A Fundamental Limit on the Performance of Geometrically-Tuned Planar Resonators

Naji, Adham; Warr, Paul A; Beach, M.A.; Morris, Kevin

doi:10.1109/tmtt.2011.2118227

Cited by 5 publications

(9 citation statements)

References 16 publications

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“…Here, the coupling strength is changed by changing the size of the perturbation cut, which may be achieved electronically by placing rows of controlled switches to link/unlink other conductive features. The resultant apertures in the conductive face of the resonator are small relative to the resonant wavelength, but, collectively, will inevitably introduce some losses 4 in the unloaded quality factor ( Q 0 ), which we estimate in the next section.…”

Section: Geometrical Perturbation Techniques For Eigenmode Manipulatimentioning

confidence: 99%

“…However, it is known that the addition of tuning elements to the resonator structure will typically degrade its performance (e.g. the unloaded quality factor, Q 0 ) 4 . This degradation is mainly attributed to two sources: (1) losses due to the added active components and their associated circuitry; and (2) the fundamental loss due to geometric alterations in the resonator structure.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the way we choose to manipulate the shape or structure of the resonator to prepare it to host tuning elements may influence the performance degradation curves greatly even before actually inserting tuning elements. The performance achieved solely by geometric alterations forms an upper limit on the achievable performance when active elements are inserted 4 . Active elements (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…switches and varactors) will later add further losses to the fundamental (geometric) loss due to their internal losses, bias circuitry layout and wires, which can couple energy from the signal’s path, typically increasing insertion loss and causing some mismatch. This can be observed by a twofold reduction in Q 0 , first due to the geometrical effect and then due to the active element losses (see 4 for an example).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Geometrical Perturbation Techniques and Approximate Analysis for Eigenmode Splitting and Shifting in Electromagnetic Planar Dual-Mode Resonators

Naji

Warr

2019

Sci Rep

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Dual-mode electromagnetic resonators are used in numerous systems and applications in physics and engineering. They rely on degenerate-mode splitting to control the spectral properties of the system that employs them. Controlling (splitting or shifting) these eigenvalues to fully tune the frequency response, however, is a nontrivial problem that involves the use of geometrical perturbation theory as well as lossy electronic elements that enable the tuning process. In this paper we present novel geometrical techniques to control the eigenmodes of dual-mode resonators, highlighting the strong connection between the chosen geometry and performance (measured by the unloaded quality factor, Q0). Key advantages of the presented structures include electronic geometric tunability for frequency splitting and shifting, as well as the use of buried feeds to improve insertion loss and return loss performance. Field analysis is used to show how the performance is degraded by geometry itself, rather than by the tuning elements. The discussion includes derivation of approximate analytical models that highlight the sources of performance degradation in the geometry even before any tuning elements are inserted. The presented concepts are verified by measurements on perturbed microwave resonators.

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Section: Geometrical Perturbation Techniques For Eigenmode Manipulatimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Geometrical Perturbation Techniques and Approximate Analysis for Eigenmode Splitting and Shifting in Electromagnetic Planar Dual-Mode Resonators

Naji

Warr

2019

Sci Rep

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“…This result can also be used in perturbation effect calculations in reconfigurable planar structures, where the insertion of tuning elements constitutes a form of geometric perturbation (e.g. [4]). …”

Section: Introductionmentioning

confidence: 99%

Proof of Perturbational Duality Between Classical Cavities and Planar Resonators With Magnetic Side-Walls

Naji

Warr

2016

IEEE Microw. Wireless Compon. Lett.

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Center Frequency Stabilization in Planar Dual-Mode Resonators during Mode-Splitting Control

Naji

Soliman

2017

Sci Rep

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Shape symmetry in dual-mode planar electromagnetic resonators results in their ability to host two degenerate resonant modes. As the designer enforces a controllable break in the symmetry, the degeneracy is removed and the two modes couple, exchanging energy and elevating the resonator into its desirable second-order resonance operation. The amount of coupling is controlled by the degree of asymmetry introduced. However, this mode coupling (or splitting) usually comes at a price. The centre frequency of the perturbed resonator is inadvertently drifted from its original value prior to coupling. Maintaining centre frequency stability during mode splitting is a nontrivial geometric design problem. In this paper, we analyse the problem and propose a novel method to compensate for this frequency drift, based on field analysis and perturbation theory, and we validate the solution through a practical design example and measurements. The analytical method used works accurately within the perturbational limit. It may also be used as a starting point for further numerical optimization algorithms, reducing the required computational time during design, when larger perturbations are made to the resonator. In addition to enabling the novel design example presented, it is hoped that the findings will inspire akin designs for other resonator shapes, in different disciplines and applications.

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A Fundamental Limit on the Performance of Geometrically-Tuned Planar Resonators

Abstract: General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/userguides/explore-bristol-research/ebr-terms/ A. Naji is with the

Cited by 5 publications

References 16 publications

Geometrical Perturbation Techniques and Approximate Analysis for Eigenmode Splitting and Shifting in Electromagnetic Planar Dual-Mode Resonators

Geometrical Perturbation Techniques and Approximate Analysis for Eigenmode Splitting and Shifting in Electromagnetic Planar Dual-Mode Resonators

Proof of Perturbational Duality Between Classical Cavities and Planar Resonators With Magnetic Side-Walls

Center Frequency Stabilization in Planar Dual-Mode Resonators during Mode-Splitting Control

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