Patent ID: 7242236

Claim:
A mixer circuit configured to be coupled to a first local oscillator signal and a second local oscillator signal which is phase-shifted with respect to the first local oscillator signal, the mixer circuit comprising: a first transistor circuit with a first control input, a second control input, a first radio frequency input and a first intermediate frequency output, wherein a first local oscillator signal is applied to the first control input, wherein the second local oscillator signal is applied to the second control input; a second transistor circuit coupled to the first control input and the second control input and comprising a second radio frequency input for a radio frequency signal which is phase-shifted with respect to a radio frequency signal at the first radio frequency input of the first transistor circuit, and comprising a second intermediate frequency output for an intermediate frequency signal which is phase-shifted with respect to an intermediate frequency signal at the first intermediate frequency output; a first positive feedback element connected between a first intermediate node and the second control input; a second positive feedback element connected between a second intermediate node of the second transistor circuit and the second control input; a first impedance element connected between the first intermediate node and the first intermediate frequency output; and a second impedance element connected between the second intermediate node and the second intermediate frequency output.