Patent ID: 7013122

Claim:
A double balanced mixer for mixing an RF input signal with a local oscillator signal to provide at an output an intermediate frequency signal, comprising: a first diode ring having a first, second, third and fourth nodes; a second diode ring having a fifth, sixth, seventh and eighth nodes; a local oscillator balun for receiving a local oscillator signal at a local oscillator port, the local oscillator balun having first, second, third and fourth windings, the first winding having one end connected to the local oscillator port and the other end connected to the first node, the second winding having both ends connected to ground, the third winding having one end connected to the local oscillator port and the other end connected to ground, the fourth winding having one end connected to ground and the other end connected to the third node and the seventh node; a radio frequency balun for receiving an RF signal at an RF port, the radio frequency balun having fifth, sixth, seventh and eighth windings, the fifth winding having one end connected to the RF port, the sixth winding having both ends connected to ground, the seventh winding having one end connected to the RF port and another end connected to ground, the eight winding having one end connected to ground; and an intermediate frequency balun for providing an intermediate frequency signal at an intermediate frequency port, the intermediate frequency balun having ninth, tenth, eleventh and twelfth windings, the ninth winding having one end connected to the fifth winding and another end connected to the fourth node, the tenth winding having one end connected to the eighth node and another end connected to the intermediate frequency port, the eleventh winding having one end connected to the second node and another end connected to the intermediate frequency port, the twelfth winding having one end connected to the sixth node and another end connected to the eighth winding.