class E power amplifier fabrication problem

Sir ,
I designed class E power amplifier with the device ATF-54143 and fabricated it. The co-simulation and circuit simulations are far different.I fabicated circuit according to Co simulation results.But after fabrication results are not matching and the drain voltage when one terminal is connected to ground changing from 3V TO 0.5V and there is increament in the voltage nob.where the fault is?

I think is not justified to design a high-efficiency Class-E power amplifier at +20dBm, because at this relative low output power the transistor cannot behave as a perfect switch, as the Class-E requires.
Especially when use a transistor that was designed and manufactured as an LNA, which theoretically should work in pure Class-A operation.

Sir,
Then which FET i have to choose for the Class E operation at low drain supplies.

That's more the domain of submicron CMOS processes. I don't know if it's feasible with discrete devices at 2.4GHz.

Sir,
I designed class-E power amplifier with device atf-54143, in simulation it showed a gain of 14 dB but when it come in to case of fabricated design it showing negative gain of -30dB where is the problem but s11 showing -10dB but no gain at all?

Post your design. What are your bias conditions, and what is your RF input power?