10 research outputs found
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
Design of a ring resonator-based optical beam forming network for phased array receive antennas
A novel squint-free ring resonator-based optical beam forming network (OBFN) for phased array antennas (PAA) is proposed. It is intended to provide broadband connectivity to airborne platforms via geostationary satellites. In this paper, we present the design of the OBFN and its control system. Our goal is to deliver large bandwidth Ku-band connectivity between antennas, mount conformal to the airplane fuselage and on a geostationary satellite, respectively.This way it would be possible to bring live DVB-S television to airplane passengers. In this paper, we present recent research conducted on a 4 Ă— 1 ring resonator-based OBFN test set-up. This OBFN has four optical input ports and one optical output port. It is tuned to provide the desired signal combination with optimal constructive interference between the modulated input signals from the PAA. Therefore, combining circuitry and delay elements are required. The OBFN is tuned by electrically heating tunable true time delay (TTD) elements. These are built using optical ring resonators (ORRs). By cascading multiple ORRs with different resonance frequencies, it is possible to create a TTD with a large bandwidth. Optical beam forming is used because it provides advantages over traditional beam forming methods. These advantages are: large bandwidth, EMI resistance, and, when integrated onto a single chip, compactness and low costs. The OBFN is created using planar optical waveguide technology and consists of the following building blocks: waveguides, Mach-Zehnder interferometers, (MZIs) couplers and ORRs. The tuning of the OBFN is done by an electronic control system using a microcontroller. Communication with a PC is possible using USB. To our knowledge, this is the first integrated ORR-based OBFN circuit for PAA satellite reception
Alertness, movement, and affective behaviour of people with profound intellectual and multiple disabilities (PIMD) on introduction of a playful interactive product:Can we get your attention?
Background: New technology may stimulate active leisure activities for people with profound intellectual and multiple disabilities (PIMD). We conducted a study of an interactive ball that responded to gross body movement, focus of attention, and vocalisations of users with PIMD. The aim was to increase alertness and body movement and elicit more expressions of positive, or fewer of negative affect.Method: Nine participants with PIMD played during 8–10 sessions. The movement was analysed automatically. Alertness and affective behaviour were coded manually. We analysed the last 5 sessions for each participant and compared 15 min of interaction with 15 min of rest.Results: Clearly positive effects were seen for three participants. Effects were seen in the unexpected direction for four participants. No strong effects were found for the remaining three participants.Conclusions: Interactive technologies may provide suitable activities for people with PIMD but individual differences play an important role
Autonomy in participation in cerebral palsy from childhood to adulthood
Aim: To determine the long-term development of autonomy in participation of individuals with cerebral palsy (CP) without intellectual disability. Method: Individuals with CP (n=189, 117 males, 72 females; mean age [SD] 21y 11mo [4y 11mo], range 12–34y); were assessed cross-sectionally (46%) or up to four times (54%), between the ages of 12 and 34 years. Autonomy in participation was classified using phase 3 of the Rotterdam Transition Profile. A logistic generalized estimating equation regression model was used to analyse autonomy in six domains (independent variables: age, Gross Motor Function Classification System [GMFCS] level, and interaction between age and GMFCS level). Proportions of autonomy were compared to references using binomial tests (p<0.05). Results: In most domains, over 90% of participants (n=189, 400 observations, 80% in GMFCS levels I and II) reached autonomy in participation in their late twenties, except for intimate/sexual relationships. Those in GMFCS levels III to V compared to those in GMFCS levels I and II had less favourable development of autonomy in the transportation, intimate relationships, employment, and housing domains, and more favourable development in the finances domain. Compared to references, fewer individuals with CP were autonomous in participation. Interpretation: This knowledge of autonomy may guide the expectations of young people with CP and their caregivers. Furthermore, rehabilitation professionals should address autonomy development in intimate relationships, employment, and housing, especially in individuals with lower gross motor function. What this paper adds: Individuals with cerebral palsy without intellectual disability achieved autonomy in most participation domains. Regarding intimate relationships, they continued to have less experience compared to age-matched references. Development of autonomy was less favourable for individuals in Gross Motor Function Classification System levels III to V
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
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