A Wideband Low-Profile Folded Transmitarray Antenna Based on Magnetoelectric Dipole Elements

A wideband folded transmitarray (TA) antenna with a low profile is proposed by combing a TA aperture and a reflective polarization-conversion surface (RPCS). The TA aperture transforms the spherical wave into the planar wave, and the phase-gradient RPCS generates a virtual feed to reduce the profile. Both the TA and RPCS elements are proposed based on the magnetoelectric (ME) dipole antenna and the true-time-delay (TTD) structure. To verify the performance of the low-profile TA antenna, a prototype operating at 27 GHz is designed, fabricated, and measured. The proposed wideband TA antenna can achieve a peak gain of 25.3 dBi and a peak aperture efficiency of 40%. The achieved 1- and 3-dB gain bandwidths are 10% and 29%, respectively. The profile is reduced to 1/5 of the focal length. All these advantages make the proposed TA antenna a promising candidate for point-to-point wireless communication.