To generate an electromagnetic wave, the oscillation of a single charge is not sufficient. An electromagnetic wave is created by the oscillation of both electric and magnetic fields, which are interconnected and propagate together.
According to Maxwell's equations, which describe the behavior of electric and magnetic fields, changing electric fields create magnetic fields, and changing magnetic fields create electric fields. This mutual dependence leads to the formation of electromagnetic waves.
In the context of generating electromagnetic waves, an oscillating charge acts as a source of the changing electric field. As the charge oscillates, it creates variations in the electric field around it. This changing electric field then generates a magnetic field. The magnetic field, in turn, induces changes in the electric field, and the process continues, resulting in the propagation of an electromagnetic wave.
Therefore, it is the interplay between the changing electric and magnetic fields that generates an electromagnetic wave. Both electric and magnetic fields are essential components of the wave and cannot exist independently of each other.