Do you know
how your mobile phone works?
Of course, you do not need to know such things. You just want
to have well-functioning and easy-controlled device, which gives
you possibility to get connection and to be reachable at any time
and any place.
However, could you imagine your mobile phone with two antennas
or the situation when you need to press a button if you speak and
to release it if you listen to?
It would be of great inconvenience.
And it would be so, if small device based on microwave ferrite
would not exist, that enables your mobile phone to operate in duplex
mode - to recieve and transmit signals simultaneously.