scholarly journals Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
L. Zhao ◽  
B. W. Bai ◽  
W. M. Bao ◽  
X. P. Li
Keyword(s):  
Patch Antenna ◽  
Polarization Characteristic ◽  
Polarization Property ◽  
Plasma Sheath ◽  
Integration Technique ◽  
Circularly Polarized ◽  
Reentry Vehicle ◽  
Mismatch Loss ◽  
Antenna Polarization ◽  
Gps Antenna

A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP) patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process.

scholarly journals Effects of Reentry Plasma Sheath on Mutual-Coupling Property of Array Antenna

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
B. W. Bai ◽  
X. P. Li ◽  
Y. M. Liu ◽  
J. Xu
Keyword(s):  
Mutual Coupling ◽  
Collision Frequency ◽  
Plasma Sheath ◽  
Array Antenna ◽  
Coupling Coefficients ◽  
Integration Technique ◽  
Reentry Vehicle ◽  
Coupling Property ◽  
Single Antenna ◽  
Array Antennas

A plasma sheath enveloping a reentry vehicle would cause the failure of on-board antennas, which is an important effect that contributes to the “blackout” problem. The method of replacing the on-board single antenna with the array antennas and using beamforming technology has been proposed to mitigate “blackout” problem by many other researchers. Because the plasma sheath is a reflective medium, plasma will alter the mutual coupling between array elements and degrade the beamforming performance of array antenna. In this paper, the effects of the plasma sheath on the mutual coupling properties between adjacent array elements are studied utilizing the algorithm of finite integration technique. Results show that mutual coupling coefficients of array elements are deteriorating more seriously with the decrease of collision frequency. Moreover, when electron density and collision frequency are both large, plasma sheath improves the mutual coupling property of array elements; this conclusion suggests that replacing the on-board single antenna with the array antennas and using beamforming technology can be adopted to mitigate the blackout problem in this condition.

scholarly journals Circularly Polarized Dual-Band LoRa/GPS Antenna for a UAV-Assisted Hazardous Gas and Aerosol Sensor

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 377
Author(s):  
Fermín Mira ◽  
Xavier Artiga ◽  
Ignacio Llamas-Garro ◽  
Francisco Vázquez-Gallego ◽  
Jesús Salvador Velázquez-González
Keyword(s):  
Data Transfer ◽  
Sensor Nodes ◽  
Dual Band ◽  
Sensor Reading ◽  
Circularly Polarized ◽  
Relative Placement ◽  
Low Profile ◽  
Gain Reduction ◽  
Antenna Polarization ◽  
Gps Antenna

UAV assisted wireless sensor networks play a key role in the detection of toxic gases and aerosols. UAVs can be used to remotely deploy sensor nodes and then collect gas concentration readings and GPS positioning from them to delimit an affected area. For such purpose, a dual-band communication system is required, supporting GPS reception, and sensor reading data transfer, which is chosen to be at 2.4 GHz using LoRa physical layer. In this work we propose a switched-beam antenna subsystem for the sensor nodes capable not only of satisfying the dual band requirements but also of maximizing communication range or energy consumption through a good antenna polarization match and improved antenna gain. This antenna subsystem is built using dual-port, dual-band, circularly polarized antenna elements, whose design and experimental validation is carefully detailed. A low profile microstrip stacked structure has been used to obtain return loss in both bands better than 15 dB, axial ratios below 1.5 dB, and wide −3 dB beamwidths around 90° and 75° for GPS and 2.4 GHz bands, respectively, thus limiting the gain reduction of the switched-beam system in critical sensor orientations. Special attention has been paid to reduce the coupling between both ports through the optimization of the relative placement of both patches and their feeding points. The measured coupling is below −30 dB.

A Broadband Circularly Polarized Cross-slotted Patch Antenna with Horizontal Meandered Strip (HMS)

Frequenz ◽  
2020 ◽  
Vol 74 (5-6) ◽  
pp. 191-199
Author(s):  
M. K. Verma ◽  
Binod K. Kanaujia ◽  
J. P. Saini ◽  
Padam S. Saini
Keyword(s):  
Circular Polarization ◽  
Patch Antenna ◽  
Impedance Matching ◽  
Axial Ratio ◽  
Impedance Bandwidth ◽  
Radiation Patterns ◽  
Circularly Polarized ◽  
Feeding Technique

AbstractA broadband circularly polarized slotted square patch antenna with horizontal meandered strip (HMS) is presented and studied. The HMS feeding technique provides the good impedance matching and broadside symmetrical radiation patterns. A set of cross asymmetrical slots are etched on the radiating patch to realize the circular polarization. An electrically small stub is added on the edge of the antenna for further improvement in performance. Measured 10-dB impedance bandwidth (IBW) and 3-dB axial ratio bandwidth (ARBW) of the proposed antenna are 32.31 % (3.14–4.35 GHz) and 20.91 % (3.34–4.12 GHz), respectively. The gain of the antenna is varied from 3.5 to 4.86dBi within 3-dB ARBW. Measured results matched well with the simulated results.

A low‐profile circularly polarized dielectric patch antenna with bandwidth expansion

2021 ◽  
Author(s):  
Jian‐Xin Chen ◽  
Xue‐Ying Wang ◽  
Ye‐Xin Huang ◽  
Ling‐Ling Yang ◽  
Shi‐Chang Tang
Keyword(s):  
Patch Antenna ◽  
Circularly Polarized ◽  
Low Profile ◽  
Bandwidth Expansion
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