Huiping Guo

An antipodal Vivaldi antenna for ultra-wideband system

Vivaldi antenna is a traditional ultra-wideband(UWB) antenna, and this paper focuses on designing its structural parameters properly to balance the bandwidth, gain, cross-polarization and other key parameters. By studying the effects of various parameters on the antenna performance, a compact Vivaldi antenna for ultra-wideband system is designed and realized. The antenna has a small size, high gain and small cross-polarization characteristics compared with the antannas in the relevant references, and it can meet the requirements of UWB system.

A miniaturized dual-frequency Wilkinson power divider using planar artificial transmission lines

In this paper, an arbitrary dual-frequency Wilkinson power divider using planar artificial transmission lines has been designed, fabricated, and measured. The results demonstrate that after such a method has been used the size of dual-frequency Wilkinson power divider can be reduced to be only 50% of the traditional power divider. Both simulations and measurements show that such a dual-frequency Wilkinson power divider has good performance of S-Parameters, which include an equal power split, impedance matching at all ports, and a good isolation between the two output ports at two arbitrary frequencies simultaneously.

Design of broadband impedance transformer using coupled microstrip transmission lines

In this paper, a novel broadband impedance transformer combining with a symmetric coupled microstrip line and an interconnecting line is presented. It has been proved that a fractional bandwidth of about 90% at −20dB reflection level can be achieved with this structure, and the insert loss is less than 2dB in the matching bandwidth. The measurement results of actual circuit are well agreed with the simulation. Its bandwidth is 2.5 times larger as compared with the traditional quarter-wavelength impedance transformer, and its length is less than half of the traditional one with the help of bending the structure.

A broadband self-complementary printed antenna with axe shape

With the idea of self-complementary structure, a broadband printed antenna with axe shape has been designed, fabricated, and measured in this paper. The key parameters which influence on the performance have been analyzed in detail. The optimized dimensions have been obtained after simulation and optimized. The measured results show that the proposed antenna has over 101.3% −10dB bandwidth, wider bandwidth, higher gain compare with the self-complementary H-antenna originally proposed in literature. Good radiation performance is also obtained.

Analysis of Large-Scale EM Scattering Using the Parallel Characteristic Basis Function Method

It is crucial to overcome the limitation of the computer capacity in analyzing the electromagnetic (EM) scattering from electrically large objects. The characteristic basis function method (CBFM) is a novel approach to solve this problem. In this paper, a more efficient method is presented by combining CBFM with the parallel technique. The matrix used in CBFM is rearranged to be suitable for parallel process. The parallel CBFM is applied to analyze the electromagnetic scattering feature of 3-D objects. The obtained results confirm the accuracy and efficiency of the proposed method in speeding up the RCS calculation of large scale objects.

The application of the equivalent dipole-moment method to electromagnetic scattering of 3D objects

In this paper, a new method called equivalent dipole-moment method for efficient generation of MoM matrices based on equivalent dipoles is presented based on the example of 3D electric object. The current basis function located in source area can be equivalent as an electrical dipole or magnetic dipole, and the matrix elements can be thought as the reaction of fields produced by the equivalent dipoles with the current basis function located in field area. The calculation results show that the proposed method has less computation cost, high accuracy and good adaptability, so that the efficiency of MoM is greatly improved. This work can be extent to arbitrary 3D objects scattering and can provide an effective way to fast compute wide band EM scattering from 3D objects.

A novel compact diplexer based on folding microstrip lines

In this paper, we proposed a compact diplexer based on folding microstrip lines. The folding microstrip lines have the characteristics of inductance and capacitance. They have filter function and compact size. The proposed diplexer employs filters with folding microstrip lines for band selection and separation. A prototype diplexer is designed at 900MHz and 1800MHz, which is proposed for GSM/DCS dual band cellular system applications. The measured insertion losses are better than 2dB for the two channels with better 30dB isolation. The diplexer collectively has the advantages of low insertion loss, high isolation, compact size and easy fabrication. The design methodology, simulated and experimental results are discussed throughout the paper.

A compact dual-mode BPF base on interdigital structure

Based on shorten wavelength effect and low-pass characteristic of interdigital structure, a compact dual-mode narrow band BPF (band-pass filter) is proposed in the paper. This filter combines interdigital structure with conventional dual-mode BPF, and takes full advantage of the blank center of conventional dual-mode loop resonator. The shorten wavelength effect and low-pass characteristic of interdigital structure is analyzed first of all, and then a structure of dual-mode narrow band BPF using interdigital structure is proposed, followed by simulation and optimization. At last, the novel filter is fabricated and the measurement results show that the proposed filter has favorable application value due to its compact size and good performance.

A D-shaped defected patch antenna with enhanced bandwidth

In this paper, a D-shaped defected patch antenna printed on a microwave substrate for increasing the bandwidth of a microstrip antenna is proposed. A second resonant frequency is introduced to achieve a wider impedance bandwidth with D-shaped defected structure. The effects of the proposed antenna structure parameters are studied in details. By simulation software, we obtained the size of an antenna operating around at 2.4GHz. The measured parameters and simulation results show that the proposed antenna can attain the impedance bandwidth that is much broader than the traditional rectangular patch antenna.

The design of a dual band antenna for high-speed train

The design is described of a dual-band antenna which is applied by high-speed train. This antenna is comprised of an alloy base, a cover and an FR4 substrate carved with two printed antennas on it. The antenna is designed to achieve dual-band operation in the 457MHz∼469MHz and 820MHz∼935MHz with a simple configuration. The simulated and measured results of the antenna, such as magnitude of the reflection coefficient (S11), gain, and radiation patterns are all presented in this paper.