Design of a Low-Cost Microstrip Directional Coupler with High Coupling for a Motion Detection Sensor

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,anoptimizationprocedurewasperformedusingthecommercialsoftwareAnsysHFSSinorder 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

A generalized finite difference approach to the computation of modes

This thesis deals with numerical techniques for the computation of modes in electromagnetic structures with arbitrary geometry. The approach proposed in this work is based on the Finite Difference (FD) and Vector Finite Difference (VFD), which are applied to rectangular, circular, elliptical geometries, and to combination of them. The FD is applied using a 2D cartesian, polar and elliptical grid in the waveguide section. A suitable Taylor expansion of the mode function allows, either for scalar and for vector FD, to take exactly into account the boundary condition. To prevent the raising of spurious modes, the VFD approximation results in a constrained eigenvalue problem, that has been solved using a decomposition method. All approaches presented have been validated comparing the results to the analytical modes of rectangular and circular waveguide, and to known data for the elliptic case. The standard calculation of the waveguide modes using FD requires the use of two different grids, namely one for TE modes and the other for TM modes, due to the different boundary condition. It has been shown that a single grid can be used for all modes, thus allowing an effective mode-matching solution. The FD approach has been extended to waveguides (and apertures) with irregular boundaries, and therefore non-regular discretization grids. It has been shown that a suitable FD approximation of the Laplace operator is still possible. A ridged-waveguide, with trapezoidal ridges, and a rounded-ended waveguide have been considered in detail

Analysis and modelling of broad-band ferrite-based coaxial transmission-line transformers

The work presented in the paper focuses on accuracy of models for broad-band ferrite based coaxial transmission-line transformers. Soft-ferrites are largely used in VHF/UHF components allowing band enlargement on the low-edge side. Degradation of frequency performance on the high-edge side are produced both by ferrite losses, and by parasitic capacitance due to connection to the thermal and electrical ground in high power applications. Both a circuital model for low-power applications and a scalable e.m. model for high-power applications are presented and discussed. © 2010 EuMA

the heterochromatin protein 1 positively regulates euchromatic gene expression by rna binding

HP1 is a well known conserved protein involved in heterochromatin formation and gene silencing in different species including humans1-4. A general model has been proposed for heterochromatin formation and epigenetic gene silencing in different species that implies an essential role for HP1. According to the model, histone methyltransferase enzymes (HMTases) methylate the histone H3 at lysine 9 (H3-MeK9), creating selective binding sites for itself and the chromodomain of HP15. This complex is thought to form a higher order chromatin state that represses gene activity. It has also been found that HP1 plays a role in telomere capping6. Surprisingly, recent data have suggested an association of HP1 in gene activity7-10 but the nature of this interaction is still completely obscure. Here we show, that HP1 is required for positive regulation of more than one hundred euchromatic genes by its association with the corresponding RNA transcripts and by its interaction with the well known proteins DDP111, HRB87F12 and PEP13, which belong to different classes of heterogeneous nuclear ribonucleoproteins (hnRNPs) involved in RNA processing . We also found that all these hnRNP proteins also bind heterochromatin and are dominant suppressors of position effect variegation. Our data together, show novel and unexpected functions for HP1 and hnRNPs proteins. All these proteins are in fact involved in both RNA transcript processing and in heterochromatin formation. This suggests that, in general, similar epigenetic mechanisms have a significant role in the metabolism of both RNA and heterochromatin

A Serious Game Approach for the Electro-Mobility Sector

Serious Games (SGs) represent a new approach to improve learning processes more effectively and economically than traditional methods. This paper aims to present a SG approach for the electro-mobility context, in order to encourage the use of electric light vehicles. The design of the SG is based on the typical elements of the classic "game" with a real gameplay with different purposes. In this work, the proposed SG aims to raise awareness on environmental issues caused by mobility and actively involve users, on improving livability in the city and on real savings using alternative means to traditional vehicles. The objective of the designed tool is to propose elements of fun and entertainment for tourists or users of electric vehicles in the cities, while giving useful information about the benefits of using such vehicles, discovering touristic and interesting places in the city to discover. In this way, the user is stimulated to explore the artistic and historical aspects of the city through an effective learning process: he/she is encouraged to search the origins and the peculiarities of the monuments.Comment: This paper has been presented at 2019 IEEE International Conference on Systems, Man and Cybernetics (SMC

Design of Multilayer Dielectric Cover to Enhance Gain and Efficiency of Slot Arrays

An effective design procedure, based on the Elliot’s synthesis method, is proposed to investigate the properties of waveguide slot arrays with multilayer dielectric cover. Then, the features of the designed arrays are analyzed by means of a FEM commercial software, namely Ansys HFSS 13. We show how a proper choice of the dielectric cover configuration allows to increase the array gain and aperture efficiency, while taking advantage of the properties of the radome structure, both in terms of insulation, protection and pressurization of the radiating waveguides. Therefore, a significant outcome of the optimal choice of the multilayer dielectric cover is the reduction of the number of slots with respect to an array radiating into free space with the same gain and efficiency, with a consequent reduction of the production cost