A Low-Profile and Wideband Unidirectional Antenna Using Bandwidth Enhanced Resonance-Based Reflector for Fifth Generation (5G) Systems Applications

Abstract

The previously proposed resonance-based reflector (RBR) antennas have the merits of wide impedance bandwidth, low-profile, and unidirectional pattern; however, their front-to-back ratio (FBR) bandwidths are narrow. In this paper, a wideband RBR is proposed for FBR bandwidth enhancing antenna with a low profile. The proposed RBR consists of a metallic ring with three stubs printed on a substrate. It has a ±90 • in-phase bandwidth of 63.57% (3.23-6.24 GHz) and its reflection magnitude values range from −0.02 to −11.5 dB within the in-phase band (−90 • < ϕ < 90 •). Compared with the existent RBRs, the proposed RBR achieves a greater reflection magnitude within the in-phase band, which would be critical for FBR enhancement of an antenna. The proposed RBR is applied to a ring-loaded teardrop-shaped bowtie antenna to form unidirectional radiation pattern. The measured −10-dB impedance bandwidth of the proposed antenna is 3.48-6.12 GHz (55.00%), while FBR values are larger than 10 dB within the whole impedance band and the maximum FBR value is up to 20.4 dB. The peak gain is bigger than 7.3 dBi within the whole impedance band. There is a reasonable agreement between the simulated and measured results. The profile of the overall unidirectional antenna is 0.15λ L at the lowest operating frequency, and the RBR has the same size as the bowtie antenna. Compared to the previous RBR antennas, the proposed RBR antenna has wider FBR bandwidth. The operating band of the antenna is suitable for 5G system applications.

Fifth Generation Antennas: A Comprehensive Review of Design and Performance Enhancement Techniques

“…A compact antenna of size 10 mm x 12 mm x 1.48mm is designed on the transparent substrate Plexiglas, but its gain is only 1.94 dBi [71]. The resonance based reflector antenna is designed by using three metallic layers with the substrate as a sandwich in between two layers to provide wider front to back ratio (FBR) bandwidth [72]. The 3D antenna is designed in [73] and it metalized by using a spray coating technique to produce a compact, lightweight, and rigid antenna.…”

Design of a Directional Antenna Based on a Resonance Based Reflector and Its Applications on Bio-Electromagnetics

“…1(b), the resonant frequency of the reflector is about 2.73 GHz (the frequency point where the value of |S 11 | is 0 dB). Compared with the reflector in [13], the resonance frequency is reduced by 18.51% with the same structure size. This phenomenon is because the current path of the ring resonator is longer as indicated in Fig.…”

A Compact Low-Profile Ring Antenna With Dual Circular Polarization and Unidirectional Radiation for Use in RFID Readers

“…The reason, as mentioned before, is that the slots in the reflector make the equivalent coupling capacitance between the radiator and the reflector relatively small so that antenna performances become relatively less sensitive to profile height h in comparisons with the conventional solid conducting plane reflector. The principle of unidirectional radiation of the proposed antenna is similar to that of the resonance based reflector in [17], [18], and the central structure of the slotted reflector is used to improve the unidirectional radiation or reduce the profile height.…”