EMI/EMC Analysis and Noise Reduction in High Frequency Devices

Electromagnetic interference (EMI) or radio frequency interference (RFI) is a type of electric or electronic emission that can degrade the performance of electronic circuit.The effects of electromagnetic interference (EMI) is particularly troublesome for printed circuit board (PCB) designed for high frequency RF circuits. The components on a PCB may be digital and analog. Transmission lines connecting the two different sections are used to transmit signals back and forth. Unfortunately, as frequency increases and signals are enhanced, noise related to those frequencies is also enhanced, thus creating EMI and RFI. In terms of propagating path, it classifies into conducted EMI and radiated EMI. The conducted EMI results from that the radiated signal stick on the power line and hard to detect and recognize. Therefore, it is necessary to build the causes and effects methodology by way of the correct measurement to maintain the electromagnetic compatibility (EMC), to target the electromagnetic interference, and to detect radio frequency interference.Electronic systems are expected to operate normally within a given environment without internally or externally radiating excessive amounts of electromagnetic energy. In this state, they are called electromagnetically compatible (EMC). This paper presents a methodology to minimize radiated EMI by proper designing of PCB and conducted EMI by using EMI filter.