Hi,
I think you must check modern communications systems as ZigBee, WiFi and so on...
Important is that their band is at 2.4GHz, ISM- worldwide usable.
You will find lot of modules/circuits and ICs too...
Search pls for Wireless or wideband wireless moduls/communicatios.
The newest one called for ex.: UWB (UltraWideBad): is effective MW system, then has a working band of ca. 2-6/8 GHz, but I dont know exactly.
My be you can/will find the most articles at wireless sensors/systems...
K.