Low Sidelobe Dual-Beam Metasurface Antenna Based on Taylor Distribution and Digital Filtering Methods

Abstract

The Taylor distribution is often used to design low sidelobe level (SLL) antennas. While using this method to reduce SLL, it also leads to gain loss. To overcome this drawback, a method combining Taylor distribution with dual median and Gaussian filtering is proposed in this letter. First, the Taylor distribution modified with an amplitude compensation matrix is adopted to reduce the SLL when using a uniform distribution. Then, an innovative dual filtering strategy is introduced, which uses median filtering to suppress the SLL and Gaussian filtering to mitigate the gain loss. Finally, by finely readjusting the unit amplitudes according to phases, optimized performance is achieved. According to these steps, a dual-beam antenna is designed, fabricated and measured, which has a low SLL of −28.91 dB and a high gain of 16.6 dBi at 10 GHz. Compared with the metasurface antenna using only phase modulation, the SLL is reduced by 7.6 dB, while the gain is just decreased by 0.3 dBi.