HIGH-FREQUENCY RADIO CIRCUIT

摘要

The invention relates to a high frequency wireless circuit apparatus mainly used in mobile communication appliances such as a portable telephone and an information communication terminal. It is hence an object to improve the reception sensitivity and immunity to interference signals. The high frequency wireless circuit apparatus of the invention is composed by connecting a phase shifter 10 between an antenna duplexer 13 and a low noise amplifier 16, so that the impedance of the receiving terminal of the antenna duplexer 13 at a transmission frequency and the input impedance of the low noise amplifier 16 may not be matched in complex conjugates of each other. Therefore it prevents the transmission output passing through the receiving terminal of the antenna duplexer 13 and the interference signal entered through the antenna 11 from making the cross modulation in the low noise amplifier. Thus it improves the reception sensitivity and immunity to interference signals of the high frequency wireless circuit apparatus at the same time. <IMAGE>