Shape optimization of a dielectric resonator for improving its unloaded quality factor

2010 ◽  
Vol 21 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Hassan Khalil ◽  
Stéphane Bila ◽  
Michel Aubourg ◽  
Dominique Baillargeat ◽  
Serge Verdeyme ◽  
...  
Keyword(s):  
Shape Optimization ◽  
Quality Factor ◽  
Dielectric Resonator ◽  
Unloaded Quality Factor

Unloaded quality factor measurement for MIC dielectric resonator applications

1981 ◽  
Vol 17 (18) ◽  
pp. 656 ◽  
Author(s):  
A. Podcameni ◽  
L.F.M. Conrado ◽  
M.M. Mosso
Keyword(s):  
Quality Factor ◽  
Dielectric Resonator ◽  
Factor Measurement ◽  
Unloaded Quality Factor

Polaron conduction loss in microwave dielectric ceramics

1999 ◽  
Vol 14 (2) ◽  
pp. 500-502
Author(s):  
Seungbum Hong ◽  
Eunah Kim ◽  
Han Wook Song ◽  
Jongwan Choi ◽  
Dae-Weon Kim ◽  
...  
Keyword(s):  
Quality Factor ◽  
Phonon Scattering ◽  
Dielectric Resonators ◽  
Frequency Range ◽  
Conduction Loss ◽  
Microwave Dielectric ◽  
Scattering Effects ◽  
Unloaded Quality Factor ◽  
Dielectric Ceramics ◽  
Polaron Conduction

It has been generally accepted that the product of the unloaded quality factor and resonant frequency is the universal parameter for comparison of dielectric resonators with different size.1,2 However, it is suggested in this study that this universal parameter should be modified due to the presence of the polarons. From the frequency dependence of the unloaded quality factor, it is possible to extract the factor determined only by the phonon scattering effects, and we denoted this parameter by Qs. It was found that the Qs parameter for ZrxSnzTiyO4 (ZST) and Ba(Zn1/3Ta2/3)O3 (BZT) ceramics showed constancy in the frequency range of 2–12 GHz, which supports the idea of polaron conduction loss contribution to the dielectric loss.

A shape optimization library for the design of microwave components

2013 ◽  
Vol 6 (1) ◽  
pp. 31-37
Author(s):  
Najib Mahdi ◽  
Stephane Bila ◽  
Serge Verdeyme ◽  
Michel Aubourg ◽  
Khaled Khoder ◽  
...  
Keyword(s):  
Shape Optimization ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Optimization Techniques ◽  
Dual Mode ◽  
3D Objects ◽  
Full Wave ◽  
Microwave Components ◽  
Unloaded Quality Factor ◽  
Aided Design

This paper outlines an original shape optimization library backed by a three dimensional (3D) full-wave electromagnetic (EM) simulator, combining several efficient structural optimization techniques and suitable for viable computer-aided design (CAD) of complex microwave components. The microwave components are modeled by finite element method (FEM) and their dimensions and shape are optimized using four techniques: design of experiments (DOE), level-set method (LS), topology gradient (TG) method, and genetic algorithm (GA). The various methods allow determining the optimal geometry, shape or topology of 2D or 3D objects within the microwave device, by minimizing iteratively a cost function related to the desired specifications. Typical demonstration illustrates the versatility of the proposed library based on the design of a dual mode dielectric resonator filter in order to improve its unloaded quality factor by keeping the same frequency isolation, their accuracy and efficiency are verified by the available measured results.

scholarly journals Miniaturized Antenna Solution Based on Lossy Planar Microresonators to Conjointly Control Radiation and Selectivity

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Biyun Ma ◽  
Anne Chousseaud ◽  
Serge Toutain
Keyword(s):  
Quality Factor ◽  
Filter Design ◽  
Radiation Loss ◽  
Distributed Load ◽  
Air Resistance ◽  
Miniaturized Antenna ◽  
Specific Frequency ◽  
Unloaded Quality Factor ◽  
First Time ◽  
Basic Radiation

We propose a new method to design miniaturized compact antennas, in which it is possible to control conjointly the radiation efficiency and the bandwidth selectivity of the antenna. And this method has been validated by the realization of prototypes based on planar resonators. The geometry of these resonators has been chosen because their unloaded quality factor can be controlled and is mainly dependent on radiation loss. In the first time, a filter with a significant potential to radiation has been realized by choosing suitable miniaturized resonators. An antenna, based on the same structure, in which the output of the filter was removed (load by air resistance) can be obtained. Modification of the quality factor of each resonator is necessary to take into account the change of the load value from the previous filter to the final structure. The position and the quality factor of the resonators are determined by a filter design concept to obtain a specific frequency response in which each resonator is a basic radiation element. Load of the antenna is ultimately a distributed load constituted by the parallel contributions of each resonators to radiation loss. In other words such an antenna can also be called radiating filter.

scholarly journals Quality Factor Enhancement of 650 MHz Superconducting Radio-Frequency Cavity for CEPC

2022 ◽  
Vol 12 (2) ◽  
pp. 546
Author(s):  
Peng Sha ◽  
Weimin Pan ◽  
Jiyuan Zhai ◽  
Zhenghui Mi ◽  
Song Jin ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Quality Factor ◽  
Microwave Surface Resistance ◽  
Medium Temperature ◽  
Residual Resistance ◽  
Electron Positron ◽  
Superconducting Radio Frequency ◽  
Unloaded Quality Factor ◽  
Srf Cavity ◽  
Vertical Test

Medium-temperature (mid-T) furnace baking was conducted at 650 MHz superconducting radio-frequency (SRF) cavity for circular electron positron collider (CEPC), which enhanced the cavity unloaded quality factor (Q0) significantly. In the vertical test (2.0 K), Q0 of 650 MHz cavity reached 6.4 × 1010 at 30 MV/m, which is remarkably high at this unexplored frequency. Additionally, the cavity quenched at 31.2 MV/m finally. There was no anti-Q-slope behavior after mid-T furnace baking, which is characteristic of 1.3 GHz cavities. The microwave surface resistance (RS) was also studied, which indicated both very low Bardeen–Cooper–Schrieffer (BCS) and residual resistance. The recipe of cavity process in this paper is simplified and easy to duplicate, which may benefit the SRF community.

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