Observations on computational outcomes for the characteristic modes of dielectric objects

Alroughani, H.; Ethier, Jonathan; McNamara, D.A.

doi:10.1109/aps.2014.6904750

Cited by 59 publications

(48 citation statements)

References 3 publications

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“…This specific formulation produces a symmetric impedance matrix which can be used to solve for the CMs of an object. However, VIE formulations are computationally complex, and even electrically compact objects are difficult to solve using this method [3], [4].…”

Section: Introductionmentioning

confidence: 99%

“…As a computationally efficient alternative, a symmetric form of the MoM surface integral equation (SIE) was formulated in [5], along with a proof that this SIE formulation can be used to solve for the modal currents of any dielectric or magnetic body. However, it was shown in [4] and later proven in [6] that these modal currents are not equivalent to the characteristic currents of the object. The modal solution to the symmetric SIE impedance matrix provides an orthogonal set of both internal (non-real) and external (real) currents; these internal modes are related to the classical MoM internal resonance problem [3].…”

Section: Introductionmentioning

confidence: 99%

“…However, by applying any of the post-processing methods described in [4] and [6], the internal resonances can be removed, with the remaining external (real) modes being equal to the complete set of CMs for the structure. Nevertheless, despite the recent progress in removing internal resonances from SIE solutions [4], [6], recent work has only focused on dielectric resonators, which are pure dielectric structures. The extent of the internal resonance problem has not been studied for other structures, such as a conventional terminal chassis which does not rely on dielectrics as the main radiators when used for antenna design.…”

Section: Introductionmentioning

confidence: 99%

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Effects of dielectrics and internal resonances on modal analysis of terminal chassis

Miers

Lau

2016

2016 10th European Conference on Antennas and Propagation (EuCAP)

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The symmetric PMCHWT method of moments (MoM) impedance matrix allows for the characteristic modes (CMs) of a structure containing dielectric to be found. Recently, this impedance matrix was proven to provide non-real solutions which can be attributed to the MoM internal resonance problem. These internal resonances can be removed through different CM post-processing techniques. However, these studies focus on dielectric structures, whereas the majority of antennas utilize electric conductors as the radiators. As such, dielectrics are often neglected to simplify the CM analysis and hence the problem of internal resonance is overlooked. This work explores the extent of the internal resonance problem in mixed conductor-dielectric structures. The results reveal that the problem is severe even when the structures only contain small amounts of dielectric materials. Moreover, the significant impact of dielectrics on CMs reveals that dielectrics should be included in CM analysis to ensure high accuracy. Index Terms-Theory of Characteristic Modes, terminal antennas, method of moments, dielectric material. I.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of dielectrics and internal resonances on modal analysis of terminal chassis

Miers

Lau

2016

2016 10th European Conference on Antennas and Propagation (EuCAP)

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“…Based on this initial idea, TCM has since been applied to optimize antenna placement in predefined structures [3], [4], synthesize antennas with reconfigurable patterns [5], and help create more than one excitable mode at frequency bands below 1 GHz while also achieving multiband capability [3]. Furthermore, recent progress has enabled substantially more efficient computation of CMs for lossless structures containing both perfect electric conductor (PEC) and dielectric materials [6]. This allows any predefined lossless structure to be optimized using CM-aided antenna design.…”

Section: Introductionmentioning

confidence: 99%

“…The vacuum can be considered the simplest dielectric material, which ideally has no influence on the CMs of the PEC plate alone [3]. The first nine eigenvalues were computed using the surface integral equation (SIE) solution as described in [6]. It is noted that the SIE approach solves for the electric and magnetic fields based on equivalent currents on the surfaces of the structures.…”

Section: Introductionmentioning

confidence: 99%

Tracking of characteristic modes through far-field pattern correlation

Miers

Lau

2015

2015 IEEE International Symposium on Antennas and Propagation &Amp; USNC/URSI National Radio Science Meeting

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Abstract-Recent developments in characteristic mode (CM) analysis enable a more systematic approach to designing multiantennas for mobile terminals. However, some of the advantages of developing antennas through CMs are based on accurate mode tracking over frequency. Existing tracking methods are primarily based on the tracking of eigencurrents over frequency, by which mode swapping and degenerate modes can occur. To solve these problems, a completely different method of tracking CM by means of far-field pattern correlation was recently developed and shown to work well for perfect electric conductors (PECs). This paper reveals that the same method can also substantially reduce tracking errors for structures with both PEC and dielectric materials, relative to state-of-the-art methods.

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Antenna Characteristic Mode Analysis and Applications

Guan

Chen

2022

Wiley Encyclopedia of Electrical and Electronics Engineering

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In the field of electromagnetism, the characteristic mode (CM) method has been applied to theoretical analysis and engineering design of electromagnetic scattering and radiation due to its clear physical meaning and complete theory. In this article, the CMs are used as the entire‐domain basis functions for solving electromagnetic scattering and radiation problems of large‐scale, arbitrary arrangement of repetitive structures. Firstly, the CM method for solving the scattering problems of nonconnected repetitive structures is reviewed, and the source mode is introduced to compensate the accuracy when analyzing radiation problems. Secondly, for connected repetitive structures, the buffer region is proposed to guarantee the current continuity on the surface of the conductor, and half‐SWG basis functions are used for dielectric connected structures. Thirdly, a series of acceleration methods are proposed to improve the computational efficiency. To generate the reduced matrix fast, the translation invariance of repetitive structures and interpolation technology are utilized to fill the matrix entries. Multilevel Fast Multipole Algorithm (MLFMA) is also used to accelerate the matrix–vector products (MVPs) between the impedance matrix and the eigenvectors. At last, a hybrid MPI–OPENMP parallel scheme is proposed for solving large‐scale finite array. The numerical examples have shown that the proposed method has a good accuracy and efficiency. It provides a strong tool for designing and optimizing antenna arrays and other EM repetitive structures.

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Observations on computational outcomes for the characteristic modes of dielectric objects

Cited by 59 publications

References 3 publications

Effects of dielectrics and internal resonances on modal analysis of terminal chassis

Effects of dielectrics and internal resonances on modal analysis of terminal chassis

Tracking of characteristic modes through far-field pattern correlation

Antenna Characteristic Mode Analysis and Applications

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