3-D-Printed mm-Wave Filtering Magnetoelectric Dipole Antenna With Wide Beamwidth and Its Application in High-Isolation E-Plane Phased Arrays

In this article, a 3-D-printed filtering magnetoelectric (ME) dipole antenna with wide beamwidth and its high-isolation E-plane phased arrays for mm-wave applications are presented. This antenna element consists of a fourth-order cross-coupling cavity feeding scheme and an ME dipole radiator with a pair of vertical electric walls, which enables both a filtering response with two radiation nulls and a wide beam. The operating principle of the filtering function and the beam shaping are analyzed in detail. Compared with traditional waveguide aperture filtering antennas, the proposed ME dipole effectively widens the beamwidth without obviously increasing the E-plane size. Subsequently, a four-unit E-plane linear phased array is constructed based on the filtering wide-beam ME dipole. The vertical electric walls of the ME dipole also act as the decoupling walls for the array and can be utilized to enhance the isolation of adjacent antenna ports. Finally, to verify the concept, the antenna element and phased array are fabricated using selective laser melting (SLM) 3-D-printing technology. The measured half-power beamwidth (HPBW) of the filtering ME dipole is 139° in the E-plane. As a result, the array achieves a measured scanning angle of ±50° with a gain fluctuation of less than 1.9 dB over the operating band, and the isolations are better than 25.5 dB. More importantly, the filtering function is simultaneously integrated into the phased array antenna to enhance the out-of-band rejection capability.