This article assesses the RF EMF exposure to nearby mobile phone base stations inside an educational facility (indoor scenario, 900/1800/1900/2100 bands). Indirect characterisation is implemented experimentally, i.e. the received power levels are compared to each other, the main scope of this research being that of identifying whether distinct locations inside the chosen building would demonstrate different received power levels (hence different EMF exposure). Our experiments proved significant exposure to EGSM-900 of all locations under consideration and also a difference of several dB for a distance of about 3 meters between two close locations. A maximum instantaneous power of - 18.15 dBm has been measured and identified in a location that seems to be most exposed to base stations RF emissions. These experimental results illustrate the importance of conducting preliminary indoor EMF exposure tests before choosing the placement of mobile phone base station antenna as long as some spots have different EMF exposure compared with others from the same building.

The last decade has shown an increasing interest in the use of the physically unclonable function (PUF) technology in the design of radio frequency identification (RFID) systems. PUFs can bring extra security and privacy at the physical level that cannot be obtained by symmetric or asymmetric cryptography at the moment. However, many PUF-based RFID schemes proposed in recent years do not even achieve the lowest privacy level in reputable security and privacy models, such as Vaudenay’s model. In contrast, the lowest privacy in this model can be achieved through standard RFID schemes that use only symmetric cryptography. The purpose of this chapter is to analyze this aspect. Thus, it is emphasized the need to use formal models in the study of the security and privacy of (PUF-based) RFID schemes. We broadly discuss the tag corruption oracle and highlight some aspects that can lead to schemes without security or privacy. We also insist on the need to formally treat the cryptographic properties of PUFs to obtain security and privacy proofs. In the end, we point out a significant benefit of using PUF technology in RFID, namely getting schemes that offer destructive privacy in Vaudenay’s model.

A microwave line-of-sight propagation scenario is tested experimentally to assess the implementation of a proximity detector for smart crosswalks. Preliminary results conducted with one human subject indicated that the particular frequency of 4 GHz could be used to monitor the presence of people, the received power decreasing sufficiently enough to make a trustful decision, able to trigger the traffic lights. Despite some expectations, further experiments conducted with more human subjects (males, females and children) demonstrated that gender and age were not relevant, the microwave link being altered in the same way. Microstrip patch array antennas were used to increase the radiative efficiency and a reference distance of 2 meters was chosen.

A 4 GHz line-of-sight propagation scenario is tested experimentally to assess the implementation of a proximity detector for smart city applications, smart crosswalk in particular. Preliminary results indicate that 4 GHz frequency could be used to monitor the presence of people, the received power decreasing sufficiently enough to make a trustful decision that could trigger the traffic lights. Microstrip antenna arrays are used to increase the radiative efficiency and a maximum distance of 2 meters is chosen for experiments, corresponding to the width of many crosswalks existent around Romanian high schools.

It is well known that all electronic devices currently available on the market radiate unintentional electromagnetic waves during normal use, fact that may leak sensitive information, especially when such unshielded electronic devices are used for official (embassy, public institutions, etc) or private use (large tech companies, subject to industrial espionage). In this regard, our research aimed to study the electromagnetic emissions of two commercial LED monitors and one notebook. A number of 59 experimental scenarios have been identified and implemented inside an anechoic chamber (80 MHz - 40 GHz, 4x8x4 m3) so a clear undistorted frequency pattern was extracted experimentally for all three DUTs. The (far-field) experiments made use of three pictures (white, black and chess picture), two simple & shielded VGA to VGA cables, one desktop computer and a notebook, two calibrated antennas and one professional R&S spectrum analyzer (@7 GHz). According to our experiments, there is a clear interdependence between the spectrum emitted by the LED monitors and the pictures shown on their screen. In the same time, the notebook radiates a cleaner spectrum, less sensitive to visual information.

This paper reviews the wideband rectangular patch microstrip antennas, as proposed in the literature. Aiming to offer some insights about frequency performances, design parameters, constraints, technology, implementation and measurement, this study covers the rectangular patch architectures reported so far in the scientific literature and implemented with single substrate layer.

This paper reviews the annular-ring microstrip antennas, as proposed in the literature. Aiming to offer useful design insights about frequency performances, typical design parameters and constraints, technology, implementation and measurement, this study covers the annular-ring architectures reported so far in the scientific literature and making use of a single ring.

This article reconsiders the impedance matching problem for common source CMOS LNA (CS-LNA) and proposes several improved equivalent models that take into account both C gd capacitance and the type of load, resistive or inductive, normally not considered by the classical approach. These newly developed models might offer valuable insights about the input impedance, amplifier stability and quality of impedance matching, all these being of great interest in LNA design. The simulation results show good agreement, in terms of frequency response, between the proposed models and transistor based CS-LNA. Hence, it would justify further consideration of C gd when designing the matching network while taking into account the load, as well. The analysis covered the frequency range 0.1-7 GHz.

Presents information on SSCS Romainian Chapter's RFIC short courses.

This paper reviews the major contributions proposed in literature for implementing multi-band low noise amplifiers in CMOS technology. Concurrent, switched and switched concurrent low noise amplifiers are investigated. Advantages and drawbacks are also discussed. The article tries to offer good insights on the implementation of multi-band low noise amplifiers. Keywords-CMOS; low noise amplifier; multi-band; noise figure

CMOS low noise amplifiers with filtering capability represent an exotic class of LNAs offering the opportunity for RF designers to minimize their design by avoiding the SAW passive filters. Thought as a state of the art, the article reviews the most outstanding architectures proposed in the literature, trying to offer some insight on designing bandpass LNAs envisaging SAW-less receivers.

CMOS low noise amplifiers with filtering capability represent an exotic class of LNAs offering the opportunity for RF designers to minimize their design by avoiding the SAW passive filters. Thought as a state of the art, the paper reviews the most outstanding architectures proposed in the literature, trying to offer some insight on designing bandpass LNAs envisaging SAW-less receivers.

In a recent letter [ibid., vol. 18, no. 10, pp. 683-685, Oct. 2008], C.L. Ler et al. present a CMOS differential active inductor (DAI) based on the single transistor source degenerated architecture proposed by those authors in ibid., vol. 44, no. 3, pp. 196-197, Jan. 2008. The aim of this Comment is to reveal the general configurations and circuit equivalences which the results in the Oct 2008 pap...

A study of the classical RLC equivalent passive model for CMOS transistor only simulated inductors (TOSI) is presented. The model is compared with a four branches RLC model and its frequency performances and limitations are discussed. The analysis is applied on a particular active inductor topology for frequencies between 0.45 GHz and 3.3 GHz, the study being focused on the resonant frequency and inductance value. As simulations show, the model accuracy is strongly dependent on transistor parasitics and device modeling. It is shown that the second model is more accurate regarding the inductance value while the classical one is helpful for simplified calculus with respect to the resonant frequency. These considerations are valid in case of using charge based transistor model only. The simulations were carried out in 0.35μm AMS CMOS process.

The gate and bulk resistances influence on the impedance matching in case of MOSFET common gate amplifiers is investigated. It is shown that using a supplementary resistance of maximum 100Ω, S 11 becomes less than -15 dB over a wide frequency range, therefore making the circuit suitable for low power wideband RF applications and less sensitive to the loading capacitor value, at the price of a supplementary noise. The simulations were carried out in 0.35μm AMS CMOS process.

A study of the classical RLC equivalent passive model for CMOS transistor only simulated inductors (TOSI) is presented. The model is compared with a four branches RLC model and its frequency performances and limitations are discussed. The analysis is applied on a particular active inductor topology for frequencies between 0.45 GHz and 3.3 GHz, the study being focused on the resonant frequency and inductance value. As simulations show, the model accuracy is strongly dependent on transistor parasitics and device modeling. It is shown that the second model is more accurate regarding the inductance value while the classical one is helpful for simplified calculus with respect to the resonant frequency. These considerations are valid in case of using charge based transistor model only. The simulations were carried out in 0.35μm AMS CMOS process.

An optimised differential topology of an RF active filter and its performances are presented. It makes use of two negative resistances in order to independently tune the central frequency and the quality factor. The differential active filter is designed in a 0.18 µm CMOS process, allows a maximum wide range of tunability between 1.6 and 2.6 GHz and exhibits high quality factor values with a maximum power consumption of 0.6 mW. The principle seems to be sufficiently general to be used for other active filters single–ended or differential topologies based on simulated inductors.

Many architectures of transistor only simulated inductors (TOSI) have been proposed until now in literature. Exhibiting tuning possibilities, low chip area and offering integration facility, they constitute promising architectures to replace passive inductors in RF circuits. An improved CMOS active inductor topology is proposed in this paper. With a novel loss compensation scheme, frequency increase up to 1.1 GHz (30%–66%) of the inductor self resonant frequency is achieved in the frequency band 1.5–3.3 GHz with large quality factors and very low current consumption. Besides, a more accurate passive model is proposed for CMOS TOSI active inductors and tested for this particular topology. Consisting of four parallel branches, it is still second order even though it contains three conservative elements. The model is sufficient general and proves superior performances over the classical RLC model mainly for higher frequencies. The simulations were carried out in a 0.18 um CMOS process.