| 摘要 |
PURPOSE: To reduce power consumption by providing at least two impedance converters and switch means on the output side of a transmitter output stage and performing switching between transmission and reception based on the change of the output impedance. CONSTITUTION: A transmission output stage 31 matches the input resistance of a secondλ/4 waveguide 33 at the time of transmission. Since the characteristic impedance of the waveguide 33 is equal to an antenna impedance, all of the transmitter power of the transmission stage 31 is transmitted to an antenna 1. At the time of reception, a first switching transistor 31 switches the output stage 31 to the high impedance state. Then, is firstλ/4 waveguide 32 is converted to high-impedance termination by characteristic impedance conversion of the waveguide 33. Thus, the input impedance of a transmission part 3 is made high. An input transistor is used together as a switching element to reduce a required space and the power consumption.
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