Analysis Of The Effect Of High-power Pulse On Microwave Circuits In FDTD

An analysis of microwave circuits under the high power electromagnetic pulse environment using FDTD method is studied in detail in this paper, with the emphasis on setting of the incident plane wave, simulation of microwave circuits and extraction of the scattering parameters. And some practical microwave circuits are analyzed with these methods.First, we reviewed the basic principle of the finite-difference time-domain method. The difference equations, the stability condition, the anisotropic PML absorbing boundary condition and the introduction method of the incident wave into the three-dimensional grid space are discussed.Second, several feasible methods incorporating the microwave devices into the FDTD simulation of microwave circuits are discussed. The first one is the extended FDTD method, including the equivalent current-source approach and the equivalent voltage-source approach. The second one is the modified extended FDTD algorithm, which can take the size of the components into account. The last one is the incorporation of SPICE analysis into FDTD codes, which can simulate the complex microwave circuits. And the general procedures of these methods are summarized in this paper.In addition, two methods for extracting the scattering parameters of microwave circuits are studied in this paper, with the emphasis on the matched load termination method. And a further research of the FDTD modeling of matched load terminating a microstrip line is made.Finally, two microwave circuits under the high power pulse environment are simulated using FDTD, a diode circuit and a microwave FET amplifier. And a brief analysis and discussion of each circuit is made to show the validity and efficiency of the FDTD method for this electromagnetic problem.