Design Of Antenna Structures Research Articles

Reducing Redundancies in Reconfigurable Antenna Structures Using Graph Models

We present an approach for reducing redundancies in the design of reconfigurable antenna structures using graph models. The basics of graph models, their rules, and how they can be applied in the design of switch-based reconfigurable antennas are introduced. Based on these rules, a methodology is developed and formulated to reduce the number of switches and parts in the antenna structure, without sacrificing the desired antenna functions. This approach not only optimizes the overall structure of the antenna but it also reduces cost and overall losses. Several examples are presented and discussed to demonstrate the validity of this new approach through simulations and measurements that present good agreement.

2328 衛星搭載用アンテナ構造設計のためのFEM数値解の精度比較(機構と設計(2),OS・一般セッション講演)

2328 衛星搭載用アンテナ構造設計のためのFEM数値解の精度比較(機構と設計(2),OS・一般セッション講演)

Triangular Lattice Dielectric EBG Antenna

A novel electromagnetic band-gap (EBG) antenna based on a triangular lattice of dielectric rods is presented and analyzed using an in-house developed finite-difference-time-domain software simulator. The design steps and the simulations results are presented, focusing on the design of antenna structures with high directivity patterns on the H-plane. Finally, the measurement results of a set of experiments carried out on a prototype designed and built to operate in the X-band are presented and discussed, showing very good agreement with simulations: 31% fractional bandwidth and an average gain of 11.5 dBi are achieved within the bandwidth with 27 dB front-to-back-ratio in the azimuthal plane.

ACCELERATED ANTENNA DESIGN METHODOLOGY EXPLOITING PARAMETERIZED CAUCHY MODELS

We propose an optimization methodology suitable for the design of various antenna structures. This methodology includes a rapidly-converging iterative scheme. In each iteration stage, the algorithm generates a parameterized Cauchy model using the available results from previous iterations. Optimization is then applied to this Cauchy model to obtain better design parameters that are also used in enhancing the accuracy of the model. This cycle continues until the speciflcations are met. In addition, this on-the-∞y technique produces an analytical model of the behavior of the antenna structure. Sensitivity and tolerance analysis can thus be e-ciently carried out without the need for further costly electromagnetic simulations.

GREEN'S FUNCTION DERIVATION OF AN ANNULAR WAVEGUIDE FOR APPLICATION IN METHOD OF MOMENT ANALYSIS OF ANNULAR WAVEGUIDE SLOT ANTENNAS

Detailed procedure for Green's function derivation of an annular waveguide is presented in this paper for the first time. The proper components of the electromagnetic fields along with their corresponding Green's functions will be derived in a useful and applicable form. Based on the derived Green's functions, a proper set of integral equations are derived in a novel general form which MoM solution will lead to complete slot field distribution in the annular waveguide slot antenna (AWSA). The proposed theory is found having high value in circuit modelling and array design of such novel antenna structures in the future.

Design of Composite Multilayer Surface Antenna Structure and Its Bending Fatigue Characteristics

The present study aims to design a multilayer microstrip antenna with composite sandwich construction and investigate fatigue behavior of this multilayer SAS (surface antenna structure) that was asymmetric sandwich structure for the next generation of structural surface technology. This term, SAS, indicates that the structural surface becomes an antenna. Constituent materials were selected considering electrical properties, dielectric constant and tangent loss as well as mechanical properties. For the antenna performance, antenna elements inserted into structural layers were designed for satellite communication at a resonant frequency of 12.2 GHz. From electrical measurements, it was shown that antenna performances were in good agreement with design requirements. In cyclic 4-point bending, flexure behavior was investigated by static and fatigue test. Fatigue life curve of the SAS was obtained. The experimental results of bending fatigue were compared with single load level fatigue life prediction equations and in good agreement. The SAS concept is can be extended to give a useful guide for manufacturers of structural body panels as well as antenna designers.

On distorted surface analysis and multidisciplinary structural optimization of large reflector antennas

The large reflector antenna structural design is a typical multidisciplinary design mainly involving structural mechanics and electromagnetics. Deformation of the antenna reflector affects antenna’s electrical characteristics. In this paper, an analysis is made of the variation of antenna’s performances under different employment conditions by applying the response surface method and the Coons divided-fitting method with presentation of the mathematical formula. Furthermore, three types of optimization models of the antenna structure are discussed and the main structural variables influencing electrical performances are analyzed. Finally, an example of multidisciplinary optimization design of an 8-m antenna is explored to illustrate the accuracy of the methods and the potential of application to improve the electrical performances of reflector antennas.

Design of load-bearing antenna structures by embedding technology of microstrip antenna in composite sandwich structure

Electrically and structurally effective antenna structure is developed for the next generation of surface technology for communication, in which the structural surface itself becomes an antenna. The basic design concept is a sandwich structure composed of composite laminates and Nomex honeycomb, with which microstrip antenna is integrated. Composite materials with high electrical loss must not reduce antenna efficiency. Stacked-patch microstrip antenna is preferred for wideband performance. An open condition that defines a position of outer facesheet is exploited in order to allow an antenna into the sandwich structure without loss of antenna performances. Measured electrical performances of fabricated structure show that the gain is more improved than original antenna and the bandwidth is as wide as specified in our requirements. With the open condition, wideband antenna can be integrated with mechanical structures without reducing any electrical performances, as confirmed experimentally here.

Two-element dual-frequency microstrip antenna with high isolation

A compact design of a dual-frequency dual-polarised microstrip antenna structure with highly decoupled input ports is presented. The proposed antenna structure consists of two radiating elements, an annular ring and a circular disk, that are placed concentrically at the same layer. The two radiating elements are fed by an aperture-coupled feed and a coplanar-microstrip-line feed, respectively. Several prototypes of the proposed dual-frequency antennas operated at the frequency ratios ranged from 1.2 to 2.6 were constructed and tested. The experimental results show the input isolation of less than −50 dB is obtained.

Key technologies for high-accuracy large mesh antenna reflectors

Nippon Telephone and Telegram Corporation (NTT) continues to develop the modular mesh-type deployable antenna. Antenna diameter can be changed from 5 m to about 20 m by changing the number of modules used with surface accuracy better than 2.4 mm RMS (including all error factors) with sufficient deployment reliability. Key technologies are the antenna's structural design, the deployment mechanism, the design tool, the analysis tool, and modularized testing/evaluation methods. This paper describes our beam steering mechanism. Tests show that it yields a beam pointing accuracy of better than 0.1°. Based on the S-band modular mesh antenna reflector, the surface accuracy degradation factors that must be considered in designing the new antenna are partially identified. The influence of modular connection errors on surface accuracy is quantitatively estimated. Our analysis tool SPADE is extended to include the addition of joint gaps. The addition of gaps allows non-linear vibration characteristics due to gapping in deployment hinges to be calculated. We intend to design a new type of mesh antenna reflector. Our new goal is an antenna for Ku or Ka band satellite communication. For this mission, the surface shape must be 5 times more accurate than is required for an S-band antenna.

Review of antenna structural design with mechatronics in China

Research on multidisciplinary optimum design of reflector antenna in China is briefly discussed in this paper, such as the integration of mechanical and electronic technologies, the integration with mechanical, electronic, and optic technologies, and so on. In addition, the future development is also discussed.

The Multi-Factor Design Evaluation of Antenna Structures by Parameter Profile Analysis

The design of antenna structures involves complex mechanical and electrical analyses. An evaluation method is proposed by which the results of such analyses can be combined to assess the overall merit of an antenna design. The method considers the antenna at different elevations to represent the range of its working conditions in service. A feature of the method is the use of the proximity of the calculated performance of the antenna with respect to certain parameters compared to the performance that can be reasonably expected for each parameter. An antenna structure is analysed and the results are used in the evaluation method to demonstrate how the method is applied.

A GUIDE-WEIGHT CRITERION METHOD FOR THE OPTIMAL DESIGN OF ANTENNA STRUCTURES

The guide-weight criterion method is an efficient rational criterion method for the optimal design of antenna structures. The algorithm incorporates a set of recursion formulae derived from the Kuhn-Tucker conditions for a conditional extreme value. It has overcome the limitations of previous methods which had to neglect The change of load caused by change of design variables, and both member cross-sectional areas and coordinates of joints are included among the design variables in the new. Method. Compared with the virtual work approach developed by Levy, much better results are obtained in respect of both the rate of convergence and the final value of the objective function.

OPTIMUM DESIGN ON ANTENNA STRUCTURES IN CHINA

This paper describes the development and state of the art of the optimum design of antenna structures. It gives a description of the work done by researchers in the People's Republic of China.

Computer-aided design of antenna structures and components

This paper discusses computer-aided design procedures for antenna reflector structures and related components. The primary design aid is a computer program that establishes cross sectional sizes of the structural members by an optimality criterion. Alternative types of deflection-dependent objectives can be selected for designs subject to constraints on structure weight. The computer program has a special-purpose formulation to design structures of the type frequently used for antenna construction. These structures, in common with many in other areas of application, are represented by analytical models that employ only the three translational degrees of freedom at each node; The special-purpose construction of the program, however, permits coding and data management simplifications that provide advantages in problem size and execution speed. Size and speed are essentially governed by the requirements of structural analysis and are relatively unaffected by the added requirements of design. Computation times to execute several design/analysis cycles are comparable to the times required by generalpurpose programs for a single analysis cycle. Examples in the paper illustrate effective design improvement for structures with several thousand degrees of freedom and within reasonable computing times.