高频电路构成的装置或设备,其金属结构件(包括外壳)的接地问题对于抗干扰十分重要。首先,如金属外壳或金属部件接地不良,在外界产生静电放电时会向内部电路辐射强大电磁脉冲,产生干扰以至损坏器件。另外,金属结构件均能传导电流,这些高频电流的辐射也会对电路造成不良影响。特别是,机械结构部件如果是电气浮接或接地不良,则会在结构本身与其它接地良好的部件之间产生电压,而此电位差会形成一偶电极并辐射出电场。因为一个简单的电容器是由两块被空气或介质相隔的金属片组成,金属片之间的电场强度就是将电位差除以金属片之间的距离。但电场不会限制于金属片的边缘,电力线 High-frequency circuit devices or devices, the metal structure (including the shell) of the grounding problem is very important for anti-interference. First of all, if the metal case or metal parts are not grounded properly, strong electromagnetic pulses will be radiated to the internal circuit when the electrostatic discharge occurs from outside to cause interference and damage to the device. In addition, the metal structure can conduct current, the radiation of these high-frequency current will have an adverse effect on the circuit. In particular, if the mechanical structure is electrically floating or poorly grounded, a voltage is generated between the structure itself and other well-grounded components that form a dipole and radiate an electric field. Because a simple capacitor consists of two pieces of metal separated by air or medium, the electric field strength between the pieces of metal is the difference in potential divided by the distance between the pieces of metal. But the electric field will not be limited to the edge of the sheet metal, power lines