scholarly journals Patches of Dual Functions for Wideband MIMO Array Antenna with Linear or Circular Polarization Characteristics

2021 ◽  
Author(s):  
Reza Zaker ◽  
Mohsen Khalily ◽  
Rahim Tafazolli ◽  
Ahmed A. Kishk
Keyword(s):  
Ground Plane ◽  
Array Antenna ◽  
Ultra Wideband ◽  
Dual Function ◽  
Peak Efficiency ◽  
Linearly Polarized ◽  
Polarization Characteristics ◽  
Broadside Radiation ◽  
First Time ◽  
Better Than

Abstract In this paper, a design of a monopole-based four-element MIMO array antenna is proposed. The design is based on a novel technique that makes a patch be a ground plane of the next patch. Thus, each patch has a dual function. This method is named the sharing technique. Thus, for the first time, two of such antennas can be merged, providing a subminiature structure. The method is introduced step by step. Then, a 2×2 MIMO array with a total area of 49×49 mm 2 is designed, which provides a miniaturized of 57% (from 0.18λ 2 0 to 0.076λ 2 0 @ 1.7GHz). Two linearly-polarized array samples are evaluated. One sample with center-fed patches and another with off-center-fed. Both samples provide a semi-end-fire pattern with a minimum front-to-back (F/B) ratio of 11dB and 360° rotation capability with wide 10-dB S 11 bandwidths over 100%. Moreover, an ultra-wideband circularly polarized array with broadside radiation can be achieved by simultaneous, sequential exciting all ports. The antenna achieves isolation better than 15dB, peak efficiency of 95%, and 5.9dBi gain verified with different measurements.

scholarly journals Cross-Slot Antenna with U-Shaped Tuning Stub for Ultra-Wideband Applications

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Dawood Seyed Javan ◽  
Mohammad Ali Salari ◽  
Omid Hashemi Ghoochani
Keyword(s):  
Radiation Pattern ◽  
Ultra Wideband ◽  
Slot Antenna ◽  
Impedance Bandwidth ◽  
Design Procedures ◽  
Linearly Polarized ◽  
Dimensional Parameters ◽  
Simulation Results ◽  
Novel Design ◽  
Better Than

A novel design of an ultra-wideband (UWB) slot antenna is presented. This antenna operates as a transmitter and receiver antenna. Effects of the antenna dimensional parameters are studied through experimental and simulation results. Design procedures are developed and verified for different frequency bands. The experimental and simulation results exhibit good impedance bandwidth, radiation pattern, and relatively constant gain over the entire band of frequency. Antenna gain and directivity at boresight and in their maximum states are close to each other and indicate high radiation efficiency. To use the antenna as a linearly polarized antenna, the radiation pattern in E-plane is better thanthat inH-plane.

A compact ultra-wideband square and circular slot ground plane planar antenna with a modified circular patch

2021 ◽  
pp. 1-6
Author(s):  
Manohar Golait ◽  
Manish Varun Yadav ◽  
Balasaheb H. Patil ◽  
Sudeep Baudha ◽  
Lokesh Kumar Bramhane
Keyword(s):  
Ground Plane ◽  
High Gain ◽  
Ultra Wideband ◽  
Planar Antenna ◽  
Fractional Bandwidth ◽  
Peak Efficiency ◽  
Circular Patch ◽  
X Band ◽  
Uwb Applications ◽  
Ku Band

Abstract A compact ultra-wideband (UWB) square and circular slot ground plane planar antenna with a modified circular patch for UWB communication is presented. This antenna has a low reflection coefficient and high gain in the range of 8.94 GHz, starting from 2.85 to 11.79 GHz. The proposed antenna demonstrates UWB behavior with electrically small dimensions of 0.18 λ0×0.14 λ0×0.015 λ0 (λ0 is the free-space wavelength at 2.85 GHz). The fractional bandwidth of the antenna is 122.1%, with stable radiations. The antenna's maximum gain stands at 2.79 dBi, and the antenna's peak efficiency stands at 72%, respectively. It is lightweight, compact, and easy to manufacture. Hence, it can be used for the complete range of UWB applications and covers Wi-Max/WLAN/ X-Band and Ku-Band.

scholarly journals A Wideband Dual-Polarized Antenna Using Planar Quasi-Open-Sleeve Dipoles for Base Station Applications

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Guan-xi Zhang ◽  
Li Sun ◽  
Bao-hua Sun
Keyword(s):  
Return Loss ◽  
Ground Plane ◽  
Base Station ◽  
Cross Polarization ◽  
High Frequencies ◽  
Feeding Structure ◽  
Polarization Characteristics ◽  
Dual Polarized ◽  
Dual Polarized Antenna ◽  
Better Than

A wideband dual-polarized antenna for WLAN, WiMAX, and LTE base station applications is presented in this paper. The proposed antenna consists of two pairs of orthogonal planar quasi-open-sleeve dipoles along the centerlines, a balanced feeding structure and a square ground plane. The planar quasi-open-sleeve dipole comprises a pair of bowtie-shaped planar dipoles with two parallel curve parasitic elements. The introduced parallel curve parasitic elements change the path of the current of the original bowtie-shaped planar dipoles at high frequencies and hence wideband characteristic is achieved. Two pairs of the planar quasi-open-sleeve dipoles placed orthogonally further broaden the bandwidth of the antenna with dual-polarization characteristics. The proposed antenna achieves a 10-dB return loss bandwidth from 2.32 to 4.03 GHz (53.9% bandwidth) using the planar quasi-open-sleeve dipole structures. The isolation between the two ports remains more than 32 dB in the whole bandwidth. Measured results show that the proposed antenna keeps the cross-polarization under −33 dB and the front-to-back ratio better than 15 dB in the operating band. The antenna has an area of 0.3λ  × 0.3λat 2.32 GHz making it easy to be extended to an array element.

Highly compact UWB bandpass filter based on composite right/left-handed transmission line and meander fractal like ring slot in ground

2016 ◽  
Vol 9 (5) ◽  
pp. 1037-1044
Author(s):  
Babu Lal Shahu ◽  
Srikanta Pal ◽  
Neela Chattoraj ◽  
Dileep Kumar Upadhyay
Keyword(s):  
Transmission Line ◽  
Insertion Loss ◽  
Return Loss ◽  
Bandpass Filter ◽  
Ground Plane ◽  
Equivalent Circuit Model ◽  
Ultra Wideband ◽  
Left Handed ◽  
Conductor Strip ◽  
Better Than

An ultra-wideband (UWB) highly compact bandpass filter with extremely high passband bandwidth is presented. The proposed structure is made using three-staged stepped-impedance lines and a composite right/left-handed transmission line (CRLH-TL) synthesized with meander fractal like ring slot in the ground and series capacitive gap in conductor strip. The capacitive gap in conductor strip and meander fractal like ring slot in the ground plane play major role for controlling the lower and higher cut-off frequencies. The equivalent circuit model of proposed filter is demonstrated and lumped parameters are extracted. A prototype is fabricated to experimentally validate the performance of proposed filter. The proposed UWB filter has extremely wide −10 dB return loss passband bandwidth from 3.14 to 18.26 GHz with relative bandwidth of 142% and insertion loss better than 0.5 dB. Also it achieves a wide upper-stopband from 19.7 to 24.4 GHz with insertion loss better than 13.0 dB, return loss <1.5 dB and sharpened rejection skirts outside the passband at both lower and upper frequency ends. Good agreement is found between simulated and measured results with measured group delay variation in the passband <0.65 ns.

Design of dual-function metasurface based on beam polarization characteristics

2021 ◽  
Vol 117 ◽  
pp. 111199
Author(s):  
Honggang Hao ◽  
Sen Zheng ◽  
Yihao Tang ◽  
Xuehong Ran
Keyword(s):  
Beam Polarization ◽  
Dual Function ◽  
Polarization Characteristics

Cuboidal quad-port UWB-MIMO antenna with WLAN rejection using spiral EBG structures

2021 ◽  
pp. 1-8
Author(s):  
Sumon Modak ◽  
Taimoor Khan
Keyword(s):  
Close Agreement ◽  
Ground Plane ◽  
Antenna System ◽  
Ultra Wideband ◽  
Electromagnetic Bandgap ◽  
Mimo Antenna ◽  
Simulated Performance ◽  
Notched Band ◽  
Multiple Input ◽  
Band Characteristic

Abstract This study presents a novel configuration of a cuboidal quad-port ultra-wideband multiple-input and multiple-output antenna with WLAN rejection characteristics. The designed antenna consists of four F-shaped elements backed by a partial ground plane. A 50 Ω microstrip line is used to feed the proposed structure. The geometry of the suggested antenna exhibits an overall size of 23 × 23 × 19 mm3, and the antenna produces an operational bandwidth of 7.6 GHz (3.1–10.7 GHz). The notched band characteristic at 5.4 GHz is accomplished by loading a pair of spiral electromagnetic bandgap structures over the ground plane. Besides this, other diversity features such as envelope correlation coefficient, and diversity gain are also evaluated. Furthermore, the proposed antenna system provides an isolation of −15 dB without using any decoupling structure. Therefore, to validate the reported design, a prototype is fabricated and characterized. The overall simulated performance is observed in very close agreement with it's measured counterpart.

scholarly journals Effect of Antibacterial Root Canal Sealer on Persistent Apical Periodontitis

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 741
Author(s):  
Zheng Wang ◽  
Ge Yang ◽  
Biao Ren ◽  
Yuan Gao ◽  
Xian Peng ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Therapeutic Effect ◽  
Root Canal ◽  
Apical Periodontitis ◽  
Control Group ◽  
Root Canal Sealer ◽  
Root Canal Filling ◽  
First Time ◽  
Cone Beam Computer Tomography ◽  
Better Than

The infection of Enterococcus faecalis and its interacting microorganisms in the root canal could cause persistent apical periodontitis (AP). Antibacterial root canal sealer has favorable prospects to inhibit biofilms. The purpose of this study was to investigated the antibacterial effect of root canal sealer containing dimethylaminododecyl methacrylate (DMADDM) on persistent AP in beagle dogs for the first time. Persistent AP was established by a two-step infection with Enterococcus faecalis and multi-bacteria (Enterococcus faecalis, Lactobacillus acidophilus, Actinomycesnaeslundii, Streptococcus gordonii). Root canal sealer containing DMADDM (0%, 1.25%, 2.5%) was used to complete root canal filling. The volume of lesions and inflammatory grade in the apical area were evaluated by cone beam computer tomography (CBCT) and hematoxylin-eosin staining. Both Enterococcus-faecalis- and multi-bacteria-induced persistent AP caused severe apical destruction, and there were no significant differences in pathogenicity between them. DMADDM-modified sealer significantly reduced the volume of periapical lesion and inflammatory grade compared with the control group, among them, the therapeutic effect of the 2.5% group was better than the 1.25% group. In addition, E.faecalis-induced reinfection was more sensitive to the 2.5% group than multi-bacteria reinfection. This study shows that root canal sealer containing DMADDM had a remarkable therapeutic effect on persistent AP, especially on E. faecalis-induced reinfection.

scholarly journals Realizing UWB Antenna Array with Dual and Wide Rejection Bands Using Metamaterial and Electromagnetic Bandgaps Techniques

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 269
Author(s):  
Ayman A. Althuwayb ◽  
Mohammad Alibakhshikenari ◽  
Bal S. Virdee ◽  
Pancham Shukla ◽  
Ernesto Limiti
Keyword(s):  
Antenna Array ◽  
Ground Plane ◽  
Ultra Wideband ◽  
Dual Band ◽  
Area Network ◽  
Electromagnetic Bandgap ◽  
Uwb Antenna ◽  
Average Gain ◽  
Left Handed ◽  
Notched Band

This research article describes a technique for realizing wideband dual notched functionality in an ultra-wideband (UWB) antenna array based on metamaterial and electromagnetic bandgap (EBG) techniques. For comparison purposes, a reference antenna array was initially designed comprising hexagonal patches that are interconnected to each other. The array was fabricated on standard FR-4 substrate with thickness of 0.8 mm. The reference antenna exhibited an average gain of 1.5 dBi across 5.25–10.1 GHz. To improve the array’s impedance bandwidth for application in UWB systems metamaterial (MTM) characteristics were applied it. This involved embedding hexagonal slots in patch and shorting the patch to the ground-plane with metallic via. This essentially transformed the antenna to a composite right/left-handed structure that behaved like series left-handed capacitance and shunt left-handed inductance. The proposed MTM antenna array now operated over a much wider frequency range (2–12 GHz) with average gain of 5 dBi. Notched band functionality was incorporated in the proposed array to eliminate unwanted interference signals from other wireless communications systems that coexist inside the UWB spectrum. This was achieved by introducing electromagnetic bandgap in the array by etching circular slots on the ground-plane that are aligned underneath each patch and interconnecting microstrip-line in the array. The proposed techniques had no effect on the dimensions of the antenna array (20 mm × 20 mm × 0.87 mm). The results presented confirm dual-band rejection at the wireless local area network (WLAN) band (5.15–5.825 GHz) and X-band satellite downlink communication band (7.10–7.76 GHz). Compared to other dual notched band designs previously published the footprint of the proposed technique is smaller and its rejection notches completely cover the bandwidth of interfering signals.

scholarly journals CPC2 Reduction with Hipparcos and Proper Motions in The Southern Hemisphere

1998 ◽  
Vol 11 (1) ◽  
pp. 551-551
Author(s):  
N. Zacharias ◽  
M.I. Zacharias ◽  
C. de Vegt ◽  
C.A. Murray
Keyword(s):  
Southern Hemisphere ◽  
Systematic Errors ◽  
Reference Star ◽  
Proper Motions ◽  
Positional Accuracy ◽  
Star Catalog ◽  
Naval Observatory ◽  
Celestial Reference System ◽  
First Time ◽  
Better Than

The Second Cape Photographic Catalog (CPC2) contains 276,131 stars covering the entire Southern Hemisphere in a 4-fold overlap pattern. Its mean epoch is 1968, which makes it a key catalog for proper motions. A new reduction of the 5687 plates using on average 40 Hipparcos stars per plate has resulted in a vastly improved catalog with a positional accuracy of about 40 mas (median value) per coordinate, which comes very close to the measuring precision. In particular, for the first time systematic errors depending on magnitude and color can be solved unambiguously and have been removed from the catalog. In combination with the Tycho Catalogue (mean epoch 1991.25) and the upcoming U.S. Naval Observatory CCD Astrograph Catalog (UCAC) project proper motions better than 2 mas/yr can be obtained. This will lead to a vastly improved reference star catalog in the Southern Hemisphere for the final Astrographic Catalogue (AC) reductions, which will then provide propermotions for millions of stars when combined with new epoch data. These data then will allow an uncompromised reduction of the southern Schmidt surveys on the International Celestial Reference System (ICRS).

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