Tunable RX filter with ferroelectric capacitors for DCS, PCS and UMTS communication systems





tunable filters, ferroelectric capacitor, microstrip resonator, duplexer, duplex spacing


A new structure of a bandpass filter with steep left slope of the frequency response, tunable by ferroelectric capacitors, is proposed. The filter can be used in receiving channel (RX) in communication systems of DCS, PCS and UMTS standards. The computer simulation of the frequency responses of the filter has been performed for the following conditions: feasible parameters of ferroelectric capacitors; small capacitance range Cmin/Cmax < 2; relatively large minimum capacitance Cmin > 0.4 pF; low quality factor Qc.


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