Conformal phased array with beam forming for airborne satellite communication

For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. To this end, phased array antennas which are conformal to the aircraft fuselage are attractive. In this paper two key aspects of conformal phased array antenna arrays are addressed: the development of a broadband Ku-band antenna and the beam synthesis for conformal array antennas. The antenna elements of the conformal array are stacked patch antennas with dual linear polarization which have sufficient bandwidth. For beam forming synthesis a method based on a truncated Singular Value Decomposition is proposed

Canine and human gastrointestinal stromal tumors display similar mutations in c-KIT exon 11

<p>Abstract</p> <p>Background</p> <p>Gastrointestinal stromal tumors (GISTs) are common mesenchymal neoplasms in the gastrointestinal tract of humans and dogs. Little is known about the pathogenesis of these tumors. This study evaluated the role of <it>c-KIT </it>in canine GISTs; specifically, we investigated activating mutations in exons 8, 9, 11, 13, and 17 of <it>c-KIT </it>and exons 12, 14, and 18 of platelet-derived growth factor receptor, alpha polypeptide (<it>PDGFRA</it>), all of which have been implicated in human GISTs.</p> <p>Methods</p> <p>Seventeen canine GISTs all confirmed to be positive for KIT immunostaining were studied. Exons 8, 9, 11, 13 and 17 of <it>c-KIT </it>and exons 12, 14, and 18 of <it>PDGFRA</it>, were amplified from DNA isolated from formalin-fixed paraffin-embedded samples.</p> <p>Results</p> <p>Of these seventeen cases, six amplicons of exon 11 of <it>c-KIT </it>showed aberrant bands on gel electrophoresis. Sequencing of these amplicons revealed heterozygous in-frame deletions in six cases. The mutations include two different but overlapping six base pair deletions. Exons 8, 9, 13, and 17 of <it>c-KIT </it>and exons 12, 14, and 18 of <it>PDGFRA </it>had no abnormalities detected by electrophoresis and sequencing did not reveal any mutations, other than synonymous single nucleotide polymorphisms (SNPs) found in exon 11 of <it>c-KIT </it>and exons 12 and 14 of <it>PDGFRA</it>.</p> <p>Conclusions</p> <p>The deletion mutations detected in canine GISTs are similar to those previously found in the juxtamembrane domain of <it>c-KIT </it>in canine cutaneous mast cell tumors in our laboratory as well as to those reported in human GISTs. Interestingly, none of the other <it>c-KIT </it>or <it>PDGFRA </it>exons showed any abnormalities in our cases. This finding underlines the critical importance of <it>c-KIT </it>in the pathophysiology of canine GISTs. The expression of KIT and the identification of these activating mutations in <it>c-KIT </it>implicate KIT in the pathogenesis of these tumors. Our results indicate that mutations in <it>c-KIT </it>may be of prognostic significance and that targeting KIT may be a rational approach to treatment of these malignant tumors. This study further demonstrates that spontaneously occurring canine GISTs share molecular features with human GISTs and are an appropriate model for human GISTs.</p

Mobilise-D insights to estimate real-world walking speed in multiple conditions with a wearable device

This study aimed to validate a wearable device’s walking speed estimation pipeline, considering complexity, speed, and walking bout duration. The goal was to provide recommendations on the use of wearable devices for real-world mobility analysis. Participants with Parkinson’s Disease, Multiple Sclerosis, Proximal Femoral Fracture, Chronic Obstructive Pulmonary Disease, Congestive Heart Failure, and healthy older adults (n = 97) were monitored in the laboratory and the real-world (2.5 h), using a lower back wearable device. Two walking speed estimation pipelines were validated across 4408/1298 (2.5 h/laboratory) detected walking bouts, compared to 4620/1365 bouts detected by a multi-sensor reference system. In the laboratory, the mean absolute error (MAE) and mean relative error (MRE) for walking speed estimation ranged from 0.06 to 0.12 m/s and − 2.1 to 14.4%, with ICCs (Intraclass correlation coefficients) between good (0.79) and excellent (0.91). Real-world MAE ranged from 0.09 to 0.13, MARE from 1.3 to 22.7%, with ICCs indicating moderate (0.57) to good (0.88) agreement. Lower errors were observed for cohorts without major gait impairments, less complex tasks, and longer walking bouts. The analytical pipelines demonstrated moderate to good accuracy in estimating walking speed. Accuracy depended on confounding factors, emphasizing the need for robust technical validation before clinical application. Trial registration: ISRCTN – 12246987

De lezer schrijft : van braakliggende grond naar bijenweide

Een flatbewonende imker wil zijn volkstuin gebruiken voor het plaatsen van bijenkasten en het kweken van drachtplanten, en beschrijft zijn ervaringen met de toepassing van borage, bladrammenas en phacelia als groenbemesters, onkruidonderdrukkers en drachtplante

Structural Integration of a Ku-band SatCom Antenna into Novel Fuselage Panel

This paper addresses the structural integration of a Ku-band SATCOM antenna in the fuselage of an aircraft. The phased array antenna consists of 25 antenna tiles that are integrated in an orthogrid fuselage panel. The specific electromagnetic aspects of the antenna integration will be discussed in this paper; this concerns the lightning protection of the antenna tiles and the electromagnetic interaction of the CFRP orthogrid and GFRP fuselage skin with the array antenna. The structural properties and thermal management of the antenna will be discussed in separate papers [1,2,3]

Broadband optical beam forming for airborne phased array antenna

For enhanced communication on board aircraft, novel antenna systems with broadband satellite-based capabilities are required. The technology will enhance airline operations by providing in-flight connectivity for flight crew information and will bring live TV and high-speed Internet connectivity to passengers. The installation of such systems on board aircraft requires for aerodynamic reasons the development a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. Major keystones for the success of steerable low-profile antennas are multi-layer printed circuit boards (PCBs) with an array of broadband antenna elements, and compact micro-wave systems with appropriate beam steering capabilities. The present paper describes the development of a prototype 8times1 optical beam forming network using cascades of optical ring resonators as part of a breadboard Ku-band phased array antenna

On-chip microwave photonic beamformer circuits operating with phase modulation and direct detection

We propose and experimentally demonstrate the working principles of two novel microwave photonic (MWP) beamformer circuits operating with phase modulation (PM) and direct detection (DD). The proposed circuits incorporate two major signal processing functionalities, namely a broadband beamforming network employing ring resonator-based delay lines and an optical sideband manipulator that renders the circuit outputs equivalent to those of intensity-modulated MWP beamformers. These functionalities allow the system to employ low-circuit-complexity modulators and detectors, which brings significant benefits on the system construction cost and operation stability. The functionalities of the proposed MWP beamformer circuits were verified in experimental demonstrations performed on two sample circuits realized in Si3N4/SiO2 waveguide technology. The measurements exhibit a 2 × 1 beamforming effect for an instantaneous RF transmission band of 3‒7 GHz, which is, to our best knowledge, the first verification of on-chip MWP beamformer circuits operating with PM and DD

Dual-frequency phased array antennas with optical beamforming for airborne satellite communication

For enhanced communication on board of aircraft, novel antenna systems with broadband satellite-based capabilities are required. So far existing L-band satellite based systems for communications are used primarily for passenger application (APC) or administrative communications (AAC); initially analogue voice and now data are tending to evolve towards broadband digital applications. Many studies are going on worldwide to employ Ku-band TV geostationary satellites for communication with mobile terminals on aircraft. For a short period broadband internet was available on aircraft via Connexion by Boeing (CBB) services. Lufthansa installed the CBB system on some of their long-haul aircraft. In the EC Sixth Framework Programme ANASTASIA (Airborne New and Advanced Satellite techniques and Technologies in A System Integrated Approach) existing and planned aeronautical SATCOM services, systems and technology have been analysed. It has been concluded that for cockpit services, L-band systems (namely Inmarsat, MTSAT, Iridium and Globalstar) are clearly most suitable, whilst Ku-band systems have appeal for passenger service

Development of the SANDRA antenna for airborne satellite communication

Novel avionics communication systems are required for increasing flight safety and operational integrity, for optimizing economy of operations and for enhancing passenger services. One of the key technologies to be developed is an antenna system that will provide broadband connectivity within aircraft cabins at an affordable price. This paper describes the development of an electronically steered Ku-band phased array antenna with low aerodynamic profile. The antenna front-end consists of at least 1800 antenna elements, of which the beam has to be steered continuously to geostationary satellites. Best performance for the beam steering is expected from a hybrid architecture with small sub-apertures having their local own beamformers (using phase shifters). The beamformer to steer the sub-apertures of the entire antenna uses True Time Delays with an optical ring resonator

Towards a broadband and squint-free ku-band phased array antenna system for airborne satellite communications

In this paper, we describe the design and the development of a Ku-band phased array antenna system for the reception of a digital video broadcasting by satellite (DVB-S)signal. A concept of optical beamforming is implemented to provide a squint-free beam steering over the entire Ku-band (10.7-12.75 GHz) as well as to achieve seamless tunability of the beam pointing direction. The total antenna system is described and the system performance is simulated. Requirements for system components are formulated and the development of these components towards the implementation of the broadband, squint-free phased array antenna system is reported