A searching method for optimal locations of decoupling capacitors based on electromagnetic field analysis by FDTD method

This paper describes a searching method for positions of decoupling capacitors on the printed circuit board (PCB). In this method, first, the distributions of electromagnetic field between power and ground planes in the time domain are simulated, using FDTD method. Next, the distribution of Poynting vectors in the frequency domain is investigated, using fast Fourier transforms (FFT). Furthermore, this method finds the optimal location of decoupling capacitor so that the Poynting vector is the highest.