This paper discusses on the miniaturization of radiofrequency (RF) front-end components such as half-wavelength resonators based on new magneto-dielectric heterostructures combining high permeability (µ = 150–250) and high permittivity (ε = 18–150). Size reduction is evaluated by means of 2-cm-long coplanar waveguides realized with silicon technology and having a resonance frequency of about 3 GHz. The experimental results show a physical length reduction of 11.2% due to the dielectric contribution (ε = 18) and 14.8% by cumulating dielectric and magnetic effects (ε = 18 and µ = 150). These results are significant with respect to the moderate thickness of the preliminary material used here (only 150 nm). In a second part, a predictive model is proposed with µ and ε as variables. When adjusting the material properties in a realistic way (µ = 250 and ε = 150), the model predicts size reduction of ~50% for the same thickness. Larger values can be expected with increasing the film thickness.

A new model of two-access reconfigurable antennas for future mobile communication systems is presented in this article. This structure is based on a slot antenna with two separated access ports, isolated and matched at 1 and 2 GHz, respectively. The novelty of this element lies in the fact that first a filtering structure is integrated in the antenna, and then any additional switching or frequency path selecting components that would induce losses and noise degradation is suppressed. Such flexible structures are assumed to be used in a future opportunistic radio, incorporating special features of “spectrum sensing”. The concept of the antenna illustrated by simulation and measurement is presented.

This paper presents measurement results providing the mapping of the opto-microwave transfer function performed on an SiGe microwave heterojunction phototransistor (HPT). This measurements will be used to extract a guideline for designing phototransistors. A mapping of the HPT's gain in low frequency helps to estimate the shape of the optical beam used for the measurement. The study also focuses on the cutoff frequency mapping of the device in phototransistor mode. Finally, these results are used to determine the general optimization rules in the SiGe HPTs design.

This paper deals with the various aspects of electromagnetic field impact modeling on the SiGe heterojunction bipolar transistor (HBT) device for microwave applications. This study differs from conventional HBT device reliability research associated with other stresses. The originality of this study comes from the generation of a localized electromagnetic field using the near-field bench. A coupling phenomenon between the electromagnetic field and the micro-strip lines connecting the transistor are evaluated by electromagnetic and electrical simulations. After stress, the input and the transmission scattering parameters are affected. This is primarily due to the deviation of the input impedance and the reduction of the transconductance, respectively. The stress effects have been related to a base current degradation. This degradation is due to a hot carrier introducing generation/recombination trap centers at the Si/SiO2 interface of the emitter–base spacer oxide, which leads to an excess recombination base current.

A high impedance surface (HIS) consisting of metallic square patches electrically connected one to each other with resistors is shown. Tunability of the absorption factor is achieved by the resistor value. The absorbing band of the loaded HIS is determined by the phase of the signal reflected by this structure. The main contribution of the paper is to demonstrate the absorption behavior over a wide range of incidence angle for both Transverse Electric (TE) and Transverse Magnetic (TM) polarizations. Using an equivalent circuit the resistor effect is investigated. It is shown that at resonance, the judicious choice of the resistor may lead to a significant absorption. The use of a waveguide simulator to characterize the performance of the loaded HIS is investigated. These methods have been used to design an ultra-thin absorber about λ8.4 GHz/35 thick.

This paper presents a behavioral electrothermal model implementation for high RF power amplifiers dedicated to the simulation of radar application in the Scilab/Scicos environment. This model, based on the direct coupling between a behavioral electrical model and a physics-based reduced thermal model, allows to predict nonlinear effects, high-frequency memory effects, and thermal effects due to the amplifier self-heating. System model implementation in Scilab/Scicos platform allows fast time domain simulation with very good convergence properties.

This paper presents an original biosensor chip allowing determination of intrinsic relative permittivity of biological cells at microwave frequencies. This sensor permits non-invasive cell identification and discrimination using an RF signal to probe intracellular medium of biological samples. Indeed, these sensors use an RF planar resonator that allows detection capabilities on less than 10 cells, thanks to the microscopic size of its sensitive area. Especially, measurements between 15 and 35 GHz show the ability label-free biosensors to differentiate two human cell types using their own electromagnetic characteristics. The real part of permittivity of cells changes from 20 to 48 for the nervous system cell types studied. The proposed biodetection method is detailed and we show how the accuracy and the repeatability of measurements have been improved to reach reproducible measurements.

About 25 years have elapsed since the first measurement by a FW-CW (called fast sweeping) reflectometer of the electronic density in magnetized fusion plasma. Substituting tube sources with solid-state components has resulted in a decrease of the sweeping time from the millisecond to the microsecond range. Based on voltage control oscillators and on active frequency multipliers, four profile reflectometers covering the range 33–155 GHz are in operation on Tore-Supra tokamak. Their originality is the use of one source for the launched and reference signal, although the detection is heterodyne. Indeed, a single side band modulator shifts the launched frequency ahead of frequency multipliers. With a sweeping time comparable to the plasma turbulence characteristic time the density profile is frozen. The density profile is then reliably measured with high radial and temporal resolution.

The great interest of optical fiber links in communicating systems especially in ultra-wide band (UWB) communications has grown up in the last decade and requires co-simulation for mixed circuits design exploiting both optical and microwave domains. In this paper, we report an original modeling method of an electro-absorption modulator associated with a distributed-feedback laser to simulate an optical transmitter of an UWB over fiber system. Large signal optoelectronic device models can be developed and implemented in a high-frequency simulator, such as advanced design system-Ptolemy to analyze the performances of fiber radio links and study the impact of the transmitter characteristics. This specific simulation way, taking into account precisely electrical characteristics of both electrical and optical circuits, links two different frequency domains by coupling electrical and optical modules in the same system simulator. Therefore, a complete simulation of an UWB multi-band orthogonal frequency division multiplexing signal transmission over fiber with an external modulator is investigated.

Metamaterials made of exclusively metallic cut wire pairs have been experimentally demonstrated to exhibit a negative refractive index at optical frequencies. However, other related works on slightly different wire and plate pairs have not shown a negative index. In this paper, we present the analogy between previously reported S-shaped metamaterials and asymmetric cut wire pairs by a simple unifying approach. These two structures present a negative index for some geometrical configurations. Using simulations and experimental measurements in the microwave domain, we investigate the material properties of the last structure. Applying the inversion method from transmission and reflection responses, we show that a negative index is exhibited due to simultaneous negative permittivity ε and permeability μ. A negative index n is experimentally verified in a bulk prism engineered by stacking several layers of the metamaterial.

This paper describes the analysis and the design of an integrated antenna on 0.13 µm SiGe BICMOS technology. A non-resonant dipole antenna integrated on SiGe is electromagnetically coupled to a radiating element reported on a printed circuit board (PCB) substrate. This integrated solution, also compatible with system in package (SIP) concept, provides significant improvements with respect to direct System On Chip (SoC) integration. The main objective of this SIP antenna lies on the optimization of integrated millimeter wave front-ends modules, considering the immediate antenna environment (especially the lossy substrate and technological dielectric/metallic levels), in order to achieve performances compatible with short range radar specifications at 79–81 GHz. One solution, using a RT/Rogers Duroid 6006 PCB (er = 6, thickness h = 127 µm), is presented, providing a 2.93 dBi gain, and 45% radiation efficiency antenna.

A new type of spectrum analyzer using RF interferometry is presented. The stationary wave integrated Fourier transform spectrometer is dedicated to the measurement of transient wideband signals. The spectrometer is mobile and cheap. It consists of spatial samplers placed along a waveguide ended by a short circuit. The standing wave caused by the short circuit is sampled and the spectrum is obtained by an FFT computation. A 0.3–5 GHz analyzer was built as a proof-of-principle demonstration and an application to RF dosimetry is shown.