IPAS - Installed Performance of Antennas on Aero Structures
Overview
Background & policy context:
Currently, the implementation process for installing antennas on aircraft results in high costs and long timescales. There are errors in the coupling calculations used to obtain isolation between antennas on opposite sides of the fuselage, the design phase uses unverified computational modelling and there is a frequency gap in the computational software used. Scaled model measurements used to bridge this gap are expensive and time consuming. In-flight trials have severe limitations and the erroneous siting of antennas results in massive time and cost implications to the whole programme.
Objectives:
The purpose of the programme was to improve computer-aided engineering design and evaluation capabilities (computational and measurement methods) for the installation of antennas on aircraft structures. This was to be achieved by bridging the frequency gap in computational electromagnetic tools using refined hybrid and multi-domain methods and the development of fast solver methods for solving full-wave integral equation methods in the frequency domain.
The performance of antennas on non-metallic and hybrid materials such as GLARE were investigated and more accurate coupling calculations based on measurements were derived empirically. This led to an improved prediction of performance of antennas and interoperability, with consequent contributions to operational safety and on-board Internet access.
The feasibility of radiation pattern measurements on full-scale aircraft using an innovative airborne platform were investigated. This is based on near-to-far-field transformations adapted to cope with irregular spatial sampling.
Methodology:
There were five technical Work Packages consisting of:
- Characterisation of antenna data.
- Improvements in computational tools, which including hybridisation (of low and high-frequency codes), multidomain, Fast Multipole methods, asymptotic techniques, application to hybrid structures.
- Verification of tools through measurements on flat panels, metal cylindrical tubes and scaled aircraft models, as well as verification of inverse methods for use in the validation of the ANTF (airborne near field facility). Additionally, empirical formulas were derived for more accurate calculations of the coupling between antennas and a CAD cleaning tool developed for reducing the number of wire segments (and hence the CPU time) for MoM tools.
- Full-scale measurements and modelling on real aircraft or full-scale mock-ups.
- Production of codes of practice for the design and qualification phases of antenna siting on aerostructures.
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