A Wideband and Low Sidelobe Magnetoelectric Dipole Antenna Array With Embedded Resistors

Abstract

A simple and effective method, by using ‘0-1’ excitations, to reduce the sidelobe level (SLL) for a wideband magnetoelectric (ME) dipole antenna array is proposed. First of all, the multiple-population genetic algorithm (MPGA) is utilized to search optimal ‘0-1’ excitations for SLL reductions. Then, the ‘0’ and ‘1’ excitation can be achieved by incorporating the absorbing element embedded with a resistor and an ME dipole antenna element, respectively. Different from the traditional tapered excitation techniques, the proposed array utilizes an equal power divider to distribute the power to each element. Finally, a planar $16\times 16$ stripline-fed antenna array according to the optimized array configuration is designed, fabricated, and measured. An overlapped impedance bandwidth of 57% (10–18 GHz) is achieved with the standing wave ratio (SWR) less than 2, and the SLLs are lower than −17.5 dB across 40% bandwidth both in E- and H-planes. In addition, the measured realized gain of this array prototype is up to 26.2 dBi with a high realized aperture efficiency ranging from 61% to 73%. The proposed lightweight, high-gain and high-integration Ku-band antenna array with low SLL characteristics shows great potential in satellite communications.