Zhenghui Xue

Full-wave analysis of broad wall slot's Characteristics in rectangular waveguides

A rigorous analysis of the resonant characteristics for a broad wall waveguide slot by using the finite-difference time-domain method is presented. Four types of slots including a radiating longitudinal shunt slot, a longitudinal/transverse coupling slot, a centered-inclined coupling slot and a compound coupling slot are analyzed. Lots of slot characteristics such as the resonant length, scattering parameters and normalized admittance in different offsets, tilt angles or slot sizes are obtained. Because the shape of slots is a rectangle with rounded ends in practical fabrication, an accurate modeling and computation for the slots with rounded ends is implemented, and the resonant lengths calculated coincide well with the Stegens measured data and method of moments results. From these computed results, it is found that all the resonant characteristics of the slots with rounded ends are significantly different from those with normal rectangular ends.

Research on a New Kind of High Directivity End-Fire Antenna Array

In this paper, a new kind of end-flre array was built by employing high directivity plate end-flre antenna as the basic element based on electromagnetic surface wave theory. Being difierent from normal end-flre array, in the new array, high directivity plate end- flre antenna elements were arranged end to end along the end-flre direction, and the interelement spacing and uniform progressive phase were carefully adjusted to achieve high directivity. The simulations and measurements showed that the whole array achieved 19.2dB directivity with four elements at 14.7dB directivity each.

Design of high-directivity end-fire antenna array

A new method of designing an end-fire plate antenna array is presented in this paper. To improve directivity and gain, the four elements array of plate surface wave antenna located along axis direction was made. From the simulations and practical measurement, the conclusion can be made that this structure is very advance to develop high-directivity end-fire antenna array.

ANTENNA TIME DOMAIN PLANAR NEAR FIELD MEASUREMENT SYSTEM

Antenna time domain planar near field measurement is a new Ultra-WideBand (UWB) technology for getting Antenna Under Test (AUT)s time or frequency domain radiant characteristics within a wide frequency band. In this paper, besides introducing basic theories and technologies, we have developed an antenna time domain planar near-field measurement system and showed from measurement results, the validity of our theories and the feasibility of our system.

Low-RCS High-Gain Partially Reflecting Surface Antenna With Metamaterial Ground Plane

In this communication, a high-gain partially reflecting surface (PRS) antenna with both in-band and out-of-band radar cross section (RCS) reduction (RCSR) is presented. A microstrip patch antenna acts as the source and is surrounded by the metamaterial ground plane (MGP), which is to reduce the in-band RCS of the proposed antenna. A PRS is located approximately one-half of the wavelength above the MGP to enhance the antenna directivity. In addition, an absorbing surface is adopted to reduce the out-of-band RCS. The design procedure of the antenna is illustrated, and the simulated results reveal that a significant RCSR has been accomplished in the frequency ranges of 8-17 GHz. Compared with the reference antenna, the average out-of-band RCSR is about 13 dB for both TE and TM polarization incident waves. What is more, the in-band RCSR is about 17 dB for the TM polarization incident wave. The simulated results match the measured results well, and the peak gain of the proposed antenna is 18.4 dBi at the operating frequency of 10 GHz.

Particle Swarm Optimization of frequency selective surface

Particle Swarm Optimization (PSO) has been successfully applied in the design and optimization of electromagnetic structures. Combined with FDTD technique, PSO is applied in the design of frequency selective surfaces. Together with the GPU acceleration, the FDTD program runs about 100 times faster while preserves the broad-band nature of the algorithm. Standard PSO and binary PSO are applied to deal with known cell structure and unknown cell structure optimization respectively. The entire optimization scheme is verified by the numerical results.

Design and analysis of a 3GHz printed dipole antenna

A printed dipole antenna for wireless communication applications is designed, simulated and optimized by HFSS, FEM electromagnetic EM simulator. Numerical and measured results of the antenna radiation characteristics, including input SWR, radiation pattern coverage and beam pattern, are presented and compared.

Analysis and application of new quasi-network characteristics of nonuniform mesh in FDTD simulation

The equation of computing the reflection coefficient between two meshes of different sizes is derived. Using the equation, quasi-network characteristics of nonuniform mesh for the finite-difference time-domain technique is found and analyzed. The so-called mesh network (MN) here is a kind of structure composed of the sections of mesh in cascade. The cell sizes of these sections change regularly. By means of choosing the number of mesh sections, length of each section, and cell sizes, some novel network characteristics are obtained, which can be used to match the reflecting wave of nonuniform mesh or improve the transmitted characteristics for a mesh wave to travel along the nonuniform mesh. Formulas for analyzing the MN are given. The characteristics are realized in both one- and three-dimensional cases. The applications and advantages of the MN are shown by computing three different structures, i.e., microstrip-gap capacitor, parallel-coupling filter, and microstrip slot-line transformer.

Research on the array weighting of plate end-fire antenna with the effect of mutual coupling

This paper focus on the array weighting of the plate end-fire antenna array with the effect of mutual coupling. The far field pattern distortions of array caused by mutual coupling were analyzed. Then, the efficacies of amplitude weighting and phase weighting in plate end-fire antenna array were discussed. Under strong mutual coupling, the efficacy of amplitude weighting was affected evidently, and the designing target was hard to be achieved. Meanwhile, the efficacy of phase weighting was achieved exactly in a large range of scanning.

A ultrathin and wideband radar absorber using slotted treble-square-loops resistive FSS

A novel ultrathin and wideband radar absorber comprising single-layer resistive frequency selective surface (FSS) is proposed in this letter. The resistive FSS layer is constructed from resistive/low-conductivity in the form of slotted treble-square-loops with a foam substrate. Simulation results reveals that the proposed absorber can provide a more than 10dB radar cross section (RCS) reduction over the frequency range of 7.8-20.1GHz, of which the relative bandwidth is 88.2%. The thickness of whole structure is 2.3mm, which is rather thin both physically and electrically. RCS reduction under oblique incidence is then depicted and influence of the position and parameters of slots is illustrated to introduce the operating principle.