In classical electromagnetism, electromagnetic waves, including radio waves, are described by Maxwell's equations. In this framework, electromagnetic waves are considered to be transverse waves, meaning their oscillations occur perpendicular to the direction of propagation. This implies that the wave has no width or height in the traditional sense, as the oscillations are purely in the plane perpendicular to the direction of propagation.
Classical electromagnetism treats electromagnetic waves as continuous fields, and their properties such as intensity, frequency, and wavelength are described by their respective equations. However, this classical description does not assign dimensions of width or height to the waves themselves.
In quantum electrodynamics (QED), which is the quantum field theory that describes electromagnetic interactions, electromagnetic waves are quantized, and their interactions are described in terms of particles called photons. Photons are considered point-like particles with no physical size or dimensions beyond their wavelength or frequency. They do not possess width or height in the classical sense.
In quantum mechanics, electromagnetic waves are described by wave functions, and the probability density associated with the wave function determines the likelihood of finding a photon at a particular position. However, the wave function does not attribute width or height to the electromagnetic waves themselves.
Therefore, whether we consider classical electromagnetism, quantum electrodynamics, or quantum mechanics, the description of electromagnetic waves does not involve dimensions of width or height beyond their length or wavelength.