Co-Design Block PA (Power Amplifier)-Antenna for 5G Application at 28 GHz Frequency Band

This subject addresses the issue related to Transmitters for the new communication standard, namely 5G. Indeed to respond to the problems of radio coverage, the speed of services as well as the rise in user demand, transmitters must have ideal characteristics to be able to meet these requirements. This chapter proposes in order to answer such a problem a block made up of a linear array of antennas has 4 elements and a transistor amplifier operating at the 28 GHz frequency band. The Design of the Block is done first by the design of the antenna then the design of the amplifier and finally the junction of the two devices with a matching network to therefore form the block of transmitters Speaking of the design of the antenna, the prepared antenna is a patch antenna with a patch shape excluding the classic shapes which is printed on a Rogers-Duriod 5880 substrate so the thickness is 0.127 mm, the linear antenna array proposed has a gain greater than 15 dB and a Good Bandwidth, the transistor amplifier is in turn printed on the same substrate has the same thickness to minimize the losses during the junction of this one with the antenna, this amplifier offers a higher gain than device 15 dB and therefore the Bandwidth is greater than 2 GHz, each transmitter has an input and output reflection coefficient of less than −10 db. The simulation of each transmitter is made with the CST-microwave software for the Antenna and the ADS (Advanced Design System) software for the amplifier and the Block PA-Antenna. It is important to note that the Block output impedance is 50 ohms making our device more practical and easily commercial.

Circular Polarization of the Square, Circular, Triangle, and Hexagonal Microstrip Antenna

Microstrip antenna with circular polarization can be applied for many applications. Some microstrip antenna with square, circular, triangular, and hexagonal shape has been designed to get return loss, axial ratio, and radiation performance. We compare twelve microstrip antenna by maintaining its substrate dimension, feeding shape, and outer patch dimension. Even though antenna has a circular patch, it doesn’t always produce circular polarization. From the simulation, we found that with add some structure, the antenna can reach multiband resonance from 1 to 6 GHz. The Circular patch antenna reached seven numbers of the multiband resonance frequency. The hexagonal patch antenna reaches the highest directivity as 9.53 dBi. The circular polarization is achieved for a square and Hexagonal patch shape with axial ratio value is 1.96 dB at 4 GHz and 1.26 dB at 4.1 GHz sequentially at phi 900 and theta 900.

Beyond range size: drivers of species’ geographic range structure in European plants

AimTo assess if and how species’ range size relates to range structure, if the observed geographic range properties can be retrieved from predicted maps based on species distribution modeling, and whether range properties are predictable from biogeophysical factors.LocationEuropeTime periodCurrentMajor taxa studied813 vascular plant species endemic to EuropeMethodsWe quantified the size and spatial structure of species’ geographic ranges and compared ranges currently occupied with those predicted by species distribution models (SDMs). SDMs were constructed using complete occurrence data from the Atlas Florae Europaeae and climatic, soil and topographic predictors. We used landscape metrics to characterize range size, range division and patch shape structure, and analysed the phylogenetic, geographic and ecological drivers of species’ range size and structure using phylogenetic generalized least squares (pGLS).ResultsRange structure metrics were mostly decoupled from species’ range size. We found large differences in range metrics between observed and predicted ranges, in particular for species with intermediate observed range size and occupied area, and species with low and high observed patch size distribution, geographic range filling, patch shape complexity and geographic range fractality. Elevation heterogeneity, proximity to continental coasts, Southerly or Easterly geographic range positions and narrow ecological niche breadth constrained species’ observed range size and range structure to different extents. The strength and direction of the relationships differed between observed and predicted ranges.Main conclusionsSeveral range structure metrics, in addition to range size, are needed to adequately describe and understand species’ ranges. Species’ range structure can be well explained by geophysical factors and species niche width, albeit not consistently for observed and predicted ranges. As range structure can have important ecological and evolutionary consequences, we highlight the need to develop better predictive models of range structure than provided by current SDMs, and we identify the kinds of species for which this is most necessary.

Physical Understanding of Transient Generation of Tire Lateral Force and Aligning Torque

ABSTRACT Increasing vehicle performance requirements and virtualization of the development process require more understanding of the physical background of tire behavior, especially in transient rolling conditions with combined slip. The focus of this research is the physical description of the transient generation of tire lateral force and aligning torque. Apart from tire force and torque measurements, two further issues were investigated experimentally. Using acceleration measurement on the tire inner liner, it was observed that the contact patch shape of the rolling tire changes nonlinearly with slip angle and becomes asymmetric. Optical measurement outside and inside the tire has clarified that carcass lateral bending features both shear and rotation angle of its cross sections. A physical simulation model was developed that considers the observed effects. The model was qualitatively validated using not only tire force and torque responses but also deformation of the tire carcass. The model-based analysis explained which tire structural parameters are responsible for which criteria of tire performance. Change in the contact patch shape had a low impact on lateral force and aligning torque. Variation of carcass-bending behavior perceptibly influenced aligning torque generation.

Simulation and experiment on the effect of patch shape on adhesive repair of composite structures

In order to investigate the performance of the adhesive bonding repair in composite structures, static tensile test is carried out on the bonding structures numerically and experimentally. The tensile stress–displacement behaviors of T7901 composite adhesive bonding structure is studied under room temperature. Based on the three-dimensional progressive damage theory, the model of adhesive bonding structures with different patch shape has been constructed, and the final failure strength is predicted using APDL language. Moreover, experiment has been performed on each adhesive bonding structure with different patch shape. The results indicate a good agreement with numerical predictions. Furthermore, it is found that the repair effect of the adhesive bonding structure with the square patch is better than others. The final damage pattern and damage range of the patch repair structure are also tested by X-ray machine, which are consistent with the simulation results.