A Compact Wideband Pattern Diversity Antenna for 5G-NR Applications

Abstract

In this letter, a novel compact wideband antenna with broadside and conical diversity patterns is presented for fifth-generation (5G)-NR applications. The capacitive loading is implemented to enhance the port isolation and for size reduction (0.35 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.29 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.047 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ). With an extra slot mode introduced by the coupled feeding scheme, a wide impedance bandwidth is obtained. A miniaturized broadband 180° hybrid coupler is designed to provide in-phase and out-of-phase excitations. It is composed of a quarter-wavelength parallel coupled-line and lumped <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> components. As a result, conical and broadside diversity radiation patterns are achieved. The proposed antenna is analyzed, fabricated, and measured. Good agreement is achieved between the simulated and measured results. The measured overlapped −10 dB impedance bandwidth is 20.5% (3.16–3.81 GHz). The measured in-band isolation is better than 22.7 dB and the peak value achieves 34.7 dB. The proposed pattern diversity antenna exhibits good overall performance, including compact size, wide bandwidth, high isolation, and good radiation performance. Therefore, it is suitable for space-limited 5G-NR applications.