My ideas: Two waves forms.
Oscillations and Modulated flow:

1.- Waves by oscillation: Continuous inertial changes (i.e. waves up/down, without lineal displacement of the medium).
"A wave is an oscillating deformation of a physical medium that needs energy to be produced and to be maintained."
For instance,
Waves of sound, waves of the sea, pressure waves through a liquid or solid, vibration of a bell, etc., all of them need continuous energy supply to be maintained.
Here the applied force or impulse moves along the medium en wave form, diminishing rapidly by the constant deformation that goes suffering the medium.
* This way, waves of oscillation need of a medium that oscillate, and then, this waves can't propagate in the vacuum.

2.- Modulated flow: Continuous inertial state of motion.(i.e. uniform motion of particles along space).
Modulated Flow (MF) means emission of flows of particles or radio-particles modulated in tops and bottoms of more and less quantity of particles per cycle, that is, they aren't waves but rays of particles modulated in quantity and time.
However these long rays of emission can be converted into waves or electric oscillations by the receiving antennas when receiving more or less particles per unit of time.

So, the emission of particles, as can be radio-frequency, light, flow of electrons, etc., aren't proper waves or oscillation, but rays of modulated flow of particles.

With this formula we can search different parameters of a flow of particles, as can be: frequency, load per cycle, intensity of flow, energy of flow, etc.