Microwave mixer performance parameters:-

• Conversion loss: The conversion loss is defined as the ratio of the available RF input signal’s amplitude and the IF output signal’s amplitude. Conversion loss is expressed in dB.

Conversion loss depends on following mixer terms:-

a. Loss due to diode resistance. (Ld)

b) Loss due to port mismatch. (Lm)

c) Loss due to harmonic generation. (Lh)

Thus total conversion loss is given as,

Lc= Ld+Lm+Lh in dB.

• Spurious performance: Basic theme behind use of mixer is either up or down convert frequency components. Poor isolation between input ports may generate spurious at the output. This may degrade system performance.

• Isolation: Isolation is very important for the performance parameter of the mixer. Isolation is a measurement of the amount of power that leaks from one port to another. Isolation between tow port defines mixer sensitivity and as well as selectivity.

Two different isolation are observed in the mixer are as follows:-

a) Isolation between RF and LO ports.

b) Isolation between IF and LO ports.

Isolation between RF and LO ports has to be maximum as possible to improve mixer performance.

• Dynamic Range: Dynamic range is the power range over which a mixer provids useful operation. Upper limit of dynamic range is limited by conversation compression point and lower limit is limited by noise figure of mixer.

• Conversion Compression: Conversion compression is a measurement of maximum RF input signal fow which the mixer will provide linear operation.