Research on the electromagnetic radiation of a PCB planar inductor

In this paper, the electromagnetic radiations of a PCB planar inductor are researched based on the antenna theory. For the far-field radiation, each turn in the spiral windings of a PCB planar inductor can be viewed as a loop antenna. According to the antenna theory, it is a small loop antenna in the frequency range of 30MHz to 300MHz. By this assumption, the radiation power of a PCB planar inductor is estimated and found to be negligible. Furthermore, by comparing the radiation resistance of a small loop antenna with it of a short electric dipole, show that the radiation power of a turn in the spiral windings of a PCB planar inductor is far smaller than a copper track with the same dimensions in the printed circuit board. The near-field coupling is discussed based on a simple resonant electric circuit with a PCB planar inductor. The 3D plot of near-field radiation intensity is given, by which illustrate that the near-field coupling is only occur in the area where the inductor is located.