I hope it's more complicated than:
"some one thing" in your ship produces "detectable radiation" that you can mitigate by "shielding".
Something more like
"Several things" in your ship produce "different kinds of detectable radiation" that you can mitigate by "shielding" and behaviours. Not all shielding or behaviour will work for all your "signature" sources. So "turning your radiators away from the enemy" would mitigate the heat sig from rads, but not the energy signature from your reactor. Active equipment use (weapons, mining lasers, thrusters) should increase your detectability. Maybe damping the energy signature of your reactor makes hiding your heat sig harder.
Even individual elements need some complexity: your reactor might emit a signal baselined on its size, but that signal should increase as the power output of the reactor actually being used increases. Shut down thrusters should be low-sig, thrusters at full burn should be high. More thrusters? Higher sig.
You might be able to run a ship entirely off batteries and have very little reactor-based signature, but that has its own issues of endurance and vulnerability to damage.
There should be the option of active detection. Downside would be, that it's extremely visible itself, and there should be ways to mitigate the return your ship gives from such a device.
The interactions of simple things can produce complex outcomes: search methods; stealth approaches; compromise solutions that aren't "can I get the ore for that?" (to which the answer is always "yes" for a large portion of the population).
It could get *very* involved, and that's probably too much, but keeping some of these concepts in mind will stop the whole shebang being a pointless exercise in "Oh, we just have to add shielding and finding PvP becomes as hard as it used to be."