Abstract
This paper presents a zero metamaterial (ZIM) structure for the gain and directivity reinforcement of the TSA. The designed ZIM cell, which consists of resonant metal structure and inductor component, can operate at low frequencies with one component of permittivity tensor reaching zero. By changing the inductance value of the inductor component, the zero point of permittivity tensor of the ZIM will shift correspondingly. We embed ZIM cells in the typical TSA to improve the gain and directivity of TSA, making the overall structure compact, and the embedded ZIM cells have no effect on the operating frequency band of the TSA. The simulated results indicate that the gain of the TSA loaded with the ZIM cells has been enhanced by 0.9–2.48 dB, and the half-power beam width has been decreased by least 10° in the frequency range of 0.575–0.590 GHz compared with typical TSA. The measured results are well consistent with the simulated ones. The new designed antenna can be applied in the grounded-penetrating radar systems.