Surface Plasmon Waveguides And Meteor Burst Communication Antennas

Under the restriction of diffraction limit, the conventional dielectric waveguiding structures are unable to meet the continuously demand of high density and miniaturization. Surface plasmon waveguide (SPW) utilizing the so-called surface plasmon polaritons (SPPs) is promising for its unique capability of manipulating light on the subwavelength scale beyond the physical limit, which can lead to integrated, high-speed and compact optical circuits.Meanwhile, as a recognized final means of communication support, the Meteor Burst Communication (MBC) has been widely utilized to military and civilian fields due to its own features. Thus, in order to satisfy the increasingly electrical characteristic requirements, the research on the key part-antenna with higher performance is becoming a daunting issue.Furthermore, numerical approaches, optimization algorithms and other computational electromagnetics methods play a major role in almost all areas of science and technology. They can analyze and design the behavior of functional devices more quickly and accurately, therefore the study focusing on these methods is very important for the development of electromagnetic wave propagation applications.Based on the research projects, in this dissertation, the parallel finite difference time domain (FDTD) method, surface plasmon waveguide and the MBC antenna are presented intensively. The author’s key contributions are sumed up as follows:1. Three-dimensional dispersive FDTD method is given. According to the lossy metal property in surface plasmon waveguides, the Drude dispersion model is applied to produce the updating three-dimensional FDTD equations, with uniaxial perfect matched layer (UPML) as the absorbing boundary condition. The corresponding dispersive FDTD algorithm is compared with the basic FDTD to demonstrate the necessity of parallel computing.2. OpenMP-based parallel FDTD algorithm is studied. Combining the dispersive FDTD with OpenMP multi-thread technique, a parallel FDTD algorithm is realized on a single multi-core processor. The parallel performance of the method is tested by dealing with non-dispersive and dispersive structures respectively. It renders that the results of the parallel FDTD are coincide with those of the serial FDTD, the computation cost can be efficiently decreased with the scalability reaching 9.54. However, owing to the limited physical characteristic of individual processer, this method can not meet the requirements of huge unknowns and storage burden.3. The parallel implementation of FDTD algorithm based on MPI protocol is proposed. MPI with high performance cluster system is used to establish the corresponding dispersive parallel FDTD algorithm. Then, by employing the parallel program to calculate two-and three-dimensional surface plasmon waveguides in turn, the parallel performance is evaluated and analyzed on different cluster systems. The numerical results denote that the MPI-based FDTD method has a stable and portable capability, it can evidently overcome the excessive consumption problem of computer resources and shrink the computation time to a great extent. The parallel scalability can reach up to 37.76 on 1024 CPU cores with 16 cores as benchmark.4. Surface plasmon waveguide micro-ring resonators are studied. A two-dimensional MPI-based FDTD method is adapted to design a double L-shaped surface plasmon rectangular-ring resonator. The dependence of transmission spectrum of the proposed waveguide on the geometrical parameters is given. Numerical results reveal that the total field extinction and frequency selectivity characteristic can be adjusted by the structure of the input/output (I/O) waveguide. The proposed waveguide is outstanding in suppressing backward propagating interference and greatly improving the transmission efficiency, which make such plasmonic resonator waveguides more functional. Finally, by applying the double L-shaped I/O waveguide, the dual waveguide coupled resonator and T-shaped splitter can obtain better performance.5. A bandgap surface plasmon waveguide filter is demonstrated numerically. The transmission line theory (TLT) is utilized to analyze the transmission characteristic of MDM waveguides with single and double stubs. To check the accuracy of the TLT, its results are compared with those obtained by the MPI-based FDTD, which verifies that the two methods are in good agreement. The influence of different stub structure and dielectric material on filtering scheme is investigated. On this basis, a bandgap SPW filter with periodic double-stub structure is proposed, the relations between the bandgap property and dielectric refractive index, number of period are given. The periodic double-stub filter can achieve a bandgap performance similar to the bragg reflector, but with better reflectivity, smaller size and simpler production, which is easier to implement large-scale integration.6. The enhanced techniques of high identity Yagi antenna fit for the MBC are studied. Appointing to the difficulties in theoretical analysis and practical redressal, the multi-objective optimization procedure of Yagi antenna is given. A broadband Yagi antenna is accomplished and fabricated by making use of an X-shaped structure as the essential driven dipole. Furthermore, in order to satisfy the demand of broadband high-gain communications, the reflector part is improved, it is also beneficial by employing the vertically stacked array method to enhance the gain. Finally, in the condition of maintaining the high gain operating characteristic, V-shaped structure and vertical stacked arraying are used to obtain a broadband wide-beam Yagi antenna. These methods make the Yagi antenna very desirable for MBC system.