In this communication, a compact flower shaped printed antenna for ultra-wideband communication is proposed. The “flower-shaped” structure is capable of transmitting UWB-band signals. The designed antenna exhibits a return loss ranging from 2.3 to 11 GHz with an 8.7 GHz central frequency and has 130% relative bandwidth. The suggested design includes a patch in the shape of a flower with several slots fed by a microstrip line. Multiple slots have been designed for better resonances at lower modes. The antenna is constructed with an FR4 substrate, and a 50 Ω A-type connector feeds it. The optimum dimensions of the designed antenna are 12 × 16 × 1.6 cubic-millimeters and 0.092λ × .12λ × 0.012λ in lambda. The proposed structure also demonstrates stable radiation patterns across the operating bandwidth. The proposed radiator has a high gain of 2.67 dBi, and an efficiency of 85%. It is compact, lightweight, and easy to make. Therefore, it can be used for UWB applications.

Semiconductor deposition on magnetron's cathode surface using different materials such as gallium nitride (GaN) and silicon carbide (SiC) semiconductors is conducted to grow approximately 80, 100 and 120 nm plasma layers. The cathode is then used to generate high frequency and low-power microwave for further comparison and analysis with the conventional magnetron operation. Parameter of analysis to identify the efficiency includes electron drift velocity, harmonic order, total harmonic distortion, low harmonic distortion, and spectrum observation. The sputtered cathode of the magnetron is used to generate a low-power microwave observing a generator efficiency up to 93 and 88% for GaN and SiC materials, respectively, compared to the conventional material, which observes 37% of efficiency at 2450 MHz, 5 W. Also reported is the quality of semiconductor sputtering on the magnetron cathode, which was manipulated by the deposition period, temperature, and plasma layer growth thickness.

This paper presents design considerations for an integrated wireless power transfer (WPT) and power line communication (PLC) system (e.g. WPT-PLC). The main goal is to enable wireless charging of mobile electronic products, along with high data rate communication over the shared wireless inductive resonant channel. Starting from a couple of resonant coils, characterized by the S-parameters matrix, the design of an impedance matching network and decoupling filters is carried out to better decouple power and data signals. A pulse-driven class-E power amplifier (PA) and a rectifier are first conceived based on the measured S-parameters and load-pull characterizations. Second, a sine-driven class-E power link, operating at 6.78 MHz, is proposed to reduce the total harmonic distortion of the integrated WPT-PLC system. These design steps aim to ensure high-power efficiency and low harmonic distortion of the class-E PA in order to mildly affect the channel capacity of the PLC. The harmonic interferences of the pulse-driven and sine-driven class-E power links are compared and discussed, together with the electromagnetic compatibility levels, the channel capacity, and the noise disturbances of the PLC channel in order to guarantee an optimized power and data transfer in the integrated WPT-PLC system.

Radiofrequency surface coils used as receivers in magnetic resonance imaging (MRI) rely on cables for communication and power from the MRI system. Complex surface coil arrays are being designed for improving acquisition speed and signal-to-noise ratio. This, in-turn makes the cables bulky, expensive, and the currents induced on cables by time-varying magnetic fields of the MRI system may cause patient harm. Though wireless power transfer (WPT) can eliminate cables and make surface coils safer, MRI poses a challenging electromagnetic environment for WPT antennas because the antennas made using long conductors interact with the static and dynamic fields of the MRI system. This paper analyses the electromagnetic compatibility of WPT antennas and reveals that commercially available antennas are not compatible with MRI systems, presenting a safety risk for patients. Even when the risk is minimized, the antennas couple with surface coils leading to misdiagnosis. This paper presents an approach to eliminate safety risks and minimize coupling using a filter named “floating filter.” A WPT antenna without a filter has a distortion of 27%, and floating filters reduce the distortion to 2.3%. Secondly, the floating filter does not affect the power transfer efficiency, and the transfer efficiency of 60% is measured with and without filters.

This paper aims at investigating the dependence of the impedance and the radiation characteristics of a cylindrical dielectric resonator antenna (DRA), on the feed point of the DRA. It is demonstrated that the resonant frequency, bandwidth, radiation pattern symmetry, and cross-polarized radiation levels depend highly on the feed point. Three standard single-ended feed mechanisms such as the microstrip line, the microstrip slot, and the coaxial probe are taken as examples, to demonstrate the feed-point dependence of the DRA performance. Standard commercial EM simulation tools (ANSYS HFSS and CST Microwave Studio) are used for generating insightful results to help the discussion. This analysis also provides a functional comparison among the above said three feed mechanisms with respect to the feed-point dependence, which is further verified through measurements of DRA prototypes employing the three feeds.

This paper studies the variation effects of incident plane wave on shielded coaxial cables, using Branin's method, which is called the method of characteristics. That model can be directly used for the time- and frequency-domain analyses. Moreover, it had the advantage of being used without the need of setting the preconditions of the charges applied to its ends. This makes it easy to insert in circuit simulators, such as SPICE, SABER, and ESACAP. The results obtained under ESACAP were remarkably similar to other results, which reinforce the validity of the model. Finally, we will discuss the effects of the variation of the incident plane wave.

An ultra-wideband (UWB) frequency-selective surface (FSS) exhibiting band rejection characteristic is presented in this paper. The proposed unit cell has the size of 14 × 14 mm2 which is approximately 0.18 × 0.18 λo, where λo corresponds to free space wavelength at the lower cut-off frequency. The proposed UWB FSS consists of a single-layer substrate and provides 20 dB attenuation level for a wide bandwidth of 7.53 GHz at the normal incidence. The proposed FSS is polarization independent and also provides angular-independent operation for the EM wave incidences of 15°, 30° and 45° with 11.5 dB attenuation over a wide range from 4 to 14 GHz.

This paper addresses the study of the variation effects of incident plane wave on a multiconductor transmission line (MTL), using a coupling circuit model of MTL line with plane wave based on the method of characteristics (Branin method). This model is valid in the time and frequency domains. It has also an advantage of not presupposing the conditions of the charges applied to its ends, which allows it to be easily inserted in circuit simulators, such as SPICE, SABER, and ESACAP. We confirm the validity of this model by comparing our simulation results under ESACAP with other results, and we discuss the variation effects of the incident plane wave on an MTL line.

This paper discusses the operating range of frequency modulated (FM) radars in the presence of interference. For this purpose, radar- and path loss equations are used to draw the equipotential lines for a given signal-to-interference ratio as a function of the spatial distribution of targets and interferers in order to identify relevant scenario constellations. Further the factors influencing the gain of signal versus deterministic interference are discussed based on measurements and simulations. Finally, the influence of different kinds of interference on the spectrum of a frequency modulated continuous wave radar is shown.

This paper presents an optimization circuit model of multiconductor transmission lines in the time domain. Several methods allow calculation of the currents and the tensions distributed on the uniform transmission line. Most of these methods are limited to lines with constant losses, and only for linear loads. The macro-model we propose, using Pade approximant, employs more variables and allows it to reduce the necessary cells' number in modelization than the traditional cells cascade method. This macro-model, using the Modified Nodal Analysis method (MNA), is suitable for an inclusion in circuit simulator, such as Esacap, Spice, and Saber. The MNA method offers an efficient means to discretize transmission lines on real and complex cells compared to the conventional lumped discretization. In addition, the model can directly handle frequency-dependent line parameters in the time domain. An example, with experimental measures taken from literature, is presented to validate the model we propose, and show its importance. It is necessary for assuring the results validity obtained from Pade macro-model to study its stability and passivity.

This paper presents the development and testing of a haptic interface compatible with a functional magnetic resonance imaging (fMRI) environment for neuroscience human motor control studies. A carbon fiber extension enables us to use the widely accepted and available haptic device Phantom 1.5.

In the first part of the paper development of the mechanical extension together with its kinematic and dynamic models are presented. The second part is focused on testing of the extended haptic interface. The experiment's results both inside and outside the fMRI environment are presented. Tests outside a scanner have shown that the mechanical extension has no notable effect on a subject performance. Experiments with the scanner have confirmed electromagnetic compatibility of the extended haptic system.

At the end it is concluded that the extended haptic device is fully compatible with the fMRI environment, and a virtual environment task that will allow neuroscientists to study a human motor control is proposed.