A method includes a first port including a first measured channel, a second port including a second measured channel, a third port including a first reference channel, and a fourth port including a second reference channel, and a vector detector configured to perform detection based on a first and second feedback signal that are respectively output by the first and second reference channel to thereby obtain a first and second signal vector in response to the first port transmitting a first signal, and perform detection based on a third and fourth feedback signal that are respectively output by the first and second reference channel, to obtain a third and fourth signal vector in response to the second port transmitting the first signal. The first, second, third, and fourth signal vector are useable to calibrate a deviation between the first and the second measured channel.