Intermodulation nulling in anti-parallel diode pair mixers

Anti-parallel diode pair mixers offer the benefit of intermodulation nulling without conversion nulls. However, the practicality of intermodulation nulling in improving mixer distortion performance is dictated by the trade-off between conversion loss and local oscillator drive power requirements. In systems where noise figure is not critical and availability of local oscillator drive power is at a premium, intermodulation nulling can be most useful. A correlation between third-degree non-linearity and intermodulation null with respect to local oscillator drive is found. This correlation allows the designer to optimize the intermodulation distortion for a given local oscillator power by changing the mixer source and load impedances.