Satellite communication works through a

Satellite communication works through a transponder, which receives, amplifies and retransmits signals.

A radar detects objects using reflected radio waves and is not the satellite relay device.

A TV is a receiving device, not the component that relays satellite signals.

A fibre optic cable is a ground based wired medium, not part of the satellite relay.

The transponder on a satellite shifts the uplink signal to a downlink frequency.

This allows a signal sent up to be broadcast back over a wide area.