耦合於微帶線之介質共振器品質因數量測

Quality Factor Measurement of Dielectric Resonator Through Microstrip Line Coupling

林沿鍾(Yen-Chung Lin)

指導教授 ： 瞿大雄

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.00272

摘要

介質共振器係由高介電常數材質構成，其電磁特性與相同幾何形狀，且包覆PMC之空腔共振器極為類似。但由於其高介電常數，相較空腔共振器，在相同工作頻率下，其體積較小。以Trans-Tech公司所提供8700系列介質共振器為例，其相對介電係數約30，相較於空腔共振器，電氣長度可縮減約5.5倍。另外介質共振器的高品質因數，使得它具有優異的窄頻共振特性，因此廣泛應用在天線、濾波器及共振器等微波及毫米波電路。
介質共振器在不同微波電路中，其品質因數為電路設計的主要依據。尤其在濾波器電路，依據[1]所敘述的濾波器設計方法，可以經由量測第一階的Qe值，確知該電路架構是否符合所設計的濾波器特性。因此，一個正確有效的品質因數量測方法，成為介質共振器應用的重要一環。
本論文係依據[2]所提出的量測方法，論文首先敘述介質共振器以及品質因數，以及簡單的等效電路，接著參考[3]的方式建立幾個基礎量測雛型，並參考[4]的方式考慮更複雜的情況，最後延伸到介質共振器耦合於微帶線的量測方法，以及敘述量測結果。

關鍵字

品質因數 ； 介質共振器 ； 品質因數量測 ； 耦合係數

並列摘要

Dielectric resonator (DR) is made of high dielectric constant materials and acts as a cavity enclosed by perfect magnetic conductor (PMC). Because of the high dielectric constant, its dimensions are much smaller than other types of resonators at the same frequency. Take the 8700 series DRs offered by Trans-Tech for example. Its εr 30, hence its electrical length is about 5.5 times smaller than that of an air-filled cavity. Besides, dielectric resonator has ultra high quality factor, resulting in a quite narrow operating bandwidth. Therefore, dielectric resonator is widely used in the microwave and millimeter wave circuits, for example, antennas, filters and oscillators.
In many aspects, the quality factor of dielectric resonator is the major characteristic to be taken into account in the microwave circuit design. Especially in filter design, for example, the method given in [1], after giving the design parameters of a filter, the circuit layout would meet the design requirements by measuring the first-order external Q of the resonator. In other words, an accurate and effective quality factor measurement becomes an important issue in the applications of dielectric resonator.
For this reason, this thesis uses the method developed in [2]. In Chapter one, we give a brief description of quality factor and dielectric resonator, then present some basic measurement models [3] based on the simple equivalent circuits. After the discussion about the advantages and disadvantages of this model, we then take more complicated situations into account based on [4] and describe in Chapter two. Finally, we consider the situation about the dielectric resonator coupled to a microstrip line in Chapter three with simulation and measurement results.

並列關鍵字

quality factor ； dielectric resonator ； measurement of quality factor ； coupling coefficient

參考文獻

[1] J.H. Lee, S. Pinel, J. Papapolymerou, J. Laskar and M.M. Tentzeris, 'Low-loss LTCC cavity filters using system-on-package technology at 60 GHz," IEEE Trans. Microwave Theory Tech., vol. MTT-53, pp. 3817-3824, Dec. 2005.

[2] A. Khanna and Y. Garault, "Determination of loaded, unloaded, and external quality factors of a dielectric resonator coupled to a microstrip line," IEEE Trans. Microwave Theory Tech., vol. MTT-31, pp. 261-264, March 1983.

[4] A.E. Bailey, Microwave Measurement, London, UK : P. Peregrinus on behalf of the Institution of Electrical Engineers, 1989.

[5] S.A. Long, M. McAllister, and L.C. Shen, "The resonant cylindrical dielectric cavity antenna," IEEE Trans. Antennas Propagat., vol. AP-31, pp. 406-412, May 1983.

[6] P. Guillon and Y. Garault, "Dielectric resonator dual modes filters," Electron. Lett., vol. 16, p.646, Aug 1980.