Raúl Fernández-García

Study of the impact of hot carrier injection to immunity of MOSFET to electromagnetic interferences

This paper presents an original study about the effect of hot carrier injection stress on the DC offsets induced by electromagnetic interferences (EMI) on a nanometric NMOS transistor, which is one of the major sources of failures in analog circuits. Measurements and simulations based on a simple model (Sakurai-Newton model) of fresh and stressed transistors are presented showing significant variations of EMI-induced DC shifts of drain current.

Reduction of Electromagnetic Interference Susceptibility in Small-Signal Analog Circuits Using Complementary Split-Ring Resonators

Low-frequency analog and digital electronic circuits are susceptible to electromagnetic interference in the radiofrequency (RF) range. This disturbance is produced when the coupled RF signal is rectified by the nonlinear behavior of the semiconductors used in the small-signal analog input stage of the electronic system. Circuits based on operational amplifiers are usually employed for such input stages. These circuits present an amplitude modulation demodulation produced by the nonlinearity of internal transistors. Such a phenomenon generates demodulated signals in the low-frequency range. In this paper, this effect is suppressed by combining the conventional printed circuit board layout with complementary split-ring resonators (CSRRs). CSRRs are constitutive elements for the synthesis of metamaterials with negative effective permittivity, which are mainly excited to the host line by means of electric coupling. Electromagnetic simulations and experimental results show an effective rejection of the undesired RF demodulation effect with no extra cost in terms of the device area or manufacturing process.

Experimental Investigations into the Effects of Electrical Stress on Electromagnetic Emission from Integrated Circuits

Recent studies have shown that the aging of integrated circuits may modify electromagnetic emission significantly. This paper reports on an experiment to elucidate the origins of emission level changes in a test chip using 90-nm CMOS technology. Circuit analysis, combined with electromagnetic emission and on-chip power supply voltage bounce measurements made during the application of electric stress, have identified the role of intrinsic wear-out mechanisms, which contribute to a progressive change in the transient current produced by the circuit.

An Alternative Wearable Tracking System Based on a Low-Power Wide-Area Network

This work presents an alternative wearable tracking system based on a low-power wide area network. A complete GPS receiver was integrated with a textile substrate, and the latitude and longitude coordinates were sent to the cloud by means of the SIM-less SIGFOX network. To send the coordinates over SIGFOX protocol, a specific codification algorithm was used and a customized UHF antenna on jeans fabric was designed, simulated and tested. Moreover, to guarantee the compliance to international regulations for human body exposure to electromagnetic radiation, the electromagnetic specific absorption rate of this antenna was analyzed. A specific remote server was developed to decode the latitude and longitude coordinates. Once the coordinates have been decoded, the remote server sends this information to the open source data viewer SENTILO to show the location of the sensor node in a map. The functionality of this system has been demonstrated experimentally. The results guarantee the utility and wearability of the proposed tracking system for the development of sensor nodes and point out that it can be a low cost alternative to other commercial products based on GSM networks.

Electromagnetic interference reduction in printed circuit boards by using metamaterials: a conduction and radiation impact analysis

This work aims to compare the implementation of two metamaterials for reducing electromagnetic interference (EMI) in printed circuit boards. Specifically, complementary split-ring resonators (CSRRs) and electromagnetic bandgaps (EBGs) were etched on the ground plane of a microstrip transmission line. Both techniques were compared as EMI filters, taking into account frequency response, signal integrity, and near- and far-field radiation with regard to a reference (solid ground) board. The results of electromagnetic simulations and experimental tests show similar EMI rejection levels in both cases, but CSRRs have a significantly better signal integrity response whereas EBGs behave as lower electromagnetic radiation elements in the operation frequency band.

Characterization and Modeling of the Conducted Emission of Integrated Circuits Up To 3 GHz

In this paper, an electrical model in order to predict the electromagnetic compatibility (EMC) conducted emission of integrated circuits (ICs) up to 3 GHz is presented. The electrical model predicts the behavior of the propagation paths of electromagnetic conducted emissions at high frequency by including all distributed effects and capacitive and inductive couplings. The proposed model has been compared with the standard IC emission model (ICEM-CE) to predict the EMC of a clock generator by means of the feature selective validation (FSV) method. The results show that the proposed model can expand the frequency range up to 3 GHz with a high degree of accuracy. Moreover, an alternative approach to model the electromagnetic noise that is based on the analysis of its spectral components is proposed.

Experimental verification of the usefulness of the nth power law MOSFET model under hot carrier wearout

In this paper the usefulness of the nth power law MOSFET model under Hot Carrier Injection (HCI) wearout has been experimentally demonstrated. In order to do that, three types of nFET transistors have been analyzed under different HCI conditions and the nth power law MOSFET model has been extracted for each sample. The results show that the model can reproduce the MOSFET behavior under HCI wearout mechanism. Therefore, the impact of HCI on circuits can be analyzed by using the nth power law MOSFET model.

Analysis of PIFA antenna coupling in nearby traces and reduction with CSRRs in PCB at 2.45 GHz

The electromagnetic coupling of a conventional planar inverted-F antenna (PIFA) antenna in the nearby layout traces is investigated in the 2.45 GHz industrial, scientific and medical radio band. The impact of a complementary split-ring resonator (CSRR) to reduce the coupling as well as the overall antenna performance after perturbing the ground plane is reported. 2.5D and 3D full electromagnetic simulations are used to design and analyze the proposed layouts. Experimental results validate the CSRR usefulness to significantly decrease the antenna coupling.

Experimental evaluation of electrical properties of fabrics elaborated with conductive yarns

In this paper, the electrical characterization of two different fabric structures elaborated with conductive yarns and several pick densities are investigated in order to evaluate their electrical properties as conductive media of digital electrical signals. The real and imaginary impedance and the signal integrity have been measured for each e-textile. The results show that the impedance depends on the fabric structures and pick density. The eye diagram measurements experimentally demonstrate the functionality of these fabrics to transmit digital electric signals to communicate sensors with microcontrollers in wearable applications.

An alternative method to quantify the electromagnetic immunity based on the Weibull distribution

It is accepted that the electromagnetic interference should be addressed with statistical analysis. Usually the impact of electromagnetic interference on different electronic samples is evaluated and the average immunity level is used as a reference. However, this method does not provide enough information to know the probability of failure to the electromagnetic interferences of an electronic circuit. An alternative statistical analysis based on the Weibull distribution is presented. The typical and proposed methods have been compared in order to analyse the electromagnetic immunity performance of two types of operational amplifier. The results confirm the feasibility of the proposed method.