The electromagnetic spectrum corresponds to the set of all types of radiation known in the universe so far. It is distributed according to the wavelength of radiation that a substance can emit or absorb. The shorter the wavelength, the higher the frequency and the higher the energy. The spectrum can be roughly represented as follows:
We see that below the microwaves are the radio waves.
So the answer will be that the type of electromagnetic wave that has less energy than a microwave is the radio wave.