Gao Yougang

Design of coil structure achieving uniform magnetic field distribution for wireless charging platform

Wireless power transfer technology via electromagnetic coupling has been widely used in the planar contactless charging platform. In this paper, a current distribution is deduced to ensure axial component of magnetic field is uniformly distributed in the charging region and zero outside the region. Based on continuous current distributions that can generate even axial component of magnetic field, two transmitting coil structures are proposed. The uniformity of the axial component of magnetic field distribution is confirmed by using the simulation tools. In the case of multiple coils in parallel, the magnetic field distribution near the margin of the charging region changes greatly. This paper analyzed the changes of magnetic field in the case of two coils in parallel, and compared the magnetic field distribution with different coil structures.

EMC design in lightning protection of computer network

Grounding design is an important design. And it is difficulty to be carried out. In the earthing concept, it is believed very simply, but in fact and in the practical application, the grounding technology is quite complex. To find some suit solutions and methods will be taken lots of time and work, the way to suit this situation but not to solve other problems. Therefore the engineers and technicians must embark in the actual construction process from the reality analyses and the solutions of the problems. The lightning protection facility which meets some disturbance questions which bring for the computer network in the lightning protection construction has been discussed in this article, and how to find the methods for these electromagnetic compatibility questions

Research on non-omnidirenctional biconical broadband antenna

This paper presents an anti-interference biconical antenna which is used for wireless communication systems existing an Electromagnetic interference source (EMI). A new method is used to realize directionality without the need for increase in size, which is different from general methods such as using array antenna or adding reflector. The H-plane radiation pattern of the proposed antenna is direnctional, its voltage standing wave ratio (VSWR) is less than 1.9 within the frequency range of 0.85GHz ∼ 2.5GHz.

Design of low cost inverted F antenna with two parasitic elements for 2.4GHz WLAN

The proliferation of wireless local area network (WLAN) devices has placed a renewed focus on small, integrated, low cost antennas[1]. In this paper, an improved low cost inverted F antenna with two parasitic elements is presented. Compared with conventional inverted F antenna[2], this antenna can produce wider frequency bandwidth by adding parasitic elements. It can be concluded from the good results of VSWR ≪1.3 at 2.4GHz and VSWR ≪1.4 at 2.5GHz, This antenna has great potential in practical application.

The Simulation of Interference between the Unmanned Aerial Vehicle (UAV) System and the CDMA System based on Simulink

With the development of the information technology, especially the wireless communications, the electromagnetic compatibility (EMC) problem between systems becomes more and more important. This paper uses Simulink to analyze the interference between the UAV system and the CDMA system, besides giving some discussion on the result

ESD Generator Analyzed by Transmission Line Theory

In this paper, the transmission line theory was used to analyze the electrostatic discharge (ESD) transient process. Finite-difference time-domain (FDTD) method is used to simulate the discharge current being prescribed in the IEC 61000-4-2. The factors influencing the current parameters were examined, the suggestion for designing ESD generator was put forward

Anti-jamming space-time processor with digital beamformer for satellite navigation

This paper presents a novel space-time adaptive processor with digital beam forming algorithm based on least mean squares (LMS) method. Furthermore, the omnidirectional optimization principle for the algorithm applied in satellite navigation field is introduced. The algorithm minimizes the deviation of the radiation pattern due to the edge effect of asymmetric substrate in the miniaturization design of antennas. The anti-jamming performance of the introduced algorithm is verified through the experiment of radiation pattern, satellite signal receiving experiment and anti-jamming experiment.

Distance boundary of antenna isolation calculation in engineering

When wireless base station antennas share a tower or site, the electromagnetic compatibility should be considered, one of which is to calculate the antenna isolation. For horizontal isolation, calculation is based on antenna pattern and the traditional far-field boundary is d>2D2/λ. In practical scenarios of antenna co-site, however, antenna distance cannot fit these boundary conditions. Regarding this issue, Magnitude Error on Sphere (MES) is defined as a new indicator of antenna far-field and near-field approach degree. The analysis has shown that the distance boundary in horizontal isolation calculation can be set as d>8λ for typical base station antenna structure. While for vertical isolation calculated by Iv(dB)=28+401g(d/λ), the distance boundary can be set as d >4λ.

The optimized polarization for indoor MIMO based on cross polarization loss and near earth loss

As has been shown by our testing, the propagation loss (PL) of vertically-polarized (VP) transmitting and horizontally-polarized (HP) receiving is larger than that of VP transmitting and VP receiving, i.e. the cross polarization loss exists. At wireless covered indoor situation, the PL of HP waves is different with that of VP waves, and the difference is traditionally described as near-earth loss. Consider the cross-polarization loss and near earth loss, a 2×2 orthogonal dual-polarization MIMO system has a total receiving power irrelevant of the polarized angle settings, but the balance of the receiving power is dependent on the angle settings. When the receiving setting is +45°/-45° dual-polarization, the two antennas receive equal power, which reaches equilibrium.

Application of multi-resolution terrain in electromagnetic wave propagation research

This paper proposes a kind of multi-resolution terrain which can be used in simulation of electromagnetic wave propagation in complex terrain. Using this kind of terrain can accelerate simulation in a large scale while keeping a high-accuracy result. It can be used as the terrain model when simulating electromagnetic wave propagation. In this paper, the author constructs a multi-resolution terrain which is transformed from a digital elevation model and makes some analysis of the simulation result.