Integrated epsilon-near-zero antenna for omnidirectional radiation

Antennas with omnidirectional radiation of electromagnetic wave have wide applications in sensing, positioning, and wireless communications. Here, we investigate the potentials of using epsilon-near-zero (ENZ) metamaterial to realize omnidirectional radiation with high degrees of freedom. We propose an omnidirectional antenna based on an ENZ cavity integrated in printed circuits board (PCB). By taking advantage of ENZ behavior, the ENZ antenna can decouple the radiation patterns and the operating frequency while maintaining the omnidirectional radiation characteristic. Based on the omnidirectional ENZ antenna element, a parallel-fed array is realized based on the low-cost PCB process. The integrated ENZ antenna array exhibits the capability of engineering the omnidirectional radiation flexibly, such as beam scanning and beam intensity control for practical applications.