8Outlook
All partners benefited from the DenseTraffic project, but obviously RoadEye benefited the most because of its role of coordinator and integrator of the FLR sensor.
ERA had the opportunity to further expand their knowledge base by developing a 77GHz multi-beam antenna based in previous molded plastic technology. Together with RoadEye, this antenna was implemented in molded Magnesium.
UMS also expanded their 77GHz MMIC’s design and production capabilities by adding two MMIC’s to their chip catalog. UMS also utilized the additional experience to implement new chip designs and packaging that should drastically reduce the cost in mass production.
EADS benefited by the opportunity to develop a very complex multi-channel RF module at 77GHz. They also developed the necessary waveform generation circuitry.
Groeneveld Groep, as principal shareholder of RoadEye FLR GP profited from the involvement in the marketing of a new safety product.
9Conclusions
DenseTraffic has been a successful project from all points of view. The partners have been able to develop technologies that not only can improve their business but also that have, synergistically contributed to the well being of the population at large and specifically the reduction of traffic accidents and the human lives and property losses due to them. But still this very lofty statement can be brought down to earth and we shall try to sum up those technical points that are the building blocks of this construction. Let us describe the principal conclusions beginning from the front of the FLR to the end:
9.1Radome
A mass production radome has been developed of molded Ultem with 10% glass fibers. Metallic stripes are printed in the interior surface of the radome which functions as polarization filter. The conductive stripes have been replaced by resistive material and a radome heater has successfully implemented which improves the FLR performance in very cold weather by melting the ice and snow that otherwise could accumulate on the aperture
9.2Antenna and Manifold
The original ERA design of the antenna was transformed to one appropriate for molding materials. The material of choice was Magnesium instead of plastic because from system considerations, it also conducts heat. The technology of Tyxo molded magnesium allows the fabrication of pieces with the mechanical tolerances required for high frequency RF. Since the Magnesium is very active, a good coating is necessary. Standard coating materials are dielectric and for RF applications a conductive coating is necessary. We have found such a coating, but the results are not yet consistent and more work has to be done in order to industrialize the process.
From the point of view of Electromagnetism, the antenna performance is very good and consistence. Still today we have to calibrate each antenna in the anechoic chamber and if we could reach a situation that a general look up table can be used for all radars, without calibration, and then the assembly cost could be greatly reduced.
9.3RF Transceiver
The initial transceiver design allowed the demonstration of a multi-beam system (ubiquitous radar as coined by M. Skolnik, 2002). It has an impressive performance and 20 modules have been fabricated which have been used to fabricate 20 FLR’s. The greatest drawback of this transceiver is its cost, which exceeds by more than a factor of 50 the target cost in mass production. It is therefore necessary to find a solution to this problem which otherwise is a non-starter. The road to cost reduction of the RF components is to recognize that not only the area of the GaAs drives the cost but also the packaging, and even be the principal cost driver. The strategy taken was to a) reduce the GaAs area from about 62 mm2 to about 30 mm2 and b) to search for a low cost solution for the packaging. The new MMIC’s developed by UMS are passivated, which implies that the hermeticity of the packaging is no longer required, and therefore it is obvious that a plastic package would be the best solution, but the quantities needed to make this solution viable are much larger than those that the market is able to absorb. We therefore decided to go through an intermediate step with a medium cost package that suits for a production level of around 10 kunits per year.
9.4Electronics
The analog and digital signal processing and the communications electronics have been integrated three times to reduce the number of cards. The next step of further integration is to develop an ASIC to reduce the number of components and their cost and also to reduce the power consumption. Again this step is only warranted if the production numbers are of the order of 100 kunits per year.
9.5Power Supply
The power supply plays an important role in a radar. The signals are so faint and the amplification so large, that any noise contributed by the power supply leaks into the radar signal and produces all kind of spurious. Essentially, the power supply is a DC to DC transformer that has an intermediate AC. The frequency has to be rather high (hundreds of kHz) and it has to be filtered out from the dc voltages to very low levels (some tenths of microvolt). There has been a large investment in obtaining a power supply that meets the requirements and also is small and low cost. Only lately, we believe, have reached this goal.
9.6Housing
The housing has been designed so that the front of the radar containing the RF module and the antennas does not change with the successive steps of size reduction. Only the back of the housing has been reduced each time the number of cards was reduced. Therefore only molds of the antenna, manifold and front housing have been fabricated while the back of the housing is still being machined. The front housing will be remade for the new RF components and all the molds will be fabricated for the preproduction phase.
As it has already stated, the issue of the coating of the Magnesium is not yet solved for mass production and more work has to be invested.
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