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Omnidirectional Circularly Polarized Monopole Antennas on Artificial Magnetic Conductor Ground Plane
(2024-01-01)
Janpangngern, Pisit
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Kuse, Ryuji
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
This research proposes omnidirectional circularly polarized monopole antennas (OCPA) with single-annular (SA-AMC) and dual-annular artificial magnetic conductor (DA-AMC) ground planes. The aim of the proposed antenna scheme is to circumvent the design rigidity of conventional OCPA whose inherent shortcoming is fixed bottom ground plane size. The OCPA with SA-AMC ground plane consists of a monopole element, four diagonally adjoined parasitic elements to convert linear to circular polarizations, and an SA-AMC ground plane. The OCPA with DA-AMC ground plane consists of a monopole element, four diagonally adjoined parasitic elements, and a DA-AMC ground plane. Unlike the conventional OCPA, the bottom ground plane radius (R-{text {g}}) of the OCPA with SA- and DA-AMC ground planes can be varied between 18.4 - 188.4 mm; and 29.2 - 119.2 mm, respectively, without affecting the omnidirectionality and impedance and axial ratio (AR) bandwidths of the OCPA. Furthermore, the SA- and DA-AMC ground planes effectively improve the impedance (left |{{S-{11}}}right | leq -,10 dB) and AR bandwidths (AR leq 3,{} dB) while reducing leakage current on the coaxial feeder cable. The measured left |{{S-{11}}}right | and AR bandwidths of the OCPA with SA-AMC ground plane, given the optimal R-{g} of 18.4 mm, are 8.08% (5.34 - 5.79 GHz) and 4.38% (5.36 - 5.60 GHz), while those of the OCPA with DA-AMC ground plane, given the optimal R-{text {g}} of 29.2 mm, are 14.37% (5.10 - 5.89 GHz) and 19.85% (4.90 - 5.98 GHz). The novelty of this research lies in the use of SA- and DA-AMC structures to circumvent the design rigidity of the conventional OCPA. Essentially, the integration of the AMC structures offers design flexibility in the realization of OCPA.
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Broadband linear-to-circular polarisation conversion using the diamond-shaped reflecting metasurface
(2020-07-29)
Chaihongsa, Warangkana
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Kuse, Ryuji
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Furuya, Koichi
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
To overcome the narrow axial ratio (AR) bandwidth inherent in conventional linearly to circularly polarised converters, this research proposes a metasurface (MS) with a diamond-shaped configuration that can mitigate the effect of surface wave (SW) along the MS edge and achieve a wider 3 dB AR bandwidth. The diamond-shaped MS structure is realised by slanting a square MS by 45°, and it consists of constituent unit cells of rectangular and arbitrary shapes. The rectangular unit cells are positioned 45° to the square dielectric substrate, and the unit cells along the MS edge are partially cut into arbitrary shape to be perfectly aligned along the edge. The 3 dB AR bandwidths and degradation of the MS are characterised by SW and magnetic current distribution. Simulations are carried out and an MS prototype is fabricated to verify the results. The effects of partially cut unit cells (PCUCs) along the MS edge on the SW are characterised. The simulation and measured 3 dB AR bandwidths of the diamond-shaped MS are 37.6 and 28.8%, respectively. The novelty of the proposed diamond-shaped MS polarisation converter lies in the implementation of arbitrary-shaped PCUCs and the use of the diamond-shaped configuration in place of conventional square geometry to realise wider AR bandwidth.
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Broadband circularly polarized microstrip patch antenna using circular artificial ground structure and meandering probe
(2020-01-01)
Pookkapund, Khanet
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Sakonkanapong, Arnon
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Kuse, Ryuji
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
To enhance axial ratio (AR) bandwidth, this research proposes a circularly polarized (CP) single-fed microstrip patch antenna using a circular artificial ground structure (AGS) and meandering probe. To achieve broader AR bandwidth, the circular AGS is populated with rectangular unit cells and partially cut unit cells along the circular contour, while the meandering probe is used to improve the impedance bandwidth. Simulations are performed and results compared with that of conventional rectangular-AGS antenna. The simulation results show that the circular-AGS antenna, given 62 mm circular ground plane, achieves broader impedance (5.12 - 9.00 GHz and 54%), AR (5.21 - 8.27 GHz and 45%) and gain bandwidths (3.85 - 7.00 GHz and 58.06%), in comparison with the rectangular-AGS antenna (4.50 - 7.45 GHz and 49%; 4.52 - 7.42 GHz and 21%; and 4.00 - 6.80 GHz and 51.58% for impedance, AR and gain bandwidths). The circular-AGS antenna is capable of converting linear polarization in the off-axial ratio band into circular polarization. To verify, a circular-AGS antenna prototype is fabricated and experiments undertaken. The experimental impedance, AR and gain bandwidths of the circular-AGS antenna are 47.82% (5.17 - 8.42 GHz), 43.81% (5.24 - 8.17 GHz) and 60.74% (3.75 - 7.00 GHz). The proposed circular-AGS antenna can achieve broader AR bandwidth and is thus ideal for broadband CP applications. The novelty of this research lies in the use of circular AGS to effectively enhance AR bandwidth, as opposed to rectangular AGS which is conventionally used in CP polarizers.
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A broadband dual-sense circularly polarized antenna
(2017-04-26)
Lertsakwimam, Kittima
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
A dual-sense circularly polarized antenna is proposed with a broadband 3-dB AR characteristics. The antenna consists of circular ring, four straight probes, which are place in along diameter direction of ring, four straight bars, and a reflector. The antenna is excited by the four straight probes to obtain both right hand circular polarization (RHCP) and left hand circular polarization (LHCP). The antenna has a 10dB-retum loss from 1.1 GHz-2.2 GHz, and the 3dB Axial Ratio (AR) bandwidth is from 1.2 GHz-2.1 GHz (the relative bandwidth is 54.5 %) and more than -30dB-level of isolation in frequency range of 1.4-1.7 GHz. The antenna element broadside gain is approximately 9.5 dBic at 1.7 GHz.
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A ring antenna for dual-sense circular polarization
(2016-10-11)
Lertsakwimarn, Kittima
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
A design of dual circularly polarized antenna is proposed. By two dual L-shaped probe structure, dual-sense circular polarization (CP) for radio astronomy is achieved. The dual L-shaped probes are place in the radial direction of a circular ring to obtain both right hand circular polarization (RHCP) and left hand circular polarization (LHCP). According to our simulation results, the proposed antenna element could achieve-10dB-level of S<inf>11</inf> and more than-20dB-level of isolation in frequency range of 1.4-1.7 GHz. The antenna element broadside gain is approximately 8.5 dBic. The axial ratio (AR) below 3dB is more than 300 MHz in each circular polarization state. The details of simulation results for the proposed design are presented and discussed.
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A Low-Profile and Compact Split-Ring Antenna with Horizontally Polarized Omnidirectional Radiation
(2015-01-01)
Lertsakwimarn, Kittima
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
This paper presents a low-profile and compact printed antenna having an omnidirectional radiation pattern with horizontal polarization to the ground. The proposed antenna consists of an inner small fed ring, an outer coupled split ring, and a ground plane. The overall dimension of the proposed antenna is 45 mm × 50.5 mm × 11.6 mm (0.138λ <inf>0</inf> × 0.155λ <inf>0</inf> × 0.036λ <inf>0</inf>). The-10-dB S 11 of the antenna covers the 920-MHz RFID band, and the gain is about 1.45 dBi in the parallel direction to the ground plane. The measured results show good agreements with the simulated results. Furthermore, the reasons for the low-profile structure and the omnidirectional radiation pattern are also discussed.
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Design of circularly polarized and electrically small antenna with omnidirectional radiation pattern
(2014-12-01)
Lertsakwimarn, Kittima
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
This paper presents an electrically small and circularly polarized antenna with an omnidirectional radiation pattern. The antenna consists of a horizontal loop element enclosed by two U-shaped elements and a vertical element from the feeding point. The radiation pattern of the circular polarization is omnidirectional and has a maximum gain of -2 dBic in parallel to the ground plane at the 900 MHz band. The antenna dimensions are 48 × 20 × 13.8mm (0.14 λ × 0.06 λ × 0.04 λ) with ka = 0.476 (i.e. < 0.5), where k is the wavenumber at the resonant frequency and a is the radius of a sphere surrounding the antenna. The dimension corresponds to the definition of an electrically small antenna. The omnidirectional circularly polarized pattern of a prototype antenna shows good agreement with that of the simulation. In addition, this paper introduces a mechanism that generates omnidirectional circular polarization from electrically small antennas.
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A horizontally polarized, low-profile and compact antenna for radiating parallel to ground plane
(2014-11-20)
Lertsakwimarn, Kittima
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
This paper presents a low-profile, horizontally polarized and compact printed antenna radiating parallel to the ground plane. The proposed antenna consists of a small inner feeding loop, a coupled split ring element and a ground plane. The dimension of the proposed antenna is 45 mm × 50.5 mm × 11.6 mm (0.138λ<inf>0</inf> × 0.155λ<inf>0</inf> × 0.036λ<inf>0</inf>). From the results, the -10-dB S<inf>11</inf> of the antenna covers the 920-MHz RFID band, and the gain is about 1.45 dBi in the parallel direction to the ground plane. The measured results show a good agreement with simulated results.
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Electrically small antenna with circularly polarized and omnidirectional radiation pattern
(2014-01-06)
Lertsakwimarn, Kittima
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
This paper deals with the design of a circularly polarized electrically small antenna that has an omnidirectional radiation pattern. The antenna which consists of a horizontal loop element enclosed with two U-shaped elements and a vertical element. The proposed antenna has a dimension of 48 mm × 20 mm × 13.8 mm (0.14λ × 0.06λ × 0.04λ) with ka = 0.476 (i.e. <0.5), where k is the wavenumber at the resonant frequency and a is the radius of a sphere surrounding the antenna. The measured results of the omnidirectional circular polarization (CP) pattern and the simulated results are in good agreement.
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Circularly polarized low-profile antenna for radiating parallel to ground plane for RFID reader applications
(2013-12-01)
Lertsakwimarn, Kittima
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
This paper presents a low-profile printed antenna with double U-shaped arms radiating circular polarization for the UHF RFID readers. The proposed antenna consists of double U-shaped strip structures and a capacitive feeding line to generate circular polarization. A part of the U-shaped arms is bent by 90° to direct the main beam parallel to the ground plane. From the results, - 10 dB | S 11 | and 3 dB axial ratio of the antenna cover a typical UHF RFID band from 920 MHz to 925 MHz. The bidirectional beam is obtained with the maximum gain of 1.8 dBic in the parallel direction to the ground plane at the 925 MHz. The overall size of the proposed antenna including ground plane is 107 mm × 57 mm × 12.8 mm (0.33 0 × 0.17 0 × 0.04 0). © 2013 Kittima Lertsakwimarn et al.

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