Device Under Test Research Articles

Alternative Setup for Long-Duration Low-Duty-Cycle 600°C Ambient Testing of SiC Integrated Circuits

Abstract A scalable, compact oven testbed system for simultaneously evaluating a multitude of high temperature integrated circuits (ICs) for prolonged operating times of up to 600 °C has been prototyped. The new testbed system enables long-duration high temperature testing in sufficient statistical quantities consistent with standard aerospace electronics engineering standards. This setup is comprised of multiple compact ovens housing chips or packages mounted to ceramic circuit boards. Each oven is a compact 15.2 cm length by 15.2 cm width by 12.7 cm depth with a maximum 400 Watts of heating power. The custom-made silicon oxide ceramic heating block inside each oven is based on a 3D printed design adapted for the easy insertion of the IC device under test (DUT). This innovative design provides the quick insertion of ICs with or without a ceramic package into a 600 °C environment by utilizing a movable 11.43 cm long ceramic substrate with electrical traces extending from the oven hot zone to external standard plastic-based board connectors. Another key oven design feature is the minimization of the DUT exposure to electromagnetic interference (EMI) by utilizing a filtered DC power source to reduce heating element noise. Additionally, the ovens can be configured in a parallel arrangement allowing global data monitoring over a single industrial RS422 serial port. This feature is important for scaling up to test multiple ICs semi-simultaneously. A USB serial port is provided to independently control the operating parameters of each oven such as the oven target temperature and oven ramp rate. The oven temperature can reach up to 600 °C with a confirmed +/− 4 °C maximum deviation across the test zone region. The ramp rate can be programmed from 1 °C/minute up to 10 °C/minute. Furthermore, a programmable switchboard is used to interface with the DUT. This switchboard comprises a National Instruments Peripheral Component Interconnect eXtension for Instrumentation (NI PXI) system and a breakout board to send and receive power, analog or digital test signals. By using this unique oven testbed system, a variety of ICs can now be tested in parallel using the same test components configured for a diverse set of requirements.

A general method for radiated emission prediction in a multiple monopole source stirred reverberation chamber

This paper presents a general and quasi-analytical method aimed at reconstructing the electric field radiated by equipment under test (EUT), in free space through the knowledge of the values of the electric field sampled on the walls of a rectangular metallic enclosure. The algorithm is based on a set of equivalent magnetic and electric currents, regularly placed in a sub volume of the chamber, whose values are determined to reconstruct the electric field due to the EUT on the samples. Results show that the method is general because it can be applied to a wide set of EUTs, but it is also flexible because it is able to exploit some a priori knowledge of the source to improve its accuracy and efficiency.

Особенности измерения теплового сопротивления мощных солнечных батарей.

The results of power solar batteries' thermal resistance measurements are described. A distinctive feature of such batteries is the high heat capacity of the semiconductor material, as well as the high total electrical capacity of p-n-junctions. This complicates the thermal resistance of the measuring process, based on heating the object by the heating current pulses and measuring the temperature of the p-n-junction in the pauses between pulses. To measure the thermal resistance of power solar battery the modulation method was used, a device under test (DUT) heated with current pulses with duration modulated harmonically. The response to the heat (a variable component of the p-n-junction temperature) is measured in the pauses between the pulses. To detect the thermal resistance component junction-to-case, the dependence of the thermal impedance on heating power modulation frequency was measured. In the measured dependence, a frequency range is found when the real part of the thermal impedance value remains constant. This allows the determining of the "junction-to-case" thermal resistance component. Were made estimates of the duration of a single measurement of thermal resistance and a conclusion about the possibility of implementing selective technological control of this parameter in the production of powerful solar cells.

A high-efficiency wideband coupler for nanosecond-level pulsed current injection.

Pulsed current injection (PCI), as a conducted vulnerability testing technique under nanosecond-level transient electromagnetic disturbance (TED), has gained great attention recently. Many kinds of TEDs, e.g., high-altitude electromagnetic pulse, very fast transient overvoltage, and electrical fast transients, have very fast rise time as well as pretty slow decay, whose frequency spectrum may cover a very wideband. Therefore, one of the challenges is that the existing inductive couplers cannot interact with the equipment under test (EUT) over the wideband efficiently, and consequently, they are inadequate to inject the proper disturbance at ports of EUT in PCI tests. To address this problem, a high-efficiency wideband PCI coupler is proposed in this paper. The coupling performance is analyzed theoretically based on the distributed-parameter model of an inductive coupler. By using the composited ferrites instead of the simplex Ni-Zn ferrites, the inductive coupling is enhanced. The capacitive coupling is also enhanced to improve the high-frequency performance by exploiting the distributed tubular winding. A PCI coupler with the dimension of 30 × 10 × 10cm3 is built to be validated experimentally. The 3 dB bandwidth has been improved from 421 kHz-14MHz to 77 kHz-39MHz, which indicates that the coupler can be applied efficiently over the frequency range of interest for PCI tests.

Novel cost-effective passive intermodulation measurement technique using a single power amplifier

The growing number of cellular devices and the introduction of high-speed data affect the network performance of mobile communication systems. Evaluation of passive intermodulation (PIM) phenomenon in the field of microwaves and mobile communications improve system performance. Typically, the PIM of the device-under-test (DUT) is measured using a set-up that involves two power amplifiers (PA), making it an expensive measurement set-up. This research aims to make PIM measurements cost-effective by using a single PA. Reflected (RFL) PIM distortion measured for two different DUTs, i.e., circulator and a microstrip (MS) line containing radio frequency interference (RFI) shielding gasket, using the presented and standard techniques. The presented PIM analyzer has a residue PIM of -104.5dBm. Comparison and error analysis suggested that the presented single PA method is feasible for DUTs having PIM between -60 and -94.5dBm at 43dBm input power. The residual PIM of the presented analyzer is high compared to the standard PIM analyzers; it is investigated that IM generated by the PA is the leading cause of this higher residual PIM product (RPIM). The proposed method will reduce overall system cost and size; it will also improve the battery efficiency of portable and desktop PIM analyzers.

A Local Oscillator Phase Compensation Technique for Ultra-Wideband Stepped-Frequency Continuous Wave Radar Based on a Low-Cost Software-Defined Radio.

The paper discusses a way to configure a stepped-frequency continuous wave (SFCW) radar using a low-cost software-defined radio (SDR). The most of high-end SDRs offer multiple transmitter (TX) and receiver (RX) channels, one of which can be used as the reference channel for compensating the initial phases of TX and RX local oscillator (LO) signals. It is same as how commercial vector network analyzers (VNAs) compensate for the LO initial phase. These SDRs can thus acquire phase-coherent in-phase and quadrature (I/Q) data without additional components and an SFCW radar can be easily configured. On the other hand, low-cost SDRs typically have only one transmitter and receiver. Therefore, the LO initial phase has to be compensated and the phases of the received I/Q signals have to be retrieved, preferably without employing an additional receiver and components to retain the system low-cost and simple. The present paper illustrates that the difference between the phases of TX and RX LO signals varies when the LO frequency is changed because of the timing of the commencement of the mixing. The paper then proposes a technique to compensate for the LO initial phases using the internal RF loopback of the transceiver chip and to reconstruct a pulse, which requires two streaming: one for the device under test (DUT) channel and the other for the internal RF loopback channel. The effect of the LO initial phase and the proposed method for the compensation are demonstrated by experiments at a single frequency and sweeping frequency, respectively. The results show that the proposed method can compensate for the LO initial phases and ultra-wideband (UWB) pulses can be reconstructed correctly from the data sampled by a low-cost SDR.

Power-HIL Application Analysis of a 3-level Inverter for PMSM Machine

Power-HIL simulation is one of the emerging areas in power electronics development nowadays. It offers a convenient test environment for the whole power electronics hardware but eliminates the necessity of motor test benches and rotating machines. Selecting a suitable power amplifier for the simulator is however a challenging task. Switching power supplies can be an interesting option as Power Amplifier, but they have to offer superior power capability and dynamic performance over the DUT (Device Under Test), while maintaining high enough switching frequency to meet the dynamic requirements as well. Using commercially available inverters as Power Amplifiers would be an attractive option, if they can achieve the desired emulation accuracy. This paper investigates the possibility of using a common 3-level inverter with an L-C-L coupling network as a Power Amplifier for a P-HIL simulator, to emulate a PMSM (Permanent Magnet Synchronous Machine) machine.

Influence Analysis of mm-Wave DUT Mounting Fixture in 5G OTA Measurement

All of the test cases in the current version of TR 38.810 in 3GPP and CTIA millimeter-Wave (mm- Wave) test plan are limited to the free space configuration. However, the truly free-space condition does not exist for mm-Wave testing of 5G user equipment since no device can float in the air. Mounting fixtures and supporting structures are needed to fix the device under test (DUT) and move it in two axes. The influence of mounting fixture on 5G mm-Wave wireless device performance is analyzed in this paper. First, a common 4×1 patch array at 28 GHz is simulated as the performance baseline. Various mounting fixture thickness & various spacing between the DUT and the mounting fixture are simulated to get a quick understanding of the mounting fixture’s influence on DUT performance. In different configurations, the working frequency of the antenna would have different degrees of deviation, while the gain could decrease or increase accordingly. Then, to explain these phenomena, an equivalent circuit is extracted utilizing the transmission line theory. Finally, according to the findings, it is recommended that the thickness of the mounting structure should be equal to an integer time of 0.5 λg to minimize the impact of the fixture for practical mounting structure design.

Test Setup Design for Measuring the Conductance in the Mechanical Part of Hybrid-Circuit-Breakers Before and After Current Commutation

The number of devices either providing or demanding direct current is growing more and more. This led to the renascence of DC grids and revealed a need for research. One critical component is the DC circuit breaker. It has to handle nominal and fault currents to keep the grid stable and operable. Interrupting currents in DC grids can be challenging because of the absence of a natural current zero crossing. Therefore, complex arcing chambers are needed. Especially at low currents, the self-induced force may not be sufficient to force the arc into the arcing chamber. Hybrid circuit breakers (HCB) are one possible solution to meet theses sophisticated requirements. There are several different topologies. All have in common that mechanical switches and semiconductors are combined to create a switch with the advantages of both technologies. One simple solution consists of two mechanical switches and one bypassing semiconductor circuit. The arc is used to achieve commutation from the mechanical to the semiconductor branch. While it carries the current, the mechanical switch regains its dielectric strength. Since this recovery time is short, the semiconductor can be overloaded within the limits of its thermal capacity. Defining the recovery time can be challenging. In addition, the effect of contact distance, arcing time and current value are unknown. To research the recovery behavior a model-switching chamber with an adjustable contact gap is developed. This device under test (DUT) was implemented into a test circuit that reproduces part of the hybrid switching process. When the arc between the contacts of the DUT reaches its steady state, a parallel commutating path is activated. The residual conductance of the decaying arc was measured. The development and several iteration steps of the test circuit and DUT are laid out. Finally, some test runs and initial measurements are presented.

Electrical Measurements and Parameter Extraction of Commercial Devices Through an Automated MATLAB-Arduino System

A quick, cheap, and portable system for measuring accurately basic electrical characteristics of electronic devices is presented—using common off-the-shelf components linked through a simple breadboard. The system is controlled using a MATLAB app that communicates to an Arduino Nano that, in turn, controls two AD5761 16-bit, 20-V, digital-to-analog converters and an INA219 high-side shunt sensor for driving the voltage and measuring the current through a device under test (DUT). The raw data from the system are plotted in real time in MATLAB and are automatically saved to a.csv file based on the current date and time. For higher current devices (above 10 mA), a simple direct-wired connection between the DUT and the measurement circuit effectively eliminates the breadboard parasitic resistance. With these techniques, the system introduced here shows a negligible difference to the data measured using a Keithley 2410 sourcemeter and a B1500 semiconductor parameter analyzer, thereby presenting a cheap and reproducible alternative to high-end instruments for measuring two- and three-terminal devices.

An Ultrawideband Magnetic Probe With High Electric Field Suppression Ratio

In this article, an ultrawideband magnetic probe with high electric field suppression ratio (EFSR) is proposed. The probe has three parts: the loop part, the transmission part, and the head part. Shield metal sheets are designed in the loop part to enhance EFSR. The tapered transmission line in the transmission part and the quasi coaxial transition in the head part are adopted for impedance matching between the induction loop and the grounded coplanar waveguide (GCPW) in the head part. Then, segmented resistance–inductance–capacitance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLC</i> ) equivalent circuit models of the probe are proposed for magnetic field coupling and electric field coupling, which are suitable for accurate modeling and efficient optimization of the magnetic probe. In addition, the coupling capacitors between the shield metal sheets and the device under test (DUT) are extracted utilizing the conformal transforming method with analytical formulas. Finally, this magnetic probe is fabricated under printed circuit board (PCB) technology and used in measuring the magnetic field distribution. The measurement and simulation results agree well. The probe has a bandwidth of 100 MHz–30 GHz and an EFSR of higher than 21 dB. Compared with the conventional probe with similar bandwidth, the proposed probe can improve the EFSR by 9 dB.

A High-Performance, Reconfigurable, Fully Integrated Time-Domain Reflectometry Architecture Using Digital I/Os

Time-domain reflectometry (TDR) is an established means of measuring impedance inhomogeneity of a variety of waveguides, providing critical data necessary to characterize and optimize the performance of high-bandwidth computational and communication systems. However, TDR systems with both the high spatial resolution (sub-cm) and voltage resolution (sub-$\muV$) required to evaluate high-performance waveguides are physically large and often cost-prohibitive, severely limiting their utility as testing platforms and greatly limiting their use in characterizing and trouble-shooting fielded hardware. Consequently, there exists a growing technical need for an electronically simple, portable, and low-cost TDR technology. The receiver of a TDR system plays a key role in recording reflection waveforms; thus, such a receiver must have high analog bandwidth, high sampling rate, and high-voltage resolution. However, these requirements are difficult to meet using low-cost analog-to-digital converters (ADCs). This article describes a new TDR architecture, namely, jitter-based APC (JAPC), which obviates the need for external components based on an alternative concept, analog-to-probability conversion (APC) that was recently proposed. These results demonstrate that a fully reconfigurable and highly integrated TDR (iTDR) can be implemented on a field-programmable gate array (FPGA) chip without using any external circuit components. Empirical evaluation of the system was conducted using an HDMI cable as the device under test (DUT), and the resulting impedance inhomogeneity pattern (IIP) of the DUT was extracted with spatial and voltage resolutions of 5 cm and 80 $\muV$, respectively. These results demonstrate the feasibility of using the prototypical JAPC-based iTDR for real-world waveguide characterization applications

Far Field Prediction From Near Field Using the Plane Wave Spectrum Method

Over the past decade, the evolution of embedded system has taken place drastically as it has been for their integration in various industries. This increases Electro-Magnetic Interferences (EMI) problems and generates new design constraints on Electro-Magnetic Compatibility (EMC). Thus, the nature of the electromagnetic environment and the prospective for undesired coupling must be taken into consideration by embedded systems engineers to avoid the equipment failure or malfunction. Accordingly, the radiated emission models are of great interest to designers of electronic equipment. This paper exploits the Plane Wave Spectrum (PWS) technique to predict and compute the magnetic field at various distances till 100mm above a Device Under Test (DUT). Good similarities are obtained between the magnetic field components calculated by PWS and the simulated ones by HFSS at different elevation from the electric dipole.

Broadband Radiation Source Reconstruction Based on Phaseless Magnetic Near-Field Scanning

An effective broadband electromagnetic interference (EMI) source reconstruction method is proposed in this letter. An equivalent dipole model incorporating the global optimization method is developed to reconstruct EMI sources on printed circuit boards (PCBs) based on the scanned magnetic near-field magnitudes of device under test (DUT). Different to conventional approaches, the locations and quantity of the equivalent dipoles are fixed for all frequencies in the interesting band. The moments and locations of these dipoles are acquired by deploying interpolation based on near-field data at three predefined frequencies only. The near-field patterns at all frequencies can thus be obtained by customizing the dipoles moments. The values of the coupled powers derived from these models are used for near-field prediction. Through numerical and physical examples, the effectiveness of this broadband modeling method is verified.

High Accuracy Distributed Polarization Extinction Ratio Measurement For a Polarization-Maintaining Device With Strong Polarization Crosstalk

Polarization extinction ratio (PER) is a quantitative indicator of the polarization-maintaining (PM) ability of a device. In this work, we present a distributed PER measurement method based on white-light interferometry. It can accurately measure the PER distribution of a PM device even in the presence of strong polarization crosstalk. We show that the distributed PER can be expressed as the reciprocal of the accumulated polarization crosstalk along the device. Thus, the PER distribution of a PM device can be calculated from the distributed polarization crosstalk. In the presence of strong polarization crosstalk, we introduced a concept of polarization crosstalk induced loss to prove that there is a significant error of the measured distributed polarization crosstalk. The error can be accurately estimated and be calibrated out from the measurement result. To verify the measurement method and the calibration accuracy, we used a commercial PER meter that can only measure the total PER of a device as the reference. We simulated a quasi-distributed PER device under test (DUT) by successively splicing 15 pieces of PM fibers and measured its total PER after splicing each piece of fiber. The calculated distributed PER of the DUT after error calibration matches well with the quasi-distributed result at the corresponding locations. Finally, we applied the method to measure the distributed PER and total PER of a PM fiber coil. After error calibration, the residual error (i.e., the difference with the commercial PER meter) in the total PER, thus of the distributed PER, is less than 0.1 dB.

Radiation testing of a commercial 6-axis MEMS inertial navigation unit at ENEA Frascati proton linear accelerator

We present the first results of a novel collaboration activity between ENEA Frascati Particle Accelerator Laboratory and University La Sapienza Guidance and Navigation Laboratory in the field of Radiation Hardness Assurance (RHA) for space applications.The aim of this research is twofold: (a) demonstrating the possibility to use the TOP-IMPLART proton accelerator for radiation hardness assurance testing, developing ad hoc dosimetric and operational procedures for RHA irradiations; (b) investigating system level radiation testing strategies for Commercial Off The Shelf (COTS) components of interest for SmallSats space missions, with focus on devices and sensors of interest for guidance, navigation and control, through simultaneous exploration of Total Ionizing Dose (TID), Displacement Damage (DD) dose and Single-Event Effects (SEE) with proton beams.A commercial 6-axis integrated Micro Electro-Mechanical Systems (MEMS) inertial navigation system (accelerometer, gyroscope) was selected as first Device Under Test (DUT). The results of experimental tests aimed to define an operational procedure and the characterization of radiation effects on the component are reported, highlighting the consequence of the device performance degradation in terms of the overall navigation system accuracy. Doses up to 50 krad(Si) were probed and cross sections for Single-Event Functional Interrupt (SEFI) evaluated at a proton energy of 30 MeV.

Adding RFC 4814 Random Port Feature to Siitperf: Design, Implementation and Performance Estimation

Siitperf is the World’s first free software RFC 8219 compliant SIIT (also called stateless NAT64) tester written in C++ using DPDK, which is also suitable for benchmarking IPv4 / IPv6 network interconnect devices in RFC 2544 / RFC 5180 compliant ways. Originally, siitperf followed RFC 2544 Appendix C.2.6.4 test frame format resulting in “hard coded” source and destination UDP port numbers. RFC 4814 Section 4.5 recommended random, uniformly distributed source and destination port numbers, which can make a very significant difference, when the DUT (Device Under Test) has multiple CPU cores, what is very common today. Therefore, adding this feature to siitperf is essential to be able to produce meaningful benchmarking results. In this paper, we disclose the design, implementation and performance estimation of this extension of siitperf.

An Audio Distortion Dynamic Range Index for Evaluating the Performance of Audio Systems

The dynamic range (DR) index lacking of an official definition leads to ambiguities in performance evaluation. The existing measurement methods of DR do not always match with the various actual application conditions, and some detailed distortion behavior of the device under test (DUT) is not extracted. In this paper, a new index for evaluating the DR performance of audio systems is proposed and validated, herein referred to as the audio distortion dynamic range (ADDR). It reduces the uncertainty of measurement conditions by an explicit definition and unifies the signal-to-noise ratio (SNR) and the signal-to-noise-and-distortion ratio (SINAD) indexes if under the same measurement condition. Moreover, to comprehensively reflect the impact of harmonic, spurious, and noise components on the DUT, the definitions of the traditional indexes based on classification of distorted components are replaced by the variable thresholds in the ADDR definition. Subsequently, the detailed steps of ADDR and the critical factors influencing its accuracy, are analyzed and then the optimized measurement conditions are given. Experiments based on simulated DUTs show the ADDR index can distinguish performance difference that the traditional indexes cannot distinguish, which proves it is an effective supplementary to the existing indexes in some real applications.

Systematic Characterization of Dual Probes for Electromagnetic Near-Field Measurement

In this paper, systematic characterization of the dual probe, which is designed for the near field simultaneous measurement of both electric and magnetic field, is investigated with a microstrip line as the device under test (DUT). The characterization includes frequency response, transmission performance, symmetry, reflection, the intrusion of probe to the DUT, isolation of electric and magnetic field responses, field profile and spatial resolution, and differential electric field suppression. The dual probes with different design are adopted to demonstrate the systematic characterization.

Correction of Over-the-Air Transmit and Receive Wireless Device Performance Errors Due to Displaced Antenna Positions in the Measurement Coordinate System

Over-the-air (OTA) performance evaluation for wireless devices require electromagnetic field measurements in the far-field (FF). This is typically achieved by using one or multiple test probes to scan a sphere encompassing the device under test (DUT), which can be either set to transmit (Tx) or receive (Rx). Measurement data are usually collected in magnitude-only and near-field to FF transformations cannot be straightforwardly applied in a majority of test cases. In the case of large DUT, the active antenna in the device may not be located at the center of the measurement coordinate system, due to mechanical positioner or anechoic chamber constraints. Such an offset is known to introduce significant errors on assessed radiated quantities, which are mostly due to variations in the path length and the angular position of the apparent phase center of the Tx/Rx structure, with respect to the probe boresight direction. This article proposes a novel solution to this problem and introduces an algorithm to compensate errors from known antenna displacements within the coordinate system. This compensation applies to both OTA Tx and Rx cases. The accuracy of the identified solution is demonstrated through simulated and experimental results, using setups operating at 5G NR millimeter-wave frequencies.