Enhanced radiation from an electrically small radiator using an array of sub-wavelength holes

Abstract

ABSTRACTAn experimental demonstration of radiation enhancement from an electrically small antenna (ESA) using an array of sub-wavelength holes engraved on a metallic plate is presented in this paper. A weakly radiating, chip inductor loaded open coplanar waveguide transmission line is used as the reference ESA. We show that an array of sub-wavelength hole loaded metallic aperture, placed near the antenna, can significantly enhance radiated power from the source. The hole array converts the high spatial reactive spectrum existing in the near-field of the antenna into a far-field propagating spectrum. The theory is validated by experiments and simulations in the microwave frequency regime. This novel radiation enhancement scheme is seen to enhance the gain of the antenna from −8.5 to −2.5−dBi and radiation efficiency from 13 to 33% around resonance.