Applied Electromagnetics and Electromagnetic Compatibility

The external surfaces of a spacecraft exposed to Earth's magnetospheric plasma can build up differential voltages which can result in an electrostatic discharge (ESD). This discharge may induce transient electromagnetic interference (EMI) in the electronics circuitry and may give rise to switching anomalies or system failure under certain environmental conditions. This paper outlines the development of Lumped Element Model (LEM) of a spacecraft for surface charging studies. A numerical solution procedure using method of moments and triangular patch modelling to determine the capacitance of conducting objects in free space has been developed. Differential equations of spacecraft charging have been derived and the surface charging of INSAT-2E spacecraft has been simulated. The results obtained for INSAT-2E using LEM concept are compared with those obtained using the NASA Charging Analysis Program (NASCAP) for a similar satellite.Using LEM of a conducting plate located in free space, and with the help of circuit simulation software, the transient structural current due to a blow-off discharge is predicted. Power supply lines, command and control lines, lines connected to antenna probes, switches and thence to microwave devices can pick up ESD transients. Hence ESD immunity should be built into microwave subsystem as well. Techniques of hardening microwave subsystem against on-board ESD have also been outlined.

It is expected that the superior high‐frequency characteristics, such as low loss and low dispersion, of superconducting oxides are applied to microwave circuits. However, low‐loss superconducting oxide films can only be fabricated on limited types of substrate materials using present technologies. Therefore, the dielectric constant, dielectric loss, and thickness of substrate materials place severe limitations on the circuit design and the propagation characteristics.This paper discusses the attenuation constants, characteristic impedances, and wiring density of three fundamental planar transmission lines, namely, stripline, microstrip line, and coplanar waveguide fabricated on substrate materials MgO and LaAlO3. This discussion is based on the TEM and quasi‐TEM analysis procedures. The thin films with low surface resistances have been fabricated on MgO and LaAlO3. It is concluded that the microstrip line is suitable for fabricating a low‐loss transmission line and the coplanar waveguide on a low dielectric constant substrate is suitable for high‐density wirings.Also measured were the characteristics of the half‐wave transmission line resonators of these three transmission line configurations, which are made of EuBa2Cu3Ox thin films on an MgO substrate. The attenuation constant of 50 Ω, 50‐μm wide coplanar waveguide is 9.7 × 10−3 Np/m (8.4 × 10−2 dB/m) at 3.9 GHz and 28 K. This value is two orders of magnitude lower than that of the copper transmission line.

Compact and robust electrostatic discharging (ESD) protection structures are critical to on-chip ESD protection for ICs. Conventional in-Si ESD protection structures have many disadvantages. A new above-IC graphene NEMS (gNEMS) switch is reported as an ESD protection structure, which features almost zero leakage and robust ESD protection. A systematic characterization of gNEMS ESD structures was conducted by transient transmission line pulse (TLP) testing. The statistical analysis reveals the relationship between ESD discharging behaviors and the influences of gNEMS device dimensions and TLP testing conditions on ESD discharging.

A fighting platform such as a ship or submarine is bristling with electronic warfare systems, communications systems, radar, sonar and many electrical power systems-to name but a few. All of these can potentially emit high powered electromagnetic waves which can so easily interfere with other items of equipment fitted on board. These systems face a threat from another quarter-those of conducted transients, induced predominantly via cables, interfering with, and possibly causing damage to, all types of equipment. Sources of such transients are numerous and include lightning, electrostatic discharge (ESD), nuclear electromagnetic pulse (NEMP) and transients caused by load changes and inductive switching of 440 V 60 Hz and other main power supplies. DERA West Drayton have been instrumental in the long term monitoring and protection of naval systems against many conducted transient threats, particularly those on power supply lines. This experience has also led to the publishing of two specialist test techniques in the UK's tri-service EMC Defence Standard 59-41 as test supplements DCS11 and DCS 12. This paper summarises experience gained during monitoring of shipboard supplies and EMC testing.

Electric vehicles typically have a large array of storage cells and for efficient operation each cell should be monitored individually. In other areas industrial processes need to be monitored often in harsh conditions. A conventional approach is to physically connect sensor and actuators to long buses. High data rates demand high frequency buses but direct connection means that loading and attenuation can be severe and impractical if a large number of devices need connection. The alternative is free space radiation. The latter was investigated for track to train communication at 2.4GHz [7] In the limited space of battery compartments rectangular wave guides are impractical, however micro strip lines can made compact enough to fit in these locations. By weakly coupling a subwavelength antenna to a micro-strip transmission line simulations and experimental data over frequencies between 600 and 1 GHz show it is possible to couple up to 100k devices without unduly loading the line. The line is not limited in length and radiation is so low that is little interference between adjacent devices and the surrounding medium. It has the added advantage that each node is electrically isolated from each other and the transmission line.

In this paper, the spoof surface plasmon polaritons (SSPPs) transmission line (TL) of periodical grooved bow-tie cells is proposed. The complex propagation constant and characteristic impedance of the SSPPs TLs and microstrip lines (MLs) are extracted using the analytical method of generalized lossy TL theory. The properties of the SSPPs TLs with different substrates and the same geometrical configuration are experimented. Then, for comparison, two ML counterparts are also experimented, which shows that the SSPPs TL is less sensitive to the thickness, dielectric constant and loss tangent of the chosen substrate below the cutoff frequency, compared with the ML ones. The single-conductor co-planar quasi-symmetry unequal power divider based on this SSPPs TL is presented in microwave frequencies. For experimental validation, the 0-dB, 2-dB, and 5-dB power dividers are designed, fabricated, and measured. Both simulated and measured results verify that the unequal power divider is a flexible option, which offers massive advantages including single-conductor co-planar quasi-symmetry structures, wide-band operation, and convenient implementations of different power-dividing ratios. Hence, it can be expected that the proposed unequal power dividers will inspire further researches on SSPPs for future design of novel planar passive and active microwave components, circuits and systems.

Second breakdown current (It2) is an important merit of Electrostatic discharge (ESD) protection devices, and it is especially critical for high voltage ESD design. The device physics involved in ESD phenomena are highly complex as ESD devices operate at high current condition within a short period of time. Technology Computer Aided Design (TCAD) simulation offers faster design optimization and quantitative evaluation of robustness, which can significantly improve ESD device’s robustness. However, an accurate TCAD simulation requires accurate modelling of sophisticated device physics. Due to the ESD’s high stress nature, understanding and modelling of such device physics are non-trivial. We applied TCAD 2D simulation to a high voltage Silicon-controlled Rectifier (SCR), 2D simulation to diode and 3D simulation to diode with different sizes. Based on comparisons of two ESD modes (HBM and CDM) and two transmission line pulses (TLP and VFTLP) simulation data, the simulation method is self-consistent and shows effective It2 prediction ability. The above-mentioned TCAD simulation method can help accelerate design iteration of ESD design and find more optimized ESD device structures.

It is recommended that the output current waveforms of ESD (electrostatic discharge) simulators for ICs be specified into a short circuit and 500 ohm load in order to insure that equivalent tests are being performed. Because this recommendation has not been in force, two alternatives have been proposed for the MIL-STD 883c ESD test circuit, which were found to differ by more than 30% from that circuit. It is strongly recommended that all future ESD test standards adopt the practice of specifying realistic ESD waveforms into at least two different loads in order to insure that tests are both repeatable and realistic. >

The purpose of the study was to develop an algorithm for the implementation of an accurate determination of the location and nature of insulation fault on the power supply line, which foundation is a mathematical model of the electrical network mode based on the theory of electrical circuits with distributed parameters. The achievement of this goal is based on the analysis and mathematical description of the replacement circuits of a distribution line with two power centers in the stationary mode with known propagation constants and wave impedances and in a fault mode. The equations of the model are described in detail, using the example of calculating typical modes of a 50 km long low-power distribution line with two power centers, it is demonstrated that it is possible to quickly, in the current time mode, obtain the coordinate of probable insulation fault and assess the degree of it, while an indication of an emergency mode was a voltage deviation at the outputs of the power centers. In general, the method for calculating the mode of the distribution line of an alternating current electric power system under consideration allows quick monitoring of damage or unauthorized connection of the load for the purpose of power take-off, while this technique is also suitable for analyzing a line with a single power supply center, and also makes it possible to quickly adjust the voltage of sources to control the load power at the required level. A promising area for further research may be the extension of the technique to branched lines with several load branches and power centers, which is typical, for example, for offshore electric power systems. In addition, a system for monitoring isolation and selective protection of branched loads can be built on the model under consideration.

This paper will demonstrate the synthesis of the high current pulse source method (e.g. used in transmission line pulse (TLP) systems) and the Picosecond Imaging Circuit Analysis (PICA) tool for the evaluation. of electrostatic discharge (ESD) and latchup phenomenon. In this fashion, the evolution of ESD and latchup can be evaluated in semiconductor devices, and in peripheral circuits at a wafer level or product level. The methodology described in this publication allows for visualization of ESD and latchup, events (e.g. animation in a picosecond time regime). The synthesis of the transmission line pulse (TLP) method and the PICA method allows for the extension of the ESD TLP methodology to terminal currents and spatial and time domain analysis for electrical characterization and reliability analysis, and the high current pulsed source extends the utilization of the PICA methodology for failure analysis on wafer and chip levels.

In this paper, we present a new ESD device using the p-channel impact ionization MOSFET (I-MOS) with its gate and source connected to the ground, and its drain connected to the input/output (I/O) pad, called as the gate grounded I-MOS (GGIMOS). The proposed GGIMOS uses the conventional thick oxide (used for 2.5-V I/O devices) for 5-V failsafe/fault-tolerant I/O applications. For positive electrostatic discharge (ESD) stress, the turn-on mechanism is through controlled avalanche multiplication. During negative stress, the GGIMOS acts as a forward-biased gated diode. The gate oxide reliability concern of the p-channel I-MOS is alleviated by implementing the device in the p-substrate instead of n-well. The physics and operation of the GGIMOS is explained using electrothermal technology computer-aided design simulations and its performance is benchmarked using the simulated transmission line pulsing (TLP), very fast TLP, and human body model results. The proposed device eliminates the need for: 1) a cascaded nMOS architecture for high-voltage capability; and 2) a return diode for negative ESD stress conditions resulting in an area-efficient ESD clamp design. This makes the GGIMOS a potential device for ESD clamping applications in the state-of-the-art CMOS technologies.

Transmission Line Pulse (TLP) is often applied for Electrostatic Discharge (ESD) devices' characteristics researches. It indicates the devices' triggering-on behaviors, holding performances and thermal run-away results. In normal cases, the thermal run-away data should correlate to ESD [1]. However, the non-correlations between TLP and ESD can be observed in the gate driving circuits [2], silicide devices [3] and poly fuses [4]. In this paper, analyses for the relations between ESD and TLP are taken into discussions for large array devices (LAD).

Power consumption has been the major bottleneck in the development of integrated circuits with reduced critical dimensions and improved integrated level. Tunnel field effect transistor (TFET) has been investigated as one of the promising replacements for traditional metal oxide semiconductor field effect transistor (MOSFET), owing to the introduction of band to band tunneling (BTBT) mechanism based on which a smaller subthreshold slope is achieved. However, a thinner oxide layer and a shorter channel length in TFET may induce localization of high current density, high electrical field distribution, and generation of heat, which abate the probability to survive electrostatic discharge (ESD). Besides, the novel BTBT operating principles also present a challenge to TFET ESD protection design. In this paper transmission line pulse test method is adopted to analyze the working principle of conventional TFET at onset, holding, discharge, and second breakdown during an ESD event. Based on these a new TFET ESD device protection design is proposed and characterized with a deeply doped n+ pocket near the source region beneath the gate, which can make effective adjustments of contact potential barrier, reduce tunneling junction width, thus better ESD design windows are obtained.

Optical pulse energy controlled delay in the propagation time of electrical picosecond pulses in YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) superconducting transmission lines has been investigated by using picosecond optoelectronic techniques. The transmission lines are microstrip lines on LaAlO/sub 3/ substrates and are illuminated by the frequency doubled output (532 nm) of a Nd:YAG laser. The propagation time of picosecond electrical pulses through the transmission lines was measured using electrical autocorrelation techniques with optical switches. By varying the optical pulse energy from 0 to 83 pJ the delay through the lines was tuned by 40 psec at 30 K. The propagation time shows a quadratic dependence on the optical pulse energy. As the optical pulse energy increases a gradual increase in pulse width was observed.

Duality transformation is introduced to the theory of generalized (nonreciprocal and nonsymmetric) transmission lines making it possible to find solutions to problems in terms of solutions to dual problems without having to go through the solution process. The generalized transmission lines have emerged when more general media have been introduced to classical waveguide geometries, for example, microstrip lines on chiral substrates. It is seen that there actually exist two duality transformations and the self-dual voltage and current solutions are propagating waves in the transmission line. The transformation can be, e.g., applied to transform a nonsymmetric transmission line to a symmetric one.