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Electrostatic discharge (ESD) failures in high-speed integrated circuits (ICs) cause critical reliability problems in electronic devices. Transient voltage suppressor (TVS) diodes are installed on high-speed I/O traces to improve system-level ESD protection. To protect the circuit, the majority of ESD current must flow into the external TVS diode rather than into the IC, but due to turn- on behavior, the TVS diode may not snap back when needed and the IC's internal protection may take most of the current. These race conditions between the internal and external ESD protection circuits were investigated for a universal serial bus(USB) interface board. The transient turn- on behavior of the on-chip and off-chip protection circuitry was characterized by measurements and by system efficient ESD design (SEED) simulations. The effect of transmission line pulses (TLP pulses) and power supply voltages of different sizes on the response of the protection circuitry were monitored and compared with SEED simulations. SEED models showed good agreement with measurements and were used to study the impact of passive components added to a high-speed trace or within the IC package on the ESD protection response. Results show the importance of properly accounting for the parasitic resistance and inductance between the on-chip diode and off-chip TVS diode, as well as the length of the transmission line when choosing the external TVS device. Results also show that testing must be performed using mid-level events to account for possible problems due to race conditions.

In this article, an efficient solution for the development of a new class of two-layer microstrip patch antenna (MPA) with orthogonal polarization ports, based on substrate-integrated waveguide (SIW) through an aperture coupling technique, is presented. Applying the SIW feeding network and aperture coupling to feed the MPA reduces the losses resulting from the feeding circuit and gives a more compact and efficient system. The proposed 4 t 4 array consists of two stacked layers, including an SIW layer as a feeding network and one layer as an antenna layer. The main design feature is the dual orthogonal port to generate different linear polarizations (LPs) (horizontal, vertical, 45d, and 135d). Each layer can be easily fabricated by a single layered printed circuit board (PCB) technology, and then PCB laminates are fixed together using screws. The measured -10-dB impedance bandwidth spans from 9.25 to 10.2 GHz (9.76%). The maximum measured gain at 9.9 GHz is 18.2 dB. The peak radiation efficiency is 84%. The proposed dual orthogonal port antenna exhibits low cost, ease of design, lightweight, high efficiency, and compactness, which makes it a suitable candidate for the polarization diversity in a transceiver for Earth-station applications.

The ability to predict the electric and magnetic fields generated by a component can solve many in-system interference problems before they occur. In this article, methods are presented to predict the high-frequency near electric and magnetic fields from a component using a method of moment approach. The current representation is estimated from a near electric-field scan by solving the electric field integral equation. The reconstruction method was validated with measurements of a test board containing a buffer integrated circuit. The current representation was shown to accurately predict fields at locations both above and to the side of the buffer with less than a 3.5-dB average error. Here, a near-field scan was only performed on a flat plane above the emitter and was used to predict sources to the side of the emitter. To accurately predict fields to the side of the emitter, the current representation must be defined on a surface between the emitter and the prediction location. An error analysis was performed to understand the impact of scan plane parameters, such as the size of the scan plane, the size of the current representation, and the relative distance between the current representation and the estimated fields on prediction accuracy.

Audio- and image-based soft failure detection methods are developed, which can detect both severe failures (such as system hang) and subtle ones (such as glitch or a momentary disturbance on display). Incorporating the developed detection methods with a robotic ESD (electrostatic discharge) tester, we developed a fully automated soft failure investigation tool. Using this fully automated tool, we obtained failure-specific susceptibility maps for a camera (our target device). These susceptibility maps not only illustrated the sensitive locations of the device, they also showed what type of soft failure is correlated with which locations.

In a multimodule system, an increase in the number of radiating optical modules will increase the electromagnetic emissions. This article investigates the scaled tendency of the emissions in a router system loaded with hundreds of optical modules. An artificial router mimicking the real system was built to investigate this tendency. A patch antenna array mimics the radiation of the optical modules. It can be excited in in-phase and random-phase configurations. The measurement data verifies the theoretical analysis and the prediction from a statistical method without performing hundreds of different experiments on a real router. Assuming that all radiators are radiating at the same frequency and have similar radiation pattern with random phases, the average of the maximal directivity of the system will saturate if the number of radiators (N) is larger than 14. Furthermore, the average of the maximal electric field radiated will increase following a 10 log10 N (dB) tendency.

In this letter, a compact monopulse antenna operating at 10 GHz is presented. The feed network consists of four rat-race couplers, which generate sum and difference patterns in orthogonal radiation planes (azimuth and elevation). The focus is on improving the performance by improving the matching circuit to generate in-phase and out-phase excitations while also maintaining a very high null-depth, which is applicable for tracking purposes. The electromagnetic energy is transmitted from the feed network to the radiators through the via-coupling structure. Using the symmetrical via-fed patch array results in the low-mutual coupling between the antenna ports. A prototype of the proposed antenna is manufactured on a printed circuit board and is tested. A suitable agreement between the measurement and simulation results is obtained. The results show a −10 dB impedance bandwidth of 2.1%, as well as −24 and −20 dB null depths on the elevation and azimuth planes, respectively, in the difference mode of operation.

Typical networking equipment contains tens of nearly identical line cards and hundreds of the optical modules. The more modules and line cards are added, the larger the radiation will be. This paper presents an idea and approach to estimate the emission of a fully populated system based on data that are obtained using an only partially populated system.

An IC protected by a transient voltage suppression (TVS) diode may fail if the TVS device does not turn on or does not turn on quickly enough, causing the IC to take the full brunt of the ESD event. System Efficient ESD Design (SEED) simulation can help predict when the TVS will turn on and the level of ESD stress seen by the IC. In the following paper, models are developed to predict the voltage and current through a TVS and on-chip protection diodes connected to a USB cable when an ESD gun discharges to a pin at the end of the cable. A hybrid simulation methodology is proposed, which uses a full-wave model of the ESD gun, cable, and enclosure combined with the ESD protection devices and test board's circuit-level models. The response of the ESD protection is studied in simulation and measurement for a variety of cable configurations. Simulations of the voltage and current waveforms match measurements 24-35%. The total charge delivered to the on-chip diode as a function of ESD gun voltage was predicted within 21%.

A conformal UWB Archimedean spiral antenna on a dielectric hemisphere is theoretically and experimentally investigated. The analysis method, design, and optimization of this type of spherical antennas is performed using an efficient spatial domain method of moments in conjunction with triangular basis functions and asymptotic Green’s functions. A special conformal mapping is used to enhance the impedance bandwidth and axial ratio (AR) bandwidth for a circularly polarized spherical spiral antenna. Emphasis is given to the efficient asymptotic approach in spherical multilayered media. To validate the theory, a UWB leaky-wave conformal spiral antenna was designed, manufactured, and tested. The measured results indicate a pretty wideband behavior for this antenna starting from 1.7 to 6 GHz (1.8 octaves) in its input impedance responses. The circular polarization is maintained over 1.26 octave with less than 3 dB AR.

A compact multi-layer substrate integrated waveguide (SIW) monopulse antenna array operating at X-band is proposed. The structure consists of four stacked layers, including one layer for the radiating 4 × 4 rectangular microstrip antenna elements and two SIW layers for the comparator network. The sum and difference modes provide orthogonal radiation patterns in the azimuth and elevation planes. The two SIW layers of the comparator network feature a compact multi-feed design while maintaining high isolation between the antenna ports. To validate the proposed antenna concept, silmulations and measuremets are carried out. The obtained resuts show good performnces, a -10-dB impedance bandwidth of 13.45 % (9.35-10.7 GHz) for the sum and difference ports, better than 30 dB isolation between the antenna ports, the difference radiation patterns better than -38 dB null-depth. The comparison between the simulated and measuremed results shows a good agreement.

The transient behavior for four different types of TVS (non-snapback, snapback, spark gap, varistor) is modeled using the same modeling framework. By a 10 ns VF-TLP, the quasi-static I-V curve and the transient turn-on are captured and modeled in ADS. The models are applied in a SEED simulation to investigate the strengths and weaknesses of the modeling frame.

This paper describes an improved reference source for conducted emission (CE) testing. It allows for selecting different modes of noise injection. It injects an arbitrary waveform generator signal into a 3-wire power cord. Different from the previous designs, the noise can be injected in four different modes: Line against Neutral; Line against PE; Line and Neutral against PE; and Line, Neutral, and PE against Local GND (i.e., common mode). The source was designed for comparing test setups, and investigating the influencing factors such as table position or cable routing on the resonances.

A system level EMC method is proposed in this paper to predict the electromagnetic interference (EMI) from multiple radiators. The problem under test consists of a large network router with 480 optical modules radiating at 10.3 GHz. The proposed method handles the analysis of this system by using different phased array antenna topologies. Systematic conclusions are presented including the effect of same frequency vs. different frequency of radiating subsystems, the possibility of missing the maximum emission (Emax) during horizontal scan and height scan, and the effect of the radiation pattern for different radiators. The results indicate the existence of a 10 Log N (dB) tendency for the Emax parameter in the case of adding a complex electric field (voltage) and random phase distribution over the line cards. It also shows similarity to an 8 Log N (dB) tendency for adding power intensity for different line cards with slightly offset frequencies. The developed method can be extended to other frequency ranges when necessary. The proposed statistical method is useful when it is not practical to assemble a complete system consisting of several radiating subsystems with different frequencies in EMI testing.

Monitoring ESD generator discharge current during IEC 61000-4-2 testing helps to better understand product failures. By acquiring the discharge waveform using an oscilloscope, this enables the operator to both document the current waveform which resulted in product failure, and to identify the presence of secondary ESD event within the product. Placing a current probe such as an F-65 current clamp at the tip of the ESD generator may change the discharge current waveform shape due to probe loading. In addition, the inclusion of an extra cable and current clamp increases physical weight at the tip of the ESD generator and reduces operator convenience during testing. In order to overcome the probe loading effect, a non-intrusive measurement method of positioning the F-65 current clamp at the ground strap of the ESD generator is proposed. The disadvantage of this configuration is that the captured waveform does not include the initial high-frequency peak current directly. Since the waveform measured at the ground strap does not contain high frequency components, mathematical processing is needed to reconstruct the initial nanosecond high-frequency current waveform which may lead to product failure. The goal of this work is to reconstruct the high-frequency discharge tip current waveform by measuring the current on the ground strap and applying deconvolution. The deconvolution method is first validated using circuit simulation. In addition, measurements are performed with different ESD generators to determine the effectiveness of the reconstruction algorithm.

This paper introduces the application of system-efficient ESD design (SEED) to ESD-induced pulses that are typical for system-level ESD. Emphasis is given to USB connectors because it has been shown that discharges to the connector shell will not lead to damaging current levels; however, the current levels are sufficient to cause soft-failures and possibly lead to latch-up of the USB IC.

A new approach based on hybrid volume-surface integral equation (VSIE) formulation in combination with spherical dyadic Green's function (DGF) is presented in this paper to analyze aperture-coupled multilayer hemispherical dielectric resonator antennas (DRA) with conformal conducting patches. Hybrid VSIE is used for the planar part of the structure and is solved with the aid of spatial-domain method of moments (MoM) in order to compute magnetic surface current in a slot cut in a finite planar perfect electric conductor (PEC) sheet. Multilayer spherical electromagnetic DGFs are used to compute loading effects of hemispherical dielectric resonators and conformal patches on antenna characteristics. The effects of variation in some parameters of the structure on the return loss of the antenna are studied. Accuracy of the presented method is validated by comparing the results obtained from the proposed method with those of CAD simulations.

The theory and experiment of a probe-fed conformal antenna with a conducting parasitic element mounted on a spherical multilayer structure are presented in this article. Linear Rao–Wilton–Glisson triangular basis functions are applied in a mixed-potential integral equation formulation. Current distributions on coaxial probe and conformal radiating elements are computed by using the proper spatial domain electrical dyadic Green's function and its asymptotic approximation. A prototype of such an antenna is fabricated and tested. The effect of the parasitic element on the input impedance, gain, and radiation patterns of the antenna is investigated. It is shown that the antenna characteristics are improved significantly with the presence of the stack. Good agreement is achieved between the results obtained from the proposed methods and measurement results.

Rigorous mathematical method of moments (MoM) for analyzing spherical microstrip aperture-coupled antennas is presented in this paper by using dyadic Green's functions (DGF) in conjunction with magnetic field integral equation (MFIE) and electric field integral equation (EFIE) formulations. With the aid of linear Rao-Wilton-Glisson (RWG) triangular basis functions, spherical three-layer aperture-coupled patch antennas are analyzed. The effect of mutual coupling between slot and patch antenna is developed and the input impedance and radiation patterns of such an antenna are presented. A prototype of a spherical aperture-coupled antenna is fabricated and tested. The measurement results are compared to the results of the proposed method and a good agreement between the results is achieved. The measured efficiency and gain of this antenna at 3.15 GHz are 85% and 5.23 dB, respectively.

This paper describes a design procedure for mm-wave voltage controlled oscillator (VCO), based on large signal behavior of oscillator transconductance. Then, a new structure of LC-VCO is presented, which utilizes a transformer feedback to enhance the transconductance of the core transistors and to cancel the undesired parasitic effects. Using a 0.18-µm RF CMOS technology, the advantage of this VCO is examined by large signal analysis and simulation. The results illustrate improvement of 5dB in phase-noise and 70% in tuning-range, compared to enhanced active gain conventional transformer feedback VCO. Finally, a compact layout for transformer design is proposed.

Presented is an ultra-broadband stripline directional coupler with significant improvement in its directivity parameter which is of interest in many measurement applications. The main focus of this paper is on the influence of using shunt stubs as capacitance compensators to improve specifications of wideband directional couplers. This improvement is performed on a two-layer non-uniform line directional coupler working in 2–18 GHz band. Experimental results, for various classes of wideband stripline couplers loaded with these stubs, exhibit remarkable improvement in the directivity parameter.

Theory and experiment of a spherical probe-fed conformal antenna with a parasitic element mounted on a spherical multilayer structure are presented in this paper. Linear Rao-Wilton-Glisson (RWG) triangular basis functions are applied in MPIE formulation. Current distributions on coaxial probe and conformal radiating elements are computed by using spatial domain Dyadic Green's Function (DGF) and its asymptotic approximation. A prototype of such an antenna is fabricated and tested. The effect of the parasitic element on the input impedance and radiation patterns of the antenna is investigated. It is shown that the antenna characteristics are improved significantly with the presence of the conducting parasitic element. Good agreement is achieved between the results obtained from the proposed methods and the measurement results.

Rigorous mathematical Method of Moment (MoM) for analyzing various radiating spherical structures is presented in this paper by using Dyadic Green's Functions (DGF) in conjunction with MPIE formulation. With the aid of linear Rao-Wilton-Glisson (RWG) triangular basis functions and by converting spherical DGF to Cartesian DGF, a conformal dipole antenna over a Perfect Electric Conductor (PEC) sphere is analyzed. Good agreement between the proposed method and asymptotic approximation as well as commercial simulator packages shows accuracy and high convergence speed of the presented method.

A single-cell tri-band composite right/left-handed (CRLH) resonant antenna is presented. The antenna is designed on a single-layer coplanar waveguide-fed based on the T-junction discontinuity equivalent circuit. The proposed antenna provides compact size, easy fabrication process, multi-band feature and higher efficiency in comparison with the previously reported CRLH resonant antennas. The single-cell CRLH resonant antenna is fabricated and the measurements are consistent with the simulation result.

In many aspects of communications from microwave Radios to local oscillators, we need to generate high frequencies efficiently. Frequency multipliers are a cost effective method to reach high frequency oscillators with small phase noise properties and stable conditions. In this work, we have designed, simulated, optimized and fabricated a frequency six folder module which multiplies the source frequency in S Band and output frequency in Ku band using active device nonlinear model. This frequency six folder is made of a frequency doubler cascading with a frequency tripler. Optimum DC bias and matching network are in detail. Simulations show good agreement with measured results.