It is similar to mobile phone(two way) or radio (one way).
The only different is the frerqency and power level of the electromagnetic wave(EM wave) used.
There is an EM wave emtiier  which produce the EM wave (with encoded message), and it propragate in space .
When EM wave received by antenna , then the message in the EM wave will be decoded to get the message being transimitted.