Binfang Wang

An Effective and Efficient Approach for Radiated Emission Prediction Based on Amplitude-Only Near-Field Measurements

A new approach is proposed for modeling electromagnetic emissions of a printed circuit board (PCB) based on amplitude-only near-field measurement data. Magnetic dipoles placed over the top layer of the PCB are introduced as the equivalent of actual radiated sources. A restarted optimization procedure based on a differential evolution algorithm is developed to determine the parameters of the dipoles (number, position, and moment components) via minimizing the difference between the measured magnetic near field and that radiated by the dipoles. These equivalent dipoles can be used to predict the radiated emissions of the PCB once being determined. The proposed approach does not need the phase of the measured near fields, and its computational complexity is very low. Numerical results are presented to demonstrate the validity and efficiency of the proposed approach.

Installed Radiation Pattern of Patch Antennas: Prediction based on a novel equivalent model.

A simple but efficient equivalent model of patch antennas is proposed for predicting the radiation pattern of patch antennas on large platforms. The equivalent model is constructed based on the radiation mechanism of a patch antenna. Only three design parameters need to be optimized, making the model more computationally efficient than those equivalent dipole models for general problems. After the equivalent model is optimized with a differential evolution (DE) algorithm, it is further installed on a platform to compute installed radiation patterns. Simulation results show that the installed radiation patterns of both a single element and an array can be accurately predicted using the equivalent model, where the root-mean-square errors (RMSEs) are less than 0.94%. The proposed equivalent model method does not require detailed geometry information of the patch antennas. Furthermore, it avoids direct modeling of antenna structures, leading to a drastic reduction in computation and storage costs.

Estimating Interference to Airborne Patch Antenna With Limited Information

In practice, the detailed geometry information of an off-the-shelf antenna is unavailable. To achieve the estimation of radio frequency interference to an airborne patch antenna with available information, this paper proposes to utilize an equivalent model of the patch antenna. The equivalent model is derived based on the patch antennas radiation pattern. It shows the same radiating and scattering performances as the original patch antenna. Since, no effective port or phase information is provided by the equivalent model, the reaction theorem was employed to calculate the interference without such information. Simulation and measurement results show that the proposed method can effectively estimate the interference to patch antennas with limited information. Furthermore, it avoids direct modeling of the complex structure of patch antennas and reuses the radiating fields of equivalent models which significantly reduces the computation time and memory cost.

A linear model of transmission coefficients for placement of monopole antennas on electrically large cylindrical surfaces

Based on the ray analysis of monopole excitation, this work proposes a linear model of transmission coefficients against the logarithm of the distance between monopole antennas on electrically large cylindrical surfaces. The linear model is determined by using two sample data, and it is then used to predict the transmission coefficient between two monopole antennas. Given the desired level of transmission coefficient, the distance between monopole antennas can be calculated using the linear spatial model, which is useful for the placement of monopole antennas on electrically large cylindrical surfaces. Simulation results are presented to illustrate the effectiveness of the proposed linear model.

Surrogate-model based isolation analysis of slotted waveguide antennas

This paper addresses the issue of isolation analysis of slotted waveguide antennas (SWAs) when their detailed structures are unavailable. A surrogate model, built from information about radiation patterns, was usually employed for this purpose. It reproduced far/near fields of the original antenna, but failed to provide port and phase information which was essential to the isolation calculation. This work fills the above gap by exploiting the reaction theorem with certain approximations. The proposed method enables the isolation analysis in the absence of detailed information of SWA, which is useful especially for antennas bought off-the-shelf. Moreover, it obviates the need for modeling the complex structure of SWA, so as to reduce the computational time and memory usage. Numerical validation illustrates the effectiveness of the proposed method.

A differential evolution based equivalent source approach for predicting electromagnetic emissions using near-field scanning

The radiated emission from a device under test is predicted by using an equivalent dipole approach which is based on amplitude-only near-field scanning. The method needs minimizing an objective function to determine the parameters of the equivalent dipoles. The objective function usually exhibits many local minima, and this limits the application of local optimization algorithms. A restarted differential evolution algorithm is hence proposed to overcome the limitation. Experimental data are used to verify the presented approach.

A hybrid technique for EMI prediction and channel modeling inside an enclosed space

In this paper, modeling of electromagnetic field distribution inside an electrically large closed environment is presented by using a hybrid simulation technique, which combines a full-wave method and an asymptotic technique. In the hybrid scheme, the Method of Moments is used to model the transmitting/receiving antennas and their nearby objects. The equivalent sources obtained from the MoM solution will be provided as input to an adaptive ray tracing technique for computing the long distance coupling between a pair of transmitting and receiving antennas. Base on this model, the radio channel characteristics of a wireless network deployed in an enclosed space as well as the levels of EMI produced from the network infrastructure can be estimated and predicted. The simulation results of an in-cabin wireless system show the capability of the presented hybrid model.

Development of a virtual lab for EMC application

In this article, we present the system development of Virtual EMC Lab (“Virtual Electromagnetic Compatibility Laboratory”). It is a toolkit developed for the electronic and electric product/system design, modelling, simulation, analysis, diagnosis and assessment tailored to the electromagnetic compatibility problems. The toolkit includes a solid modelling front-end which simplifies the geometrical structure of equipment under test (EUT), analytical and numerical solvers for different applications, and visualization tools. It is dedicated to solve electromagnetic interference, immunity and emission problems in board level and system level.

Near-field scanning and its EMC applications

This paper first briefly surveys the near-field scanning for antenna measurements, then focuses on the near-field scanning for electromagnetic compatibility (EMC) applications. Key theories and practices are covered, and some latest development and open issues regarding the near-field scanning for EMC applications are finally presented.

Analysis of antennas on large platforms using equivalent model method

Summary form only given: Installed radiation pattern and isolation are critical performance indicators for antennas on large platforms. Prediction of these indicators is highly desirable for antenna placement. Conventional simulation methods require a detailed geometric model of the antenna to be mounted which is, in practice, unavailable from antennas datasheets. This talk will introduce an effective and efficient equivalent model method for the analysis of two types of airborne antennas - patch antenna and slotted waveguide antenna (SWA) with information available on antennas datasheets. By taking the radiation mechanism of these two types of antennas into account, the proposed equivalent models yield almost identical radiating and scattering performances to those of the original antennas. Furthermore, it requires less design parameters than conventional general-purpose equivalent models, leading to a faster optimization process. Simulation results show that, by using the proposed equivalent model, the installed radiation patterns of the patch antenna and the SWA can be accurately predicted. This feature is also valid in the situation of patch antenna array and SWA array. For the isolation between antennas, additional simulation runs always make the prediction more time-consuming. A combination of the proposed equivalent model and the reaction theorem is then developed which efficiently estimates antenna isolation with limited information. Moreover, a drastic reduction in computation and storage costs is also achieved for the multi-scale simulation due to the simple structure of the proposed equivalent model. Therefore, the proposed equivalent model method is highly suitable for the analysis of antennas on large platforms.