like they said, you have to solve this at the source, not along some 2" long trace.
Start with bypass caps right a the chip that is making the signal. 1000 PF in Parallel with 0.1 uF, as close as possible to the power supply pin and the ground pin. that will keep the circulating ground currents to a minimum. If you do not have a decent ground under the chip (such as a ground plane), or if your ground plane is cut under the chip, then stich over the cut with short soldered on wires.
After that, maybe near the chip output, you put a series L-C circuit to ground that is tuned to 520 MHz.