Fang Shaojun

Analysis of characteristic impedance of asymmetric coplanar waveguide using finite-difference time-domain method

The paper presents a detailed analysis of characteristic impedance of asymmetric coplanar waveguide (ACPW) using the finite-difference time-domain (FDTD) method, and the results agree well with available theoretical and experimental data over a wide frequency range. The transient propagating waveforms along the ACPW, which are excited by retarded Gaussian pulse, are found in the time domain. After the time-domain field distributions are obtained, frequency-domain parameters such as the characteristic impedance are calculated using Fourier transformations

Analysis of Characteristic Impedance of Asymmetrical Coplanar Waveguide using Multi-resolution Time Domain Method

The characteristic impedance of asymmetrical coplanar waveguide (ACPW) was calculated using multi-resolution time domain (MRTD) method which based on Daubechies compactly supported scaling functions. The good agreement between this paper and the conventional FDTD method was obtained. Efficiency of MRTD method was compared with FDTD method. Time and frequency domain results have been presented and explained. The curves of characteristic impedance varying with frequency were drawn from 1GHz to 60GHz. The effect of side strip width on characteristic impedance was analyzed.

Analysis and optimization design of compact microstrip patch antennas loaded with shorting pins

Based on the cavity model method, which proposes a theoretical analysis method for rectangular microstrip patch antennas loaded with shorting pins, we calculated the input impedance and return loss performance of a rectangular patch antenna loaded with a single shorting pin and a rectangular patch antenna loaded with two shorting pins. The calculated results were then compared with each other. Based on this analytical method, and using an optimization technique, we proposed a design method for this type of antenna, and designed a rectangular patch antenna loaded with a single shorting pin which meets mobile communication demands both in operating frequency and impedance.

Calculation and analysis of ACPW and UWB ACPW-slotline transition

The paper calculated the dispersion characteristic of asymmetrical coplanar waveguide (ACPW) using FDTD method. The results of theoretical calculation show very good agreement with XFDTD formulation and experimental data over a wide frequency range. And the time of the FDTD calculation is about one fourth of XFDTD formulation. On this basis, a novel approach for designing a UWB ACPW to slotline transition is presented. A slotline hollow patch creates open circuit conditions on one arm of the ACPW and resonates the transition so that maximum power transfer may occur. The S-parameters of ACPW-Slotline transition was calculated using FDTD method based on Mur-PML absorbing boundary condition. The results agree well with available theoretical and experimental data over a wide frequency range. It is shown that ACPW is easier to connect with slotline in circuit structure and impendence match compare with symmetrical CPW.

Wideband circularly polarized antenna for GPS/Glonass

In this paper, a novel circularly polarized, single-feed microstrip antenna is presented. The operating frequency can be controlled by adjusting the S-slot arm lengths and the feed point. The design has a reduced antenna size compared to the conventional circularly polarized microstrip antenna at a given operating frequency. Further more, the circularly polarized radiation quality is excellent over the entire upper hemisphere. The simulated 10dB return loss bandwidths is about 10% (1500M∼1655M), which covers the global positioning system and Glonass.

Wideband dual-band microstrip antenna for WLAN application using organic magnetic substrate

This paper describes a novel microstrip antenna on organic magnetic substrate for WLAN systems. The dual-band operation is obtained by embedding a pair of L-shaped slots. The organic magnetic material is adopted because the substrate can reduce size of the antenna 40%, comparing with a rectangular microstrip antenna on normal dielectric substrate, and have wider bandwidths for both bands. Details of the proposed antenna design are presented and discussed, which can be candidate for the requirement of WLAN, operating in 2.45, 4.9 and 5.25GHz

Design of a novel antenna element for BGAN phased array antenna system

A novel antenna element has been proposed for maritime satellite communication Broadband Global Area Network (BGAN) phased array antenna system. The proposed antenna element is composed of a square radiating patch, two vertical trapezoidal coupling strips and a T-junction power splitter feeding network. A dual orthogonal side coupled feeding technique has been adopted to realize a circularly polarized square patch antenna. Design concepts and procedures are introduced, followed by simulations and discussions. Good antenna characteristics are achieved in the entire BGAN working band, having input impedance match characteristics of S11<;-15dB, antenna gain higher than 7dBi, and the axial ratio lower than 4dB.

Effects of shorting pin on the Substrate Integrated Cylindrical Cavity

Substrate Integrated Cylindrical Cavity (SICC) can be used to design compact planar circuits. For the same size, SICC loaded with shorting pin can resonate at higher frequency than no shorting pin SICC. This property can be used to implement the millimeter wave circuits. In this paper, the effects of shorting pin on SICC are analyzed theoretically. With the help of electromagnetic simulation software, the effects of shorting pin position, radius and number on the resonant frequency of SICC are studied. Some results and conclusions are given in the paper, they will be useful for the SICC based millimeter wave device design.