about mixer IIP3 simulation testbench,please help.

The mixer is differential RF/LO in and differential IF out (see schematics). RF and LO port input signal is AC coupled and DC bias is after the AC coupling CAP.

The mixer is onchip IC and previous stage is on chip LNA. The stage after the mixer is also onchip IF filter. So there is no matching problem here. But looking at some reference they all require balun something to match.

what is the right setup by present I am using power sine source in RF input with 50 ohm source resistor. The LO port only use voltage sine source and the output is terminated with 2k ohm which is the IF filter's input resistor.

In the above setup the IIP3 simulated is about 3dbm which is less than I expected. What is wrong with my setup.

Thanks.

Added after 7 minutes:

why I cannot attach an 700k image.

As your circuit is characterized by voltage (and not power) gain, be sure you appy and measure correct sources and loads.
A common practice is to talk about equivalent power levels. for example you can express the input voltage as equivalent power to 50 Ohm load.
To do so, take the 50 Ohm source and connect to 50 Ohm resistor. Take the input voltage and convert it into differential using voltage controlled voltage sources. Use these voltages to supply the Mixer.
Check that the input voltage is what you expect.
Similar you can do for your circuit load, if you're interested also in voltage to power conversion at output.
Be aware if you simulate noise!
The bench is a little different and depends on noise quantity you want to calculate.

I hope it can help.
Mazz

Thanks Mazz.

I read post in the forum including yours former posts. I find people just like me is confused by power and voltage. When we use power gain and when to use voltage gain?

For the mixer case, using the method as you mentioned above it is basically talking about voltage rather than power since IIP3 is a voltage convept but people want it in power unit so just convert this iip3 voltage to power via a preagreed 50 ohm or 75 ohm.

In my case the RF and LO signal is AC coupled to the mixer port. why donot I need some mathing in these ports. In what condition need I to match the LNA's output impedance conjugate matched with the LO's RF input port?

Thanks