An ENZ-Inspired Antenna with Controllable Double-Difference Radiation Pattern

Inspired by the epsilon-near-zero (ENZ) medium, a novel planar antenna with tunable difference radiation pattern is proposed in this work, which is constructed by the series-fed two-element effective ENZ antenna array. The intriguing property of the infinite wavelength within the ENZ medium allows for the radiation independent of the antenna's geometry. In this manner, the directions as well as the gain of the four lobes can be altered flexibly via stretching the antenna elements at the same operating frequency. The fabricated prototype demonstrated a double different pattern with the measured realized gain of the four lobes higher than 4.3 dBi and the 17-dB null depth at the broadside.