Tvrtko Mandic

Characterizing the TEM Cell Electric and Magnetic Field Coupling to PCB Transmission Lines

This paper presents the models of the coupling between the transverse electromagnetic (TEM) field generated in the TEM cell and the arbitrarily oriented microstrip (MS) lines and coplanar waveguides (CPW). The lines are modeled in the frequency and time domain by taking into account different geometries and two types of subminiature version A connectors. The method of lines is used to calculate the capacitance matrix for the MS and CPW lines inserted in the TEM cell. The capacitance matrix is then used to calculate the inductance matrix, i.e., self- and coupling inductances. A number of simulations are performed in order to obtain the set of capacitance and inductance matrices for various line geometries. These results are fitted by using linear regression models. The closed-form equations for the coupling parameters are derived. The closed-form equations are used for the evaluation of coupling of arbitrarily oriented lines. The coupling models are compared against the measurements and found to be very accurate and can be used for efficient coupling modeling between the MS and CPW lines and TEM cell.

Simple and Scalable Methodology for Equivalent Circuit Modeling of IC Packages

This paper presents a methodology for scalable modeling of IC packages by lumped element equivalent circuits. The response surface methodology is used for modeling of the IC package pins, lead frame, and bond wires, whereas the paddle is modeled as a pair of planes. The design of experiment (DOE) approach is used to systematically vary geometrical parameters of the simplified package structures, which are then simulated in a 3-D electromagnetic (EM) simulator. These simplified structures are used as building blocks of the IC packages and EM simulations of the simplified structures are used to build their parameterized equivalent circuit models. The extracted parameters of the equivalent circuit model form the response surface. Simple regression models are used for the response surface modeling. The model of the whole IC package is generated by cascading the models of the simplified structures. The range of the geometrical parameters used in the DOE is selected to cover a wide range of IC package geometries. The response surface models are verified against measurements performed on several IC package types and the accuracy is very good. The scalability and accuracy of the response surface models make this methodology suitable for modeling of a wide range of IC packages. The efficiency and accuracy of the presented models enable the statistical analysis of package performance with respect to package manufacturing parameters.

Equivalent circuit model of the TEM cell electric and magnetic field coupling to microstrip lines

Electromagnetic compatibility (EMC) analysis of high-speed circuits is becoming mandatory due to the rapid increase in operating frequencies, RF interference and layout densities. Radiated susceptibility tests are important part of overall EMC analysis. In this paper the focus of investigation is on models of the coupling between a transverse electromagnetic (TEM) field generated by the TEM cell and the microstrip lines. In order to accurately model the coupling the models for microstrip lines, SMA connectors and TEM cell are developed. The coupling models are provided for transversal and longitudinal microstrip lines. The results for coupling capacitances are compared against results obtained by Method of Lines (MoL). The presented models are very accurate and include only passive elements, and therefore can be used for efficient coupling modelling between microstrip lines and the TEM cell septum.

Broadband characterization of SMA connectors by measurements

This paper presents the characterization of various types of SubMiniature version A (SMA) connectors. The characterization is performed by measurements in frequency and time domain. The SMA connectors are mounted on microstrip (MS) and conductor-backed coplanar waveguide (CPW-CB) manufactured on high-frequency (HF) laminates. The designed characteristic impedance of the transmission lines is 50 Ω and deviation from the designed characteristic impedance is measured. The measurement results suggest that for a given combination of the transmission line and SMA connector, the discontinuity in terms of characteristic impedance can be significantly improved by choosing the right connector type.

Active-learning implementation proposal for course Electronics at undergraduate level

The course “Electronics 1” is taught at undergraduate level and covers broad area of electronics starting from the physics of semiconductors to the complex electronic system such as operational amplifier. This course is obligatory for sophomore students enrolled in Electrical Engineering and Information Technology undergraduate program as well as in Computing undergraduate program. Due to the course comprehensiveness and recognised lack of interest, students tend to study without understanding the studied concepts and their practical application. This paper presents the proposal to increase the interest in electronics by introduction of the active learning (AL) process. This AL process is supported by the developed AL module, i.e. clicker, which provides the hands-on experience of the topics studied throughout the course. We provide questionnaire proposal that will be given to groups of students and the results will be compared to the control group to assess the usefulness of the proposed approach.

Response of aquatic protists to electric field exposure

Abstract Purpose: To test the effects of short-term exposure of aquatic organisms to electric field (EF) with negligible magnetic component. Materials and methods: We built a plate capacitor that served as a source of EF of strengths that can be found in nature near transmission lines. We exposed two cultured protist species Euglena viridis and Paramecium caudatum to EFs for 24 hours and monitored their abundance, morphology, intracellular superoxide anion (by dihydroethidium [DHE]), hydrogen peroxide by (H2DCF) and lipid peroxidation (MDA) contents, catalase (CAT) and superoxide dismutase (SOD) activity. Results: We found that even short-term exposure to low strength EF causes changes in population abundance, morphology and oxidative stress response in both species. As the EF strength increased, abundance of both species decreased. However, at weaker EFs, fission rates were seemingly promoted. We noted a decrease in size in both organisms in directions perpendicular to their fission planes correlated with EF strength. DHE and H2DCF fluorescence intensity and SOD activity were higher in organisms exposed to the stronger EFs. Conclusions: We suggest that the electric component of the field, rather than the magnetic, is the main cause of all the noted effects. As a result, aquatic organisms should be given greater importance in studies assessing the effects of EMFs in spite of the attenuating effects of water to EF strengths.

Effects influencing repeatability of direct power injection measurements

The electromagnetic compatibility (EMC) performance of the voltage regulators is the significant factor in the EMC performance of the complete electronic system. In this paper the characterization of the voltage regulator by direct power injection (DPI) method is presented. Although, the DPI method is defined by various standards, the repeatability of the measurement can be compromised by several factors. The DPI method measurement results are presented for the L4949 voltage regulator. The repeatability of the method is assessed by various factors related to the operating point of the voltage regulator and to the measurement set-up. The obtained results are compared to the results presented by other authors.