Design and Fabrication of a Dual-Band Bandpass Filter Using a Dual-Mode Ring Resonator with Two Short-Circuited Stubs for WLAN Application

두 단락 스터브를 갖는 이중 모드 링 공진기를 이용한 WLAN용 이중대역 대역통과 여파기의 설계 및 제작

Choi, Byung-Chang

  • Received : 2015.07.20
  • Accepted : 2015.09.03
  • Published : 2015.09.30


In this paper, A high selective dual-band bandpass filter was proposed using a dual-mode ring resonator with two short-circuited stubs. For dual-mode resonance, the ring resonator is directly connected with non-orthogonal feed-lines via coupling capacitors. Two short-circuited stubs which are unequal lengths are simultaneously placed at two corners along the two symmetry plane of the ring resonator in order to obtain dual-band responses. Because the feeding angle perturbated ring resonator of the proposed dual-band bandpass filter has the symmetrical structure, Even/Odd mode analysis can be well applied to extract the scattering parameters and transmission zero frequencies. The proposed dual-band bandpass filter was designed and fabricated for WLAN(Wireless Local Area Network) application of IEEE 802.11n standard. The measured results showed a good agreement with the simulation results, and it should be well applied not only for WLAN applications but also for any other communication systems.


Dual-Band Bandpass Filter;Dual-Mode Ring Resonator;Short-Circuited Stub;Transmission Zero


  1. J. Ryynanen, K. Kivekas, J. Jussila, A. Parssinen, and K. A. I. Halonen, "A dual-band RF front-end for WCDMA and GSM applications", IEEE Solid-State Circuits, 36, 1198-1204, 2001.
  2. H. Miyake, S. Kitazawa, T. Ishizaki, T. Yamada, and Y. Nagatow, "A miniaturized monolithic dual band filter using ceramic lamination technique for dual mode portable telephones", IEEE MTT-S International Microwave Symposium Digest, pp. 789-792, 1997.
  3. Jian-Xin Chen, Tsz Yin Yum, Jia-Lin Li, and Quan Xue, "Dual-mode dual-band bandpass filter using stacked-loop structure", IEEE Microwave and Wireless Components Letters, vol. 16, no. 9, pp. 502-504, Sep. 2006.
  4. E. E. Djoumessi, K. Wu, "Multilayer dual-mode dualbandpass filter", IEEE Microwave and Wireless Components Letters, vol. 19, no. 1, pp. 21-23, Jan. 2009.
  5. Chang-Sin Ye, Min-Kuin Su, Min-Hang Weng, and Ru- Yuan Yang, "Design of a high selectivity dual-band bandpass filter with stepped impedance resonator", IEEE Proceedings of the 39th European Microwave Conference, pp. 311-313, 2009.
  6. Yu-Chi Chang, Chia-Hsiung Kao, Min-Hang Weng, and Ru-Yuan Yang, "Design of the compact dual-band bandpass filter with high isolation for GPS/WLAN applications", IEEE Microwave and Wireless Component Letters, vol. 19, no. 12, pp. 780-782, Dec. 2009.
  7. Atallah Balalem, Jan Machac, and Abbas Omar, "Dualband bandpass filter by using square-loop dual-mode resonator", Microwave Optical Technology Letters, vol. 50, no. 6, pp. 1567-1570, Jun. 2008.
  8. Tsung-Hui Huang, Han-Jan Chen, Chin-Sheng Chang, Lih- Shan Chen, Yeong-Her Wang, and Mau-Phon Houng, "A novel compact ring dual-mode filter with adjustable second- passband for dual-band applications", IEEE Microwave and Wireless Components Letters, vol. 16, no. 6, pp. 360-362, Jun. 2006.
  9. Sha Luo, Lei Zhu, and Sheng Sun, "A dual-mode dualband bandpass filter using a single ring resonator", IEEE Asia-Pacific Microwave Conference, pp. 921-924, 2009.
  10. M. Makimoto, S. Yamashita, Microwave Resonators and Filters for Wireless Communication, Springer.
  11. K. Chang, L. H. Hsieh, Microwave Ring Circuits and Related Structures, Wiley, New York, 2004.
  12. Arun Chandra Kundu, Ikuo Awai, "Control of attenuation pole frequency of a dual-mode microstrip ring resonator bandpass filter", IEEE Transactions on Microwave Theory and Techniques, vol. 49, no. 6, pp. 1113- 1117, Jun. 2001.
  13. Wu Seong Lee, Gi Moon Lee, Byung Chang Choi, Ha Chul Kim, and Hyun Chul Choi, "A band-stop RF switch using a dual-mode stepped-impedance microstrip ring resonator", IEEE Proceedings of the 40th European Microwave Conference, pp. 316-319, 2010.