I designed this circuit board and was warned the 5 Ghz smt transistor might oscillate. It does! I thought I was doing the right thing when I opened up the ground plane under the transistor. Now I find that a wire across the opening I made stops the oscillation. I just layed the wire across the open area, I haven't soldered the wire yet. ( I hope that doesn't bring a surprise) Here's the PCB (Top left), red circle shows where smt transistor is mounted. (Top right) shows opening I made in ground plane. (Lower Right) shows single wire across open area that stops oscillation.
Any one want to tell me what I might have done different, and what I should do now. Oh, I thought putting it in the metal box would stop the oscillation, it got worse. Hmm.. maybe my (wire) will not solve the problem when I put it in the box. (Only need 10 Mhz band width.) Thanks, Mikek