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Superconducting circuits can operate at higher energy efficiencies than their room-temperature counterparts and have the potential to enable large-scale control and readout of quantum computers. However, the required interface with room-temperature electronics creates difficulties in scaling up such cryogenic systems. One option is to use optical fibres as a medium in conjunction with fast optical modulators that can be efficiently driven by electrical signals at low temperatures. However, as superconducting circuits are current operated with low impedances, they interface poorly with conventional electro-optical modulators. Here we report an integrated current-driven modulator that is based on the magneto-optic effect and can operate at temperatures as low as 4 K. The device combines a magneto-optic garnet crystal with a silicon waveguide resonator and integrates an electromagnet to modulate the refractive index of the garnet. The modulator offers data rates of up to 2 Gbps with an energy consumption below 4 pJ per bit of transferred information, which could be reduced to less than 50 fJ per bit by replacing dissipative electrodes with superconductors and optimizing the geometric parameters.

New possibilities in antenna and microwave manufacturing are opening up through the exploitation of additive manufacturing (AM) 3D printing techniques. Despite being used primarily for the fabrication of dielectric structures, with the right filament, these procedures could also be able to print conductive parts, giving birth to true fully-3D-printed radiating elements. However, to take full advantage of these thermoplastic materials, a rigorous electromagnetic characterization needs to be performed. Based on this, the dielectric properties of one of the most common plastic 3D-printable materials are investigated, and, in addition, the electric conductivity of one of the most promising conductive filaments (Electrifi) is experimentally evaluated in a wide frequency range (0.5-7.5 GHz) and then validated in the design of different fully-3D-printable patch antennas.

Aims The aim of this work was to assess the effects of a probiotic diet on well-being of healthy seniors living in boarding and private homes in Marche Region, Italy. In particular, we focused on the modulation of high-sensitivity C-reactive protein (HsCRP), intestinal microbiota and short-chain fatty acids (SCFAs). Methods and Results Ninety-seven healthy seniors took part in a double-blind, placebo-controlled feeding study (59 fed probiotics, 38 fed placebo) for 6 months. Each volunteer ingested daily one food product or a dietary supplement enriched with Synbio® blend (Synbiotec Srl, Camerino, Italy) or the placebo (control group). Blood and faecal samples were collected before and at the end of the intervention period to perform biochemical and microbiological analyses. The serum HsCRP difference value after 6 months of treatment was significantly higher in the probiotic group than placebo (p < 0.05). After the intervention, a significant increase in faecal lactobacilli and a bifidobacteria increase in more participants were observed in the probiotic group. The 16S NGS analysis on the probiotic group showed a decreasing trend of Proteobacteria at the end of the treatment and conversely, an increasing trend of Actinobacteria and Verrucomicrobia phyla, to which the increase of Akkermansiaceae and Bifidobacteriaceae contributes at the family level. Finally, total short-chain fatty acids (SCFAs) and butyric acid were significantly higher in the probiotic group at the end of the treatment respect to the beginning. Conclusions Overall, this study emphasizes the beneficial anti-inflammageing effect of a prolonged diet based on functional foods enriched with Synbio® through the modulation of the intestinal microbiota and the consequent increase in the SCFA production. Significance and Impact of the Study Synbio® integration in elderly daily diet may be a preventive strategy to support healthy ageing.

A wearable textile antenna based on the fundamental mode of an eighth-mode substrate-integrated waveguide is presented, operating in the UHF frequency band, at 915 MHz. The proposed structure has a compact size, and presents a very good isolation from the human body. Compared to its SIW resonator counterpart, the proposed antenna size has been reduced by almost 87.5%, without degrading its performance. It has been simulated using CST Microwave Studio, with a broadside radiation pattern. All these features make this antenna very promising for Lo-Ra systems and applications, such as internet of things (IoT) applications.

A wearable textile antenna based on the fundamental mode of an eighth-mode substrate-integrated waveguide is presented, operating in the UHF frequency band, at 915 MHz. The proposed structure has a compact size, and presents a very good isolation from the human body. Compared to its SIW resonator counterpart, the proposed antenna size has been reduced by almost 87.5%, without degrading its performance. It has been simulated using CST Microwave Studio, with a broadside radiation pattern. All these features make this antenna very promising for Lo-Ra systems and applications, such as internet of things (IoT) applications.

A wearable textile antenna based on the fundamental mode of an eighth-mode substrate-integrated waveguide cavity is presented for Low-Power Wide-Area Network (LPWAN) applications. The antenna operates in the UHF frequency band, at 867 MHz, and exhibits compact size, minimal manufacturing complexity and very low production cost. High isolation from the human body is observed, and a planar size reduction by more than 50% is achieved compared to similar SIW antennas in the literature. The proposed wearable antenna has been designed using CST Microwave Studio, then manufactured and tested, showing very good agreement with predicted performance.

In this work a compact 2.4 GHz wearable antenna for BLE applications, specifically designed to be fully integrated in a leather-made shoe, is designed and simulated. A slotted microstrip layout has been chosen and optimized under both electromagnetic and manufacturing point of view to be fully integrated with the shoe and to guarantee a robust wireless link with the smartphone receiver, typically placed on the upper part of the body. For these reasons the same leather has been selected as antenna substrate material, and conductive fabric to design the radiating parts and the substrate. Both antenna directivity and circular polarization have been optimized to guarantee a robust communication while saving power. The antenna shows a very satisfying performance, with a -10 dB input matching frequency bandwidth equal to 10%, and an Axial-Ratio 3 dB bandwidth of 3%.

Microstrip patch antennas are widely employed in several applications, thanks to their low profile, low cost, and easy manufacturing. However, the demand for new technologies providing compactness and high performance poses a long-lasting challenge for the antenna designer. Traditional methods for bandwidth improvement and size reduction have some drawbacks, tied mostly to poor radiation performance or troublesome implementation. In this letter, a novel, simple, but effective patch antenna layout exploiting the customizable form factor guaranteed by 3-D printing (or other fabrication techniques) is presented. An appropriate modification in the vertical profile of the radiator is introduced. Specifically, without loss of generality, a cylindrical shape has been selected as a proof of concept. The proposed solution allows to increase the impedance bandwidth from 2.9% of a standard flat microstrip patch to 9%. Additionally, the projected antenna resonant size can be reduced up to 38% compared to its flat counterpart.

A wearable textile antenna based on the fundamental mode of a quarter-mode substrate integrated waveguide is presented for short-range wireless applications. The antenna operates in the UHF frequen...

A novel printed antenna is designed for wearable and RFID applications in the UHF band. The antenna design is performed following energy-based design guidelines available in the recent literature. High robustness with respect to the human body coupling is achieved by confining the electric energy density in a region far from the antenna borders. The proposed configuration also provides a compact realization, and a high versatility, since it can be easily matched to different commercial chips. A prototype of this wearable antenna has been manufactured and tested in an anechoic environment. Experimental measurements of the read range confirm the results of the numerical simulations and demonstrate the antenna robustness with respect to the variations of the body–antenna coupling scenario.

The robustness of wearable UHF-band ungrounded antennas with respect to body-coupling effects is addressed. Two different configurations of single-layer antennas, with different energy density distributions, are presented, and a design criterion to improve their performance with respect to the antenna-body separation is derived. Through an analysis of the antenna electric and magnetic energy density distributions, it is shown that the degradation of the antenna performance due to the proximity of the human body can be reduced if the electric energy density is confined in specific regions far from the antenna border. The proposed design criterion has been validated by numerical simulations and experimental measurements.

A microwave resonant cavity with rectangular section used as catalyzer for chemical reactions is presented, operating at the center frequency of 2.45 GHz, where two parallel metallic walls of the cavity are replaced with perfect magnetic conductors (PMC). This choice allows to obtain a uniform electric field distribution in each transversal section of the designed cavity, improving the power transfer to the fluid, if compared with the resonant cavity with electric walls. Moreover, the number of the tubes containing the reagent solution, can be significantly increased per surface unit. The cavity resonator has been designed using CST Microwave Studio, a commercial general purpose software for the electromagnetic simulation of three-dimensional high-frequency components.

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The robustness of wearable Ultra-High Frequency (UHF)-band planar inverted-F Antennas (PIFAs) with respect to coupling with the human body is an extremely difficult challenge for the designer. In this work a design strategy is presented to help the designer to adequately shape and extend the antenna ground plane, which has been derived by accurately analyzing the distribution of the electric and magnetic energy densities of the antenna in a region around the antenna borders. The optimal extension of the ground plane will be discussed for three different grounded antennas, both in terms of free space wavelength, and in terms of electric energy density magnitude. Following these rules, the antenna robustness with respect to the coupling with the human body can be significantly improved, but with a minimal impact on the antenna size. The antenna robustness has been successfully tested considering several models for the human phantom in the simulation environment. The numerical simulations, performed using Computer Simulation Technology (CST) Microwave Studio, have been confirmed by experimental data measured for one of the analyzed grounded antenna configurations.

A 3D-Printed antenna, designed on a polylactic acid (PLA) substrate, is proposed as a passive tag antenna for UHF radio frequency identification (RFID). The presented antenna operating bandwidth includes all worldwide UHF RFID bands, has a very simple geometry, and can be easily tuned to match many of the commercial RFID chips. The antenna has been designed using a general-purpose 3D computer-aided design (CAD), CST Microwave Studio, and measured results are in very good agreement with simulations. © 2019 IEEE.

Planar waveguide slot arrays (WSAs) have been used since 1940 and are currently used as performing antennas for high frequencies, especially in applications such as communication and RADAR systems. We present in this work a review of the most typical waveguide slot array configurations proposed in the literature, describing their main limitations and drawbacks along with possible effective countermeasures. Our attention has been focused mainly on the improved available design techniques to obtain high performance WSAs. In particular, the addressed topics have been reported in the following. Partially filled WSAs, or WSAs covered with single or multilayer dielectric slabs, are discussed. The most prominent second-order effects in the planar array feeding network are introduced and accurately modeled. The attention is focused on the T-junction feeding the array, on the effect of interaction between each slot coupler of the feeding network and the radiating slots nearest to this coupler, and on the waveguide bends. All these effects can critically increase the first sidelobes if compared to the ideal case, causing a sensible worsening in the performance of the array.

The robustness of wearable UHF-band planar inverted-F antennas (PIFAs), with respect to body–antenna separation and human tissue dispersion, is addressed through numerical investigations. The main goal is gaining physical insights into the relationship between the grounded antenna performance and the distribution of the electric and magnetic energy densities in the antenna near-field region close to the ground plane border. A criterion for choosing a proper shape of the antenna ground plane is suggested, which can improve the antenna robustness with respect to the random variations of the body–antenna coupling scenario, but with a minimal impact on the antenna size.

The Elliott’s procedure for the design of planar waveguide arrays of longitudinal slots has been extended to the cylindrical conformal case. The presented procedure has been devised to deal with the most general case of a cylindrical conformal substrate integrated waveguide (SIW) longitudinal slot array with a dielectric cover. Both external and internal mutual coupling have been accurately and effectively taken into account. The results of the synthesis procedure have been validated using both Ansys HFSS simulations and experimental results, showing a good agreement with the design specifications.

A coupled-line coupler based on the asymmetric cascade connection of two coupled line sections is used to achieve a high coupling factor using low-cost material and technology in the X frequency band, and its performance is compared with a standard quarter-wave, coupled-line coupler, showing an increase in the coupling factor of about 3 dB. The proposed coupler can be effectively used in a Doppler motion detection sensor, due to its strong coupling and relatively high isolation. The coupler is designed through a simple, yet rigorous, equivalent circuital model. Then, an optimization procedure was performed using the commercial software Ansys HFSS in order to compensate for losses and second order effects. A prototype of the designed coupler was realized, and the measured data show very good agreement with simulations.

The robustness of wearable antennas to the human body proximity can be improved by properly placing the radiating element over a ground plane, or by shaping the ground plane, on the basis of the antenna electric and magnetic energy density distributions, aiming to confine the electric energy density in specific regions far from the antenna border. The effectiveness of the above design criterion has been assessed through both numerical analysis and experimental measurements, by optimizing the position of the radiating element of a wearable grounded ultrahigh frequency radio frequency identification tag operating at the ETSI band (865–868 MHz), with respect to its ground plane. A flexible tag characterization and performance evaluation platform is used to measure the tag sensitivity as a function of the antenna-body distance.

We present here the design and analysis of a microwave resonant cavity to evaluate the effect of RF electromagnetic field on enzyme reactions. The cavity has been first designed using CST Microwave Studio. Then, its behaviour in the actual use has been evaluated using the COMSOL multiphysics. The presented results show that such cavity can be quite effective.

A printed Log-periodic dipole array (LPDA) is presented as a multiband feed for reflector antennas in weather radar applications. The antenna has been designed starting from Carrel’s theory, optimized using CST Microwave Studio 2012, and then realized. The comparison between simulated and measured results shows that the proposed antenna can be used for weather radar applications both in the S- (2.7–3 GHz) and C- (5.4–5.8 GHz) frequency bands, with a very good input matching and a satisfactory end-fire radiation pattern. Moreover, it has a compact size, is very easy to realize, and presents an excellent out-of-band rejection, without the use of stop-band filters, thus avoiding interferences out of the weather radars’ operating frequency band. In order to obtain the same beamwidth both in E-plane and H-plane, a V-shaped configuration is proposed, which allows to improve the aperture efficiency of a reflector antenna fed by the presented LPDA.

Several wearable antennas have been presented in the open scientific literature, showing a good robustness with respect to the body coupling effect, both on the input matching and on the antenna ef...

An experimental approach is proposed to validate the theoretical energy-based considerations for wearable UHF RFID antenna design. On the basis of numerical analysis, it has been shown that wearable antennas presenting an energy density peak far from the antenna border are more robust with respect to the distance from the human body. A flexible and cost-effective RFID tag characterization and performance evaluation platform is used here to validate the theoretical approach by considering a grounded UHF RFID tag. © 2017 ACES.

An antenna design criterion based on the simulated distribution of electric and magnetic energy densities has been proposed to improve the robustness of wearable antennas. A flexible tag characterization and performance evaluation platform is here used to assess the effectiveness of this theoretical approach. Specifically, the analysis has been carried out by considering a single layer UHF RFID tag operating at the ETSI band (865–868 MHz).