24 GHz microstrip bandpass filter on output is mentioned here:
https://electronics.stackexchange.com/questions/440004/has-anyone-designed-a-low-noise-amplifier-in-the-ism-band-24-ghz-using-the-dis

I took a fast look at that FET but could not stabilize it in the ten minutes I spent, without messing up the minimum noise figure. I hope to mess with it later, I don;t like it when instability wins.

Does anyone have any experience with balanced LNAs? A friend of mine claims that almost automatically stabilizes the circuit but I am skeptical.

Steve

In my previous job, we had the same problem with a SiGe transistor. We copied the application circuit at the datasheet, but it was really bad regarding wideband stability. A low-pass type network including biasing circuit worked well. But it degraded noise performance a little. If you are not a big customer, usually vendors do not reply your e-mails.

I've had a lot of experience using FETs like these down in L band to squeeze out the best noise temp possible for atmospheric instrumentation. The issue is these FETs have lots of available gain at low frequencies, so you have to give that gain somewhere else to go. The "easiest" method which I've had success with is using series-C, shunt-L, and maybe another series-L depending, on the input to match gamma_opt, and AC couple that shunt-L to ground with an RF decoupling cap good in your band of interest, and and also terminating it to 50 ohms with a "DC" decoupling cap. The gate voltage is fed through. In my case here, with 10 minutes of futzing around, I get series C of 0.22pF, shunt L of 1.78nH, and RF decoupling of 0.5pF. In this case, it wasn't quite enough for unconditional stability, but adding a 5 ohm series resistor at the drain fixed that. Degrades NFmin by a 0.037 dB, but stabilizes it everywhere. I didn't go so far as adding the drain bias network. The idea is that the FET will see the RF ground through the 0.5pF more than it sees the noise from the termination resistor in your band of interest. Hope that helps.

jmcghee... any possibility you could sketch that out?

Also, is it possible to add a bandpass filter that is designed so that it makes it "nearly impossible" to present an unstable load to the part? Maybe the unstable region is on the open side of the Smith Chart, and you make sure that the device sees a short circuit. I have never analyzed this, maybe you can't get there without some real resistance.

Thanks!