It's not a MiniCircuits MMIC because the input and output traces are reversed (MiniCircuits marks the input with a dot). The most likely candidate I can come up with is a GaAs RF MOSFET, part # ATF-10736. In any event, the resistance between that pin and ground should not be so low.
That said, cutting through the input trace to make that resistance measurement was a bad move, as the trace is designed to act as an impedance matching network at high frequencies (>1GHz). Thus you can expect degraded performance (higher noise floor, more spurs, etc.) even if replacing this part solves the problem.