ANTENNA SHARING DEVICE AND COMMUNICATION EQUIPMENT DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain a miniaturized antenna sharing device and communication equipment device capable of efficiently removing the higher harmonic waves in a transmission signal generated by a transmission/reception changeover switch. SOLUTION: This antenna device is provided with a frequency variable filter 13 for switching transmission and reception bands through voltage controlled PIN diodes D1-D3 and a transmission/reception changeover switch 14 connected to an input/output terminal at one end of this frequency variable filter 13. The frequency variable filter 13 couples three stages of resonators 24-26 through coupling capacitors C4 and C5. An input/output terminal P1 of the frequency variable filter 13 is electrically connected through aπ-shaped LC circuit (low-pass filter) composed of a coupling coil L5 and capacitors C6 and C7 to the resonator 24. An input/output terminal P2 is electrically connected through aπ-shaped LC circuit (low-pass filter) composed of a coupling coil L6 and capacitors C8 and C9 to the resonator 26.