In this paper, a simple method to obtain the equivalent radiation emitting sources of an electronic circuit using the near-field scanning method is presented. The model is based on a set of elemental dipoles that substitutes the electronic circuit and radiates the same magnetic field. Two different approaches are presented: a set of electric dipoles and a set of magnetic dipoles. In order to build the model, both the magnitude and phase of the magnetic field are required. These measurements are carried out using the "near-field scanning method," and two procedures are presented: using the vector network analyzer and the spectrum analyzer. Finally, the model is applied to two different cases: to obtain the radiated near-field of a component (microcontroller) and to obtain the field of a complete electronic board.

Modeling Magnetic Radiations of Electronic Circuits Using Near-Field Scanning Method

A completely automatic near-field mapping system has been developed within the Research Institute for Electronic Embedded Systems (IRSEEM) in order to determine the electromagnetic field created by electronic systems and components. This test bench uses a 3-D positioning system of the probe to make accurate measurements. This paper presents some applications of the near-field techniques in EMC investigations. In the first part, near-field measurements are used to locate precisely the electromagnetic sources of a limiter device. In the second part, we present an equivalent model of the radiated emission of an integrated circuit. In the last part, the near-field test bench is used to characterize faults in a cable.

Applications of the Near-Field Techniques in EMC Investigations

A new particle swarm optimization (PSO) technique for electromagnetic applications is proposed. The method is based on quantum mechanics rather than the Newtonian rules assumed in all previous versions of PSO, which we refer to as classical PSO. A general procedure is suggested to derive many different versions of the quantum PSO algorithm (QPSO). The QPSO is applied first to linear array antenna synthesis, which is one of the standard problems used by antenna engineers. The performance of the QPSO is compared against an improved version of the classical PSO. The new algorithm outperforms the classical one most of the time in convergence speed and achieves better levels for the cost function. As another application, the algorithm is used to find a set of infinitesimal dipoles that produces the same near and far fields of a circular dielectric resonator antenna (DRA). In addition, the QPSO method is employed to find an equivalent circuit model for the DRA that can be used to predict some interesting parameters like the Q-factor. The QPSO contains only one control parameter that can be tuned easily by trial and error or by suggested simple linear variation. Based on our understanding of the physical background of the method, various explanations of the theoretical aspects of the algorithm are presented

Quantum Particle Swarm Optimization for Electromagnetics

https://paginas.fe.up.pt/%7Eniadr/PUBLICATIONS/LIACC_publications_2011_12/pdf/R6_PL.pdf

Bio-inspired multi-agent systems for reconfigurable manufacturing systems

In this paper, a method for representing electromagnetic emissions from a printed circuit board (PCB) using an equivalent dipole model deduced from near-field scanning is proposed. The basic idea is to replace the PCB with a set of infinitesimal dipoles that generate the same radiated fields. Parameters of the equivalent dipoles are determined by directly fitting to the measured magnetic near fields. In closed-environment simulations, the equivalent method is extended to a dipole-dielectric conducting plane model to account for the interactions between the PCB and enclosure by including the basic physical features of the PCB. The electromagnetic emissions can then be predicted by solving the equivalent model with numerical methods, thereby, significantly reducing the simulation time and storage costs. A basic test board and a more complex practical telemetry PCB are modeled in different configurations and compared with measurements and full-field simulations, confirming the validity and efficiency of the model.

Modeling Electromagnetic Emissions From Printed Circuit Boards in Closed Environments Using Equivalent Dipoles

A new method for predicting the far-field radiated emissions and for finding the radiation sources of a device from near-field measurements is presented. It is based on the substitution of the original device by an equivalent set of elemental dipoles, placed over the main radiating sources, which radiate the same near-field (and therefore, far-field). This equivalent set of elemental dipoles is generated using a genetic algorithm. From the position and type of the equivalent elemental dipoles, the position of the actual radiating sources is determined. Since the field produced by an elemental dipole is known, the far-field radiation of the actual radiating source can be calculated. The new method has been tested using synthetic data and real measurements from the radiation generated by a modem PCB demonstrating its viability and usefulness.

A genetic algorithm based method for source identification and far-field radiated emissions prediction from near-field measurements for PCB characterization

A novel method for predicting the radiated emissions of a device from near-field measurements is presented. It is based on the substitution (using a genetic algorithm) of the original device by an equivalent set of elemental dipoles, which radiates the same near-field (and therefore, far-field). Since the field produced by a dipole is known, the far-field radiation of the actual radiating source can be calculated. This avoids the use of large semianechoic chambers to measure far-field since it is deducted from the near one. Moreover, this method allows the identification of the radiating sources. Simulations show the viability and usefulness of the new method.

A genetic algorithm based method for predicting far-field radiated emissions from near-field measurements

A novel method for predicting the equivalent OATS radiated emissions of a DUT from anechoic chamber measurements is presented. This method allows the use of a single environment (the anechoic chamber) for both radiated emissions and immunity tests. It is based on the substitution of the DUT by an equivalent set of elemental dipoles (using a hybrid genetic algorithm-gradient method) which radiates the same anechoic field. Since the field generated by an elemental dipole is known, OATS equivalent radiated emissions can be calculated using image theory. Simulations show the viability and usefulness of the new method.

Radiated emissions conversion from anechoic environment to OATS using a hybrid genetic algorithm-gradient method

Electromagnetic interference (EMI) instrumentation has significantly evolved over the last thirty years. In this paper, the classical architecture of a conventional receiver is described and compared with the newest architecture of a Fast-Fourier-transform (FFT) based receiver. Additionally, different ways to measure the modal emissions, that is, the common and differential modes, with both types of receivers are described. In a conventional receiver, modal emissions can be measured using an external noise separator. In a dual-port FFT-based receiver, this can be done in the digital domain. Both receivers have been used to measure a device under test emitting non-stationary interference.

J.-R. Regue

Papers

A genetic algorithm based method for source identification and far-field radiated emissions prediction from near-field measurements for PCB characterization

A genetic algorithm based method for predicting far-field radiated emissions from near-field measurements

Radiated emissions conversion from anechoic environment to OATS using a hybrid genetic algorithm-gradient method

Common- and Differential-Mode Conducted Emissions Measurements using Conventional Receivers versus FFT-Based Receivers