This project is to develop a low cost, ultra-low profile antenna which can be used as part of a tracking antenna system to receive direct TV satellite broadcast signals on a vehicle "on-the-move" for the US market. ERA has developed a unique technology which makes it possible to mechanically vary the width of a low loss waveguide. The antenna developed in this project uses an array of these waveguides, each of which includes a longitudinal radiating slot in one broad wall. The direction from which energy is received by these waveguides can be varied in one plane, without the use of electronic phase shifters, by mechanically reconfiguring the antenna without affecting its height. This technology, for which a patent application is in place, makes it possible to realise a very low cost scanning antenna. The project includes the design and demonstration of a prototype antenna and the manufacture and demonstration of pre-production parts manufactured using high volume, low cost manufacturing techniques based on metallised injection moulded plastic parts.|
click for larger image
Radome Horn plate Radiating plate Scanning plate Base plate Polariser The antenna will consist of a number of radiating lines combined using a waveguide beamformer, as shown in block diagram form below. The antenna uses 16 lines, each of which has a slot radiating into a sectoral horn. A square, three layer meander line polariser covers the whole antenna which can be rotated through 90° to realise one or other of the two hands of circular polarisation.
Antenna Block Diagram
click for larger image The basic antenna is formed from four metallised plastic plates. The base plate interfaces between the main antenna components and the positioner. The moving plate contains a series of "half waveguides". The slot plate consists of the second set of "half waveguides", and will include the radiating slots. A separate flare plate is used to form the sectoral horns, since mouldings must use a constant wall thickness throughout to prevent material shrinkage. The complete antenna is enclosed in a static radome which forms an integral part of the polariser design. The moving plate moves laterally with respect to the rest of the antenna in order to achieve the required scan angle in elevation using a simple mechanical actuator. No other electronic components (ie phase shifters) are required.
click for larger image
The project started in 2002 and will be completed in September 2004.
The project has addressed the following issues:
Use of high volume, low cost production technologies for high performance antennas
- Development of mechanically actuated low profile scanning antenna with the performance of a phased array and a price 1-2 orders of magnitude less than an equivalent phased array
- Development of mechanically actuated low profile scanning antenna with better performance and at least equivalent profile when compared to any other competing low profile scanning antenna
- Direct development of a cost-effective European-designed low profile scanning antenna which can compete against US-manufactured products in the US automotive market
- Application of production processes and technologies that can be applied to other antenna concepts and provide cost-effective production solutions
- Created a platform for the future exploitation of cost-effective European-designed low profile scanning antenna technologies in a wide range of other commercial and defence applications
The project Final Presentation will be at ESTEC on 23rd September 2004. Sales of production antennas are expected to start before the end of 2004.
Last Update: 13 Dec 2007