Low-Profile Wideband Antenna Arrays for Mobile Satellite and 5G Communication

Three innovative low-profile antenna arrays are designed and tested for vehicular satellite and 5G communication. All of the systems presented target key challenges of GEO, LEO and 5G communication. Each design provides a high level of performance for the given application in a far more compact and lower cost design than existing systems.Firstly, a wideband curl antenna array is developed to enable L-band GEO satellite communication for emergency vehicles. This novel 1×3 rotated array utilises a hybrid switch beam and phase shifting technique to enable full beamforming down to 70° in all directions with 40% lower cost than standard phased array systems. Uniquely, this provides excellent azimuth beam steering at low angles from a linear array. This system also utilises a high impedance surface to reduce the height of the antenna elements by 50% compared to existing curl antenna designs.Secondly, a shared aperture antenna array is developed to enable Ka-band LEO satellite communication for vehicular integration. This system utilise a new combination of circular polarised triangular antennas in an interlaced planar triangular lattice such that the topology provides optimal tessellation. As a result, the system provides high performance beam steering and reconfigurable circular polarisation in a highly compact design. This array has been developed such that it is suitable for common PCB manufacturing methods. Unlike existing shared aperture arrays for LEO terminals, this topology enables reconfigurable circular polarisation in a single, planar PCB structure.Finally, a low-cost wideband compressed spiral antenna array is designed and fabricated for global 5G ground-to-air communication for aircraft. An innovative spiral antenna optimisation is presented where the spiral is highly compressed such that it can provide an axial beam over a wide bandwidth while maintaining a lower profile than existing wideband solutions

A Circularly Polarized Low-Cost Flat Panel Antenna Array With a High Impedance Surface Meta-Substrate for Satellite On-the-Move Medical IoT Applications

A 1×3 linear antenna array consisting of Quad-Arm Curl antenna with a High impedance meta-surface (QACH) is presented. We believe that it is the first linear phased array solution which can provide 360° azimuth coverage. This array has been designed to operate at L-Band (1.518 - 1.675 GHz) and generate right hand circularly polarized radiation to primarily target the Inmarsat BGAN satellite constellation. The metamaterial structure integrated into each antenna element allows a low-profile height of 17.2 mm (λ1.597/10.9). Since the curl element has wideband characteristics, the array is able to provide shared aperture functionality. The array guarantees high gain beam steering for low elevation angles (up to θ = 70° from the zenith) with an average gain of 7.96 dBic at θ = 70°. In comparison, to achieve an equivalent high gain a conventional 4×5 patch array would be required (3 elements vs 20 elements). This means that the proposed array requires 80% fewer phase shifters, amplifiers and LNAs. This translates to a crucial commercial advantage in relation to manufacturing cost. This development can lead to disruption of the existing Satcom market by lowering the barrier-to-entry for customers looking for a mass deployable, low-cost IoT on Satcom solution

MicroRNA-regulated pathways of flow-stimulated angiogenesis and vascular remodeling in vivo

Background: Vascular shear stress promotes endothelial cell sprouting in vitro. The impact of hemodynamic forces on microRNA (miRNA) and gene expression within growing vascular networks in vivo, however, remain poorly investi‑ gated. Arteriovenous (AV) shunts are an established model for induction of neoangiogenesis in vivo and can serve as a tool for analysis of hemodynamic efects on miRNA and gene expression profles over time. Methods: AV shunts were microsurgically created in rats and explanted on postoperative days 5, 10 and 15. Neoan‑ giogenesis was confrmed by histologic analysis and micro-computed tomography. MiRNA and gene expression pro‑ fles were determined in tissue specimens from AV shunts by microarray analysis and quantitative real-time polymer‑ ase chain reaction and compared with sham-operated veins by bioinformatics analysis. Changes in protein expression within AV shunt endothelial cells were determined by immunohistochemistry. Results: Samples from AV shunts exhibited a strong overexpression of proangiogenic cytokines, oxygenationassociated genes (HIF1A, HMOX1), and angiopoetic growth factors. Signifcant inverse correlations of the expressions of miR-223-3p, miR-130b-3p, miR-19b-3p, miR-449a-5p, and miR-511-3p which were up-regulated in AV shunts, and miR-27b-3p, miR-10b-5p, let-7b-5p, and let-7c-5p, which were down-regulated in AV shunts, with their predicted interacting targets C–X–C chemokine receptor 2 (CXCR2), interleukin-1 alpha (IL1A), ephrin receptor kinase 2 (EPHA2), synaptojanin-2 binding protein (SYNJ2BP), forkhead box C1 (FOXC1) were present. CXCL2 and IL1A overexpression in AV shunt endothelium was confrmed at the protein level by immunohistochemistry. Conclusions: Our data indicate that fow-stimulated angiogenesis is determined by an upregulation of cytokines, oxygenation associated genes and miRNA-dependent regulation of FOXC1, EPHA2 and SYNJ2BP

MicroRNA-regulated pathways of flow-stimulated angiogenesis and vascular remodeling in vivo

Background: Vascular shear stress promotes endothelial cell sprouting in vitro. The impact of hemodynamic forces on microRNA (miRNA) and gene expression within growing vascular networks in vivo, however, remain poorly investigated. Arteriovenous (AV) shunts are an established model for induction of neoangiogenesis in vivo and can serve as a tool for analysis of hemodynamic effects on miRNA and gene expression profiles over time. Methods: AV shunts were microsurgically created in rats and explanted on postoperative days 5, 10 and 15. Neoangiogenesis was confirmed by histologic analysis and micro-computed tomography. MiRNA and gene expression profiles were determined in tissue specimens from AV shunts by microarray analysis and quantitative real-time polymerase chain reaction and compared with sham-operated veins by bioinformatics analysis. Changes in protein expression within AV shunt endothelial cells were determined by immunohistochemistry. Results: Samples from AV shunts exhibited a strong overexpression of proangiogenic cytokines, oxygenation-associated genes (HIF1A, HMOX1), and angiopoetic growth factors. Significant inverse correlations of the expressions of miR-223-3p, miR-130b-3p, miR-19b-3p, miR-449a-5p, and miR-511-3p which were up-regulated in AV shunts, and miR-27b-3p, miR-10b-5p, let-7b-5p, and let-7c-5p, which were down-regulated in AV shunts, with their predicted interacting targets C–X–C chemokine receptor 2 (CXCR2), interleukin-1 alpha (IL1A), ephrin receptor kinase 2 (EPHA2), synaptojanin-2 binding protein (SYNJ2BP), forkhead box C1 (FOXC1) were present. CXCL2 and IL1A overexpression in AV shunt endothelium was confirmed at the protein level by immunohistochemistry. Conclusions: Our data indicate that flow-stimulated angiogenesis is determined by an upregulation of cytokines, oxygenation associated genes and miRNA-dependent regulation of FOXC1, EPHA2 and SYNJ2BP

A low-profile wideband compressed single-arm spiral antenna array for mid-band 5G beam steering applications.

A low profile wideband spiral antenna array is presented for global mid-band 5G beam steering applications. In the global rollout of mid-band 5G, different frequencies have been licensed within each region (e.g. 3.4-3.8 GHz in the EU and 3.7-5 GHz in the USA). Therefore, antenna arrays must be able to cover a bandwidth of 3.3 GHz to 5 GHz to provide true global coverage. Initially, this work presents the design of a wideband compressed spiral antenna that provides an axial beam throughout its operational bandwidth of 3.3 GHz to 5 GHz, enabling beam steering functionality. Then, this antenna has been placed in a 4 × 4 array with a triangular lattice. The proposed spiral antenna array can provide a scanning range of - 40° ≤ θ ≤  + 40° in all azimuth directions with an average back lobe level of less than - 9.5 dB. This development will allow for low-cost integration of 5G systems for global use, such as passenger aircraft, UAVs, drones, and marine and ground vehicles

Decarbonisation and its discontents: a critical energy justice perspective on four low-carbon transitions

Low carbon transitions are often assumed as normative goods, because they supposedly reduce carbon emissions, yet without vigilance there is evidence that they can in fact create new injustices and vulnerabilities, while also failing to address pre-existing structural drivers of injustice in energy markets and the wider socio-economy. With this in mind, we examine four European low-carbon transitions from an unusual normative perspective: that of energy justice. Because a multitude of studies looks at the co-benefits renewable energy, low-carbon mobility, or climate change mitigation, we instead ask in this paper: what are the types of injustices associated with low-carbon transitions? Relatedly, in what ways do low-carbon transitions worsen social risks or vulnerabilities? Lastly, what policies might be deployed to make these transitions more just? We answer these questions by first elaborating an “energy justice” framework consisting of four distinct dimensions—distributive justice (costs and benefits), procedural justice (due process), cosmopolitan justice (global externalities), and recognition justice (vulnerable groups). We then examine four European low-carbon transitions—nuclear power in France, smart meters in Great Britain, electric vehicles in Norway, and solar energy in Germany—through this critical justice lens. In doing so, we draw from original data collected from 64 semi-structured interviews with expert partisans as well as five public focus groups and the monitoring of twelve internet forums. We document 120 distinct energy injustices across these four transitions, including 19 commonly recurring injustices. We aim to show how when low-carbon transitions unfold, deeper injustices related to equity, distribution, and fairness invariably arise

Cross-validation in cryo-EM-based structural modeling

Single-particle cryo-electron microscopy (cryo-EM) is a powerful approach to determine the structure of large macromolecules and assemblies thereof in many cases at subnanometer resolution. It has become popular to refine or flexibly fit atomic models into density maps derived from cryo-EM experiments. These density maps are typically significantly lower in resolution than electron density maps obtained from X-ray diffraction experiments, such that the number of parameters that need to be determined is much larger than the number of experimental observables. Overfitting and misinterpretation of the density, thus, becomes a serious problem. For diffraction data a cross-validation approach has been introduced almost twenty years ago, however, no such approach has been described yet for structure refinement against cryo-EM density maps, even though the overfitting problem is, due to the lower resolution, significantly larger. We present a cross-validation approach for real-space refinement against cryo-EM density maps in analogy to cross-validation typically used in crystallography. Our approach is able to detect overfitting and allows for optimizing the choice of restraints used in the refinement. The approach is demonstrated on three protein structures with simulated data and on experimental data of the rotavirus double-layer particle. Since cross-validation requires splitting the data set into at least two independent sets, we further present an approach to quantify correlations between the structure factor sets. This analysis is also helpful for other cross-validation applications, such as refinements against diffraction data or 3D reconstructions of cryo-EM density maps

Energy policy and climate change

This chapter offers an overview of the nexus between energy policy and climate change, surveys barriers to low-carbon technologies, discusses solutions and mechanisms that can overcome those barriers, and concludes with some reflections on the implications of recent research for global policy