Pattern-Reconfigurable Magnetoelectric Antenna Utilizing Asymmetrical Dipole Arms

Abstract

Magnetoelectric (ME)-dipole antennas are designed based on Huygens source theory. ME antennas create a unidirectional radiation by the superposition of perpendicularly located magnetic and electric dipoles’ patterns. If the radiation pattern of any of these two dipoles is altered, the overall radiation pattern of the antenna will change. This phenomenon is utilized in this letter to reconfigure the radiation pattern of the ME-dipole antenna by controlling the effective lengths of the dipole's two arms. As a result, an asymmetry is created in the radiation pattern due to a stronger radiation from one arm than the other. To electronically control the arm lengths of the electric-dipole element, each arm is divided into two pieces that are connected using five strip lines. To control current flow and thus the effective length of the dipole, each line is loaded with three pin-diodes. A Г-shaped probe is utilized to adjust the antenna's matching. The measured results show that the radiation pattern can be reconfigured at ±26° on elevation plane with a peak front-to-back ratio and gain values of more than 18 dB and 6.2 dBi, respectively. Moreover, the antenna maintains wide operating bandwidth at 1–1.82 GHz with peak efficiency of 85%.