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

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 C_min/C_max <; 2; relatively large minimum capacitance C_min > 0.4 pF; low quality factor Q_c.