Title:
VARIABLE FREQUENCY FILTER, ANTENNA SHARING DEVICE AND COMMUNICATION EQUIPMENT
Document Type and Number:
Japanese Patent JP3465630
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an antenna sharing device that can cope with two frequency bands and decreases the bias voltage applied to a diode to switch the frequency characteristics without deteriorating the stability of the frequency characteristic and increasing distortion and to provide a communication equipment.
SOLUTION: Diodes with smaller capacitance in an OFF state than diodes D4, D5 provided in other resonators are employed for diodes D1, D2, D3 provided in resonators R1, R2 of each stage of a transmission filter and a resonator R3 at a first stage of a reception filter respectively. Furthermore, diodes with a smaller forward resistance in the case of ON state and with a higher Q in the OFF state than the other diodes are employed for the diodes D4, D5.
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Inventors:
Hiroyuki Ushirokawa
Application Number:
JP15476299A
Publication Date:
November 10, 2003
Filing Date:
June 02, 1999
Export Citation:
Assignee:
MURATA MANUFACTURING CO.,LTD.
International Classes:
H01P1/205; H01P1/213; H03H7/12; H03H7/46; H01P1/20; H04B1/44; (IPC1-7): H03H7/12; H01P1/20; H03H7/46; H04B1/44
Domestic Patent References:
| JP11122139A | ||||
| JP1280903A | ||||
| JP7321509A | ||||
| JP200059109A | ||||
| JP11243304A | ||||
| JP10247833A | ||||
| JP7336267A | ||||
| JP7321586A | ||||
| JP7147503A |
Attorney, Agent or Firm:
Hisao Komori