A device for mixing or multiplying frequency, comprising: a metal housing, comprising a box body and a cover buckled together to define a metal cavity; at least one frequency conversion unit, comprising: a microstrip line located in the metal cavity; and a channel structure comprising a radio frequency signal input channel , a local oscillator signal input channel and a signal output channel, the radio frequency signal input channel , the local oscillator signal input channel and the signal output channel pass through the metal housing and are coupled to the microstrip line respectively, wherein at least two of a plane where the radio frequency signal input channel is located, a plane where the local oscillator signal input channel is located and a plane where the signal output channel is located are not coplanar, wherein the signal output channel is led out perpendicularly to a plane where the microstrip line is located; wherein each of the radio frequency signal input channel and the local oscillator signal input channel is located in a plane in parallel to the plane where the microstrip line is located, characterized in that : each of the radio frequency signal input channel and the local oscillator signal input channel extends in a direction in parallel to a length direction of the microstrip line ; and wherein each of the radio frequency signal input channel and the local oscillator signal input channel is coupled to the microstrip line through a turn. a metal housing, comprising a box body and a cover buckled together to define a metal cavity; at least one frequency conversion unit, comprising: a microstrip line located in the metal cavity; and a channel structure comprising a radio frequency signal input channel , a local oscillator signal input channel and a signal output channel, the radio frequency signal input channel , the local oscillator signal input channel and the signal output channel pass through the metal housing and are coupled to the microstrip line respectively, wherein at least two of a plane where the radio frequency signal input channel is located, a plane where the local oscillator signal input channel is located and a plane where the signal output channel is located are not coplanar, a microstrip line located in the metal cavity; and a channel structure comprising a radio frequency signal input channel , a local oscillator signal input channel and a signal output channel, the radio frequency signal input channel , the local oscillator signal input channel and the signal output channel pass through the metal housing and are coupled to the microstrip line respectively, wherein at least two of a plane where the radio frequency signal input channel is located, a plane where the local oscillator signal input channel is located and a plane where the signal output channel is located are not coplanar, wherein the signal output channel is led out perpendicularly to a plane where the microstrip line is located; wherein each of the radio frequency signal input channel and the local oscillator signal input channel is located in a plane in parallel to the plane where the microstrip line is located, characterized in that : each of the radio frequency signal input channel and the local oscillator signal input channel extends in a direction in parallel to a length direction of the microstrip line ; and wherein each of the radio frequency signal input channel and the local oscillator signal input channel is coupled to the microstrip line through a turn. <EOS>