Dual-Polarized, High-Gain, and Low-Profile Magnetic Current Array Antenna

Abstract

In this communication, a dual-polarized 36-element (3 × 6 × 2) magnetic current array antenna is designed without using complex feeding network. Instead, a pair of differential feeds is adopted to excite the overall dual-polarized array within a low profile. Such a simple feeding strategy is achieved by using the TM90 mode of a microstrip antenna, which is loaded by 3 × 4 identical half-wavelength slots for each polarization. In this configuration, an in-phase 3 × 6 element singlepolarized magnetic current array is achieved for high gain, but with narrow bandwidth due to the high-order mode. By trivially 90° rotating and combining, the proposed dual-polarized, high-gain, and low-profile magnetic current array is designed, constructed, and measured. Within a total size of 2.92λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 2.92λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.085λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free-space wavelength at the center frequency), the measured maximum gain is 15.5 dBi, also with the merits of low profile, low sidelobes, simple feeding, and high port isolation, exhibiting promising usage in MIMO and diversity applications.