RF Module with ruler for size reference. An RF module (radio frequency module) is a (usually) small electronic device used to transmit and/or receive radio signals between two devices.In an embedded system it is often desirable to communicate with another device wirelessly.n RF transmitter module is a small PCB sub-assembly capable of transmitting a radio wave and modulating that wave to carry data. Transmitter modules are usually implemented alongside a micro controller which will provide data to the module which can be transmitted.