Wideband Omnidirectional Circularly Polarized Patch Antenna Based on Vortex Slots and Shorting Vias

Abstract-A wideband omnidirectional circularly polarized (CP) patch antenna is proposed in this paper. The proposed antenna is composed of a disk-loaded coaxial probe and four pairs of modified Γ-shaped strips loaded with shorting pins. Each pair of modified Γ-shaped strips consists of an inner Γ-shaped strip and an outer Γ-shaped strip. The approach employed in this design for improving the operating bandwidth is to add an inner Γ-shaped strip and make it couple to the outer one. By introducing the two coupled Γ-shaped strips, two different monopole modes can be achieved simultaneously and controlled separately by two different corresponding parts of these two Γ-shaped strips, respectively, and they can be merged to realize a wide-band impedance matching. Meanwhile, two minimum axial ratio (AR) points around the resonances of the antenna are excited by the coupled Γ-shaped strips, and they can be reallocated closely to each other for wide AR bandwidth. The measured results show that the proposed design has a 10-dB impedance bandwidth of 22.7% (2.26-2.84 GHz), 3-dB AR bandwidth of 33.6% (2.1-2.95 GHz) and low profile of 0.1λ 0 (λ 0 is the free-space wavelength at center frequency). In addition, a parametric discussion is conducted to further verify the proposed design.

Section: Antenna Design and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wideband Omnidirectional Circularly Polarized Patch Antenna With Multi-Resonant Structure

Yang¹,

Zhang²,

Ji³

et al. 2017

“…And then several inclined slits are fabricated on the sidewalls of the DRA to achieve omnidirectional CP fields. Recently, many antennas with low profiles using higher-order modes are also proposed to achieve good omnidirectional CP performances [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Dual-Band Omnidirectional Circularly Polarized Patch Antenna With Etched Slots and Shorting Vias

Zhang¹,

Zhang²,

Wang³

et al. 2017

Abstract-A dual-band omnidirectional circularly polarized (CP) patch antenna with conical radiation patterns is presented in this paper. The antenna consists of a patch with inclined slots, a ground plane with L-shaped slots and a coaxial probe. In addition, by loading shorting vias between the patch and the ground plane, the vertical polarizations of the proposed antenna at TM 01 and TM 02 modes can be obtained. Two sets of slots etched on the ground and the patch contribute to the horizontal polarizations for the two modes, respectively. Omnidirectional CP fields can be achieved at both resonant modes when the two orthogonal polarizations are equal in amplitude and different in phase by 90 • . To verify the design, a prototype operating at 2.4 GHz WLAN and 3.5 GHz WiMAX bands has been fabricated and measured. The measured average axial ratios (ARs) at two resonant modes in the azimuth plane are 1.1 and 1.5 dB, respectively. Experimental results show good agreement with the simulated data.

“…With the wideband demand for high performance and big capacity telecommunication systems, wideband omnidirectional CP antennas have been proposed and investigated over the past few years [1][2][3][4][5][6][7][8][9][10][11]. Working at TM 21 mode of a circular microstrip antenna, early wideband omnidirectional CP antenna [1] uses a 90 • phase shifter and hybrid feeding mechanism to get the broad working bandwidth of 28.2%.…”

Section: Introductionmentioning

confidence: 99%

“…By removing the shorting vias of the mushroom structure and increasing the profile of the antenna in [5], a omnidirectional CP DRA [6] has a wider usable bandwidth of 7%. Based on symmetric vortex slots and shorting vias, a center-fed circular microstrip patch antenna can radiate omnidirectional RHCP waves with a usable bandwidth of 51.7% [7].…”

Section: Introductionmentioning

confidence: 99%

Low-Profile Wideband Circularly Polarized Microstrip Antenna With Conical Radiation Pattern

Yu¹,

Wan²,

Zhang³

2017

Self Cite

Abstract-A low-profile wideband circularly polarized (CP) microstrip antenna with conical radiation patterns is designed in this paper. Based on the center-fed circular microstrip patch structure, the proposed antenna symmetrically employs 5 shorting vias connecting the patch and the ground plane to provide the θ-polarization and 11 slant sector branches at the edge of circular patch to generate the φ-polarization. With the phase difference of 90 • between the two orthogonal polarizations, the design radiates right-handed circularly polarized (RHCP) waves. The proposed antenna works at three resonant modes. To realize broad operating bandwidth, the slant sector branches should be carefully adjusted to make the second resonant mode couple the first mode (TM 01 mode) and third mode (TM 02 mode) together. The measured results show that the proposed antenna has a low profile of 0.025λ, impedance bandwidth of 35. , and axial ratio (AR) bandwidth of 38% (3.7-5.45 GHz). To further verify the characteristics of the proposed antenna, the studies on several important parameters are carried out by HFSS simulation, and a simple design guideline is provided.