A Wideband Circularly Polarized Omnidirectional Antenna Based on Excitation of Two Orthogonal Circular TE21 Modes

2017 ◽  
Vol 65 (8) ◽  
pp. 3877-3888 ◽  
Author(s):  
Behzad Yektakhah ◽  
Kamal Sarabandi
Keyword(s):  
Circularly Polarized ◽  
Omnidirectional Antenna

A Dual Circularly Polarized Omnidirectional Antenna for Radar-Warning Receiver

2021 ◽  
Author(s):  
Ahmed Alieldin ◽  
Ahmed F. El-Agamy ◽  
Mohamed Mowafy ◽  
Abdelrahman M. El-Akhdar
Keyword(s):  
Circularly Polarized ◽  
Omnidirectional Antenna

scholarly journals Circularly Polarized Omnidirectional Antenna with Dipole Core and Diagonally Adjoined Parasitic Braces for ISM Band Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Piyapong Dangkham ◽  
Sitthichai Dentri ◽  
Chuwong Phongcharoenpanich ◽  
Prayoot Akkaraekthalin
Keyword(s):  
Circular Polarization ◽  
Dipole Antenna ◽  
Experimental Results ◽  
Antenna Gain ◽  
Circularly Polarized ◽  
Ism Band ◽  
Omnidirectional Antenna ◽  
Quarter Wave ◽  
Radio Band ◽  
Good Agreement

This research proposes a circularly polarized (CP) single-fed omnidirectional dipole antenna operable in 2.45 GHz frequency for the industrial, scientific, and medical (ISM) radio band applications. The proposed antenna consisted of bisectional dipole core, a pair of quarter-wave baluns, and four diagonally adjoined parasitic braces. The bisectional dipole core was utilized to improve the antenna gain and realize omnidirectional radiation pattern, and the quarter-wave baluns were to symmetrize the current on the bisectional core. The four parasitic braces collectively generated circular polarization. In the study, simulations were conducted using CST Microwave Studio and a prototype antenna fabricated. To validate, experiments were carried out, and simulation and experimental results compared. The finding revealed good agreement between the simulation and experimental results. Essentially, in addition to achieving an antenna gain of 2.07 dBic, the proposed CP single-fed omnidirectional antenna is suited to ISM frequency band applications.

scholarly journals Dual Circularly Polarized Omnidirectional Antenna with Slot Array on Coaxial Cylinder

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Bin Zhou ◽  
Junping Geng ◽  
Zhe Li ◽  
Wenzhi Wang ◽  
Xianling Liang ◽  
...  
Keyword(s):  
Return Loss ◽  
Axial Ratio ◽  
Coaxial Cylinder ◽  
Circularly Polarized ◽  
Left Hand ◽  
Omnidirectional Antenna ◽  
Right Hand ◽  
Two Sides

A dual circularly polarized (CP) omnidirectional antenna based on slot array in coaxial cylinder structure is presented in this paper. It is constructed by perpendicular slot pairs around and along the axis of the coaxial cylinder to realize the omnidirectional CP property, and two ports are assigned in its two sides as left hand circularly polarized (LHCP) port and right hand circularly polarized (RHCP) port, respectively. The proposed antenna achieves a bandwidth of 16.4% ranging from 5.05 to 5.95 GHz with an isolation higher than 15 dB between the two CP ports, and the return loss (RL) is higher than 10 dB within the bandwidth in both of the two ports. From the measured results, the average axial ratio (AR) of the proposed antenna in omnidirectional plane is lower than 1.5 dB.

scholarly journals Implementation Method for Circularly Polarized Omnidirectional Antenna

2019 ◽  
Vol 154 ◽  
pp. 477-480 ◽  
Author(s):  
Hui Yong Zeng ◽  
Jian An ◽  
Zhong Wu Yu ◽  
Shi Qiang Wang
Keyword(s):  
Circularly Polarized ◽  
Omnidirectional Antenna ◽  
Implementation Method

scholarly journals A Dual-Band Dual-Polarized Omnidirectional Antenna

2020 ◽  
Vol 8 ◽  
Author(s):  
Hui Gu ◽  
Lei Ge ◽  
Jihong Zhang
Keyword(s):  
Axial Ratio ◽  
Dual Band ◽  
Impedance Bandwidth ◽  
Circularly Polarized ◽  
Circular Patch ◽  
Omnidirectional Antenna ◽  
Circularly Polarized Radiation ◽  
Dual Polarized ◽  
High Band ◽  
Polarized Radiation

A dual-band dual-polarized omnidirectional antenna is investigated. The two bands are generated by a lower circular patch and an upper circular patch, respectively. A set of conductive vias and a coupled ring are utilized to widen the antenna bandwidth. Curved branches are introduced to contribute to circularly polarized radiation. A prototype was designed, fabricated and measured to demonstrate the performance of the antenna. Measured results show that an overlapped bandwidth of 15% from 2.22 to 2.58 GHz for both S11 ≤ −10 dB and axial ratio ≤3 dB is obtained in the low band, and an impedance bandwidth of 11.1% from 5.63 to 6.29 GHz is achieved in the high band. Measured peak gains are approximately 4.3 dBic and 5.4 dBi at two bands. Moreover, omnidirectional radiation patterns are also obtained within the operating band.

Differential polarization imaging of sickled cells

1988 ◽  
Vol 46 ◽  
pp. 62-63
Author(s):  
Marcos F. Maestre
Keyword(s):  
Optical Properties ◽  
Theoretical Approach ◽  
Polarized Light ◽  
Polarization Microscopy ◽  
Spectroscopic Techniques ◽  
Polarization Imaging ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Microscopic Scale ◽  
Chiral Structures

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.

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