3D Power Synthesis with Reduction of Near-Field and Dynamic Range Ratio for Conformal Antenna Arrays

2011 ◽  
Vol 59 (4) ◽  
pp. 1164-1174 ◽  
Author(s):  
Massimiliano Comisso ◽  
Roberto Vescovo
Keyword(s):  
Antenna Arrays ◽  
Dynamic Range ◽  
Near Field ◽  
Conformal Antenna

scholarly journals Reconfigurable Antenna Arrays with Multiple Requirements: A Versatile 3D Approach

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Massimiliano Comisso ◽  
Giulia Buttazzoni ◽  
Roberto Vescovo
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Dynamic Range ◽  
Near Field ◽  
Field Pattern ◽  
Deterministic Method ◽  
Iterative Minimization ◽  
Array Structures ◽  
Far Field Pattern ◽  
Ratio Reduction

This paper proposes a deterministic method for the 3D synthesis of antenna arrays that jointly accounts for far-field pattern reconfigurability, polarization setting, dynamic range ratio reduction, and near-field control. The conceived algorithm, which generalizes some existing solutions, relies on a weighted cost function, whose iterative minimization is accomplished by properly derived closed-form expressions. This feature, combined with the possibility of selecting the weighting parameters, provides a fast and versatile approach, whose capabilities are numerically checked by considering different synthesis problems and array structures in the presence of mutual coupling.

scholarly journals Fast 3D Pattern Synthesis with Polarization and Dynamic Range Ratio Control for Conformal Antenna Arrays

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Massimiliano Comisso ◽  
Roberto Vescovo
Keyword(s):  
Antenna Arrays ◽  
Dynamic Range ◽  
Polarization State ◽  
Field Pattern ◽  
Pattern Synthesis ◽  
Conformal Antenna ◽  
Cpu Time ◽  
Conformal Arrays ◽  
Far Field Pattern ◽  
Joint Pattern

This paper proposes an iterative algorithm for the 3D synthesis of the electric far-field pattern of a conformal antenna array in the presence of requirements on both the polarization and the dynamic range ratio (DRR) of the excitations. Thanks to the use of selectable weights, the algorithm allows a versatile control of the DRR and of the polarization in a given angular region and requires a low CPU time to provide the array excitations. Furthermore, a modified version of the algorithm is developed to enable the optimization of the polarization state by phase-only control. Numerical results are presented to verify the usefulness of the proposed approach for the joint pattern and polarization synthesis of conformal arrays with reduced or even unitary DRR.

The mechanical basis of Drosophila audition

2002 ◽  
Vol 205 (9) ◽  
pp. 1199-1208 ◽  
Author(s):  
Martin C. Göpfert ◽  
Daniel Robert
Keyword(s):  
Mechanical Response ◽  
Dynamic Range ◽  
Near Field ◽  
Sense Organ ◽  
Field Measurements ◽  
Longitudinal Axis ◽  
Acoustic Energy ◽  
Linear Effect ◽  
Response Characteristics ◽  
Non Linear

SUMMARY In Drosophila melanogaster, antennal hearing organs mediate the detection of conspecific songs. Combining laser Doppler vibrometry, acoustic near-field measurements and anatomical analysis, we have investigated the first steps in Drosophila audition, i.e. the conversion of acoustic energy into mechanical vibrations and the subsequent transmission of vibrations to the auditory receptors in the base of the antenna. Examination of the mechanical responses of the antennal structures established that the distal antennal parts (the funiculus and the arista) together constitute a mechanical entity, the sound receiver. Unconventionally, this receiver is asymmetric, resulting in an unusual, rotatory pattern of vibration; in the presence of sound, the arista and the funiculus together rotate about the longitudinal axis of the latter. According to the mechanical response characteristics, the antennal receiver represents a moderately damped simple harmonic oscillator. The receiver's resonance frequency increases continuously with the stimulus intensity, demonstrating the presence of a non-linear stiffness that may be introduced by the auditory sense organ. This surprising,non-linear effect is relevant for close-range acoustic communication in Drosophila; by improving antennal sensitivity at low song intensities and reducing sensitivity when intensity is high, it brings about dynamic range compression in the fly's auditory system.

Evolution of conformal antenna design with the aid of probability improved crow search algorithm

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nama Ajay Nagendra ◽  
Lakshman Pappula
Keyword(s):  
Antenna Arrays ◽  
Search Algorithm ◽  
Fundamental Problem ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Antenna Element ◽  
Content Type ◽  
Conformal Antenna ◽  
Adopted Model ◽  
Better Than

PurposeThe issues of radiating sources in the existence of smooth convex matters by such objects are of huge significance in the modeling of antennas on structures. Conformal antenna arrays are necessary when an antenna has to match to certain platforms. A fundamental problem in the design is that the possible surfaces for a conformal antenna are infinite in number. Furthermore, if there is no symmetry, each element will see a different environment, and this complicates the mathematics. As a consequence, the element factor cannot be factored out from the array factor.Design/methodology/approachThis paper intends to enhance the design of the conformal antenna. Here, the main objective of this task is to maximize the antenna gain and directivity from the first-side lobe and other side-lobes in the two way radiation pattern. Thus the adopted model is designed as a multiobjective concern. In order to attain this multiobjective function, both the element spacing and the radius of each antenna element should be optimized based on the probability of the Crow Search Algorithm (CSA). Thus the proposed method is named Probability Improved CSA (PI-CSA). Here, the First Null Beam Width (FNBW) and Side-Lobe Level (SLL) are minimized. Moreover, the adopted scheme is compared with conventional algorithms, and the results are attained.FindingsFrom the analysis, the gain of the presented PI-CSA scheme in terms of best performance was 52.68% superior to ABC, 25.11% superior to PSO, 13.38% superior to FF and 3.21% superior to CS algorithms. Moreover, the mean performance of the adopted model was 62.94% better than ABC, 13.06% better than PSO, 24.34% better than FF and 10.05% better than CS algorithms. By maximizing the gain and directivity, FNBW and SLL were decreased. Thus, the optimal design of the conformal antenna has been attained by the proposed PI-CSA algorithm in an effective way.Originality/valueThis paper presents a technique for enhancing the design of the conformal antenna using the PI-CSA algorithm. This is the first work that utilizes PI-CSA-based optimization for improving the design of the conformal antenna.

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