degrees to +51 degrees, respectively.