Backward to Forward Scanning Periodic Leaky-Wave Antenna with Eliminated Reflected Side Lobe

A backward-to-forward continuous beam scanning periodic leaky wave antenna (PLWA) with eliminated reflected side lobe is presented in this paper. The proposed antenna consists of ten nonuniform unit cells (UCs) periodically cascaded along the direction of propagation. By optimizing the geometry of the UCs which are composed of orthogonally bending transmission lines, the reflected side lobe suppression is achieved without changing the original scanning property. A prototype of the antenna is simulated, fabricated and measured. The measured results show that the main beam scans from backward quadrant (i.e., -47°) to forward quadrant (i.e., +55°) through broadside with eliminated open stopband (OSB). The proposed antenna features a low reflected side lobe level within the operating band of 3.7-6.5 GHz, and achieves a maximum reduction of 7.1 dB at 6.5 GHz compared to the uniform PLWA.