Electronic circuit, radar apparatus, and method of correcting radar transmission channels

A radar apparatus, comprising:

• an oscillating circuit;
• a plurality of transmission channels configured to transmit transmission signals to antennas;
• a plurality of reception channels configured to receive reception signals from antennas;
• and
• a test circuit configured to perform a test with respect to the transmission channels, wherein the plurality of transmission channels include:
• a plurality of adjustment units configured to receive a same oscillating signal having a predetermined frequency generated by the oscillating circuit, and configured to adjust a phase and an amplitude of the oscillating signal to produce output oscillating signals;
• and
• a plurality of coupling points configured to supply the output oscillating signals produced by the plurality of adjustment units to transmission antennas,
• wherein the test circuit includes:
• a plurality of couplers provided in one-to-one correspondence with outputs of the plurality of adjustment units;
• a plurality of equal-length lines sharing the same length and extending from the plurality of couplers, respectively;
• a plurality of mixer circuits coupled to the plurality of equal-length lines, respectively, each of the plurality of mixer circuits being configured to receive a same reference oscillating signal having the predetermined frequency and a corresponding one of the output oscillating signals;
• and
• a control circuit configured to cause the plurality of adjustment units to adjust at least one of the phase and the amplitude in response to direct-current components in outputs of the plurality of mixer circuits.