Title :
Tuning a bandpass filter by optical control of a negative-resistance circuit
Author :
Yamamoto, Yukio ; Imon, Yoshiharu ; Mikumo, Satoshi ; Katsuragi, Motohira
Author_Institution :
Dept. of Electr. Eng. & Electron., Osaka Sangyo Univ., Japan
fDate :
12/1/1998 12:00:00 AM
Abstract :
A novel tunable active bandpass filter is presented in X-band. Basically, this is an end-coupled half-wavelength microstrip bandpass filter coupled by a high-Q value negative-resistance circuit, which is optically tunable. In this filter, one MESFET works both as a tuning element and negative resistance. To increase the tunability of the active MESFET circuit compared with the half-wavelength resonator, the port of the negative resistance is connected to the open stub through one side line in the quarter-wavelength coupler. Tuning range of 123 MHz is achieved by optical tuning. This optically tunable range of the active bandpass filter exceeds 1% of the center frequency
Keywords :
MESFET circuits; active filters; band-pass filters; circuit tuning; microstrip filters; microwave photonics; negative resistance circuits; optical tuning; MESFET; X-band; active microstrip bandpass filter; half-wavelength resonator; negative resistance circuit; optical tuning; Band pass filters; Circuit optimization; Coupling circuits; Microstrip filters; Optical control; Optical coupling; Optical filters; Optical resonators; Optical tuning; Tunable circuits and devices;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
