Synthesis of SAR radiation patterns incorporating mutual coupling by using genetic methods

1995 ◽  
Author(s):  
P. James
Keyword(s):  
Mutual Coupling ◽  
Radiation Patterns

scholarly journals Wideband characteristics of density tapered array antennas

2021 ◽  
Vol 11 (2) ◽  
pp. 1356
Author(s):  
Nguyen Thanh Binh ◽  
Nguyen Quoc Dinh ◽  
Yoshihide Yamada
Keyword(s):  
Input Impedance ◽  
Mutual Coupling ◽  
Radiation Patterns ◽  
Coupling Effects ◽  
Grating Lobe ◽  
Array Antennas

In this paper, wideband characteristics of density tapered arrays are clarified by comparing directly the array factors and radiation patterns of 3 tapered arrays structures with array factors and radiation patterns of equally spaced arrays. Calculated results for a density tapered distribution array consisting of 30 elements claims that the array can perform within a bandwidth of 2.5:1 with grating lobe levels lower than -7.8 dB. Additionally, this paper shows a method of determining the effectiveness of unequal spacing arrays in the design of actual antennas. The method is based on calculation and analysis of input impedance of array elements caused by mutual coupling effects among array elements.

scholarly journals Mutual Coupling Reduction between Patch Antennas Using Meander Line

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Qian Li ◽  
Chong Ding ◽  
Ruichao Yang ◽  
Mingtao Tan ◽  
Gangxiong Wu ◽  
...  
Keyword(s):  
Antenna Array ◽  
Microstrip Antenna ◽  
Mutual Coupling ◽  
Ground Plane ◽  
Patch Antennas ◽  
Radiation Patterns ◽  
Simple Method ◽  
Microstrip Patch ◽  
Microstrip Antenna Array ◽  
Meander Line

Meander lines (MLs) in two configurations are presented to reduce the mutual coupling (MC) between two microstrip patch antenna elements. Inserting a slot in the ground plane between the antenna elements is a simple method to reduce the MC, while adding the MLs in the slot of the ground can further reduce the MC. In the first configuration, one ML is inserted in the slot of the ground and a maximum MC reduction of 39 dB throughout the −10 dB bandwidth is achieved. What’s more, the radiation patterns are not changed compared with the dual-element microstrip antenna array with a slotted ground. For the second configuration, two MLs are added in the slot of the ground. It is found that a maximum isolation of 53 dB can be obtained. However, the radiation patterns are slightly changed compared with the dual-element microstrip antenna array with a slot in the ground. Meanwhile, the measured peak gain and efficiency of the dual-element microstrip antenna array in the two configurations are given. Along with this paper, several prototypes have been fabricated and measured. The simulated results are in good accordance with the measurements, which are presented to verify that MC reduction can be achieved between microstrip antenna elements by adding the MLs in the slotted ground.

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.

scholarly journals Decoupled and Descattered Monopole MIMO Antenna Array with Orthogonal Radiation Patterns

2020 ◽  
Author(s):  
Hussain Al-Rizzo ◽  
Ayman A. Isaac ◽  
Sulaiman Z. Tariq ◽  
Samer Yahya
Keyword(s):  
Antenna Array ◽  
Mutual Coupling ◽  
Ground Plane ◽  
Design Concept ◽  
Impedance Bandwidth ◽  
Antenna Element ◽  
Radiation Patterns ◽  
Mimo Antenna ◽  
Single Antenna ◽  
Novel Design

This chapter introduces a novel design concept to reduce mutual coupling among closely-spaced antenna elements of a MIMO array. This design concept significantly reduces the complexity of traditional/existing design approaches such as metamaterials, defected ground plane structures, soft electromagnetic surfaces, parasitic elements, matching and decoupling networks using a simple, yet a novel design alternative. The approach is based on a planar single decoupling element, consisting of a rectangular metallic ring resonator printed on one face of an ungrounded substrate. The decoupling structure surrounds a two-element vertical monopole antenna array fed by a coplanar waveguide structure. The design is shown both by simulations and measurements to reduce the mutual coupling by at least 20 dB, maintain the impedance bandwidth over which S11, is less than −10 dB, and reduce the envelope correlation coefficient to below 0.001. The boresight of the far-field radiation patterns of the two vertical monopole wire antennas operating at 2.4 GHz and separated by 8 mm (λo/16), where λo is the free-space wavelength at 2.45 GHz, is shown to be orthogonal and inclined by 45° with respect to the horizontal (azimuthal) plane while maintaining the shape of the isolated single antenna element.

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays

2011 ◽  
Vol 57 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Mariusz Zamłyński ◽  
Piotr Słobodzian
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Planar Antenna ◽  
Sidelobe Level ◽  
Edge Diffraction ◽  
Narrow Angle ◽  
Compensation Technique ◽  
Diffraction Effects ◽  
Linear Antenna Arrays

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays In this paper the quality of a technique to compensate for mutual coupling (and other phenomena) in small linear antenna arrays is investigated. The technique consists in calculation of a coupling matrix, which is than used to determine corrected antenna array excitation coefficients. Although the technique is known for more than 20 years, there is still very little information about how different phenomena existing in a real antenna arrays influence its performance. In this paper two models of antenna arrays are used. In the first model the effect of mutual coupling is separated from the aperture edge diffraction. In the second model antenna both mutual coupling and aperture edge diffraction effects are included. It is shown that mutual coupling itself can be compensated very well and an ultralow sidelobe level (i.e. -50 dB) could be achieved in practice. In the presence of diffraction effects -46.3 dB sidelobe level has been attained, but radiation pattern can be controled only in narrow angle range (i.e. up to ±60°).

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