マイクロ波誘電体リング共振器を用いた物質の含水率と誘電率測定

博士学位論文の要旨 学位記番号:工博甲第235号甲第320号publishe

Optimality Conditions for Nonsmooth Generalized Semi-Infinite Programs

We consider a class of nonsmooth generalized semi-infinite programming problems. We apply results from parametric optimization to the lower level problems of generalized semi-infinite programming problems to get estimates for the value functions of the lower level problems and thus derive necessary optimality conditions for generalized semi-infinite programming problems. We also derive some new estimates for the value functions of the lower level problems in terms of generalized differentiation and further obtain the necessary optimality conditions

Fractional Fourier Transform-Based Radio Frequency Interference Suppression for High-Frequency Surface Wave Radar

High-frequency surface wave radar (HF SWR) plays an important role in marine stereoscopic monitoring system. Nevertheless, the congestion of external radio frequency interference (RFI) in HF band degrades its performance seriously. In this article, two novel fractional Fourier transform (FRFT)-based RFI suppression approaches are proposed. One is based on the orthogonal projection of sequences from fractional Fourier domain, and the other is based on singular value decomposition (SVD) of Hankel matrix of sequences from fractional inverse-Fourier domain. Simulation and experimental data collected by HF SWR from Wuhan University were used to test the effectiveness as well as the application condition of the proposed RFI suppression algorithms. The FRFT-based orthogonal projection algorithm is practicable for suppressing stationary RFI with unvaried carrier frequency, while the FRFT-based SVD algorithm is applicable equally for mitigating nonstationary RFI with time-varying carrier frequency or occasional duration time. The processing results may provide useful guidelines for interference suppression of HF SWR, and inspiring the further application of the FRFT-based methods for signal processing

Electromagnetic band gaps from H-shaped fractals

This paper presents a new method to simulate the properties of Frequency Selective Surface (FSS) composed of planar H-shaped fractals structure exhibiting multiple band gaps of electromagnetic waves. The FSS sample can be easily fabricated as that of the Printed Circuit Board (PCB). The electromagnetic characteristics of this H-shaped fractal structure were studied mainly by numerical simulation based on Finite Integration Technique (FIT). The simulation results present a direct image of surface currents when certain frequency electromagnetic waves incident on the surface of the sample, which is in a considerably good agreement with the experimental results. Based on the comparison of simulated and experimental result it is suggested that the planar H-shaped fractals structure has quasi-periodic multiple band gaps and the size can be significantly smaller than the relevant electromagnetic band gap wavelength