A Novel Frequency Control Loop for Tunable Notch Filters

• Published in: IEEE transactions on microwave theory and techniques Vol. 59; no. 9; pp. 2265 - 2274
• Main Authors: De Luis, Javier R., Qizheng Gu, Morris, Arthur S., De Flaviis, Franco
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.09.2011; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuation delay; Applied sciences; Automatic frequency control; Capacitors; Circuit properties; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; filter frequency control loop; Frequency control; Frequency filters; loop convergence; Mathematical model; Micro- and nanoelectromechanical devices (mems/nems); Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; Mobile communication; notch filter; Notch filters; Phase change; Radiocommunications; Reference signals; Reflection; RF microelectromechanical systems (MEMS); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Telecommunications; Telecommunications and information theory; Transmitters; Transmitters. Receivers; tunable capacitors; tunable filter; Tuning; Tunable circuit; Wireless telecommunication; RF microelectromechanical systems (MEMS); Transmitter; Control synthesis; Mobile communication; Microwave filter; Frequency control; Notch filter; Actuation delay; Delay time; Microelectromechanical device; tunable capacitors; Target tracking; Phase change; Control system; loop convergence; filter frequency control loop; RF systems; Control loop; Tunable filter; Insertion loss; Band stop filter; Passband; Capacitor
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2011.2160962

In this paper, a novel frequency control loop system for tunable notch filters is presented. The frequency control loop is designed for automatically tuning a microelectromechancial systems tunable notch filter, which has 22-dB rejection in the notch band and less than 0.8-dB insertion loss over a 5-MHz passband bandwidth in the International Mobile Telecommunications band (2.1 GHz). The filter frequency control loop is based on sensing the reflection phase change of a reference signal (in this case, the transmitter carrier) and is developed to track the transmitter operation frequency.