ZTE Communications ›› 2011, Vol. 9 ›› Issue (2): 12-19.

• Special Topic • Previous Articles     Next Articles

Single Mode DR Filters for Wireless Base Stations

Ji-Fuh Liang, Guo-Chun Liang, Marco Song, George He, and Tony An   

  1. Pivotone Communication Technologies
  • Online:2011-06-25 Published:2011-06-25
  • About author:Ji-Fuh Liang (Jifuh.liang@pivotone.com)received the B.S. Degree in electronics engineering from National Chaio-Tung University, Taiwan in 1981, M.S. Degree in electrical engineering from National Taiwan University, Taiwan in 1985, and Ph.D. degree in electrical engineering from University of Maryland in 1994.
    From 1985 to 1988 he was a member of technical staff and Project Leader at Microelectronics Technology Inc., Hsin-Chun, Taiwan. He maybe the earliest microwave engineer using dielectric resonator cavity for PCS 5MHz and 15MHz filter and HTS development. He joint BenQ corporation from 2000 to 2005 in Taiwan, as senior member of technical staff, senior manager and director for CDMA and handset technologies.
    He involved in FBAR filter design from 2006 to 2010 at Avago, where he designed first FBAR Wi-Fi and WiMAX filters for wireless handheld devices. Since March, 2010, he joint Pivotone Communication Technologies as CTO and VP of technology. His current research areas include DR cavity filter, waveguide filter and multiplexer for wireless base stations, and point-to-point communications.

    Guo-Chun Liang (gcliang@pivotone.com) received the B.S. degree from the East China Institute of Technology, China in 1982, the master’s degree from the University of Electronics Science and Technology of China (UESTC) in 1985, and Ph.D. degree from University of California at Berkely in 1990. All majors were in electrical engineering.
    He worked at the center of UESTC in 1985-1986, and developed a series of RF and microwave devices there. He had been with Conductus, Inc., Sunnyvale, CA, from 1990 to 2001, where he developed most advanced superconductor components and filters for wireless base station applications. In 2002, he found Allizon Communication Technology in Shanghai, which was acquired by Smith Group. He is now the president and CEO of Pivotone Communication Technology Inc.

    Marco Song (marco_song@pivotone.com) received the B.S. degrees in microwave from University of Electronics Science and Technology of China (UESTC) in 1999. He is now the RF manager with Pivotone Communication Tech., Inc. His research interests include RF and microwave passive components and measurements.

    George He (george_he@pivotone.com) received the B.S. degrees in microwave from University of Electronics Science and Technology of China (UESTC) in 2001. He joint Shanghai Institute of Control and Communication, from 2001 to 2003, for microstrip circuits research and development. In 2003, he joint Metac communication equipment inc as a senior RF engineer, and was responsible for developing coaxial resonator, dielectric cavity filters and LNA for wireless base station applications. In 2009, he joint Powerwave and continued his research and development in similar applications. Now, he is a senior RF engineer and project leader in Pivotone Communication Technologies, Inc.

    Tony An (tony_an@pivotone.com) graduated from University of Electronic Science and Technology of China (UESTC), majored in Electromagnetic Fields and Microwave Engineering (2001.9-2005.7). Tony has been engaged in research and development of passive radio frequency device, include GSM, CDMA, MAX, LTE, waveguide filters, diplexers and other radio frequency devices. His experience of product design ranges from 30 MHz-42 GHz. He also has deep understanding and good experience in designing other passive products. Now, Tony is working with Pivotone as RF senior engineer and project leader, mainly in waveguide filter, diplexer and other related components.

Abstract: This paper presents state-of-the-art high Q single-mode dielectric resonator (DR) cavity filters for PCS wireless base stations. DR cavity filters shrink the cavity size significantly more than waveguide cavity filters and offer about twice higher Q than coaxial resonators. Thus, they have important applications in wireless base stations operating below 2.5 GHz. Dual-mode and triple-mode DR cavity filters have existed for a while; however, single-mode DR cavity filters are predominant because they are cheaper to manufacture. This paper summarizes the main characteristics of TE01 mode DR cavities, including mode chart and field distribution, and compares cavity Q with waveguide and combline (coaxial) cavities. Dielectric combline and TM010 mode DR cavities are analyzed and compared to TE01 mode DR cavities. General filter design techniques are discussed, and several design examples are given to show how filter technology has developed.

Key words: microwave resonator, cavity filter, DR cavity, dielectric resonator loaded cavity