I would like to buy a small router which has one poe port to connect the AP. Could you give me a model of the device?
Your IPCam and AP is probably 802.3af/at (which is a standard). Many Mikrotik products are PoE but only output at 24v, so not 8.2.3af/at.
The Hex Poe router supports 802.3af but comes with a 24 volt power supply, so you have to buy the 48POW power supply separately.
The RBGPOE is a power injector. It does not come with a power supply, so you can use the one that comes with your AP or IPCam, or buy a 48V power supply (the 48POW from Mikrotik).
Hex POE: https://mikrotik.com/product/RB960PGS
RBGPOE: https://mikrotik.com/product/RBGPOE
48POW: https://mikrotik.com/product/48POW