Numerical and experimental analysis of EMI effects on circuits with MESFET devices

This study develops theoretical formulae to model the time domain and frequency domain characteristics of the noise spectrum of a MESFET device induced by varying EMI conditions. The theoretical results are then compared with the experimental measurements. The experimental and numerical results reveal that the magnitude of the EMI-induced noise is related to the pulse height, the output load, the parasitic capacitance, the interference frequency and the interference amplitude. It is shown that a higher interference amplitude or frequency increases the harmonic noise. The theoretical method presented in this paper provides a convenient means of evaluating the EMI effects and signal-to-noise ratio (SNR) of MESFET and similar wavelength devices.