Limitations for the Radiation Q of a Small Antenna Enclosed in a Spheroidal Volume: Axial Polarisation

Stén, Johan C.-E.; Koivisto, Päivi; Hujanen, Arto

doi:10.1078/1434-8411-00030

Cited by 17 publications

(31 citation statements)

References 10 publications

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“…Mode expansions have dominated the research on physical bounds since these expansions were introduced by Chu, see e.g., [18,24,25,27,48,61,77,85,88,91,105,110,119] and the historical expose in [115]. In particular Collin & Rothschild [18] used spherical mode expansions and analytic evaluation of (3.8) to derive closed form expressions of the Q-factor for spherical modes of arbitrary order, e.g.,…”

Section: Circuit Models and Mode Expansionsmentioning

confidence: 99%

“…He showed that the dipole modes have the lowest Q-factor and that the Q-factor of antennas can be reduced by letting the antenna excite a combination of electric (transverse magnetic TM) and magnetic (transverse electric TE) modes. Mode expansions have dominated the research on physical bounds since Chu's work, see e.g., [18,19,24,25,27,29,48,60,61,77,83,85,88,91,105,110,119] and the historical expose in [115]. The mode expansion approach to physical limitations provides simple analytic formulas for the lower bound on the Q-factor for single modes [18,85].…”

Section: Background and Overviewmentioning

confidence: 99%

“…Physical bounds on antennas are often derived using the electromagnetic fields that surround the antenna [18,24,25,27,61,77,85,105,110,115,119]. Consider an antenna confined to the region Ω as depicted in Fig.…”

Section: Stored Electric and Magnetic Energiesmentioning

confidence: 99%

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Physical Bounds of Antennas

Gustafsson¹,

Tayli²,

Cismasu³

2016

Handbook of Antenna Technologies

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Design of small antennas is challenging because fundamental physics limits the performance. Physical bounds provide basic restrictions on the antenna performance solely expressed in the available antenna design space. These limits offer antenna designers a-priori information about the feasibility of antenna designs and a figure of merit for different designs. Here, an overview of physical bounds on antennas and the development from circumscribing spheres to arbitrary shaped regions and embedded antennas are presented. The underlying assumptions for the methods based on circuit models, mode expansions, forward scattering, and current optimization are illustrated and their pros and cons are discussed. The physical bounds are compared with numerical data for several antennas.

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Section: Circuit Models and Mode Expansionsmentioning

confidence: 99%

Section: Background and Overviewmentioning

confidence: 99%

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Physical Bounds of Antennas

Gustafsson¹,

Tayli²,

Cismasu³

2016

Handbook of Antenna Technologies

View full text Add to dashboard Cite

show abstract

“…This has encouraged researchers to extend the mode expansions to non-spherical regions. Collin and Rothschild [18] used cylindrical waves to derive bounds for infinite cylinders and Foltz & McLean [25] and Sten, Koivisto, and Hujanen [105] used expansions in spheroidal coordinates to derive bounds for antennas confined to spheroidal volumes. However, it turns out to be difficult to extend the results from spherical regions using mode expansions.…”

Section: Circuit Models and Mode Expansionsmentioning

confidence: 99%

“…In small antenna theory, matching bandwidth and the efficiency are two performance parameters often considered for analysis, e.g., [14,18,24,25,27,29,48,60,61,77,85,88,91,105,110,116,119]. The radiation pattern and the polarization are also of importance in some studies [40,43,44].…”

Section: Introductionmentioning

confidence: 99%