Let's not confuse Phantom Power with Plug in Power. Phantom power is a 12v-48v low current, DC power signal that is superimposed on the balanced input to the microphone. As such, it is cancelled out by the differential stages without any filtering - hence the name Phantom! If a microphone does not require phantom power, it will happily ignore the signal as if it wasn't there. It is only really found on XLR mic connections.
Plug in power is 1.5V - 5V low current DC power that is applied to the signal line of an unbalanced mic connection and needs to be filtered out so that it does not interfere with the signal. If is commonly used on radio mics and consumer camcorders, laptops and phones etc. as it is easy to implement and does not complicate the wiring. There are a few different standards out there, including mini XLR, mini jack, Lemo, etc. and some manufacturers use different wiring standards, with the ring rather than the tip used as the power connection.
This means that just because a mic has a "stereo" (Tip, Ring, Sleeve) 3.5mm connection, it may still be mono, but the power is being supplied via the ring rather than the tip of the connection.
Stereo mics are normally more bulky as they have 2 capsules and are of limited value for recording 1 person speaking. Just to confuse things further, noise cancelling mics might have 2 capsules connected together to provide the noise cancelling effect, have a (Stereo) TRS connection but will of course still be mono. It might even be that the mic outputs are brought out on separate lines to facilitate processing in the main unit, but I have only ever seen this with some hands free phone kits for vehicles.