scholarly journals Multi-Beam Circular Polarized Reflectarray on Parabolic Reflector by Variable Rotation Technique

2019 ◽  
Vol 9 (13) ◽  
pp. 2659 ◽  
Author(s):  
Somolinos ◽  
Florencio ◽  
González ◽  
Cátedra
Keyword(s):  
High Speed ◽  
Angular Separation ◽  
Personal Communication ◽  
Phase Shifts ◽  
Cross Polarization ◽  
Internet Applications ◽  
Communication Satellite ◽  
Direct Broadcast Satellite ◽  
Focused Beams ◽  
Polarization Level

Multi-beams antennas are currently being used for direct broadcast satellite, personal communication satellite, military communication satellite, and high-speed internet applications. In this work, a circularly polarized (CP) multi-spot beam satellite parabolic reflectarray antenna is designed to provide six spot beams at 19.7 GHz. For this purpose, an easy technique to compute the required phase shifts to produce two focused beams in specular directions for a CP parabolic reflectarray is proposed. These required phase shifts are added to the reflected fields by the variable rotation of the reflectarray elements printed on the surface of a parabolic antenna which are fed by a dual-CP feed-horn. For this purpose, a reflectarray cell made of a conductive cross embedded in a grounded multilayered substrate is optimized to produce very linear phase-shift and low cross-polarization level. To demonstrate the multibeam capacity, a 1.8-meter offset parabolic reflectarray made of the optimized reflectarray element was designed to generate six focused beams in dual-CP with three dual-CP feed-horns. The six main spots fulfill the typical multi spot satellite requirement with angular separation less than 0.56°, 0.4 dB loss in the gain, and cross-polarization level below 35 dB with respect to the maximum of radiation.

scholarly journals Transparent Metasurface for Generating Microwave Vortex Beams with Cross-Polarization Conversion

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2448 ◽  
Author(s):  
Hongyu Shi ◽  
Luyi Wang ◽  
Mengran Zhao ◽  
Juan Chen ◽  
Anxue Zhang ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Phase Distribution ◽  
Polarization Conversion ◽  
Vortex Beam ◽  
Cross Polarization ◽  
Measurement Results ◽  
Vortex Beams ◽  
Simulation Results ◽  
Polarization Level ◽  
Transmission Phase

In this paper, metasurfaces with both cross-polarization conversion and vortex beam-generating are proposed. The proposed finite metasurface designs are able to change the polarization of incident electromagnetic (EM) waves to its cross-polarization. In addition, they also can modulate the incidences into beams carrying orbital angular momentum (OAM) with different orders ( l = + 1 , l = + 2 , l = − 1 and l = − 2 ) by applying corresponding transmission phase distribution schemes on the metasurface aperture. The generated vortex beams are at 5.14 GHz. The transmission loss is lower than 0.5 dB while the co-polarization level is −10 dB compared to the cross-polarization level. The measurement results confirmed the simulation results and verified the properties of the proposed designs.

Compact line source generator for feeding continuous transverse stub arrays

2021 ◽  
pp. 1-12
Author(s):  
Houtong Qiu ◽  
Xue-Xia Yang ◽  
Meiling Li ◽  
Zixuan Yi
Keyword(s):  
Line Source ◽  
Cylindrical Wave ◽  
Center Frequency ◽  
Continuous Beam ◽  
Cross Polarization ◽  
Beam Scanning ◽  
Rotationally Symmetric ◽  
Planar Wave ◽  
Scanning Range ◽  
Polarization Level

Abstract Based on a substrate integrated lens (SIL), a compact line source generator (LSG) for feeding continuous transverse stub (CTS) arrays with linear-polarized (LP) beam scanning and dual-polarized (DP) operations is presented in this paper. The SIL consists of metamaterial cells with different sizes being arranged as concentric annulus and is printed on the center surface of two substrate layers. The SIL can convert the cylindrical wave generated by the feed probe of SIW-horn to the planar wave for feeding the CTS array. This rotationally symmetric SIL can be used conveniently to design LSG for feeding CTS arrays with the continuous beam scanning and DP operations, which has been verified by the fabrications and measurements. By simply rotating the SIW-horn along the edge of SIL, the 10-element LP-CTS array obtains a measured beam scanning range of ±35° with the highest gain of 20.6 dBi. By setting two orthogonal SIW-horns at the edge of the proposed SIL, the nine-element DP-CTS array with orthogonal radiation stubs is excited. The DP array obtains the gain of 20.3 dBi at the center frequency with the isolation of 28 dB and the cross-polarization level <−25 dB.

scholarly journals Low Cross-Polarization Improved-Gain Rectangular Patch Antenna

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1189 ◽  
Author(s):  
Anurag Singh ◽  
Sandip Vijay ◽  
Rudra Narayan Baral
Keyword(s):  
Patch Antenna ◽  
Frequency Selective Surface ◽  
Cross Polarization ◽  
Gain Enhancement ◽  
Rectangular Patch ◽  
Shorting Pin ◽  
Half Power ◽  
Broadside Radiation ◽  
Polarization Level ◽  
Good Agreement

In this paper, a low cross-polarization improved-gain rectangular patch antenna is presented. A patch-ground shorting pin with defected patch structure (DPS) is introduced to suppress the cross-polarization level. A High Reflective Frequency Selective Surface (HRFSS) superstrate is designed and placed over the proposed antenna at an optimized position to intensify the gain. To characterize the unit-cell of the superstrate, its transmission characteristics are extracted and discussed. Integration of the superstrate achieves a beam contraction resulting in a gain enhancement to 10.65 dBi. The proposed antenna has perfect broadside radiation with a cross-polarization level of below −30 dB in the entire half power beamwidth. The prototype of the antenna exhibits good agreement between experimental and simulated results.

Adaptive Transmission of Multimedia Data over UMTS

2007 ◽  
pp. 20-24
Author(s):  
A. Alexiou
Keyword(s):  
High Speed ◽  
Limited Resource ◽  
Mobile User ◽  
Wireless Channel ◽  
Multimedia Data ◽  
The Internet ◽  
Wireless Data ◽  
Multimedia Services ◽  
Internet Applications ◽  
Universal Mobile Telecommunications System

As communications technology is being developed, users’ demand for multimedia services raises. Meanwhile, the Internet has enjoyed tremendous growth in recent years. Consequently, there is a great interest in using the IP-based networks to provide multimedia services. One of the most important areas in which the issues are being debated is the development of standards for the universal mobile telecommunications system (UMTS). UMTS constitutes the third generation of cellular wireless networks which aims to provide high-speed data access along with real-time voice calls. Wireless data is one of the major boosters of wireless communications and one of the main motivations of the next-generation standards. Bandwidth is a valuable and limited resource for UMTS and every wireless network in general. Therefore, it is of extreme importance to exploit this resource in the most efficient way. Consequently, when a user experiences a streaming video, there should be enough bandwidth available at any time for any other application that the mobile user might need. In addition, when two different applications run together, the network should guarantee that there is no possibility for any of the above-mentioned applications to prevail against the other by taking all the available channel bandwidth. Since Internet applications adopt mainly TCP as the transport protocol, while streaming applications mainly use RTP, the network should guarantee that RTP does not prevail against the TCP traffic. This means that there should be enough bandwidth available in the wireless channel for the Internet applications to run properly.

scholarly journals A High-Isolation Dual-Polarization Substrate-Integrated Fabry-Pérot Cavity Antenna

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Chang Chen ◽  
Bo-Liang Liu ◽  
Ling Ji ◽  
Wei-Dong Chen
Keyword(s):  
Near Field ◽  
Ground Plane ◽  
Cross Polarization ◽  
Dual Polarization ◽  
High Isolation ◽  
Fabry Perot ◽  
Feeding Structure ◽  
Operating Bandwidth ◽  
High Degree ◽  
Polarization Level

A dual-polarization substrate-integrated Fabry-Pérot cavity (SI-FPC) antenna is presented in this paper. The patch embedded in SI-FPC is excited with a near-field coupled feeding structure for V-polarization and with a slot-coupled feeding structure for H-polarization. The feeding structures are separated by a ground plane to improve the isolation between the ports. As a design example, an antenna operating at 10.0 GHz is fabricated and measured. A high degree of port isolation (<−40 dB) over the whole operating bandwidth (9.5–10.2 GHz) and good cross-polarization level (>25 dB) can be achieved.

scholarly journals Suppression of Cross-Polarization of the Microstrip Integrated Balun-Fed Printed Dipole Antenna

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Huang Jingjian ◽  
Zhang Xiaofa ◽  
Xie Shaoyi ◽  
Wu Weiwei ◽  
Yuan Naichang
Keyword(s):  
Frequency Band ◽  
Dipole Antenna ◽  
Equivalent Model ◽  
Substrate Thickness ◽  
Cross Polarization ◽  
Engineering Applications ◽  
Novel Structure ◽  
The Cross ◽  
Polarization Level

The high cross-polarization of the microstrip integrated balun-fed printed dipole antenna cannot meet the demands of many engineering applications. This kind of antennas has high cross-polarization levels (about −20 dB). And we find that the high cross-polarization radiation is mainly produced by the microstrip integrated balun rather than the dipole itself. The very limited method to lower the cross-polarization level of this kind of antennas is to reduce the substrate thickness. In this paper, to improve the low cross-polarized performance, firstly, an equivalent model is presented to analyze the cross-polarization radiation. Secondly, a novel structure with low cross-polarization is proposed. The microstrip integrated balun is enclosed by a center slotted cavity. The E-field of the microstrip integrated balun is transformed parallel to the dipole arms by the slot, so the radiation of the cross-polarized component is suppressed. Measured results show that this structure can achieve a bandwidth wider than 40% while reducing the cross-polarization level to less than −35 dB within the frequency band.

Modulated sequences for cross polarization during high-speed MAS

1992 ◽  
Vol 99 (2) ◽  
pp. 439-442 ◽  
Author(s):  
Thomas M. Barbara ◽  
Evan H. Williams
Keyword(s):  
High Speed ◽  
Cross Polarization

scholarly journals Cross-polarization level in radiation from a microstrip dipole antenna

1988 ◽  
Vol 36 (9) ◽  
pp. 1197-1203 ◽  
Author(s):  
A. Hoorfar ◽  
K.C. Gupta ◽  
D.C. Chang
Keyword(s):  
Dipole Antenna ◽  
Cross Polarization ◽  
Polarization Level

Omnidirectional multi-band stacked microstrip patch antenna with wide impedance bandwidth and suppressed cross-polarization

2016 ◽  
Vol 9 (3) ◽  
pp. 629-638 ◽  
Author(s):  
Jaishanker Prasad Keshari ◽  
Binod Kumar Kanaujia ◽  
Mukesh Kumar Khandelwal ◽  
Pritam Singh Bakariya ◽  
Ram Mohan Mehra
Keyword(s):  
Ground Plane ◽  
Impedance Bandwidth ◽  
Triple Resonance ◽  
Patch Antennas ◽  
Cross Polarization ◽  
Microstrip Patch Antennas ◽  
Microstrip Patch ◽  
Resonance Frequencies ◽  
Polarization Level ◽  
Triple Band

In this paper, triple-band stacked microstrip patch antennas (MPAs) are presented with wide impedance bandwidth and suppressed cross-polarization level. Triangular and circular shaped slots are embedded in the patch of antenna. Slot-loaded microstrip patches are fed with meandered microstrip line supported by a semi-ground plane structure. Triangular shaped slot-loaded MPA shows triple resonance at frequencies 2.2, 4.45, and 5.3 GHz having bandwidth of 45.9, 19.23, and 15.67%, respectively. Circular shaped slot-loaded MPA also shows triple resonance at frequencies 2.2, 4.42, and 5.38 GHz having bandwidth of 50.24, 33.21, and 13.43%, respectively. Using circular slot in place of triangular; bandwidth of the first and the second band is improved by 4.34 and 13.98%, respectively. Both the proposed antennas show an omnidirectional radiation pattern at all three resonance frequencies in the xz-plane with almost 0 dBi gain. Both the proposed antennas are fabricated on a FR-4 epoxy substrate and show a minimum level of cross-polarization radiations.

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