Protecting fet amp from output mismatch

I have a 30 watt amplifier that I need to protect from various mismatches. I could put a ferrite isolator in between the load and amp fet, but can not afford the cost.

Is there some way I can use two 15 watt fets and a hybrid coupler at the output, and connect it up so that much of the reflected mismatch power ends up in a 50 ohm load instead of my fet drains? I know there are plenty of balanced amps made like this, but their purpose is to make s22 look good, not to protect the amp drains.

Unfortunately whatever topology is used, single amplifier, or parallel, or push-pull, the transistor(s) shall tolerate substantially increased over-voltage stress, as collector/drain voltage waveforms show much higher peaks under mismatch conditions than in nominal operation.
There are some approaches that use VSWR protection by clamping the voltage peaks either at the collector/drain or base/gate of the power transistor. But clamping protection circuits may result in RF performance degradation.

The only proven approach is accomplished by a feedback control system, which detects the peak voltage at the output collector node and clamps its value to a specific threshold by varying the amplifier gain or the input power.

On the other hand the 3dB insertion loss of the output hybrid it will improve with 6dB the output return loss, which will help under reasonable poor VSWR conditions.

While ago I found in the news that Freescale produced some 65:1 VSWR transistors, but probably they cost more than 10 isolators.
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I think Cascode Power amplifier can protect the amplifier from unwanted mismatch overvoltages..
Because, when the reflection occurs, the voltage across two transistors will be half..
But to be honest I have never seen a 30W Power Amplifier in cascode config.

Unfortunately I need to power thru when the big mismatch ocurs. I can't throttle back the input power to help protect it.

I was beginning to think of some sort of active matching network, but that might end up costing more than a cheap ferrite isolator too.