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The Theory of Characteristic Modes Revisited: A Contribution to the Design of Antennas for Modern Applications

Univ. Politecnica de Valencia, Valencia
IEEE Antennas and Propagation Magazine (Impact Factor: 1.15). 11/2007; 49(5):52 - 68. DOI: 10.1109/MAP.2007.4395295
Source: IEEE Xplore

ABSTRACT The objective of this paper is to summarize the work that has been developed by the authors for the last several years, in order to demonstrate that the Theory of Characteristic Modes can be used to perform a systematic design of different types of antennas. Characteristic modes are real current modes that can be computed numerically for conducting bodies of arbitrary shape. Since characteristic modes form a set of orthogonal functions, they can be used to expand the total current on the surface of the body. However, this paper shows that what makes characteristic modes really attractive for antenna design is the physical insight they bring into the radiating phenomena taking place in the antenna. The resonance frequency of modes, as well as their radiating behavior, can be determined from the information provided by the eigenvalues associated with the characteristic modes. Moreover, by studying the current distribution of modes, an optimum feeding arrangement can be found in order to obtain the desired radiating behavior.

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    • "La naturaleza de bajas pérdidas en estos substratos a frecuencias de microondas y ondas milimétricas hace de LTCC una tecnología de fabricación muy interesante. Cabe destacar, que tras eí exito en losúltimos años por diseñar antenas metálicas con la Teoría de Modos Característicos (TMC) [4], la TMC está siendo extendida en la actualidad para el diseño de las DRA [5], [6]. Hasta ahora no hay muchas aplicaciones , pero crecen cada día por el papel tan importante que la TMC juega a la hora de buscar resonancias en las cavidades diléctricas, o para entender mejor su naturaleza radiante. "
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    DESCRIPTION: A novel method to design a Coplanar-Waveguide Fed Slot-Coupled Rectangular Dielectric Resonator Antenna is presented in this paper. A new concept of Characteristic Modes to design a slot-coupled rectangular Dielectric Resonator Antenna is applied here for the first time. This study permits to optimize the radiation bandwidth in the same analysis process for both, the dielectric and the slot. The complete antenna is designed for Low-Temperature Co-fired Ceramic fabrication. The goals are to fabricate all the antenna for low permittivity in the same process, to match the dielectric resonator to the CPW feed line for the frequency range of ISM at 60GHz. The obtained results show that the radiation bandwidth, determined by 10-dB return loss, of the proposed antenna can be as large as 14GHz, more than 23 %, centered at about 60GHz.
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    • "To analyze the characteristics modes, firstly the eigenvalues are analyzed as they provide information of how the associated modes (Jn) radiate and how they are related to the resonance. It is proven that a few modes are required to characterize the mechanism of a small antenna [73] [76]. "
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    ABSTRACT: With the increasingly new ultra wide-band applications, antenna researchers face huge challenges in designing novel operational geometries. Mono-pole and quasi-mono-pole antennas are seen to be the most compact and easily incorporate able solution for portable devices taking the advantages of printed circuit board (PCB) techniques. Most antennas of such type have symmetrical structures. It is possible to attain wider operating bandwidths by meeting symmetry conditions while chopping the antenna into halves for a compact structure. However, there is no generalized way of applying such a technique. The presented paper addresses this issue by proposing a common feeding technique that can be applied to any antenna which is miniaturized using its symmetrical structure. The proposed technique enables feeding the halved structure to achieve wider and better impedance matching than the reported full-size antennas. The theory of characteristic modes is applied to quasi-mono-pole structures to get an insight of the antennas mechanism. The radiation patterns are also correlated with modal current distributions to understand the radiation characteristics of the modified structure. Lastly, the method is implemented on some example antennas to illustrate its potential.
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    • "How such a single element antenna works as a diversity antenna can be explained by the theory of characteristics modes: diversity gain can be achieved by exciting different modes of the antenna which result in different radiation patterns [8]. Here different modes on the radiator top plate and ground plane of the PIFA are excited to produce the desired diversity gain. "
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    ABSTRACT: In recent years planar inverted-F antenna stay as one of the most popular antenna used in mobile phone, because of its low profile, light weight and simple structure. This study presents a simulation of a planar inverted-F antenna (PIFA) with a radiating plate to the associated ground plane by a shorting plate and a FR-4 substrate between the ground plane and the radiating plate. The PIFA antenna is fed by a coaxial cable through a SMA connector. In this work the different parameters are changed to observe their effects on the characteristics of PIFA as the resonance frequency, the length of the bandwidth and the radiation pattern. The kind of this PIFA element is to cover a wide frequency band from 2.31 GHz to 2.71 GHz; therefore, we can find these applications: Wi-Fi (2.45GHz), Bluetooth (2.4 GHz) and the two Long Term Evolution bands (LTE 2.3GHz, LTE 2.5GHz) includes.
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