基于滤波器应用的PCB平面电感的电磁辐射研究

Some Electromagnetic Aspects of a PCB Planar Inductor Used in a Filter

为了研究PCB(printedcircuitboard)平面电感的电磁辐射问题,基于天线理论把平面电感线圈中的每一圈看作一个环形天线,估算了其远场辐射功率,说明其电磁辐射非常小,可以忽略不计.平面电感的近场耦合问题通过一个无源带通滤波电路加以讨论.逐点测出电路中某一个电感附近的辐射强度,并用MATLAB绘出三维辐射强度图,说明平面电感的近场辐射只发生在电感周围很近的区域,与线路中的导线相比对电路其他部分没有太大影响.

In order to study the electromagnetic radiations of a PCB （printed circuit board） planar inductor, each turn in the spiral windings of the inductor is taken as a loop antenna based on the antenna theory. Its far-field radiation power is estimated and found to be negligible. Its near--field coupling is discussed based on a passive band-pass filter contained PCB planar inductors. The radiation intensity of one of the inductors in the circuit is measured one by one point and the 3-D plot of it is given by MATLAB. The plot shows that the near-field coupling is only occurring in the area where the inductor is located, which hardly affect the rest of the circuit comparing with the track in the same PCB.