Yang Zhoubing

UWB pulse generation and radiation using a photoconductive switching in GaAs:Cr

We are conducting research in photoconductive switching for the purpose of generating a microwave pulse. This paper describes our experiments of ultra-wideband (UWB) pulse generation using a photoconductive switch in GaAs:Cr operating in the linear mode and radiation by an exponential flared section to the line. The pulse waveform radiated is measured by a UWB conical antenna and the peak electric field is about 1 kV/m in 3 m from the end of the flared line.

Microwave imaging for arbitrary cross section conducting cylinder excited by UWB pulse

The paper presents a microwave imaging approach based on the time-domain and real-coded genetic algorithm (RGA) for a 2D perfectly conducting cylinder with arbitrary cross section in free space. The Gauss pulse is used as an ultrawideband (UWB) wave source. The unknown object is denoted by a shape function which is approximated by trigonometric series. The scattering problem is solved using FDTD technique. The inverse problem is turned into a restrained optimization problem. The coefficients of the trigonometric series are the variables to be optimized. The relative error between the measured scattered electric field changing with time and the simulated one is the object function to be minimized. Numerical examples are given to demonstrate the performance of this method.