Millimeter-Wave Broadband Substrate Integrated Magneto-Electric Dipole Arrays With Corporate Low-Profile Microstrip Feeding Structures

Abstract

A millimeter-wave (mm-Wave) broadband linearly polarized (LP) substrate integrated magneto-electric dipole (ME-dipole) with a low-profile microstrip feeding structure covering the 22–33 GHz band is proposed in this article. It owns a good performance, particularly in terms of bandwidth and gain flatness. Importantly, the proposed substrate integrated LP ME-dipole element can be easily expanded into a full-corporate fed array without bandwidth degradation and requiring additional dielectric substrates. Moreover, its low-profile microstrip feeding structure locating on a hybrid substrate (include a thin dielectric substrate and a bonding film) makes the antennas amenable for direct integration with mm-Wave front-end circuits. Design, fabrication, and measurement of two arrays containing $4 \times 4$ and $8\,\, \times \,\, 8$ ME-dipoles are carried out, respectively. The measured results agree well with the simulated ones, validating the correctness of the proposed designs. The measured results of the $4 \times 4$ and $8\times 8$ array antennas show that both the two prototypes exhibit a wide available bandwidth (considering |S11| < −10 dB and 3 dB gain bandwidth) of more than 44%, a cross-polarization level of lower than −35 dB, a low-profile feeding layer of only 0.227 mm, a peak gain of 19.18 and 25 dBi, respectively, etc. The exhibited performance metrics of the proposed array antennas are promising for a number of applications ranging from 5G communications, satellite communications, to automotive radars, and so on.