Design of Plasma Diagnostic System Based on Linear Frequency-Modulated Continuous Wave

In this study, a plasma diagnostic system based on linear frequency-modulated continuous wave (LFMCW) is designed to calculate the electron density by determining the change of electromagnetic wave propagation time delay. The system adopts a swept microwave interferometry method to accurately measure the effect of plasma on the propagation time delay and solves the problem of phase-periodic ambiguity in the traditional microwave diagnostic method. This article describes the system design, including hardware selection, signal processing flow, and system simulation. Experiments show that the system can effectively diagnose high electron density plasma.