Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Single-Feed Circularly Polarized Super Realized Gain Antenna

Georgia Psychogiou, Donal P. Lynch, Spyridon N. Daskalakis, Manos M. Tentzeris, George Goussetis, Stylianos D. Asimonis

TL;DR

To address the need for compact, circularly polarized, high-directivity antennas in sub-6 GHz systems, the paper presents a two-element, single-feed crossed-dipole end-fire array with a passive reactive load on the parasitic element. The approach relies on strong mutual coupling with a carefully tuned geometry and reactive loading to realize LHCP realized gain without external networks, demonstrated via optimization in ANSYS HFSS. Key results show an impedance bandwidth of 23.75%, an axial ratio bandwidth of 4%, and a peak LHCP realized gain of about 6.1 dB at 3.5 GHz with ka ≈ 1.65, approaching Harrington's limit of about 7.9 dBi. The low-profile design demonstrates that circular polarization and superdirectivity can be achieved in a simple two-element configuration, enabling integration into compact sub-6 GHz platforms for wireless sensing and communications.

Abstract

This paper presents a super realized gain, circularly polarized strip-crossed dipole antenna operating at 3.5 GHz. Superdirective behavior is achieved by leveraging strong inter-element mutual coupling through careful adjustment of the strip dimensions. The antenna features a single driven element, with the other element passively loaded with a reactive impedance. The structure is optimized to maximize left-hand circularly polarized (LHCP) realized gain, ensuring high polarization purity and good impedance matching. The optimized design exhibits a 50 $Ω$ impedance bandwidth of 3.29 - 4.17 GHz (23.75%) and an axial-ratio bandwidth of 3.43 - 3.57 GHz (4%). At 3.5 GHz, the antenna achieves a peak realized gain of 6.1 dB ($ka \approx 1.65$), with an axial ratio of 1.4 dB. These results demonstrate that circular polarization and superdirectivity can be simultaneously realized in a geometrically simple, low-profile ($0.15λ$) antenna, rendering it suitable for integration into compact sub-6~GHz wireless and sensing platforms.

Single-Feed Circularly Polarized Super Realized Gain Antenna

TL;DR

To address the need for compact, circularly polarized, high-directivity antennas in sub-6 GHz systems, the paper presents a two-element, single-feed crossed-dipole end-fire array with a passive reactive load on the parasitic element. The approach relies on strong mutual coupling with a carefully tuned geometry and reactive loading to realize LHCP realized gain without external networks, demonstrated via optimization in ANSYS HFSS. Key results show an impedance bandwidth of 23.75%, an axial ratio bandwidth of 4%, and a peak LHCP realized gain of about 6.1 dB at 3.5 GHz with ka ≈ 1.65, approaching Harrington's limit of about 7.9 dBi. The low-profile design demonstrates that circular polarization and superdirectivity can be achieved in a simple two-element configuration, enabling integration into compact sub-6 GHz platforms for wireless sensing and communications.

Abstract

This paper presents a super realized gain, circularly polarized strip-crossed dipole antenna operating at 3.5 GHz. Superdirective behavior is achieved by leveraging strong inter-element mutual coupling through careful adjustment of the strip dimensions. The antenna features a single driven element, with the other element passively loaded with a reactive impedance. The structure is optimized to maximize left-hand circularly polarized (LHCP) realized gain, ensuring high polarization purity and good impedance matching. The optimized design exhibits a 50 impedance bandwidth of 3.29 - 4.17 GHz (23.75%) and an axial-ratio bandwidth of 3.43 - 3.57 GHz (4%). At 3.5 GHz, the antenna achieves a peak realized gain of 6.1 dB (), with an axial ratio of 1.4 dB. These results demonstrate that circular polarization and superdirectivity can be simultaneously realized in a geometrically simple, low-profile () antenna, rendering it suitable for integration into compact sub-6~GHz wireless and sensing platforms.
Paper Structure (4 sections, 1 equation, 2 figures, 1 table)

This paper contains 4 sections, 1 equation, 2 figures, 1 table.

Table of Contents

  1. Introduction
  2. Antenna Configuration and Design
  3. Simulation Results and Analysis
  4. Conclusion

Figures (2)

  • Figure 1: Geometry of the optimized two-element crossed-dipole array showing all design parameters ($l_{x1}$--$l_{x2}$, $l_{y1}$--$l_{y2}$, $w_{x1}$--$w_{y2}$) and inter-element spacing $d$ along the $z$-axis. Each element is differentially fed at its center, and the lower element includes the reactive load $Z_L$.
  • Figure 2: Simulated results of the optimized crossed-dipole array: (a) reflection coefficient $|S_{11}|$, (b) directivity and realized-gain, and (c) axial ratio.