Designing Hand-Immune Handset Antennas With Adaptive Excitation and Characteristic Modes

Luomaniemi, Rasmus; Ylä‐Oijala, Pasi; Lehtovuori, Anu; Viikari, Ville

doi:10.1109/tap.2020.3044640

Cited by 30 publications

(12 citation statements)

References 34 publications

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“…In the lossy case, they are complex, the real part having the same interpretation as in the lossless case and the imaginary part giving the ratio of dissipated and radiated power. Since the non-orthogonality of the CMs is rather moderate with low losses, the modes can still give important physical insight into radiation properties and loss mechanisms of the structure [22].…”

Section: Discussionmentioning

confidence: 99%

Orthogonality Properties of Characteristic Modes for Lossy Structures

Kuosmanen

Ylä‐Oijala

Holopainen

et al. 2022

IEEE Trans. Antennas Propagat.

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Orthogonality of the characteristic modes with respect to the weight operator of the generalized eigenvalue equation, and in the far field, is investigated in the case of lossy conducting and dielectric objects. Linking the weight operator to radiated power is shown to provide orthogonal far fields in the lossless case. In the lossy case, both the orthogonality of the characteristic far fields and the weight operator orthogonality of the modal currents are satisfied with respect to the Hermitian inner products only for sufficiently symmetric geometries, such as a sphere. For irregular lossy shapes, independently of the symmetry of the formulation, the far-field orthogonality can be obtained only with respect to the symmetric (non-Hermitian) product. The weight operator orthogonality can be satisfied with (complex) symmetric formulations, but again only with respect to the symmetric product. Since the symmetric products are not related to any physical power quantity, the modes do not form a (radiated) power orthogonal set in the lossy case. Hence, for lossy structures CMs do not satisfy their classical definition and they need to be redefined.

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Section: Discussionmentioning

confidence: 99%

Orthogonality Properties of Characteristic Modes for Lossy Structures

Kuosmanen

Ylä‐Oijala

Holopainen

et al. 2022

IEEE Trans. Antennas Propagat.

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“…To solve this issue (and avoid spurious modes), recent work [48]- [53] proposes a different weighting matrix, and the resulting eigenvalue is complex, with the real and imaginary parts dealing with reactive power and dissipated power (ohmic loss). The method has been applied to design handset with robust antenna performance [54]. However, the modal far-field orthogonality has not been confirmed.…”

Section: A Formulations For Dielectric and Magnetic Structuresmentioning

confidence: 99%

Characteristic Modes: Progress, overview, and emerging topics

Lau

Čapek

Hassan

2022

IEEE Antennas Propag. Mag.

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Over the past decade, characteristic mode analysis (CMA) research has grown from a niche topic to a mainstream topic, warranting a tutorial-style special issue to survey the significant progress that has been made in this field. In this introductory article (PAPER 1), the focus is on providing the big picture. We start with a simple description of characteristic modes. Next, we examine the trends in this field, followed by providing further insights into CMA's historical development. We will also address common myths surrounding the subject. Then, leaving the detailed coverage of major topics to the following papers, we summarize recent applications of CMA in scattering and other emerging topics. Finally, we conclude with some future perspectives on this field.

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“…This is done by combining both the matching component and the feeding signal optimization into the same process. In this work, we use a numerical optimization method similar to one presented in [41] to find both the fixed components and the values for the tunable capacitors when also the optimal feeding amplitudes and phases are taken into account.…”

Section: B Study Of the Tunable Operationmentioning

confidence: 99%

Extremely Low-Profile Tunable Multiport Handset Antenna

Luomaniemi

Lehtovuori

Ilvonen³

et al. 2022

IEEE Trans. Antennas Propagat.

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This paper presents an extremely low-profile tunable antenna design for smartphones with height of only 0.75 mm. The proposed antenna is integrated into the back cover of the device to utilize the existing gap between the battery and the back cover as efficiently as possible. By utilizing both tunable components and adjustable feeding weights, the designed multiport antenna system covers 3300-4200 MHz frequency range with 100 MHz instantaneous bands. In addition to just frequency tuning, these tunable elements can be utilized to adapt the antenna for different operation environments, such as changes in the structure of the device or the user effect. We show that the proposed antenna can be extended for two-and four-element multiple-input multipleoutput (MIMO) operation. The proposed design is manufactured and measured and the results confirm good antenna performance with average total efficiencies of 35 % and 25 % in free space and with a hand phantom, respectively.

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Designing Hand-Immune Handset Antennas With Adaptive Excitation and Characteristic Modes

Cited by 30 publications

References 34 publications

Orthogonality Properties of Characteristic Modes for Lossy Structures

Orthogonality Properties of Characteristic Modes for Lossy Structures

Characteristic Modes: Progress, overview, and emerging topics

Extremely Low-Profile Tunable Multiport Handset Antenna

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