Frequency-characteristics variable filter, duplexer, and communication apparatus
Patent 6414566 Issued on July 2, 2002. Estimated Expiration Date: 
June 1, 2020. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 1, 2020. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesAntenna diversity switching device with switching circuits between the receiver terminal and each antenna Resonator filter with variable tuning Antenna duplexer Patent #: 6085071 InventorAssigneeApplicationNo. 585201 filed on 06/01/2000US Classes:333/134, Utilizing long line element333/103Having semiconductor operating meansExaminersPrimary: Pascal, RobertAssistant: Takaoka, Dean Attorney, Agent or FirmForeign Patent References
International ClassH01P 001/20Foreign Application Priority Data1999-06-02 JPAbstractA frequency-characteristics variable filter, a duplexer, and a communication apparatus that can be operated at reduced bias voltages that are applied to diodes provided for switching frequency characteristics without reducing the stability of frequency characteristics and without increasing the occurrence of skews. Also, the single duplexer can be used for two frequency bands. As a diode for each of resonators in a transmitting filter and the first resonator in a receiving resonator, a diode having an interterminal electrostatic capacitance in the off state smaller than that of a diode used for other resonators is used. Also, the diodes for the resonators excluding the first resonator in the receiving filter has a lower forward resistance in the on state and an Q value in the off state higher than those of other diodes. | |
