help,why my VSWR(S22) is so big?

Size isn't matter, the function is important..

that IS big. Tune for maximum smoke, then retest.

hi，biff
what is the meaning of the maximum smoke?

The output side of whatever the device is.. is not the right impedance to match to the load. A VSWR approaching 3.0 means nearly half the energy is being reflected. That it is frequency-dependent around 2.6GHz might indicate some network components or structure resonant at 2.6GHz loading or contributing to the mismatch.

If it cannot be adjusted, or altered to make the output impedance match the load, then there is needed to be added a "matching network section" to do this.

"Tune for maximum smoke" is a humorous allusion to a perfectly reasonable ad-hoc diagnostic procedure that saves much time, and many of us are guilty of using at times. When you spot the part getting hot, or even expiring in smoke, you know you have found where the problem is, or at least you have gained substantial pointers to what it might be consequential to. :)

Example: Lacking a power meter, then putting a drop of oil onto a too-small 50-ohms resistor soldered across a chassis connector, then tuning the PA until smoke is seen .. is a fast way to learn something useful.

hi,Darktrax
thnx for ur help!