A Dual-Mode 2-D Frequency-Scanning Microstrip Periodic Leaky-Wave Antenna Array

A dual-mode two-dimensional (2-D) frequency-scanning microstrip periodic leaky-wave antenna array is presented. The antenna array consists of four rampart lines with 1-D frequency-scanning capability and a matching feeding structure. The antenna array has dual-mode 2-D frequency-scanning capability. In the low-frequency range, the antenna array is in a four-beam scanning mode, and as the frequency increases, the four beams gradually move toward the broadside direction. In the high-frequency range, the antenna array is in a bowl-shaped radiation mode, and as the frequency increases, the bowl-shaped radiation gradually moves away from the broadside direction. A prototype of antenna array is fabricated and tested. The measurement results verify that the antenna array achieves dual-mode 2-D frequency scanning. In the low-frequency range, the four beam radiation scans from 8° to 49° in the $\varphi $ = 45° plane. The bowl-shaped radiation in the high-frequency range scans from 17° to 38° in the $\varphi $ = 0°(x-z)-plane.