Near-field scanning based shielding effectiveness extraction for board level shielding cans

The conventional definition of shielding effectiveness is well suited for calculating electromagnetic shielding in the far-field. However, in the near field, shielding effectiveness calculation is not so straight forward. In radio frequency interference problems, most of the field coupling occurs in near field. Having a well-defined method to calculate near-field shielding effectiveness is important for estimating the suppression of radio frequency interference using the shield cans. In this research, a method to extract the shielding effectiveness of board level shielding cans using near field scanning is developed. Shielding effectiveness is defined by modelling the shielded noise source as equivalent dipole moments. Accuracy of the equivalent source is analyzed by using least square error and correlation coefficient as confidence check parameters. Applying reciprocity theorem, the voltage coupled on a PIFA antenna from an unshielded and a shielded source is calculated. Coupled voltage from a shielded noise source serves as the reference and is used to validate the effectiveness of the developed method. Practical shield cans were used to study and develop the shielding effectiveness extraction method using full wave 3D simulations --Abstract, page iv

Implementation of packaged integrated antenna with embedded front end for Bluetooth applications

The design, integration and realization of system in enhanced package approach towards fully functional system level integration by using a compact Bluetooth USB dongle as the demonstrator is presented here. The integration was done on FR4 substrates, which is totally compatible with today’s printed circuit board manufacturing capability. A commercially available Bluetooth integrated chip was chosen as the chipset of our demonstrator, and a package integrated antenna together with an embedded front end completes the system in package integration. The front end developed here is based on an embedded meander line combline filter and an embedded transformer balun. The filter has a 35% area reduction when compared with the classical combline filter and similar performance. The balun has the coils distributed on three layers that minimized the board area needed it and optimizes the performances. The proposed packaged integrated antenna approach is successfully demonstrated here and the new module shows excellent performance when compared with a commercial solution, surpassing the normal Bluetooth class II dongle range which is up to 10 m and increasing the module range up to 120 m without an extra power amplifier

EMI measurement and modeling techniques for complex electronic circuits and modules

This dissertation consists of four papers. In the first paper, a combined model for predicting the most critical radiated emissions and total radiated power due to the display signals in a TV by incorporating the main processing board using the Huygens Equivalence theorem and the radiation due to the flex cable based on active probe measurements was developed. In the second paper, a frequency-tunable resonant magnetic field probe was designed in the frequency range 900-2260 MHz for near-field scanning applications for the radio frequency interference studies by using a varactor diode providing the required capacitance and the parasitic inductance of a magnetic field loop (i.e., a parallel LC circuit). Measurement results showed good agreement with the simulated results. In the third paper, a wideband microwave method was developed as a means for rapid detection of slight dissimilarities (including counterfeit) and aging effects in integrated circuits (ICs) based on measuring the complex reflection coefficient of an IC when illuminated with an open-ended rectangular waveguide probe, at K-band (18-26.5 GHz) and Ka-band (26.5-40 GHz) microwave frequencies. In the fourth paper, a method to predict radiated emissions from DC-DC converters with cables attached on the input side to a LISN and on the output side to a DC brushless motor as load based on linear terminal equivalent circuit modeling was demonstrated. The linear terminal equivalent model was extracted using measured input and output side common mode currents for various characterization impedances connected at the input and output terminals of the converter --Abstract, page iv

Coupling of Energy Into PCB Traces in a Reverberant Environment: Absorption Cross-section and Probability of Susceptibility

Predicting the risk of susceptibility to electromagnetic interference for a system would be of significant interest to the EMC community. In this paper, we consider the coupling of electromagnetic energy into Printed Circuit Board (PCB) traces and how it relates to the power balance model of shielding effectiveness. We show results of some measurements of the absorption cross-section of a load on a PCB trace and compare them with previously published results

Constructing conducted emission models for integrated circuits

Conducted emissions, noise conducted out of integrated circuit pins, play an important role in determining the system level EMC performance. Characterizing conducted emissions from ICs is investigated and the corresponding noise models are developed in this thesis. Both simulation IBIS and measurement based methods for noise-model construction are studied. The constructed noise source model for a test IC is applied in system-level simulations and the calculated far field radiation is validated with measurements. The agreement in the simulated and measured results demonstrates the effectiveness of the constructed model for characterizing the conducted emissions from an IC I/O pin --Abstract, page iii

Prediction on optimistic and motivation factor to relapse among former drug abuse

Purpose: The objective of this study is to identify predictors (optimistic and motivation) that correspond to relapse among former drug abuse in Malaysia. Methodology: This study involves 50 former drug abuse who completed their questionnaire treatment and rehabilitation period and utilises three instruments, the Relapse Motivation Questionnaire (RMQ), Optimism used Life Orientation Test (LOT) and relaps was using the Inventory of Drug-Taking Situations (IDTS). This study uses descriptive statistical method or frequency to see the percentage for the demographic factor, while the inferential statistical method such as the Pearson correlation and multiple linear regression were used to test the research question. Main findings: Results showed that there is not any correlation between relapse towards drug addiction and optimism is (r=-0.261, p-value=.067) while there is significant correlation between relapse towards drug addiction and motivational (r= -.387**, p-value=.006) as well as motivational and optimism (r= .536**, p-value=.000). This relationship between motivational and relapse is negative between motivational and relapse while positive between motivational and optimism, which indicates that as the motivational increase the chances of relapse towards drug addiction decrease while on the other hand if motivational increase then optimism increase. Multiple regression analysis indicated that a both the variables statistically not significant and didn’t predict F (3, 46) = 57.208, p-value < .005, R2 = .789. So, without optimism, motivational behavior and strong cooperation among human beings it would be complicated to help former addicts to restart their lives as common human beings this country

Lunar surface exploration by satellite. An integrated experiment package to perform measurements of the composition of the lunar surface Final report

Integrated experiment package to measure lunar surface composition - gamma ray, alpha particle, X ray fluorescence, and neutron albedo experiment

Characterization of noise on PDN and electromagnetic shielding

Modern FPGA and microprocessor have complex logic inside them, which draw current from the Power Distribution Network (PDN). This current drawn from the PDN creates disturbance on the PDN, which then propagates to other IC in different places on the Printed Circuit Board (PCB), and appears as a noise voltage. Ability to predict noise voltage at any point on the PCB gives a greater ability to carefully design the board and the PDN. In order to accurately predict the noise, it is important to accurately predict the current drawn and the transfer impedance from the source to the victim point. A methodology is presented herein to accurately predict noise at any point on the PCB for any given logic running inside the FPGA. The second problem in this work is the study of composite absorbing and reflecting shielding materials capable of providing shielding to electronic equipment --Abstract, page iii

Aircraft electromagnetic compatibility

Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting

Avionics system design for high energy fields: A guide for the designer and airworthiness specialist

Because of the significant differences in transient susceptibility, the use of digital electronics in flight critical systems, and the reduced shielding effects of composite materials, there is a definite need to define pracitices which will minimize electromagnetic susceptibility, to investigate the operational environment, and to develop appropriate testing methods for flight critical systems. The design practices which will lead to reduced electromagnetic susceptibility of avionics systems in high energy fields is described. The levels of emission that can be anticipated from generic digital devices. It is assumed that as data processing equipment becomes an ever larger part of the avionics package, the construction methods of the data processing industry will increasingly carry over into aircraft. In Appendix 1 tentative revisions to RTCA DO-160B, Environmental Conditions and Test Procedures for Airborne Equipment, are presented. These revisions are intended to safeguard flight critical systems from the effects of high energy electromagnetic fields. A very extensive and useful bibliography on both electromagnetic compatibility and avionics issues is included