What device generates high frequency power that is radiated through space?

The correct answer is a transmitter, as it is the device specifically designed to generate high frequency power and convert it into electromagnetic waves that can be radiated into space. Transmitters play a crucial role in communication systems by modulating a signal for broadcast.

In the context of radio frequency systems, the transmitter creates the initial signal that is then sent through an antenna for radiation into the environment. The transmitter's high frequency capability allows it to effectively communicate over long distances and through various media.

The other options, while related to communication, do not generate high frequency power themselves. A receiver is designed to capture and decode signals transmitted by the transmitter; an antenna primarily functions to radiate or receive electromagnetic waves but does not generate them. A coaxial cable serves as an electrical conductor for transmitting signals between devices, but it does not create high frequency power on its own.

Overall, understanding the role of each device in the communication process is key, and the transmitter is essential for producing the initial high frequency signals used for wireless communication.