Federico Alimenti

Modeling and characterization of the bonding-wire interconnection

In this paper, the bonding-wire interconnection has been studied from the points of view of its modeling and electrical characterization. Both singleand double-wire structures have been considered, the latter under the assumption of parallel wires. Two electrical models of the bonding wire are discussed. First, the finite-difference time-domain (FDTD) method is proposed for the rigorous analysis of such structures. This method uses a suitable discretization technique, which accounts for the wire curvature by means of a polygonal approximation. A quasi-static model of the bonding wire, suitable for commercial microwave computer-aided-design tools is then proposed. This model is based on the representation of the structure with four sections of a uniform transmission line and the model parameters are evaluated analytically from the dimensions of the interconnection. Accuracy and applicability of the quasi-static model have been assessed by analyzing several test structures, the reference results being obtained with the FDTD method. Finally, the quasi-static model has been used to provide an extensive electrical characterization of the bonding wire versus its main geometrical parameters. This characterization is given in terms of an equivalent series inductance and two equivalent shunt capacitances forming a /spl pi/ low-pass network. This representation is particularly useful in the matching of the bonding-wire discontinuity.

A new algorithm for the incorporation of arbitrary linear lumped networks into FDTD simulators

The inclusion of lumped elements, both linear and nonlinear, into the finite-difference time-domain (FDTD) algorithm has been recently made possible by the introduction of the lumped element FDTD method. Such a method, however, cannot efficiently and accurately account for two-terminal networks made of several lumped elements, arbitrarily connected together. This limitation can be removed as proposed in this paper by describing the network in terms of its impedance in the Laplace domain and by using appropriate digital signal-processing methodologies to fit the resulting description to Yees algorithm. The resulting difference equations allow an arbitrary two-terminal network to be inserted into one FDTD cell, preserving the full explicit nature of the conventional FDTD scheme and requiring a minimum number of additional storage variables. The new approach has been validated by comparison with the exact solution of a parallel-plate waveguide loaded with lumped networks in the transverse plane.

No Battery Required: Perpetual RFID-Enabled Wireless Sensors for Cognitive Intelligence Applications

Over the last decade, radio frequency identification (RFID) systems have been increasingly used for identification and object tracking due to their low-power, low-cost wireless features. In addition, the explosive demand for ubiquitous rugged low-power, compact wireless sensors for Internet-of-Things, ambient intelligence, and biomonitoring/ quality-of-life application has sparked a plethora of research efforts to integrate sensors with an RFID-enabled platform. The rapid evolution of large-area electronics printing technologies (e.g., ink-jet printing and gravure printing) has enhanced the development of low-cost RFID-enabled sensors as well as accelerated their large-scale deployment. This article presents a brief overview of the recent progress in the area of RFID-based sensor systems and especially the state-of-the-art RFID-enabled wireless sensor tags realized through the use of ink-jet printing technology.

A 5.6-GHz UWB Position Measurement System

This paper describes the design and realization of a 5.6-GHz ultrawide-bandwidth-based position measurement system. The system was entirely made using off-the-shelf components and achieves centimeter-level accuracy in an indoor environment. It is based on asynchronous modulated pulse round-trip time measurements. Both system level and realization details are described along with experimental results including estimates of measurement uncertainties.

A New Contactless Assembly Method for Paper Substrate Antennas and UHF RFID Chips

This paper deals with a low-cost method for the assembly of flexible substrate antennas and UHF RF identification silicon (Si) chips. Such a method exploits a magnetic coupling mechanism, thus not requiring for galvanic contacts between the Si chip and antenna itself. The magnetic coupling is established by a planar transformer, the primary and secondary windings of which are implemented on flexible substrate and Si chip, respectively. As a result, the Si chip can be assembled on the antenna with a mere placing and gluing process. First, the idea has been validated by theory. Electromagnetic simulations of a square heterogeneous transformer (1.0-mm side) show a maximum available power gain (MAG) of -0.4 dB at 868 MHz. In addition, the heterogeneous transformer is also quite tolerant with respect to misalignment between primary and secondary. An offset error of 150 μm reduces the MAG to - 0.5 dB. A sub-optimal matching strategy, exploiting a simple on-chip capacitor, is then developed for antennas with 50- Ω input impedances. Finally, the idea has been experimentally validated exploiting printed circuit board (PCB) prototypes. A PCB transformer (1.5-mm side) and a transformer rectifier (two-diode Dickson multiplier) have been fabricated and tested. Measurements indicates a MAG of -0.3 dB at 868 MHz for the transformer and the capability of the developed rectifier to supply a 220-kΩ load at 1.5 V with a - 2-dBm input power.

Microwave Circuits in Paper Substrates Exploiting Conductive Adhesive Tapes

In this work, a new technique to fabricate microwave circuits in paper substrates is proposed. This technique relies on a copper adhesive tape that is shaped by a photo-lithographic process and then transferred to the hosting substrate by means of a sacrificial layer. Microstrip lines in paper substrates have been electromagnetically characterized accounting also for the adhesive layers. Experimental results show an insertion loss better than 0.6 dB/cm at 10 GHz.

A revised formulation of modal absorbing and matched modal source boundary conditions for the efficient FDTD analysis of waveguide structures

A revised formulation of modal absorbing and matched modal source boundary condition is proposed for the efficient analysis of a waveguide circuit with the finite-difference time-domain (FDTD) method. The formulation is based on a suitable translation operator modeling, in time domain, the propagation in a uniform hollow waveguide. By applying this operator, a multimodal absorbing boundary condition is obtained. Moreover, a source algorithm is developed that generates a given incident wave, while absorbing each modal component reflected from a discontinuity. The source is capable of separating incident and reflected waves without requiring any presimulation of long uniform waveguides. The validity and effectiveness of the formulation is verified by means of three numerical experiments. The first two refer to waveguide discontinuities. In these cases, the FDTD results are compared to mode-matching results. The third example is a transition from waveguide to printed circuit transmission line. The numerical simulation is compared with published experimental results. The presented examples show that the generalized scattering matrix of a waveguide circuit can be evaluated accurately in the smallest computational space allowed by the structure.

Smart Surfaces: Large Area Electronics Systems for Internet of Things Enabled by Energy Harvesting

Energy harvesting is well established as one of the prominent enabling technologies [along with radio-frequency identification (RFID), wireless power transfer, and green electronics] for the pervasive development of Internet of Things (IoT). This paper focuses on a particular, yet broad, class of systems that falls in the IoT category of large area electronics (LAE). This class is represented by “smart surfaces.” The paper, after an introductory overview about how smart surfaces are collocated in the IoT and LAE scenario, first deals with technologies and architectures involved, namely, materials, antennas, RFID systems, and chipless structures; then, some exemplifying solutions are illustrated to show the present development of these concurrent technologies in this area and to stimulate further solutions. Conclusions and future trends are then drawn.

THEORY OF ZERO-POWER RFID SENSORS BASED ON HARMONIC GENERATION AND ORTHOGONALLY POLARIZED ANTENNAS

In this paper a novel approach is proposed to solve the issue of the absolute accuracy required by the most of the passive chip-less RFID sensors. To this purpose the sensor information is encoded as the phase difierence between two signals, one of the two acting as the reference signal for the other one. First the tag receives a carrier at frequency f0, then two equal signals at frequency 2f0 are generated by means of a diode-based frequency doubler and a power divider. At this point one of the two signals is phase-shifted using a passive sensing element. Finally the 2f0 signals are re-irradiated by exploiting two orthogonally polarized antennas. With this approach the sensor information can be extracted by a suitable reader equipped with two complex (I/Q) receivers. The idea will be flrst developed from a theoretical basis and then verifled with several particular cases. The novel tag concept is compatible with paper substrate and inkjet printing technology since antennas diodes and passive sensing elements, i.e., all the main tag components, are going to be developed on paper materials.

A cost driven 24 GHz Doppler radar sensor development for automotive applications

This paper deals with a low-cost 24 GHz Doppler radar sensor for traffic surveillance. The basic building blocks of the transmit/receive chain, namely the antennas, the balanced power amplifier (PA), the dielectric resonator oscillator (DRO), the low noise amplifier (LNA) and the down conversion diode mixer will be presented underlining the key technologies and manufacturing approaches by means the required performances can be attained while keeping industrial costs extremely lowThis paper deals with a low-cost 24GHz Doppler radar sensor for traffic surveillance. The basic building blocks of the transmit/receive chain, namely the antennas, the balanced power amplifier (PA), the dielectric resonator oscillator (DRO), the low noise amplifier (LNA) and the down conversion diode mixer are presented underlining the key technologies and manufacturing approaches by means the required performances can be attained while keeping industrial costs extremely low.