RF Mixers

Function: Frequency translation via nonlinear mixing of two input signals (RF and LO) to produce sum and difference frequencies (IF).

Key Parameters:

• Conversion Gain/Loss
• LO Drive Level
• Input/Output VSWR
• Isolation (LO-RF, LO-IF, RF-IF)
• 1dB Compression Point (P1dB)
• Third-Order Intercept (IP3)
• Noise Figure

Types:

• Passive Mixers: Use diodes; good linearity, require higher LO power.
• Active Mixers: Use transistors; provide conversion gain, better isolation, higher noise.
• Single-Balanced: Balanced LO or RF port.
• Double-Balanced (Gilbert Cell): Both ports balanced; superior rejection of unwanted signals.

Applications: Upconversion, downconversion in radios, radar, test equipment.