A High-Gain, Wideband, Circularly Polarized Antenna With Multibeam Radiation for Millimeter-Wave Applications

This article proposes a wideband differential fed circularly polarized (CP) antenna [48% overlapped bandwidth, which is the minimum value of axial ratio (AR) bandwidth, gain bandwidth, and impedance matching bandwidth] with multiple beams radiation across V- and W-band enabled by a parabolic reflector, a long-slot radiator, and a wideband 3-D printed polarizer. The long-slot structure is an array consists with substrate integrated waveguide (SIW)-based open-slot elements (the vias besides a conventional SIW slot are moved to form an open slot), which yields wideband characteristics when compared with traditional slot array. Cooperating with wideband parabolic reflector and modified 3-D printed polarizer, it finally achieves 48% CP bandwidth. Finally, by setting multiple ports on the feeding network, multibeam radiation can be achieved. For validation, a multibeam CP antenna operating from 58 to 94.5 GHz with 20.5-dBic peak gain level and three radiation beams is fabricated and measured. Based on the authors’ extensive research, the proposed antenna yields a superior bandwidth when compared with recently reported millimeter-wave (mm-wave) long-slot structures and high-gain CP antennas.

I. Introduction

Millimeter-wave (mm-wave) technology is a highly promising solution in the realm of communication systems for 5G and beyond 5G applications, offering high-speed and low-latency data transmission [1], [2]. Radio frequency front end of mm-wave systems requires antennas, which yields high performances, such as wideband, high gain, low profile, low cost, and multicoverage beams. Conventional antennas used for mm-wave applications, such as horn, lens, and reflector antennas, can realized wideband and high-gain performances. However, they are commonly high-profiled, bulky, and high cost for fabrication. In recent years, some antennas with high gain, wideband, and low profile have been proposed [3], [4], [5], [6], [7], [8], but most of these antennas suffer from narrower bandwidth (less than 30%), which limits practical application of them.