| Summary: | 碩士 === 國立交通大學 === 電信工程研究所 === 102 === There are so many researches focusing on Electromagnetic band-bap structure (EBG) recently; for their well-known characteristic of being as a high-impedance surface in frequency stop-band that can suppress surface waves. Besides, EBG structure can be used to realize a new high-frequency waveguide in the gap between the parallel plate waveguides. The similar concept can also be found in the rectangular waveguide. [1]
Recently, a new type of novel meta-surfaces, which is called “pin-lattice” or “bed-of-nails” is being widely researched.[2] Its characteristics are similar to those of EBG structures. [3][4]
Furthermore, we can see that the “bed-of-nails” structure is also applied in ridge gap waveguide. The reason of this structure being used is because that can usually mimic the ideal impedance boundary. When we put a ridge in the parallel plate and surrounded infinitely periodic pins, the “bed-of-nails” structure would be similar with PMC (Perfectly Magnetic Conducting) surface when the air gap is smaller than quarter-wavelength and let TEM wave propagate following on the ridge.[5]
In recent years, the insertion of additional structures into empty waveguide has been practiced a lot, which can discuss about the characteristics of the propagation through the measurement of the waveguides. Furthermore, the insertion has ranging from the simplest use of dielectric fillings for reduction of cutoff frequency to the plugging in of dielectric layers to serve as impedance match-tunners. In this paper, we use the structure that is a waveguide filling the dielectric in the sidewall and loading with uniform embedded lattice of metallic pins (Perfect Electric Conductor, PEC). Next, we analyzed its characteristic equation by asymptotic solution, and simulated with the tools to get the dispersion diagrams. By agreements of simulating results in CST and HFSS, we can assume its accuracy, and we will analyze the characteristics with the MATLAB tool.
On the other hand, we will introduce another simpler structure before the sidewall loaded with embedded pins waveguide; first, we imagine that there is a dielectric grounded plane filling with infinitely periodic array of metallic pins. Next, we derive it by the concept of electromagnetics and get the characteristic equation through the asymptotic solution. Then, we compare the result through the simulated tools with the result of the Transverse Resonance Technique (TRT), and we can get the agreement of the results and the dependability of the asymptotic solution.[2] Meanwhile, we will explain the objective of choosing this field analyzing method.
|
|---|
