HARMONIC SUPPRESSED DUAL-BAND BANDPASS FILTERS WITH TUNABLE PASSBANDS

摘要

PURPOSE: A harmonic-suppressed variable dual band pass filter (BPF) is provided to widen the range of adjustable frequencies in dual pass band compared to a normal variable filter. CONSTITUTION: A harmonic-suppressed variable dual BPF comprises a transmission line (TL), two varactor diodes, and a resonator. The transmission line has characteristic admittance and physical length (L1-L3). The two varactor diodes are connected to both ends (TLin,TLout) of the transmission line. The resonator comprises one varactor diode. The one varactor diode is short connected to the center of the transmission line. [Reference numerals] (AA,BB) Resonator