An electrostatic discharge (ESD) to the glass of a touchscreen display can damage capacitive touch sensor circuitry and traces. The ESD creates a sparkless corona discharge on the glass surface, which couples to sense patches on the other side of the glass. Currents induced on sense traces during the corona discharge are measured in an evaluation setup, which resembles the touchscreen design. Waveforms for current induced at different distances from the discharge position are recorded and compared. The induced currents are analyzed by their peak value and the total charge or energy delivered to the sense trace for different discharge polarities and voltage levels and for 20 different touchscreen configurations. Trends in the dissipated energy were found as a function of the glass thickness, the capacitance from the sense patch to reference ground, and the resistance of the sense trace. A simulation model to estimate coupling to touchscreen circuitry was developed by representing the ionized corona as concentric rings on the glass surface centered at the discharge location. Using a circuit model and data measured experimentally, the current source waveforms for different rings can be found and used in full-wave simulations to excite the rings and predict the current coupled to the sensor patches. This methodology can be used for a variety of touchscreen designs that are similar to those measured to explore the impact of design changes on ESD immunity.

A wireless power transfer (WPT) system suffers from eddy loss if a conductive object is placed near the coupling coil. In this paper, a 3-coil equivalent circuit model for the coupling coil in a WPT system is proposed for analyzing the eddy loss due to nearby conductors. This model uses a third coil with inductive coupling to the original transmitting and receiving coils to model the eddy loss. The proposed model was validated by comparing the Z-parameters with a full-wave simulation and showing good correlation over the frequency of interest, where the traditional 2-coil model fails. The 3-coil model is compared with the Steinmetz equivalent circuit model and shows better accuracy in terms of efficiency simulation. This proposed model can be used in efficiency analysis and design optimization of a WPT system.

Emission source microscopy technique can be utilized to localize the radiation sources in complex and electrically large electronic systems. In the two-dimensional emission source microscopy algorithm, both magnitude and phase of the field need to be measured, and a vector network analyzer or an oscilloscope has to be used as a receiver, resulting in reduced signal-to-noise ratio and longer measurement time compared to a spectrum analyzer (SA). In this article, a phaseless electromagnetic interference source imaging method is proposed based on microwave holography. The field produced by the device under test is not measured directly, instead, the interference pattern between the emitted field and the reference wave is created and measured as the hologram. The hologram is a real-valued function that can be measured using a SA. The proposed method is validated through measurements for both passive and active devices. The proposed algorithm is efficient and reliable in identifying major radiation sources and determining their location and relative strength.

Corona discharge to a glass surface is challenging to model due to a poorly understood air and surface ionization process. A modeling methodology based on the transmission line modeling (TLM) approach is proposed to simulate the streamer propagation process. The time-changing corona streamer resistance is estimated using the Rompe and Weizel spark model. The streamer is represented using small segments consisting of the arc resistance, per unit length (PUL) capacitance of the streamer, PUL inductance, a switch representing streamer formation, and a surface discharge gap voltage representing the voltage drop caused by ions within the streamer length. The propagation of the corona streamer depends on the tangential electric field strength at the streamer tip being higher or lower than the breakdown threshold for streamer formation. This preliminary 1D model shows plausible results for the current waveform shape, Lichtenburg dust figure diameter and streamer propagation velocity for a positive surface discharge to the glass. Although the model requires further improvement to predict propagation of multiple corona streamers, it provides a basis for simulation of a corona discharge on a glass surface which is related to the behavior of the underlying physics.

Unwanted field coupling is a major concern when using magnetic near-field probes for high-frequency scanning. The unwanted coupling of the tangential electric field to a tangential magnetic field probe has been studied extensively. This article shows a second unwanted coupling mechanism: coupling from a vertical magnetic field. The standing wave of a shorted pure TEM microstrip in air is utilized to separate the magnetic and electric field coupling. Simulations show that the eddy currents induced within the probe by the vertical magnetic field couple inductively to the pickup loop if the layer stack up is not symmetric. The unwanted magnetic field coupling mechanism is validated through both simulation and measurement. Two improved designs are proposed to mitigate the impact.

Evaluating the far-field radio frequency (RF) susceptibility of electronic devices often depends on extensive testing or full wave simulations. These methods are effective when complete system information is available but require substantial time and resources to evaluate a large number of variations in system configurations, where trace routings, integrated circuit (IC) package styles, trace terminations, arrival angle, and polarization of incoming wave, etc., are varied from one configuration to another. The goal of the following article is to develop simulation techniques for studying the statistical characteristics of coupling to typical printed circuit board (PCB) structures. Simulation time can be reduced by breaking the structure into small segments, determining the coupling and transmission characteristics of each segment analytically or in a full-wave model, and then determining the coupling to the overall structure by assembling the individual segments in a circuit simulation. Reusing premodeled segments of commonly occurring structures (e.g., IC package, trace, etc.) allows one to make estimates with minimal computational effort even for a complicated PCB design. Simulation time is estimated to improve by a factor of 40 or more over traditional full-wave modeling using this approach. This methodology enables the analysis of statistical electromagnetic coupling to random PCB geometries.

Electromagnetic interference can be highly disruptive to global navigation satellite system (GNSS) receivers. Interference can be intentional, but can also occur from electronics modules placed within the same system, where these modules may create sufficient unintended radiated emissions to disrupt GNSS operation. In this paper, GNSS receiver performance is evaluated in the presence of multi-tone interference. An expression for the GNSS correlator output in the presence of continuous wave interference (CWI) is derived and is extended to predict the carrier to noise density ratio, C/N 0 , of the receiver in the presence of multi-tone interference. C/N 0 is widely used for characterizing interference with GNSS receivers. Analytical estimates of C/N 0 are compared to results from measurements performed on a commercially available GNSS unit. The value of C/N 0 was predicted within a standard deviation of 0.97 dB when the noise type and level was varied, demonstrating the accuracy of the derived equations. These equations will be used in the future to develop more intelligent guidelines for evaluating the impact of interference from electronic modules placed in the same system as a GNSS receiver.

In this paper, the characteristic mode analysis (CMA) has been used to quantify external electromagnetic (EM) field coupling to a realistic printed circuit board (PCB) and to its traces. In our analysis, we show how the location of a trace on a PCB is important in determining the EM field coupling and we illustrate how CMA can be used to optimize the location of a PCB trace for interference control.

Waveforms that maximize coupling to linear loads have been theoretically synthesized but have not been experimentally validated. These waveforms can be calculated using the device's frequency domain transfer function. This work aims to experimentally validate the RF coupling performance of these theoretical worst-case waveforms to a device composed of concentric copper loops loaded with a nonlinear diode. Experimental results show that the worst-case broadband excitation generates a coupled voltage double that of narrowband excitation. However, the same waveform only couples similar to 25% of the energy of a narrowband waveform centered at the peak of the device's transfer function. This work provides the first experimental validation of the coupling performance of optimized waveforms.

Electrostatic discharge to a touchscreen display leads to a corona discharge which creates corona streamers that| propagate along the glass surface. The streamers couple energy to touch sensors underneath the glass which may then cause failure. Modeling the ionized air resistance and the current distribution on the glass surface from corona discharge is challenging. A new methodology is proposed for modeling corona discharge to a touchscreen surface with the help of experimentally measured dust figures. A geometric analysis of the dust figure and how streamer currents couple to the sensor patch matrix is given to explain the modeling method. A SPICE model is proposed to better correlate the ESD gun current with the current coupled to the sensor patches. The ability of the model to predict peak current, charge and rise time is evaluated. Predictions of peak current and charge are within 30% error.

Characterizing the susceptibility of an IC while it is integrated within a system can be challenging. Characterization is even harder if one wants to know the waveform at the target IC pin when injecting a signal on the pin. In this work, the feasibility of a direct injection probe with a capacitively coupled return and integrated voltage monitor is proposed. This probe is advantageous because it does not need to be soldered to the test device and its ability to provide a measurement of the waveform on the target IC pin during the injection. Methods for reconstructing the pin waveform based on probe measurements are discussed. Initial results indicate that the presented probe is generally insensitive to landing position variations and can accurately provide the waveform at the target IC during an injection. Future work is focused on further validation of the presented probe.

RF switches are typically used in the RF front-end of portable devices such as antenna or matching tuners to improve the RF link performance. They are usually the first active devices after the antenna and are vulnerable to primary or secondary ESD discharges to the antennas. This paper investigates the ESD behavior of one of the high frequency switches used in the RF-front-end of portable devices and expresses the importance of the ESD pulse that passes through the switch and reaches the next stage in the RF path, possibly damaging the next stage

Transmission lines referenced to meshed return planes are widely used because of the physical flexibility imparted by the meshed plane. Poor accounting for the meshed ground, however, can lead to severe signal integrity and radio frequency interference issues. Full-wave simulation can characterize the electrical performance at an early design stage, but it is both time and computational resource consuming. To make the simulation more efficient, a method is proposed in this study to model transmission lines with a meshed reference ground using 2D analysis. The 2D analysis is performed at several locations along the length of the trace above the meshed return to determine per-unit-length RLGC parameters and partial self - and mutual-inductances of the trace and meshed return. The partial self-inductance of the return is then corrected to account for the current direction along the mesh. Cascading the corrected S-parameters for each segment is then used to estimate the overall characteristics of the transmission line. Results found using this approach closely match those found with 3D full-wave simulation.

Equivalent sources found from near-electric and magnetic field scans are often used to predict and solve interference problems. While there are many ways to represent the source, the user lacks the ability to determine which of the many possible source configurations is more likely to represent the "true" source, and thus accurately represent field data outside the measurement area and in the presence of typical measurement errors. A methodology is proposed for estimating which of many possible dipole source representations of near-field scan data are likely to give better estimates of fields outside the measurement scan plane when utilizing imperfect measurement data. A quality metric for determining better configurations is proposed, which utilizes the statistical variation of the global difference measure (GDM) in the predicted and measured fields. Equivalent sources are estimated when adding noise to measurement data, and prediction statistics are generated for multiple instantiations of measured noise. Results demonstrate that the better configurations minimize the average plus standard deviation of the GDM. The ability of the technique to identify robust source configurations was tested when measurements were subject to additive measurement noise, cross-field coupling, and systematic errors in probe position, and was evaluated based on its ability to predict fields at points above and to the side of the measurement plane. The method consistently identified better source configurations using both simulated and measured data.

Integrated circuits (ICs) connected to a universal serial bus (USB) interface require robust electrostatic discharge (ESD) protection strategies due to the nature of the high-speed interface and the regular access by users. System-efficient ESD design (SEED) simulations can help predict the level of ESD stress seen by the IC when protected by a transient voltage suppressor (TVS). In the following paper, previously developed models were improved to predict the voltage and current seen by a TVS and an on-chip protection diode when an ESD gun was discharged to one USB cable pin. Models were improved, in part, by accurately modeling the conductivity modulation within the behavioral TVS model and by using a measured equivalent source to represent the complex interaction between the ESD gun, USB cable, and enclosure. The response of the TVS and on-chip diode was studied in simulation and measurement for several cable configurations and when adding passive components between the TVS and on-chip diode. Simulations predicted peak and quasi-static voltages and currents at the TVS and on-chip diode within 30% of those seen in measurements. The proposed modeling process can help engineers to evaluate and optimize the effectiveness of their ESD protection strategies under complicated test conditions.

Although corona discharge to a touchscreen display is not associated with the spark, it could cause soft and hard failures due to electromagnetic coupling to sensitive electronics beneath the glass. Experimental data were obtained to characterize these sparkless discharges and an equivalent circuit model was constructed to predict the resulting coupling to touchscreen electronics. Measurements and simulation indicate that a thinner glass and a higher touchscreen indium-tin-oxide (ITO) sense trace impedance both lead to higher ESD risk by delivering higher energy into the sensing IC. A CST co-simulation model is proposed and is shown to model the displacement current accurately. Charge movement and dissipation on the glass surface is represented using a disk with conductivity proportional to the reciprocal of radial distance. Dust figure measurements were used to study the effects of the glass type, glass thickness and voltage level on the corona discharge and the current coupled to the touchscreen patch on the display. These results can be used to drive full wave co-simulation models which try to anticipate the impact of sparkless discharges on the touchscreen electronics.

According to the third Generation Partnership Project specification, a period of 8–12.8 h is required to evaluate the multiple-input–multiple-output (MIMO) performance of a wireless terminal for a single frequency point and channel model combination. The following article proposes a semi-simulation, semi-measurement-based MIMO throughput modeling scheme which can reduce the 8–12.8-h measurement time to 40–60 min, corresponding to more than a ten times improvement of the test efficiency, without loss of the test accuracy.

This proof-of-concept communication demonstrates the feasibility of using a slide projector to steer the beam of a transmit array by adding solar cells and varactor diodes to each unit cell. By irradiating each solar cell with the light of different intensities from a slide projector, the measured phase of the wave transmitted by the $4\times4$ transmit array shifts within 92° at 4.26 GHz, while the variation in magnitude is measured within 4 dB. Different light configurations are identified via a searching algorithm to achieve peak/null beamforming in a particular direction. The beam of the prototypical $4\times4$ transmit array can be shifted by ±24° in terms of the peaks and −30° to 36° in terms of nulls. The concept of adding light modulation to the transmit array with a slide projector can provide update rates of tens of milliseconds with control of brightness and color distributed over a large area of the array.