Radar device and method for changing reception gain of radar device

A method for changing a reception gain of a radar device, comprising:

• repeatedly generating, at a time interval, a transmission signal to be output to an antenna in order to transmit a detection signal from the antenna by a transmission signal generator;
• converting a frequency of an echo signal obtained by reflecting the detection signal and receiving the detection signal by the antenna and amplifying a signal level thereof, by a frequency convertor, within a period from a time when the transmission signal generator completes outputting the transmission signal to the antenna to a time when a next one of the transmission signal starts to be output to the antenna, and performing processing on an amplified signal by a processing circuitry;
• inputting the transmission signal to the frequency convertor by a path switch as a calibration signal at a timing while the transmission signal is being output to the antenna, and converting a frequency of the calibration signal by the frequency convertor and amplifying a signal level thereof;
• and
• changing an amplification gain of the frequency convertor, by an amplification gain adjuster, based on a signal level of the calibration signal input to the frequency convertor and a signal level of the calibration signal having been amplified by the frequency convertor.