This study mainly involved examining a high-directivity radiation system with spherical dielectric resonator as pseudo multipole source. The method of spherical wave expansion is focused on wherein the plane wave that is infinitely spread can be radiated from or absorbed by multipoles at the origin. It is not possible to explain this phenomenon by Huygens' principle, which is a basic principle of aperture antenna theory. Thus, in the study, a high-directivity beam design is proposed by synthesizing spherical waves. The directivity of the synthesized spherical wave corresponds with the angular momentum and angle, which is an uncertainty relation different from that of the aperture source. The estimation of the effective aperture of the synthesized spherical wave indicates that the wave intrinsic source is assumed to exist at the surface of the cutoff region. Finally, the results reveal that a radiation system without a singular point can be composed using a spherical dielectric resonator. The study discusses the potential of a high-directivity radiation system constructed by a multi-mode degenerate spherical dielectric resonator as a pseudo multipole source.