What is wave communication?

When an electrical field changes sign, some of the energy will radiate into space. When the sign reverses the field will change again.

Thus radiated into space at approx the speed of light will be a series of electromagnetic waves.

These waves can also carry modulation - a characteristic of the wave may be varied. In the simplest form, the amplitude of the radio wave (commonly known as the carrier) may be varied by applying a speech signal for example.

Several other modulation styles are also available, and I'll just name them, rather than describing them. Phase Modulation, Frequency Modulation, Pulse Modulation.

In addition, the polarization of a wave may be varied.