Investigations of Non-Physical Characteristic Modes of Material Bodies

© 2018 IEEE. Recently, researchers noticed that there are non-physical modes in characteristic modes of material bodies. In this paper, those non-physical modes are investigated. The reason for the non-physical modes is discussed. The influence of integral equations' internal resonance on the non-physical modes are studied. It is concluded that the internal resonance is not responsible for the non-physical modes. Meanwhile, based on the extinction theorem, the dependent relationship between the equivalent surface electric and magnetic currents are proposed, and it is observed that the non-physical modes do not obey the dependent relationship, whereas the physical modes are governed by the dependent relationship. Therefore, it can be concluded that the lack of the dependent relationship causes the non-physical modes. Besides, based on the dependent relationship, a novel post-processing method to remove the non-physical modes is proposed. Numerical results of a dielectric cylinder are presented to validate the discussions and new post-processing method

Designing Slot Antennas in Finite Platforms using Characteristic Modes

(c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.[EN] In this paper, the application of the Theory of Characteristic Modes for the design of narrow-in-width open slot antennas embedded in finite platforms is investigated. Purely magnetic and electric characteristic modes (CM) of a slot etched in both an infinite and a finite ground plane are analyzed, with the aim to provide a physical understanding of the slot behavior and its interaction with the metallic ground plane. Instead of traditional CM analysis, an alternative approach is proposed, which consists in dividing the design procedure into the separate and complementary analysis of purely magnetic and electric CM. Based on this analysis, some guidelines for the design of open slot antennas are provided, and a simple and compact narrow-in-width wideband open slot antenna is designed. Simulations and measurements are presented for the optimized slot antenna, showing an impedance bandwidth of 47.48% with a very stable radiation pattern.This work was supported by the Spanish Ministry of Economy and Competitiveness under Project TEC2016-78028-C3-3.Mohamed Mohamed-Hicho, N.; Antonino Daviu, E.; Cabedo Fabres, M.; Ferrando Bataller, M. (2018). Designing Slot Antennas in Finite Platforms using Characteristic Modes. IEEE Access. 6:41346-41355. https://doi.org/10.1109/ACCESS.2018.2847726S4134641355