scholarly journals A Broadband Circularly Polarized Antenna with Low-Profile and Wide Axial Ratio Beamwidth

2021 ◽  
Vol 18 (11) ◽  
Author(s):  
Madhuri SAHAL ◽  
Vivekanand TIWARI ◽  
Dinesh YADAV ◽  
Deepak BHATNAGAR ◽  
Tejpal Tejpal
Keyword(s):  
Axial Ratio ◽  
Center Frequency ◽  
Ieee 802.11A ◽  
Frequency Bands ◽  
Military Application ◽  
Multiple Application ◽  
Low Profile ◽  
Polarization Characteristics ◽  
Application Frequency

In this work, the design and the characterization of a broadband circular polarized monopole having low-profile and wide axial ratio beamwidth were presented. The antenna was designed on readily available, inexpensive glass-reinforced epoxy substrate having an overall size of 0.56λ0×0.50λ0×0.029λ0 (at center frequency 5.5 GHz). The proposed antenna was a modification of a square-shaped monopole antenna, which incorporates a pair of peripheral slits and an off-center slot for a elliptical polarized radiation. A v-shaped notch below the feed line was introduced and extended as antenna ground to generate broadband circular polarization characteristics. The −10 dB reflection coefficient bandwidth and 3-dB axial-ratio bandwidth of the proposed antenna were measured to be of 47.6 and 27 %, respectively. The 3-dB axial ratio beamwidth of the antenna was 93.5°. The antenna proposed in this work covers multiple application frequency bands including HiperLAN/2 IEEE 802.11a (5.15 - 5.35 GHz / 5.47 - 5.725 GHz) band, WLAN frequency band (5.1 - 5.9 GHz), C-band uplink (5.925 - 6.325 GHz) and part of military application band (4.75 - 4.99 GHz). HIGHLIGHTS Design and characterization of a broadband circular polarized monopole having low-profile and wide axial ratio beamwidth Proposed antenna covers multiple application frequency bands including HiperLAN/2 IEEE 802.11a, WLAN, C-band uplink and part of military application bands Proposed antenna is compact, low-profile and exhibits good polarization purity GRAPHICAL ABSTRACT

Design and characterization of an efficient multi-layered circularly polarized microstrip antenna

2015 ◽  
Vol 8 (7) ◽  
pp. 1101-1109 ◽  
Author(s):  
Pravin R. Prajapati ◽  
Amalendu Patnaik ◽  
M. V. Kartikeyan
Keyword(s):  
Microstrip Antenna ◽  
Axial Ratio ◽  
High Gain ◽  
Center Frequency ◽  
Impedance Bandwidth ◽  
Mobile Telecommunication ◽  
Defected Ground Structure ◽  
Circularly Polarized ◽  
Laboratory Prototype

A novel asymmetric “+” shaped fractal slotted circularly polarized microstrip antenna with a Yagi–Uda structure is proposed. Four asymmetric plus shape slots are embedded symmetrically in the center of all four quadrants of a square patch. To suppress undesirable higher modes, dumbbell-shaped defected ground structure (DGS) is introduced at the ground layer of the antenna. We introduce a method to compensate the reduction in gain occurring due to the presence of DGS, without changing in the overall size of the antenna. A 3 dB axial ratio bandwidth of 4 MHz at center frequency of 862 MHz, 10 dB impedance bandwidth of 13.20 MHz and a gain of 4.25 dB is achieved with the proposed antenna. A laboratory prototype of the proposed antenna is made to cross-verify the simulation results. Very good agreements between the two are obtained. The proposed antenna may prove useful for International Mobile Telecommunication application for designing high-gain arrays.

scholarly journals An Artificial Magnetic Conductor-Based Wideband Circularly Polarized Antenna with Low-Profile and Enhanced Gain

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2121
Author(s):  
Lina Qiu ◽  
Gaobiao Xiao
Keyword(s):  
Impedance Matching ◽  
Axial Ratio ◽  
Center Frequency ◽  
Impedance Bandwidth ◽  
Orthogonal Polarization ◽  
Magnetic Conductor ◽  
Circularly Polarized ◽  
Artificial Magnetic Conductor ◽  
Low Profile ◽  
Simulation And Experiment

A broadband circularly polarized (CP) antenna with enhanced gain and low profile is proposed. Two identical dipoles with full wavelength are placed orthogonally to generate radiation waves with equal amplitude and orthogonal polarization. The arms of the dipoles are designed as stepped patches to enlarge the impedance matching bandwidth and axial ratio (AR) bandwidth. Crossed-dipoles with full wavelength are utilized as the main radiators to provide a wide operating bandwidth and enhanced gain, and an artificial magnetic conductor (AMC) structure is introduced as the reflector to reduce the profile of the whole antenna. Due to the introduction of the AMC structure, the antenna profile is reduced from 12.8 to 6.9 mm, that is, reduced to 0.14λ0 (where λ0 denotes the wavelength corresponding to the center frequency of the passband, 4.0–8.5 GHz). A simulation and experiment were carried out to verify the performance of the proposed antenna. Experimental results showed that the antenna realized an impedance bandwidth of 74%, an AR bandwidth of 67.7%, a peak gain of 12.1 dBic, and an average gain of 10.69 dBic.

scholarly journals Design and Impedance Modeling of a Compact Sequentially Rotated Quasi-Lumped Antenna Array for Wi-Fi Applications

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yazeed M. I. Qasaymeh
Keyword(s):  
Antenna Array ◽  
Axial Ratio ◽  
Center Frequency ◽  
Resonance Model ◽  
Ieee 802.11A ◽  
Circularly Polarized ◽  
Quarter Wavelength ◽  
Impedance Modeling ◽  
Physical Insight ◽  
Insight Into

In this study, a miniaturized 2 × 2 sequentially rotated (SR), circularly polarized (CP), and quasi-lumped antenna array that resonates in the IEEE 802.11a band is introduced. The shorting pins technique is implemented to achieve circular radiation patterns, and the resonating elements are excited using a SR quarter-wavelength feeding network. A resonance model of the four radiating elements array is postulated to give a physical insight into the relative dimensions and to allow for a study of the resonance characteristics and the effect of the shorting pins. An antenna model is simulated, fabricated, and measured to authenticate this arrangement, giving results of |S11| < −10 dB and axial ratio (AR) < 3 dB for bandwidths of 3.85% (5.645–5.867 GHz) and 1.54% (5.77–5.86 GHz) for right-hand circular polarization (RHCP). The size of the antenna array structure is 0.696 λ 0 × 0.599 λ 0 × 0.0157 λ 0 at a center frequency of 5.8 GHz.

scholarly journals Compact Broadband Circularly Polarized CPW-Fed Antenna with Characteristic Mode Analysis

2022 ◽  
Vol 2022 ◽  
pp. 1-11
Author(s):  
Wei Xu ◽  
Jingchang Nan ◽  
Mingming Gao
Keyword(s):  
Coplanar Waveguide ◽  
Impedance Matching ◽  
Axial Ratio ◽  
Mode Analysis ◽  
Center Frequency ◽  
Impedance Bandwidth ◽  
Characteristic Mode ◽  
Circularly Polarized ◽  
Low Profile ◽  
Compact Size

A compact circularly polarized (CP) antenna is proposed for low-profile and wideband operation based on characteristic mode analysis (CMA). A ring patch with a gap and two arc-shaped metallic stubs as the radiator is analyzed and optimized by CMA to figure out the orthogonal modes and operating frequency band for potential good axial ratio (AR) performance. The studies of these CP modes provide a physical insight into the property of broadband circular polarization. Such an in-depth understanding paves the way for the proposal of novel CP antenna with separation between the design of radiator and feeding network. A 50-Ω coplanar waveguide (CPW) is introduced and placed appropriately to excite the desired modes based on the information from CMA, which employs two asymmetric ground planes to improve the performance in terms of AR and impedance matching. The antenna with a compact size of 0.71λ0 × 0.76λ0 × 0.038λ0 (λ0 is the free-space wavelength at the center frequency of the 3-dB AR bandwidth) is fabricated and measured for validation. The realized gain varies from 1.6 to 3.1 dBic over the operating bandwidth characterized by the measured 10-dB impedance bandwidth of 83.8% (3.98–9.72 GHz) and 3-dB AR bandwidth of 70.3% (4.59–9.57 GHz), respectively.

Bilayer split-ring chiral metamaterial based reconfigurable antenna for polarization conversion

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Preet Kaur ◽  
Pravin R. Prajapati
Keyword(s):  
Low Cost ◽  
Axial Ratio ◽  
Center Frequency ◽  
Impedance Bandwidth ◽  
Split Ring ◽  
Circularly Polarized ◽  
Left Hand ◽  
Rectangular Patch ◽  
Mode 2 ◽  
Chiral Metamaterial

Abstract A bilayer split-ring chiral metamaterial converts the linearly polarized wave, into a nearly perfect left or right-handed circularly polarized wave. The proposed antenna is intended to operate at center frequency of 5.80 GHz with switchable polarization capability. The polarization re-configurability is achieved by electronically switching of two PIN-diode pairs, which are embedded into bilayer split-ring Chiral Metamaterial. The optimized length of rectangular patch is 16 mm and width is 12.1 mm. Two types of radiation characteristics offered by the proposed antenna; left hand circularly polarized in mode 1 and right hand circularly polarized in mode 2. Measured results show that its impedance bandwidth is 155 MHz from 5.70 to 5.855 GHz for both mode 1 and mode 2. The measured axial-ratio bandwidth is 100 MHz from 5.75 to 5.85 GHz for mode 1 and 110 MHz from 5.73 to 5.84 GHz for mode 2. Antenna has LHCP gain of 2.52 dBi and RHCP gain of −23 dBi in mode 1. RHCP gain of 2 dBi and polarization purity of about −20 dBi is obtained in mode 2. The proposed antenna has simple structure, low cost and it has potential application in field of wireless communication (i.e., WiMax, WLAN etc.).

scholarly journals Design and characterization of a low profile NaI(Tl) gamma camera for dedicated molecular breast tomosynthesis

2016 ◽  
Author(s):  
Andrew M. Polemi ◽  
Justin Niestroy ◽  
Alexander Stolin ◽  
Gangadhar Jaliparthi ◽  
Randy Wojcik ◽  
...  
Keyword(s):  
Gamma Camera ◽  
Breast Tomosynthesis ◽  
Low Profile

A thin and optically transparent infrared-radar compatible stealth structure with low emissivity and broadband absorption

2021 ◽  
Author(s):  
Xiaoxue Tan ◽  
Juan Chen ◽  
Jianxing Li
Keyword(s):  
Dual Band ◽  
Center Frequency ◽  
Infrared Emissivity ◽  
Infrared Band ◽  
Functional Layer ◽  
Resistive Film ◽  
Broadband Absorption ◽  
Low Profile ◽  
Optically Transparent ◽  
Transparent Composite

Abstract In this paper, an optically transparent structure that combines broadband absorption and low infrared emissivity for dual-band stealth is proposed. The whole structure includes two functional layers. The periodic resistive film of the upper functional layer acts on infrared stealth. Its emissivity in the infrared band of 8-14μm is lower than 0.3. Another functional layer achieves greater than 90% wide absorption from 6 to 18.5 GHz. The whole optically transparent composite structure has a low profile of 0.141λ0, where λ0 is the wavelength of free space at the center frequency. It has an absorptivity that greater than 90% in the region of 5.7-16.5 GHz and has wide angular stability. Measured result is consistent with the simulation which verify the performance of the proposal. The infrared-radar compatible stealth structure proposed in this paper has potential application in the field of multi-spectrum compatible stealth.

scholarly journals CPW-fed circularly-polarized antenna array with high front-to-back ratio and low-profile

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 651-655 ◽  
Author(s):  
Yilin Liu ◽  
Kama Huang
Keyword(s):  
Antenna Array ◽  
Coplanar Waveguide ◽  
Ground Plane ◽  
Axial Ratio ◽  
Antenna Design ◽  
Impedance Bandwidth ◽  
Feeding Method ◽  
Circularly Polarized ◽  
Low Profile ◽  
Novel Design

Abstract A novel design of a coplanar waveguide (CPW) feed antenna array with circular polarization (CP) and a high front-to-back ratio is described. The proposed CP array is achieved by using a compact CPW–slotline transition network etched in the ground plane. The measured results show that this kind of feeding method can improve the impedance bandwidth, as well as the axial ratio bandwidth of the CP antenna array and provide adequate gain. The proposed array can achieve a 6.08% impedance bandwidth and a 4.10% CP bandwidth. Details of the antenna design and experimental results are presented and discussed.

scholarly journals Controlling Refraction Using Sub-Wavelength Resonators

2018 ◽  
Vol 8 (10) ◽  
pp. 1942
Author(s):  
Yue Chen ◽  
Robert Lipton
Keyword(s):  
Frequency Dependence ◽  
Free Space ◽  
Near Infrared ◽  
Center Frequency ◽  
Negative Index ◽  
Index Properties ◽  
Frequency Bands ◽  
Transmitted Signal ◽  
Sub Wavelength

We construct metamaterials from sub-wavelength nonmagnetic resonators and consider the refraction of incoming signals traveling from free space into the metamaterial. We show that the direction of the transmitted signal is a function of its center frequency and bandwidth. The directionality of the transmitted signal and its frequency dependence is shown to be explicitly controlled by sub-wavelength resonances that can be calculated from the geometry of the sub-wavelength scatters. We outline how to construct a medium with both positive and negative index properties across different frequency bands in the near infrared and optical regime.

scholarly journals Improved Low-Profile Helical Antenna Design for INMARSAT Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Shiqiang Fu ◽  
Yuan Cao ◽  
Yue Zhou ◽  
Shaojun Fang
Keyword(s):  
Pitch Angle ◽  
Satellite Communication ◽  
Design Method ◽  
Impedance Matching ◽  
Axial Ratio ◽  
Antenna Element ◽  
Helical Antenna ◽  
Copper Strip ◽  
Antenna Structure ◽  
Low Profile

A new low-profile variable pitch angle cylindrical helical antenna employing a copper strip as impedance transformer is proposed in this paper. Under the circumstance of a limited antenna height, the circular polarization performance of the antenna has been enhanced by changing the pitch angle and the input impedance matching has been improved by adjusting the copper strip match stub. The design method of the proposed antenna is given. The optimal antenna structure for INMARSAT application has been fabricated and measured. The measured results show that in the whole maritime satellite communication work band the VSWR is less than 1.2, its antenna gain is higher than 9 dBi, and the axial ratio is lower than 2.5 dB. The experimental results have a good agreement with the simulations. The proposed antenna is compact and easy tuning. It provides a promising antenna element for maritime satellite communication applications.

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