Patent ID: 6847269
Filing Date: 2005-01-25
Classification: H01L,H01P,H03H,H04B

Abstract:
1. A high-frequency composite part connected among a transmitting circuit, a receiving circuit and an antenna for controlling the connection between said transmitting circuit and said antenna, and the connection between said receiving circuit and said antenna, comprising: a transmitting signal control means comprising a first phase-shifting circuit and a high-frequency amplifier between said antenna and said transmitting circuit, wherein said high-frequency composite part comprises said high-frequency amplifier having impedance characteristics of being in a substantially short-circuited state at a stop in a frequency band of a receiving signal and said first phase-shifting circuit is connected to said high-frequency amplifier, and a receiving signal control means comprising a second phase-shifting circuit and a band pass filter placed between said antenna and said receiving circuit, said transmitting signal control means having impedance characteristics of being in a substantially open state in a frequency band of a receiving signal, while said high-frequency amplifier is at a stop, said receiving signal control means having impedance characteristics in a substantially open state in a frequency band of a transmitting signal, said transmitting circuit being connected to said antenna at transmitting, while said high-frequency amplifier is at work, and said antenna being connected to said receiving circuit at receiving, while said high-frequency amplifier is at a stop.