Development of a broadband and squint-free Ku-band phased array antenna system for airborne satellite communications

Novel avionic communication systems are required for various purposes, for example to increase the flight safety and operational integrity as well as to enhance the quality of service to passengers on board. To serve these purposes, a key technology that is essential to be developed is an antenna system that can provide broadband connectivity within aircraft cabins at an affordable price. Currently, in the European Commission (EC) 7th Framework Programme SANDRA project (SANDRA, 2011), a development of such an antenna system is being carried out. The system is an electronically-steered phased-array antenna (PAA) with a low aerodynamic profile. The reception of digital video broadcasting by satellite (DVB-S) signal which is in the frequency range of 10.7-12.75 GHz (Ku-band) is being considered. In order to ensure the quality of service provided to the passengers, the developed antenna should be able to receive the entire DVB-S band at once while complying with the requirements of the DVB-S system (Morello & Mignone, 2006). These requirements, as will be explained later, dictate a broadband antenna system where the beam is squint-free, i.e. no variation of beam pointing direction for all the frequencies in the desired band. Additionally, to track the satellite, the seamless tunability of the beam pointing direction of this antenna is also required. In this work, a concept of optical beamforming (Riza & Thompson, 1997) is implemented to provide a squint-free beam over the entire Ku-band for all the desired pointing directions. The optical beamformer itself consists of continuously tunable optical delay lines that enable seamless tunability of the beam pointing direction

Architectures for ku-band broadband airborne satellite communication antennas

This paper describes different architectures for a broadband antenna for satellite communication on aircraft. The antenna is a steerable (conformal) phased array antenna in Ku-band (receive-only). First the requirements for such a system are addressed. Subsequently a number of potential architectures are discussed in detail: a) an architecture with only optical true time delays, b) an architecture with optical phase shifters and optical true time delays and c) an architecture with optical true time delays and RF phase\ud shifters (or RF true time delays). The last two architectures use sub-arrays to reduce complexity of the antenna system. The advantages and disadvantages of the different architectures are evaluated and an optimal architecture is selected

VHF Antenna Integrated into a Classical Fibre Metal Laminate Fuselage Panel

Replacement of protruding antennas by integrated alternatives will reduce the energy consumption and NOx and CO2 emissions of an aircraft. This paper proposes and integrated VHF cavity backed slot antenna that is suitable to replace blade antennas. To reduce the size of the cavity a parallel plate resonator is used. The slot is integrated into a fibre metal laminate fuselage panel. A bookleafing principle is used to reinforce the panel at the position of the slot, making sure the material quality is not reduced. Measurement results of a demonstrator antenna show the feasibility of the proposed antenna. Moreover, the paper discusses several electromagnetic and structural design trade-offs for this integrated antenna

GNSS Antenna Integrated into a Classical Fibre Metal Laminate Fuselage Panel

Fibre Metal Laminate materials, like Glass Laminate Aluminum Reinforced Epoxy (GLARE), provide a unique opportunity to integrate patch antennas directly into the fuselage of aircraft. This integration will contribute to the reduction of carbon emissions of aircraft due to the reduction of aerodynamic drag. This paper discusses the integration of a double patch GNSS antenna directly into a classical Fiber Metal Laminate. A demonstrator of the antenna was manufactured and measured. The antenna has a flush finish on the outside of the fuselage. The preliminary results of these measurements show promising antenna performance, but more measurements are required to fully characterize this integrated antenna

RF Analyses of Integrated Ku-band Antenna

In the ACASIAS project an integrated antenna for Ku-band satellite communication has been developed. The design of this integrated antenna has to meet structural, electromagnetic and thermal requirements. This paper addresses the electromagnetic performance of the antenna both by design and by measurement. For the design of the antenna, the electromagnetic interaction of the antenna with the conducting Carbon Fibre Reinforced Plastic (CFRP) ribs of the orthogrid and the interaction with the Glass Fibre Reinforced Plastic (GFRP) skin of the panel have been analysed. In addition, the influence of potential lightning diverters on the antenna performance has been analysed. The radiation pattern of a single antenna tile and the radiation pattern of an antenna tile integrated in the orthogrid fuselage panel were measured. The results of the antenna measurements are compared with the results of the simulations carried out for the design of the antenna

Novel ring resonator-based integrated photonic beamformer for broadband phased array receive antennas - part I: design and performance analysis

A novel optical beamformer concept is introduced that can be used for seamless control of the reception angle in broadband wireless receivers employing a large phased array antenna (PAA). The core of this beamformer is an optical beamforming network (OBFN), using ring resonator-based broadband delays, and coherent optical combining. The electro-optical conversion is performed by means of single-sideband suppressed carrier modulation, employing a common laser, Mach-Zehnder modulators, and a common optical sideband filter after the OBFN. The unmodulated laser signal is then re-injected in order to perform balanced coherent optical detection, for the opto-electrical conversion. This scheme minimizes the requirements on the complexity of the OBFN, and has potential for compact realization by means of full integration on chip. The impact of the optical beamformer concept on the performance of the full receiver system is analyzed, by modeling the combination of the PAA and the beamformer as an equivalent two-port RF system. The results are illustrated by a numerical example of a PAA receiver for satellite TV reception, showing that—when properly designed—the beamformer hardly affects the sensitivity of the receiver

Towards structural integration of airborne Ku-band SatCom antenna

The paper describes research towards a fully structurally integrated Ku-band SatCom antenna. This antenna covers the complete receive band for aeronautical earth stations and DVB-S broadcast in Ku band (10.7 - 12.75 GHz). The antenna front-end consists of 32 tiles where each tile has 8×8 Ku-band stacked patch antenna elements. Optical True Time Delays (TTDs) in an Optical Beam Forming Network (OBFN) enable a squint free beam steering over the whole band to geostationary satellites. The Ku-band antenna itself covers the whole frequency band in input impedance matching and radiation pattern. The performance of a Ku-band antenna tile will be discussed. A design is presented for the structural integration of 32 tiles and the associated optical beam forming networks into a fuselage panel of an aircraft

Multifunctional Structures to Reduce the Energy Consumption of Future Aircraft with Integrated Ku-Band Antennas

The CO2 and NOX emissions of international air traffic must be reduced, making aviation more sustainable, requiring innovative technologies that reduce aircraft fuel consumption. The Horizon 2020 ACASIAS project takes up this challenge by improving aerodynamic performance and facilitating fuel-efficient engines such as Counter-Rotating Open Rotors (CROR). ACASIAS improves the aerodynamics through the conformal and structural integration of antennas into innovative aerostructures. Nowadays, installed aircraft antennas are protruding structures that generate turbulence and aerodynamic drag, thus increasing the fuel consumption, i.e. currently available Ku-band satellite antennas still require exterior installation on the fuselage. Hence, the conformal flush integration of a Kuband SATCOM antenna will reduce the drag, as well as CO2 and NOX emissions. Furthermore, ACASIAS will also reduce maintenance costs and minimise operational delays through structurally integrated antennas, reducing the risk of damage to protruding antennas

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