Low profile dipole antenna over compact AMC surface

Abstract

In this paper, an alternative technique is proposed to miniaturize the Artificial Magnetic Conductors (AMC) unit cell. Novel unit cell achieves 60% surface size reduction at the same operating frequency compared to conventional mushroom-like unit cell. An AMC surface of 5×5 cells is designed under a dipole antenna with a distance of 0.05λ0, where λ0 denotes the free space wavelength at 0.9 GHz, for gain enhancement and radiation control. Both the dipole antenna and the AMC surface are fabricated and measured to demonstrate the potential of this new structure. At 0.92 GHz, a peak realized gain of 4.3 dBi of the antenna is achieved. The front-to-back ratio is under −15 dB and the maximum cross-polarization level, in the main beam, is less than −25 dB for both E and H plane. The simulated and the measured results are in good agreement.