The Simulation Of Hybrid Circuit By Higher Order FDTD Method

The high order finite-difference time-domain method is one of several numerical methods to solve electromagnetic problems. This thesis describes the using of the high order finite-difference time-domain method simulation in microwave circuits. When the operating frequency of the microwave active circuit increases, the electromagnetic coupling, crosstalk and electromagnetic radiation between the various elements must be taken into account. However, the conventional circuit analysis method ignores the high-frequency electromagnetic interference. Because the microwave circuits contain relatively small size elements, the higher order finite-difference time-domain method that solving Maxwell equations take the interaction between the electromagnetic wave and microwave circuit elements into account. Including electromagnetic interference, the method will increase the accuracy and effectiveness of the simulation. Based on the above advantages, the higher order finite-difference time-domain method is increasingly becoming more and more effective and acclaimed electromagnetic simulation method.First of all, we introduces some basic concepts and formulas of the high order finite-difference time-domain method, which include the differential equations, iterative formulas of higher order finite-difference time-domain method, the stability conditions, the absorbing boundary conditions and the excitation source.Next, we introduced the modeling of microwave circuit by high order finite-difference time-domain method. Also, how to use the volt-ampere characteristics of the circuit setting the Lumped element to D-H iterative formulas of high order finite-difference time-domain method is included. Then the linear lumped element resistance, inductance, capacitance and nonlinear lumped-element diode were simulated. The various parameters of simulation are closer to the data obtained by software simulation. So the high order finite-difference time-domain method is more suitable to simulate active circuit of lumped elements.Finally, we introduced three instances of the hybrid circuit. Then these examples are simulated with the high order finite-difference time-domain method. The electric field diagrams and voltage diagrams of the microwave circuit at different times are presented, which provides an important basis of the electromagnetic coupling of the microwave circuit. The simulated various parameters were very consistent with data by software, so high order finite-difference time-domain method is effective in solving such problems.