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In this paper, a permalloy layer has been employed in the fabrication of a coupled line electromagnetic bandgap (EMBG) device to tune both amplitude and phase. A magnetically biased microwave coplanar configuration manufactured with evaporated permalloy has been measured, and a circuit modelling has been studied to evaluate the measured effects in terms of variable attenuation and phase shift. Starting from a permalloy made by the mixture 80% nickel and 20% iron content, we fabricated an electromagnetic bandgap (EMBG) structure based on a periodic arrangement of single sections of a transmission line with variable impedance, also including a central region with coupled lines. The bandpass characteristics of the EMBG device can be tuned by changing permalloy's permeability through the application of a DC magnetic field H0 (parallel to the plane of the structure). In particular, using a magnetic field up to 3000 Oe, it was possible to change the phase by ca. 45° and the amplitude by ca. 7 dB in the X band.

We have analyzed the self-action effects in the propagation of surface magnetostatic wave (SMSW) pulses in a 1D magnonic crystal–dielectric–metal structure in which the region of anomalous dispersion controlled by the selection of thickness h of the insulator and ensuring the fulfillment of the Lighthill criterion in the generation of SMSW solitons is formed. It is shown that when the metallization-induced region of anomalous dispersion coincides with the Bragg resonance frequency range, no SMSW solitons form.

Microwave near field microscopy and spectroscopy are currently studied for imaging and local characterization in material science, as a non-invasive diagnostic technique in many fields of interest, encompassing dielectric, magnetic and biological samples. Monitoring cultural heritage artefacts is also possible measuring biodeterioration by near field microwave microscopy, to find bio-inclusions with a non-invasive approach. In this paper, is presented a preliminary work for testing a homemade measurement system for local characterization of plants, to determine the necessary sensitivity to study the changes induced by modification of the bio-sample over the time due to an aging process. Preliminary experimental results, showing the capabilities of the developed system, are shown and discussed. In particular, changes in the order of few ohms can be recorded using an impedance measurement, using both real and imaginary part of a reflected signal, to obtain the losses contribution and their evolution due to the natural aging.

In this work, a thin-film packaging was developed to be used for radio-frequency microelectromechanical system configurations. The fabricated packages are suspended membranes in the multilayer SixNy/aSi/SixNy on conductive coplanar waveguides (CPWs) of different length. Several geometric parameters of the membranes, which are the length, the curvature radius at the vertices of the rectangular base, the density and the diameter of holes on the capping surface, were also varied. The mechanical properties of the suspended membranes were investigated by mechanical simulations and surface profilometry measurements as a function of the geometric parameters. RF characterization was performed to evaluate the impact of the package on the CPW performance. Finally, network analysis was carried out, allowing to clarify the origin of the RF losses measured for the fabricated microdevices.

In this paper is presented the design and fabrication of an Electromagnetic Band Gap (EMBG) resonator in coupled lines configuration, to obtain tunable Magnetostatic Wave (MSW) Band Stop Resonators using a magnetic material, namely YIG (yttrium Iron garnet) biased by means of an external magnetic DC field. In particular, a microwave tunable resonator configuration based on a MSW resonator, working at frequencies up to 16 GHz has been studied. The specific purpose of this work is to analyze the filtering response of coplanar waveguide (CPW) EMBG magnetically tunable resonators in a band stop configuration. Measurements of the S 21 parameter demonstrate an important attenuation with more than 20 dB of the higher order modes. They exhibit a good selectivity obtained by the combination between EMBG resonators and YIG ones in the frequency range 5-18 GHz. Tunable EMBG YIG resonators from 5 GHz to 18 GHz, corresponding to the X band and to the Ku band in the microwave region, which are presently a focus for many ground and space applications, have been studied.

The paper presents a methodology for de-embedding scanning microwave microscopy (SMM) measurements, mainly for semiconductor characterization. Analytical modeling, a parametric study and experimental verification are presented. The proposed methodology is based on the analysis of system response in the linear scale, instead of the dB scale commonly utilized in RF measurements, and on expressing the standard calibration capacitances per unit area. In this way the total measured capacitance is determined by the tip area which is then obtained as a result of the model fitting on the experimental data. Additional evaluation is performed by a straightforward experimental comparison with the usually adopted technique that is based on the electrostatic force microscopy approach curve method. The results obtained by the application of both techniques on the same tip during the same experiment were found to be in good agreement and moreover allowed a detailed discussion on the features of each one of the two methodologies. The paper provides also in this way useful knowledge for the potential users in order to choose the most appropriate technique according to the corresponding SMM application. Display Omitted A methodology for de-embedding scanning microwave microscopy measurements is presented.The proposed analysis is based on the assessment of the SMM system response in the linear scale.The methodology is experimentally evaluated by a straightforward comparison with an EFM based calibration method.Based on the obtained results the features of each methodology are also discussed in details.The paper provides a full picture of the up to date available experimental techniques for de-embedding SMM measurements.

Contact resistance is the main parameter used for assessing the high cycling reliability of RF microelectromechanical (RF-MEMS) switches. In this paper the use of a modified contact material is tested and compared to pure gold in cycling experiments performed on a RF-MEMS switch in shunt capacitive configuration. The modified contact material is a gold-based multilayer with a thin layer of platinum sandwiched between two layers of gold. The experiment consists in comparing devices with the same layout but with different contact material. While the two types of switch start with similar RF performances, the device with the modified material shows a marked improvement in cycling reliability and a lower series resistance up to 106 cycles when compared to gold contact devices.

In this work, an electromagnetic technique for imaging and spectroscopy of materials and devices, suitable for the characterization of MEMS and microelectronics configurations as a function of frequency in the microwave range, will be presented. In particular, near field measurements will be shown for the evaluation of dielectric properties of the materials and for imaging of RF devices. Perspective utilization in the evaluation of quantities having specific interest for the microelectronics and MEMS industries will be discussed, with reference to properties that can be deduced from the measured surface impedance, like the morphology and the frequency dependence of the material properties.

In this work, we present a sensor suitable for performing the spectroscopy on a localized micrometric volume of a generic liquid, in the spectral range comprised between 1 and 20 GHz. The sensor is based on two ungrounded, open-ended coplanar waveguides, acting as Input/Output ports, with a microfluidic channel passing through them. It works by detecting the change of the reflection and transmission of microwaves due to the variation of the dielectric properties characteristic of the liquid. The devices have been designed and numerically simulated to obtain the electromagnetic response in different conditions: an empty channel for having a zero-reference response and for observing variations as a function of liquids filling the channel. We considered standard (i.e., common in literature) liquids (deionized water, ethanol, and glycerol); by means of that set of simulations we were able to start the creation of the calibration curves and defining the sensitivity of the sensor with respect to dielectric properties of the liquid under test. Then, we realized a batch of prototypes utilizing a standard photolithographic process. Later we proceeded to check the operation of the sensors. We recorded experimental data by a Vector Network Analyser connected to the devices by means of microwave probes. Sensors are designed to perform both reflection and transmission measurements on the liquid sample, and local microscopy on a micrometric volume of the solution under test. Actually, the device works avoiding any contact between the metallic parts and the liquid that can flow uncontaminated through the microfluidic channel.

In this paper, the basic principles of Near-Field Microscopy will be reviewed with focus on the micro- and nano-scale resolution configurations for material science measurements. Results on doping profile, dielectric and magnetic properties will be presented, with details on the calibration protocols needed for quantitative estimation of the dielectric constant and of the permeability.

In this paper we present the methodology and the numerical results related to the analysis of aging of the SU-8 polymer when used as a primary layer for the realization of Coplanar Waveguide (CPW) structures. As test devices, we used a set of transmission lines with different lengths and T-shaped open stubs shunt resonators; by using these geometries, we are able to acquire the data in a broadband range, in principle between 1 GHz and 40 GHz. We conduct the analysis by comparing two different technology run: the first wafer with a deposited layer by a 12-year-old SU-8 and the second wafer, with the same photolithographed metallic geometries, with a brand-new processed SU-8 photoresist.

In this paper, we present a sensor suitable for performing the spectroscopy on a localized micrometric volume of a generic liquid, in the spectral range comprised between 1 GHz and 20 GHz. The sensor is based on two ungrounded, open-ended coplanar waveguides, acting as Input/Output ports, with a microfluidic channel passing through them to perform also transmission through the liquid analysis. The sensor has been designed and numerically simulated to obtain the electromagnetic response in different conditions: an empty channel for having a zero-reference response and for observing variations as a function of liquids filling the channel.

In this work, the authors present a technique for the local characterization of the dielectric properties of materials. More in details, a setup will be described, and the related measurement modeling will be discussed. In this way, it is possible to obtain a calibrated and nondestructive determination of the dielectric constant in a submicrometric region; the detection of any surface or buried metallization is a straightforward application for microelectronics. The analysis is performed as a function of the frequency in the microwave range and, further on, the data can be transformed in time domain for one dimensional tomography. The authors will show that microwave spectroscopy can be performed by means of standard coaxial pins employed as probes for measurements both in reflection and transmission mode, giving the information of the frequency dependent properties of the exploited material or structure by means of the measured impedance. Experiments are performed in the range between 1 and 18 GHz, and different dielectric samples are tested. In order to evaluate the surface and subsurface measuring capability, samples obtained by thin metallic film deposition on a silicon wafer and buried by a polymeric layer are realized and characterized.

In this work, thin film packages were developed for radio-frequency microelectromechanical system (RF MEMS) configurations. The fabricated packages are suspended membranes in the multilayer SixNyHz/aSi/SixNyHz on conductive coplanar lines of different length. Several geometric parameters of the membranes, which are the length, the curvature radius at the vertices of the rectangular base, the density and the diameter of holes, were also varied. The mechanical properties of the suspended membranes were investigated by surface profilometry as a function of the geometric parameters. Finally, the RF characterization was performed to evaluate the impact of the package on the coplanar line performance. Hence, the proposed study provides results of crucial importance for the application of thin-film suspended microstructures for the packaging of RF MEMS devices.

RF MEMS in Low-Temperature Co-fired Ceramics (LTCC) technology have been designed, manufactured and tested for potential utilization in reconfigurable space sub-systems. Specifically, single-pole-single-throw (SPST) and single-pole-double-throw (SPDT) ohmic switch configurations have been studied for wide-band applications. Advantages coming from the measured RF performances and from the integration of RF MEMS by means of the LTCC technology only, to be used also for packaging, are discussed.

session poster; International audience; The paper presents an experimental study aiming to highlight the potential of scanning microwave microscopy (SMM) as a non-destructive high precision characterization tool for SOI technology. Two identical SOI wafers having passivated and non-passivated top Si film surfaces have been assessed. Differential microwave measurements were found capable of detecting differences in the structures of the two samples. The results support the conclusion that, after appropriate calibration method, SMM may provide a powerful tool offering nm scale characterization for SOI technology.

Triangular resonators, designed by using Radio Frequency Micro Electro Mechanical Systems (RF MEMS) cantilevers in coplanar waveguide (CPW) configuration, have been proposed, fabricated on alumina and on silicon substrates and tested up to 40 GHz. They can be utilized as building blocks for realizing reconfigurable filters. A triangular split ring resonator has been etched in the central conductor of the CPW transmission line and the split is provided by the presence of a technologically actuated cantilever beam, i.e. with metal directly deposited without the sacrificial layer, to emulate the ideal actuation and to get preliminary information of the expected microwave response in comparison to numerical simulations. Two main configurations of the triangular transmission line have been studied for narrow-band microwave switching, the first one without the MEMS cantilever and the second one with a technologically actuated MEMS cantilever switch. Because of the contributions of both the resonator and the switch, the device has a narrow band filtering feature. Moreover, these geometries can also be characterized in the broad class of metamaterial devices, because the unit cell can be described by negative equivalent electric permittivity and/or magnetic permeability, by means of a transmission line parameters extraction method. This finding contributes to the possibility of miniaturization implementations of the resonating structures. A simple but effective lumped element circuit for the modeling of the single triangular resonator is presented in the end.

In this paper, we present in detail the design, both electromagnetic and mechanical, the fabrication, and the test of the first prototype of a Scanning Microwave Microscope (SMM) suitable for a two-port transmission measurement, recording, and processing the high frequency transmission scattering parameter S21 passing through the investigated sample. The S21 toolbox is composed by a microwave emitter, placed below the sample, which excites an electromagnetic wave passing through the sample under test, and is collected by the cantilever used as the detector, electrically matched for high frequency measurements. This prototype enhances the actual capability of the instrument for a sub-surface imaging at the nanoscale. Moreover, it allows the study of the electromagnetic properties of the material under test obtained through the measurement of the reflection (S11) and transmission (S21) parameters at the same time. The SMM operates between 1 GHz and 20 GHz, current limit for the microwave matching of the cantilever, and the high frequency signal is recorded by means of a two-port Vector Network Analyzer, using both contact and no-contact modes of operation, the latter, especially minded for a fully nondestructive and topography-free characterization. This tool is an upgrade of the already established setup for the reflection mode S11 measurement. Actually, the proposed setup is able to give richer information in terms of scattering parameters, including amplitude and phase measurements, by means of the two-port arrangement.

In this work, microwave characterization of magnetic materials using the scanning microwave microscopy (SMM) technique is presented. The capabilities of the SMM are employed for analyzing and imaging local magnetic properties of the materials under test at the nanoscale. The analyses are performed by acquiring both amplitude and phase of the reflected microwave signal. The changes in the reflection coefficient S-11 are related to the local properties of the material under investigation, and the changes in its magnetic properties have been studied as a function of an external DC magnetic bias. Yttrium iron garnet (YIG) films deposited by RF sputtering and grown by liquid phase epitaxial (LPE) on gadolinium gallium garnet (GGG) substrates and permalloy samples have been characterized. An equivalent electromagnetic transmission line model is discussed for the quantitative analysis of the local magnetic properties. We also observed the hysteretic behavior of the reflection coefficient S11 with an external bias field. The imaging and spectroscopy analysis on the experimental results are evidently indicating the possibilities of measuring local changes in the intrinsic magnetic properties on the surface of the material. (C) 2016 Elsevier B.V. All rights reserved.

Shunt capacitive RF MEMS switches have been developed using III-V technology and employing (tantalum pentoxide) Ta2O5thin films as dielectric layers. In order to evaluate the potential of the Ta2O5thin films for the considered application, the compositional, structural, and electrical characterization of the deposited films has been performed, demonstrating that they are good candidates to be used as dielectric layers for the fabrication of RF MEMS switches. Specifically, Ta2O5films are found to show a leakage current density of few nA/cm2forE∼1 MV/cm and a high dielectric constant of 32. Moreover, the charging process has been investigated, finding that it follows a stretched exponential law. The fabricated switches show actuation voltages in the range 15–20 V, an insertion loss better than −0.8 dB up to 30 GHz, and an isolation of ~−40 dB at the resonant frequency which is around 25 GHz.

In this paper a new approach to manufacture low losses coplanar waveguide (CPW) lines for microwave and millimeter wave signal processing is presented. A photolithographic process is performed by using SU-8 thick negative photo-resist on low resistivity silicon wafers, to obtain CPW lines elevated with respect to the substrate, in order to take advantages, in terms of propagation losses, from transmission line structures which are almost on-the-air.

The analytical modelling of a grounded truncated metallic cone is presented in this work as a contribution to the de-embedding and calibration of a scanning microwave system based on capacitance measurements for imaging and spectroscopy purposes. First, an expression for the capacitance of a uniform cylinder is derived, and successively a procedure to determine an effective uniform cylinder radius for the truncated cone is developed. The truncated cone was chosen as a suitable geometry for the calculation of the stray capacitance versus ground of a metallic tip used for scanning probe microscopy and, more specifically, microwave sensing. An accurate calculation of the aforementioned capacitance is of outmost importance for system calibration in scanning microwave microscopy (SMM) technique.

Shunt capacitive radio-frequency microelectromechanical (RF MEMS) switches were modelled, fabricated and characterized in the K-band domain. Design allowed to predict the RF behaviour of the switches as a function of the bridge geometric parameters. The modelled switches were fabricated on silicon substrate, using a surface micromachining approach. In addition to the geometric parameters, the material structure in the bridge-actuator area was modified for switches fabricated on the same wafer, thanks to the removal/addition of two technological steps of crucial importance for RF MEMS switches performance, which are the use of the sacrificial layer and the deposition of a floating metal layer on the actuator. Surface profilometry analysis was used to check the material layer structure in the different regions of the bridge area as well as to investigate the mechanical behaviour of the moveable bridge under the application of a loaded force. The RF behaviour of all the fabricated switches was measured, observing the impact on the isolation of the manipulation of the bridge size and of the variations in the fabrication process.

In this work, we present the analytical modeling and preliminary experimental results for the choice of the optimal frequencies when performing amplitude and phase measurements with a scanning microwave microscope. In particular, the analysis is related to the reflection mode operation of the instrument, i.e., the acquisition of the complex reflection coefficient data, usually referred as S-11. The studied configuration is composed of an atomic force microscope with a microwave matched nanometric cantilever probe tip, connected by a lambda/2 coaxial cable resonator to a vector network analyzer. The set-up is provided by Keysight Technologies. As a peculiar result, the optimal frequencies, where the maximum sensitivity is achieved, are different for the amplitude and for the phase signals. The analysis is focused on measurements of dielectric samples, like semiconductor devices, textile pieces, and biological specimens. (C) 2015 AIP Publishing LLC.

A methodology towards de-embedding contact mode scanning microwave microscopy (SMM) reflection measurements is presented. A calibration standard that consists of differently doped stripes is required, while the reflection coefficient amplitude |S11|, is modeled and analyzed in the linear scale, instead of the commonly adopted dB scale. This allows the straightforward experimental determination of important parameters such as the effective tip radius and the magnitude of stray capacitances. Values of 145 nm and 22 fF have been obtained respectively. The proposed methodology can be easily and repeatedly performed during the experimental procedure, offering in this way the necessary de-embedding to get an enhanced accuracy on SMM measurements for semiconductors characterization.

Triangular metamaterial resonators, designed by RF MEMS cantilevers in coplanar waveguide (CPW) configuration, have been fabricated on alumina substrate and tested up to 40 GHz. A triangular split ring resonator has been etched in the central conductor of the CPW transmission line and the split is provided by a technologically actuated cantilever beam, i.e. with metal directly deposited without the sacrificial layer, to emulate the ideal actuation. Two main configurations of the triangular transmission line have been studied for narrowband microwave switching, the first one without the MEMS cantilever and the second one with a technologically actuated MEMS cantilever switch. Because of the contributions of both the resonator and the switch, the device has a narrow band switching feature. Moreover, the parameters extraction obtained by both the experiment and the simulation, show a metamaterial behavior of the exploited configuration.

Reflection mode scanning microwave microscopy (SMM) is compared to a newly developed transmission mode imaging hardware for extended scattering S11 and S12 measurements. Transmission mode imaging is realized by an SMA connector placed below the sample to excite an electromagnetic wave towards the cantilever acting as nanoscale-sized receiver structure. The frequency response was investigated between 1–20 GHz and a circuitry model of the SMM matching network was combined with a 3D finite element model of the tip-sample system. Modeling results include the local 3D electric field distribution around the nanoscale cantilever tip in contact to the sample. Reflection mode measurements were calibrated using a simple three error-parameter workflow allowing for quantitative impedance and capacitance imaging. A qualitative agreement was obtained between measurements and SMM models for both S11 and S12.

The paper presents a calibration of scanning microwave microscopy signals for doping profiling in MOS systems. The experimentally obtained S-parameters are matched through a linear relation to the calculated MOS system capacitance and then to doping. The proposed approach is verified by simulations with the equivalent LCR circuit as well as by experimental results obtained on a calibration sample with differently doped areas.

The effect of dispersion on the propagation of linear rectangular pulses of magnetostatic waves in YIG films is studied. With surface magnetostatic waves propagating in YIG filins and composite ferrite-insulator-metal structures. it is demonstrated that, for the near-rectangular phase-unmodulated input pulse and the distance between input and output transducers equal roughly to half the dispersion length of' the pulse, the FWHM of the output pulses is 50-60% of the initial value. This fact can be used for estimating the dispersion coefficient of magnetostatic waves.

Bulk and micromachined magnetostatic wave frequency tunable resonators have been designed, realized, and tested. Four resonator configurations, two on a silicon bulk substrate and other two on a micromachined silicon membrane, have been characterized and compared by measuring their S parameter responses at different dc magnetic bias fields. The frequency has been swept between 2 GHz and 5 GHz for silicon bulk resonators and between 2 GHz and 6.5 GHz for the resonators supported by the silicon membrane. By using the membrane technological solution, the insertion losses for membrane supported resonators decrease by about 18 dB with respect to the bulk silicon supported ones. Moreover, the quality factor measured for these configurations was Q(L)approximate to450, about twice that for silicon bulk supported straight edge resonators. The obtained results demonstrate both: (i) the possibility to combine the magnetostatic wave technology with the micromachining one, and (ii) the improvement of the electrical performances for the resonators supported on a silicon membrane, with a strong decrease in the insertion losses and a doubling of the value for the quality factor. Finally, the obtained electrical response is quite good as compared to the classical alumina-based devices, with the novelty to have realized the resonators in an all-silicon environment.

This paper presents the fabrication processes for micromachined millimetre-wave devices, on two different types of semiconductor substrates. The first process uses micromachining on high-resistivity oriented silicon. A three-layer dielectric membrane, with a total thickness of 1.5 µm is used as support for the millimetre-wave structures. This process was used for the manufacturing of two coupled line filters, with central operating frequencies of 38 and 77 GHz, respectively. The second process is based on GaAs micromachining. For the first time, a 2.2 µm thin GaAs/AlGaAs membrane, obtained by molecular beam epitaxy growth and micromachining of semi-insulating GaAs, is used as a support for millimetre-wave filter structures. Cascaded coplanar waveguide open-end series stubs filter type structures, with central frequencies of 38 and 77 GHz, respectively, were designed and manufactured on a GaAs micromachined substrate. `On wafer' measurements for the filter structures were performed. Losses of less than 1.5 dB at 38 GHz and less than 2 dB at 77 GHz have been obtained for both the silicon as well as for the GaAs-based micromachined filters.

This work presents the design, technology and experiment on a frequency tunable narrow-band filter based on coupled straight edge resonators (SERs). A number of series configurations of cascaded resonators have been obtained by properly masking a yttrium iron garnet (YIG) magnetic film, and by using a wet chemical etching technique in hot phosphoric acid to get the coupled SERs directly onto the gadolinium gallium garnet (GGG) substrate used for the epitaxial growth. Ferromagnetic resonance (FMR) measurements of the coupled SERs are done. Theoretical design and circuit simulation are also presented.

In this work the optical absorption properties of Ca-substituted yttrium iron garnet films are discussed. In particular the optical absorption of sputtered amorphous garnets film and the contribution of Ca-ions are analyzed. A comparison with the optical response of crystalline garnets is also made.

Metamaterial (MM) structures exhibit phase and group velocities having opposite sign and negative effective permittivities, making them good candidates for novel applications in microwave sub-systems. Several analytical and experimental results are available concerning the shape optimization of resonating MM configurations. In this paper, a Complementary Sierpinksi Triangular Resonator (C-TSR) in coplanar waveguide (CPW) has been studied for C and X Band applications. The peculiarity of the triangular structure to exhibit multiple resonances is proposed for dual and three-band purposes, to obtain efficient unit cells for high performance microwave tunable oscillators. The MM nature of the resonators has been studied deriving the effective dielectric and magnetic permittivity by means of the Y- and Z- electrical parameters. Single and back-to-back triangles, even including the presence of inner small triangular resonators, have been simulated, optimizing the performances of the notch response in terms of quality factor Q and impedance matching. As a result, a proper shape and number of inner triangles can change the frequency of resonance of the entire structure. Q-values up to 10000 have been predicted, and an isolation better than 30 dB between the resonance peaks has been evaluated.

Micro-electromechanical switches for Radio Frequency applications (RF MEMS switches)[1][4] are movable micro-systems which pass from an ON to an OFF state by means of the collapse of a metalized beam. They can be actuated in several ways but, generally, the electrostatic actuation is preferred because no current is flowing in the device nor power absorption has to be involved in the process. The bias DC voltage signal is usually separated with respect to the RF signal for application purposes. Anyway, in the simplest mechanical model, a voltage difference V is imposed between the metal bridge, connected to the ground plane of a coplanar waveguide (CPW) structure, and the central conductor of the CPW, which also carries the high frequency signal. Under these circumstances, the switch will experience an electrostatic force which is balanced by its mechanical stiffness, measured in terms of a spring constant k. The balance is theoretically obtained until the bridge is going down approximately (1/3) of its initial height. After that, the bridge is fully actuated, and it needs a value of V less than the initial one to remain in the OFF (actuated) position, because contact forces and induced charging effects help in maintaining it in the down position. A general layout of the switch is diagrammed in Fig. 1a, with its simplified equivalent lumped electrical circuit. In Fig. 1b the cross-section of the device is shown, with the quantities to be used for the definition of the geometry and of the physical properties of the structure. The actuation as well as the de-actuation are affected also by the presence of a medium (typically air, or preferably nitrogen for eliminating humidity residual contributions in a packaged device) which introduces its own friction, causing a damping, and altering the speed of the switch [5]-[7]. Several models are currently available to account for a detailed treatment of the damping, including also the presence of holes in the metal beam [8]-[11]. Moreover, the damping modifies the natural frequency of oscillation for the bridge. In particular, the actuation and de-actuation mechanisms will be consequently affected, leading to simple oscillations (no fluid damping contribution) or damped oscillations (fluid contribution) up to over-damping for particular values of the bridge dimensions or material properties. Experimental problems related to the dynamic characterization of

Charge accumulation in dielectrics solicited by an applied voltage, and the associated temperature and time dependencies are well known in scientific literature since a number of years [1]. The potential utilization of materials being part of a device useful for space applications is a serious issue because of the harsh environmental conditions and the necessity of long term predictions about aging, out-gassing, charging and other characteristic responses [2], [3]. Micro-mechanical Systems (MEMS) for RF applications have been considered for sensor applications as well as for high frequency signal processing during more than one decade [4], [5], [6], [7], [8], [9]. In this framework, RF MEMS switches are micro-mechanical devices utilizing, preferably, a DC bias voltage for controlling the collapse of metalized beams [8]. Magnetic [10], thermal [11] and piezoelectric [12] actuations have been also evaluated, but the electrostatic one seems to be until now preferred for no current flowing, i.e. a virtual zero power consumption, less complicated manufacturing processes and more promising reliable devices [13].

We develop shunt capacitive RF MEMS switches in III-V technology making use of materials which can be alternative to the ones commonly used, in order to overcome some technological constraints concerning the RF MEMS reliability. Specifically, we evaluate the potential of tantalum nitride (TaN) and tantalum pentoxide (Ta 2 O 5 ) to be used for the switches actuation pads and dielectric layers, respectively. To this scope, a compositional, structural and electrical characterization of TaN and Ta 2 O 5 films as a function of the deposition parameters, such as the substrate temperature and the sputtering mixture composition, is performed. The realized switches show good actuation voltages, in the range 15- 20 V, an insertion loss better than -0.8 dB up to 30 GHz, and an isolation of ~ -40 dB at the resonant frequency. A comparison between the measured S-parameter values and the results of a circuit simulation is also presented and discussed, providing useful information on the operation of the fabricated switches.

The growth by rf diode sputtering of magnetic garnet thin single and multiple layers and their morphological, compositional and optical absorption characterization are described. Crystalline, defect-free layers and multilayer structures can be obtained by properly imposing the sputtering conditions (substrate temperature and rf power) and the thermal post-annealing cycle to crystallize ex-situ the garnet films.

Ferromagnetic resonance cavity and microstrip excitation experiments have been performed on a straight edge yttrium iron garnet resonator. Both excitation systems have been modeled as band-stop configurations and a mapping from the swept bias magnetic field domain to the frequency domain has been elaborated to compare them in terms of the dispersion and the amplitude of the magnetostatic wave modes.

RF MEMS switches are currently considered for isolation and transmission of RF signals as the ideal next generation devices with respect to PIN diodes, because of the very low losses, high reliability, no signal distortion and no power consumption. In this work, RF MEMS shunt switches in coplanar waveguide (CPW) configuration have been designed, realized and tested for wideband isolation purposes. SU-8 negative resist technology has been introduced for improving the bridge mechanics and the RF performances of the device. The polymeric material is used to elevate the ground planes of the CPW structure, with minor consequences on the electrical matching and an improvement in the bridge ends definition. The EM design has been followed by a six-step photo-lithographic process on a 4" oxidized high resistivity silicon wafer, up to the release of the bridge by using a plasma etching technique.

The technology for the realization of RF MEMS ohmic series switches on LTCC substrates has been set up for their implementation in true time delay line configurations. Alumina and LTCC structures for validating the technological process on the individual switches have been obtained and characterized. Static delay lines on LTCC have been manufactured and tested to get the expected electrical performances for the final configuration.

Coplanar wave-guide grounded lines (CPWG) have been designed, realized by micro-machining of high resistivity silicon wafers and tested up to 40 GHz. Different configurations have been compared between them by changing the dimensions of the micro-machined via-holes used for the ground connection, as well as their number and separation, to get the optimal electrical matching conditions. Wide-band matching and losses as low as 0.1-0.2 dB/mm have been obtained within the 40 GHz range, in agreement with the predicted behaviour.

We report on the microwave properties of single‐crystal YIG/gadolinium gallium garnet/YIG grown in (110) layers, where YIG is yttrium iron garnet. The YIG layers were sufficiently thin so that single domain ferromagnetic resonance (FMR) was observed. FMR fields were measured as a function of field direction and magnitude and frequency. Bulk magnetic parameters deduced from FMR and vibrating‐sample magnetometer measurements agree with published values. In addition, FMR measurements at low fields show typical ‘‘butterfly’’ variations of the FMR fields with a frequency for H, the magnetic field, parallel to either the 〈100〉 or 〈110〉 axis. However, a new butterfly pattern was also observed for the magnetic field parallel to the 〈111〉 axis. This result is intrinsic to layered structures and not to single layer excitations. We attribute this new result to nonuniform distribution of strain in the two YIG layers, and as a consequence, we predict that magnetostatic fringe fields from edges are sufficient to induce...

RF MEMS shunt switches in coplanar waveguide (CPW) configuration have been designed, realized and tested for wideband isolation purposes. SU-8 negative photo-resist technology has been introduced for improving the bridge mechanics and the RF performances of the device. The polymeric material is used to elevate the ground planes of the CPW structure, with minor consequences on the electrical matching and an improvement in the bridge ends definition. The EM design has been followed by a sixstep photolithographic process on a 4" oxidized high resistivity silicon wafer, up to the release of the bridge by using a plasma etching technique.

This paper presents the results in modeling, technological realization and measurements of a coupled-line directional coupler, based on CRLH (Composite Right/Left-Handed) transmission lines. The CRLH transmission lines consists of series connected CPW inter digital capacitors and parallel connected CPW inductors. The studied devices were fabricated on silicon substrate for a subsequent integration in a more complex circuit. A very good agreement between the simulation data and the experimental results has been found out for these CRLH transmission lines devices in the 10-14 GHz frequency domain.

Coupled-line directional coupler based on CRLH (C omposite Right/Left-Handed) cascaded structures is designed, analyzed and then fabricated. The technological realization of the coupler involves one mask process on silicon substrate, using CPWs (C oPlanar Waveguides). The preliminary measurements were also performed, showing that the experimental results fit well the simulation results.

The paper presents results obtained in modeling, technological fabrication and measurements for a CPW (coplanar waveguide) zeroth-order resonating antenna, based on CRLH TL (composite right/left-handed transmission line). The CRLH TL consists of cascaded cells of series CPW interdigital capacitors and parallel CPWs. The antenna was fabricated on silicon substrate. This was designed and analyzed using commercial electromagnetic software (IE3D-Zeland), A very good agreement between the experimental and the simulation results has been observed for the return-loss as well as for the gain and the radiation pattern.

Coplanar wave-guide grounded lines (CPWG) have been designed for being realized by micromachining of high resistivity silicon wafers. Actually, different configurations have been compared between them by changing the dimensions of micromachined via-holes, as well as their number and separation, to get the optimal electrical matching conditions for CPWG lines. Wide-band matching and low losses have been predicted up to 30 GHz, and preliminary experimental results about the technology have been obtained.

RF micromechanical switches are fabricated using dry releasing techniques. LTCC is used as substrate. Amorphous silicon, as an alternative sacrificial layer to silicon dioxide, has been used followed by dry plasma release. The silicon deposition has been optimized to obtain low mechanical stress and allowing thick sacrificial layer deposition. The use of amorphous silicon extends the flexibility of the design of the devices and of the packaging procedure.

International audience; This paper presents the full modeling and a methodology for de-embedding the interferometric scanning microwave microscopy measurements by means of dopant profile calibration. A Si calibration sample with different boron-doping level areas is used to that end. The analysis of the experimentally obtained S11 amplitudes based on the proposed model confirms the validity of the methodology. As a specific finding, changes in the tip radius between new and used tips have been clearly identified, leading to values for the effective tip radius in the range of 45 nm to 85 nm, respectively. Experimental results are also discussed in terms of the effective area concept, taking into consideration details related to the nature of tip-to-sample interaction.The authors wish to acknowledge the support from EC by means of “Marie Curie” fellowship in the framework of PEOPLE-2012-ITN project: Microwave Nanotechnology for Semiconductor and Life Science—NANOMICROWAVE, under GA: 317116, as well as the Region Nord-Pas-de-Calais for supporting this work under the project CPER CIA research and the National Research Agency (ANR) under the program Equipex (EXCELSIOR project).