scholarly journals Special beamforming by means of a semi-spherical Lüneburg lens

2021 ◽  
pp. 28-34
Author(s):  
D. V. Denisov ◽  
A. A. Tangamyan
Keyword(s):  
Dielectric Substrate ◽  
Side Lobe ◽  
Substrate Thickness ◽  
Radiation Patterns ◽  
Antenna Feed ◽  
Feed Angle ◽  
Luneburg Lens

The paper considers a semi-spherical Lüneburg lens with a conductive shield. In certain conditions a lens of such design may form radiation patterns without the side lobe or cosecant-type patterns. Such radiation patterns can be formed by controlling the following parameters: antenna feed angle, conductive shield diameter, dielectric substrate thickness. The paper focuses on particular cases of obtaining special-type radiation patterns.

Far-field patterns of line sources mounted between four-dielectric substrates

1992 ◽  
Vol 70 (2-3) ◽  
pp. 173-178 ◽  
Author(s):  
Ioanna Diamandi ◽  
Costas Mertzianidis ◽  
John N. Sahalos
Keyword(s):  
Remote Sensing ◽  
Line Source ◽  
Dielectric Substrate ◽  
Microstrip Antennas ◽  
Field Pattern ◽  
Substrate Thickness ◽  
Far Field ◽  
Dielectric Substrates ◽  
Field Patterns ◽  
Far Field Pattern

The far-field pattern characteristics of line sources lying between the slabs of a four-dielectric substrate configuration are presented. The patterns are calculated for several cases of the substrate thickness as well as for several line-source locations. The considerations that are made give useful applications in remote sensing and microstrip antennas.

Design and performance of a microstrip reflectarray on a uniaxial substrate

2002 ◽  
Vol 80 (1) ◽  
pp. 7-17 ◽  
Author(s):  
A Iliadis ◽  
K Siakavara
Keyword(s):  
Electromagnetic Field ◽  
Green's Function ◽  
Method Of Moments ◽  
Dielectric Substrate ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Dual Polarization ◽  
Full Wave ◽  
Wave Technique ◽  
And Performance

A design formulation of microstrip reflectarrays is presented in this paper. Previous published articles, referring to this subject, present results for reflectarrays on a uniform dielectric substrate. In this work microstrip reflectarrays with offset feed, dual polarization, and side-lobe level under control, fabricated on a uniaxial substrate were studied. The method of moments, combined with the full-wave technique, and the corresponding dyadic Green's function is used for the specification of the electromagnetic field scattered by the array. PACS No.: 84.40B

IMPROVEMENT OF DIPOLE ANTENNA GAIN USING 8 CBU AMC-EBG AND 8 CBU FSS

2017 ◽  
Vol 79 (4) ◽  
Author(s):  
Maisarah Abu ◽  
Siti Adlina Md Ali ◽  
Siti Normi Zabri
Keyword(s):  
Transport System ◽  
Ground Plane ◽  
Side Lobe ◽  
High Gain ◽  
Dipole Antenna ◽  
Intelligent Transport System ◽  
Antenna Gain ◽  
Radiation Patterns ◽  
Intelligent Transport

This paper investigates the performances of dipole antenna incorporated with and without 8 CBU AMC-EBG and 8 CBU FSS at 5.8 GHz. The designs are simulated on Rogers RO 3010. Due to the flexibility of the material used as a substrate, the effect of a different angle is investigated. Both 8 CBU AMC-EBG and 8 CBU FSS act as reasonably good ground plane for the dipole antenna and help improving the realised gain and improve the radiation patterns by push the front lobe at the same time reduce the side lobes. The maximum improvements led by dipole antenna with 8 CBU AMC-EBG thus 8.543 dB of realised gain achieved and the front lobe is pushed higher and the side lobe is significantly lowered than with 8 CBU FSS. The designs of dipole antenna with 8 CBU AMC-EBG and 8 CBU FSS can be applied as high gain  atenna for Intelligent Transport System (ITS).

A printed wide-beamwidth circularly polarized antenna via two pairs of radiating slots placed in a square contour

2016 ◽  
Vol 9 (3) ◽  
pp. 649-656 ◽  
Author(s):  
Neng-Wu Liu ◽  
Lei Zhu ◽  
Wai-Wa Choi
Keyword(s):  
Ground Plane ◽  
Large Angle ◽  
Axial Ratio ◽  
Dielectric Substrate ◽  
Slot Antenna ◽  
Radiation Patterns ◽  
Circularly Polarized ◽  
Low Profile ◽  
Orthogonal Pairs ◽  
Good Agreement

A low-profile circularly polarized (CP) slot antenna to achieve a wide axial-ratio (AR) beamwidth is proposed in this paper. The radiating patch consists of two orthogonal pairs of parallel slots etched symmetrically onto a ground plane. Firstly, our theoretical study demonstrates that the CP radiation can be satisfactorily achieved at the broadside, when the vertical and horizontal paired-slots are excited in the same amplitude with 90° phase difference. Secondly, the principle of CP radiation of the proposed antenna on an infinite ground plane is described. Through analyzing the spacing between two parallel slots, the |Eθ| and |Eφ| radiation patterns can be made approximately identical with each other over a large angle range. As such, the slot antenna achieves a wide AR beamwidth. After that, the 3 dB AR beamwidth with respect to the size of a finite ground plane is investigated to constitute a practical CP antenna on a finite ground plane. In final, the proposed CP antenna with a 1–4 probe-to-microstrip feeding network is designed and fabricated on a finite ground plane of a dielectric substrate. Measured results are shown to be in good agreement with the simulated ones about the gain, reflection coefficient, AR bandwidth, and radiation patterns. Most importantly, a wide 3 dB AR beamwidth of 126° and low-profile property with the height of 0.036λ0 are achieved.

scholarly journals Low-Cost Dielectric Substrate for Designing Low Profile Multiband Monopole Microstrip Antenna

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Ahsan ◽  
M. T. Islam ◽  
M. Habib Ullah ◽  
H. Arshad ◽  
M. F. Mansor
Keyword(s):  
Microstrip Antenna ◽  
Dielectric Material ◽  
Low Cost ◽  
Cost Effective ◽  
Dielectric Substrate ◽  
The Finite Element Method ◽  
Radiation Patterns ◽  
Polymer Resin ◽  
Full Wave ◽  
Low Profile

This paper proposes a small sized, low-cost multiband monopole antenna which can cover the WiMAX bands and C-band. The proposed antenna of 20 × 20 mm2radiating patch is printed on cost effective 1.6 mm thick fiberglass polymer resin dielectric material substrate and fed by 4 mm long microstrip line. The finite element method based, full wave electromagnetic simulator HFSS is efficiently utilized for designing and analyzing the proposed antenna and the antenna parameters are measured in a standard far-field anechoic chamber. The experimental results show that the prototype of the antenna has achieved operating bandwidths (voltage stand wave ratio (VSWR) less than 2) 360 MHz (2.53–2.89 GHz) and 440 MHz (3.47–3.91 GHz) for WiMAX and 1550 MHz (6.28–7.83 GHz) for C-band. The simulated and measured results for VSWR, radiation patterns, and gain are well matched. Nearly omnidirectional radiation patterns are achieved and the peak gains are of 3.62 dBi, 3.67 dBi, and 5.7 dBi at 2.66 GHz, 3.65 GHz, and 6.58 GHz, respectively.

scholarly journals Radiation-Scattering–Integrated Design of Multi-Functional Metasurfaces Based on Antenna-Embedded Substrates

2022 ◽  
Vol 8 ◽  
Author(s):  
Xinmin Fu ◽  
Ya Fan ◽  
Yajuan Han ◽  
Jiafu Wang ◽  
Zhuangzhuang Wang ◽  
...  
Keyword(s):  
Antenna Array ◽  
High Efficiency ◽  
Design Method ◽  
Structural Parameters ◽  
Ground Plane ◽  
Integrated Design ◽  
Frequency Selective Surface ◽  
Dielectric Substrate ◽  
Substrate Thickness ◽  
Radiation Scattering

The integration of the metasurface and antenna has brought new vitality to function integration and performance improvement for metasurfaces. In this study, we propose a radiation-scattering–integrated (RSI) design method of functional metasurfaces by incorporating antenna radiators into the substrates. The antenna radiators can also be considered as a band-stop frequency selective surface (FSS) embedded within the dielectric substrate, which adds up to the degree of freedom (DOF) in tailoring electromagnetic (EM) properties of the substrate. In this way, not only radiation function is added to the metasurfaces but also the original scattering-manipulation function is augmented. As an example, we apply this method to the design of a metasurface that can achieve a high radiation gain in-band and low-RCS out-of-band simultaneously. An antenna array was first designed, which uses circular patches as the radiators. Then, the antenna array was used as the substrate of a typical polarization conversion (PC) metasurface. The circular patch lies between the ground plane and the PC meta-atom, providing optimal electrical substrate thickness for PC at two separate bands. By adjusting structural parameters, the operating band of the antenna array can be made to lie in between the two PC bands. In this way, the metasurface can simultaneously possess high-gain radiation function in-band and high-efficiency PC function for RCS reduction out-of-band. A prototype was fabricated and measured. Both the simulated and measured results show that the metasurface can achieve satisfactory radiation gain in-band and significant RCS reduction out of band. This work provides an alternative method of designing multi-functional metasurfaces, which may find applications in smart skins and others.

scholarly journals Enhanced radiation characteristics for antipodal Vivaldi antenna using high permittivity dielectric director

2017 ◽  
Vol 07 (03) ◽  
pp. 1750018 ◽  
Author(s):  
Rabiaa Herzi ◽  
Moufida Bouslama ◽  
Ali Gharsallah
Keyword(s):  
Antenna Array ◽  
Frequency Band ◽  
Mutual Coupling ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Radiation Patterns ◽  
Antenna Aperture ◽  
Radiation Characteristics ◽  
High Permittivity ◽  
Vivaldi Antenna

In this paper, we investigate the influence of higher permittivity dielectric director on the radiation performances of an antipodal Vivaldi antenna. An elliptical dielectric director with high permittivity is inserted in an antipodal Vivaldi antenna aperture in order to ameliorate the radiation characteristics of the antenna. Due to the capacity of elevated permittivity dielectric to confine and guide energy in the desired direction, an increment of 4[Formula: see text]dB in the gain of the antenna is obtained. This antenna, which covers an ultra-wide frequency band of 146.8% from 2.3[Formula: see text]GHz to 15[Formula: see text]GHz, has approximately regular radiation patterns with reduced side lobe level and narrower beamwidth. In the interest to achieve radar application necessities, the proposed antenna is exploited to develop an antenna array which consists of four connected elements. Adding dielectric directors can significantly enhance the radiations characteristics of the antenna and reduce the mutual coupling inter-elements. So using four elements with dielectric director in the antenna array can achieve the same results obtained with eight elements without directors. This can decrease the used number of elements that form the antenna array.

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