Shi Xiaowei

Analysis of the multiband behavior on Sierpinski carpet fractal antennas

The electromagnetic properties of two antennas were studied respectively, the Sierpinski carpet dipole antenna in the positive configuration and the Sierpinski carpet microstrip antenna in the negative configuration. Their reflection coefficient and current distribution were analyzed using Ansoft HFSS and IE3D, and some useful conclusions were obtained: it is not any antenna with fractal shape can achieve multiband behavior, and some antennas which performed multiband behavior are not the result of its fractal shape, but for other reasons.

Modeling with NURBS surfaces used for RCS computation of electrically large objects

The non-uniform rational B-spline (NURBS) model is constructed based on the data points on the surface of a target, and the B-Spline basis functions are analyzed. The radar cross section (RCS) is calculated with the physical optics (PO) and LUDWIG integral method based on NURBS models, which verifies the validity of the modeling method mentioned in this paper.

Design and Analysis of a Doherty Amplifier for Retrodirective Communication System

A high efficiency and linearity Doherty power amplifier (DPA) is presented with GaAs field-effect transistor (FET) for its application in retrodirective communication system. By optimizing the bias circuit, power-added efficiency (PAE) is as high as 53.56% while its linear power amplification increases 6 dB greater than the conventional power amplifiers. The simulation results show that the performance of the Doherty power amplifier is better than other power amplifiers in their efficiency, PAE, linearity and inter-modulation distortion (IMD). It is more suitable for retrodirective communication system application. It can be widely used in linearity power amplifier application for microwave retrodirective communication systems.