Electric and magnetic waves travel together (i.e., radiate) at the speed of light. "Spectrum" refers to all electromagnetic energy, regardless of the source. The electromagnetic energy emitted by transmitting antennas includes radio waves and microwaves.
Radiofrequency (RF) energy or radiation is the general term used to describe this type of energy or radiation. It is important to note that "radiation" does not mean "radioactive." When referring to electromagnetic or RF energy, "electromagnetic field" or "radiofrequency field" is commonly used.
The antenna's RF waves are generated by the electrical charges moving within the antenna. The wavelength and frequency of electromagnetic waves can be used to identify them. Electromagnetic waves have wavelengths and frequencies, which determine how far a wave travels in a single cycle of electromagnetic radiation. "hertz" is the most common unit for expressing the frequency of a radio frequency (RF) signal (abbreviated "Hz").
It is one cycle per second that is equal to one Hz. Every second, one million cycles occur at the rate of one megahertz (MHz).
The wavelengths and frequencies of electromagnetic energy are used to categorize different types of electromagnetic energy. The radiofrequency (RF) spectrum encompasses electromagnetic waves with frequencies ranging from 3 kilohertz (3 kHz) to 300 gigahertz (GHz) (300 GHz). In general, radiofrequency energy at frequencies between about 1 GHz and 30 GHz is called "microwaves."