Low-Profile Broadband Vertically Polarized Microstrip Magnetic Dipole Antenna With Endfire Radiation

Abstract

A low-profile broadband vertically polarized microstrip magnetic dipole antenna with endfire radiation is proposed for millimeter-wave (mmWave) applications. For the bandwidth enhancement, a lower resonance is introduced by the parasitic patches firstly. Then, a top-loaded circular probe and an inset proximity-coupled feed structure are employed for adjusting the resonances from the magnetic dipole antenna and the parasitic patches. In this way, a broad impedance bandwidth is attained. After that, a 1 × 4 antenna array prototype is designed, fabricated and tested. Experimental results demonstrate that the proposed array features an impedance bandwidth wider than 19% at 28 GHz mmWave frequency band under an ultralow-profile of 0.075 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> at the center frequency.