Developing full-wave simulators for high-frequency circuit simulation is a topic many researchers have investigated. Generally speaking, methods invoking analytic pre-processing of the device¡¦s V-I relations (admittance or impedance) are computationally more efficient than methods employing numerical procedure to iteratively process the device at each time step. For circuits providing complex functionality, two-port or possibly multi-port devices whether passive or active, are sure to appear in the circuits. Therefore, extensions to currently available full-wave methods for handling one-port devices to process multi-port devices would be useful for hybrid microwave circuit designs. In this dissertation, an efficient scheme for processing arbitrary multi-port devices in the finite-difference time-domain (FDTD) method is proposed. The device¡¦s admittance is analytically pre-processed and fitted into one grid cell. With an improved time-stepping expression, the computation efficiency is further increased. Multi-port devices in the circuit can be systematically incorporated and analyzed in a full-wave manner. The accuracy of the proposed method is verified by comparison with results from the equivalent current-source method and is numerically stable.

The finite-difference time-domain (FDTD) method is one of the most popular numerical electromagnetic analysis tools. This method has been applied to a wide variety of problems such as antennas, electronic packaging, waveguides, etc. However, it is not suitable for large scale structures. The enormous memory requirement prohibits the use of FDTD to a large electrical size. Recently, the pseudospectral time-domain (PSTD) method has been introduced for solution of Maxwell¡¦s equation. This method adopts the Fourier transform algorithm to perform the spatial derivatives. According to Nyquist sampling theorem, it requires only 2 cells per wavelength, so that it is possible to efficiently model larger scale problems. This thesis describes a combination of PSTD and FDTD method applied in different directions. The FDTD be applied to directions along fine structures and the PSTD be applied in direction along large structures.

In this paper,we used Finite-Difference Time-Domain Method to Analyze CPW and Antenna.In CPW ,we had to process excitiation source and ABC.Or we couldn`t get correct result.In antenna analysis,we used KSIR to calculate antenna pattern.

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FDTD is a numerical method that uses the second-order central-difference method to discrete the Maxwell¡¦s equations in differential form, and positioning electromagnetic field in space grids and time grids. It is applied to analyze many electromagnetic problems in time domain. In this report the FDTD method is extended to include lumped-elements (as resistor, inductor, capacity),and nonlinear elements(as diode, transistor) to combine the circuit elements and electromagnetic fields, it¡¦s so called LE-FDTD algorithm. The first, we will introduce the theory derivations and simulate some circuit structures in 2D, and then in order to simulate the real circuits, we will extend this algorithm in 3D to make full-wave analysis.

For the advanced high speed digital circuits with faster edge rate, smaller packaged size, and higher layout density, crosstalk becomes one of the serious problems for good signal integrity (SI) in the circuits. Accurate extraction of the equivalent model of the general three conductors transmission lines structure can help us understand the behavior of the crosstalk phenomenon. Based on combining the Layer Peeling Technique (LPT) and Finite-Difference Time-Domain (FDTD) numerical approach, both the impedance profile and the equivalent lumped model of the three-conductors transmission lines are theoretically obtained. The equivalent model can easily incorporate into SPICE program. The transient behavior of the these extracted model is compared with the experienced results measured by Time-domain Reflectometry (TDR). The agreement is good.

Because SAW filters are small, high reliability, and it cannot be easily integrated with silicon substrate, they have become one of the most popular communication passive components recently. As the working frequency becomes higher, SAW filters are more sensitive to electromagnetic interference introduced by the package. Discrepancy in performance between design and measurement can be large if the packing effects are not considered. In this thesis, we make use of Finite Difference Time Domain method (FDTD) and develop a procedure combining High Frequency Structure Simulator (HFSS) with ADS software to simulate electromagnetic effect of a packaged SAW Filter. This is a full-wave method that integrates electromagnetic wave and acoustic wave. Measurement is also carried out to verify the simulated results. Preliminary results show that this method that we provide can predict frequency response in package effectively. Our Prediction can save factory design time and production cost.

FDTD is an electromagnetic field computation method with the ability of considering circuit elements. Traditional lump element method is insufficient for simulating circuit. In this thesis, we use equivalent source method to combine non-linear circuit elements like active devices into the FDTD simulation. The advantages of this is powerful and time-saving. The accuracy of this method is checked of transmission line driving by CMOS circuits. By employing this method, we find that it will increase EMI phenomenon by strengthening current of driving load, and the load of coupling line will affect noise due to impedance mismatch.

The FDTD method is a numerical method that uses the second-order central-difference method to discrete the Maxwell¡¦s equations in differential form, and positioning electromagnetic field in space grids and time grids. It is applied to analyze many electromagnetic problems in time domain. In the thesis, we applied FDTD methods to solve EMC/EMI problems like the interference to a mixer from an antenna, and the packaging effects to a small signal microwave amplifier and so on. Therefore, we applied equivalent current source approach to simulate each microwave elements at first. And, we extend the approach to field of EMC/EMI. researching the advantages of FDTD methods in Full-Wave analysis.

The finite-Difference Time Domain method (FDTD) is to derive the discrete form of the Maxwell¡¦s equations by second-order central difference with the electromagnetic distribution of the Yee space lattice, and computes the value of the electric field and magnetic field in the simulation space by using leapfrog for time derivatives. This method is also different with the frequency domain method which needs to analyze its value individually (ex. Finite Element method). The frequency domain method needs to take a long time for analyzing the response on each spectrum point when the bandwidth is very wide. The advantage of time domain analysis is to obtain the complete frequency response from the simulation value through Fourier Transform method. It¡¦s impossible to combine the electromagnetic analysis with the lumped circuit simulation in current simulation CAD. Thereby the performance of the simulation result and the practical implementation always occurs error because of the lake of the consideration. The FDTD method is the full-wave algorithm which can also simulate the lump element, nonlinear element or active element in simulation space by linking to SPICE or S-parameter. The purpose of this thesis is to develop the method for simulating microwave circuit, and to verify the credibility between the equivalent source method and the S-parameter method in FDTD by the simulation of active antenna and low-noise amplifier.