Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanopores for improved radar sensor technology

07.07.2015

Nanostructures etched into the surface: TU Wien develops a new processing technology to improve the electrical properties of glass ceramic circuit boards.

As you ease your foot off the accelerator, a radar sensor detects how far away you are from the other cars and intelligently adjusts your speed appropriately. Technology like this is already helping to improve road safety and is set to become even more commonplace.


New etching technique created a porous surface with higher emission.

TU Wien


Consistent metallization on porous surface created by pulse plating processes.

TU Wien

From an electrical engineering perspective, manufacturing sensors of this kind is an extremely tricky process: the sensors have to be able to operate at very high frequencies but still need to be precise and efficient. TU Wien has now managed to develop a new processing technology for the high-precision nanostructuring of glass ceramic circuit boards. This means that the material properties can be adjusted, thereby significantly improving the electromagnetic behaviour of the sensor.

The material affects the radiation properties

Radar sensor antennas have very little in common with the metal rods that you might see protruding from a radio set. That is because today's sensor antennas are extremely compact and mounted directly onto the circuit boards. The circuit boards themselves can, for example, be made from special glass ceramics (called 'low-temperature co-fired ceramics' or 'LTCC') comprising various layers with the PCB tracks mounted in between. The patch antenna is located on the top layer.

'The radiation characteristic of an antenna is heavily influenced by the underlying material,' explains Prof. Ulrich Schmid from the Institut für Sensor- und Aktuatorsysteme at TU Wien (the Institute for Sensor and Actuator Systems at TU Wien). Depending on the electromagnetic properties of the circuit board, the material may interfere with the radiation process and absorb the waves being emitted.

In extreme cases, it may even heat up to such an extent that the semiconductor chips are also affected. This is particularly problematic in the high-frequency range: car radar sensors operate at around 77 GHz for a mixture of technical and legal reasons, with this frequency range having been specifically reserved by law for radar sensors used in road traffic applications.

Attempts have already been made to prevent the material from interfering by combining the circuit board glass ceramics with organic materials. However this brings with it a whole new set of problems. 'It is best to avoid transitions between different materials,' says Ulrich Schmid. Situations involving different categories of material that expand to different extents when they heat up are particularly likely to shorten the life span of the radar sensor.

The nanopore technique

For the reasons outlined above, researchers at TU Wien decided to look for a way of changing the electromagnetic properties of the circuit boards in a very specific manner without having to use an additional material. The glass ceramics consist of tiny grains that are 'welded together' by heat.

This baking process produces feldspar, which can be etched away using acid, leaving behind the rest of the substrate material. What the research team discovered was that this technique could be used to provide the glass ceramic material with a complex pore structure at a nanolevel, thereby changing the properties of the material at specific points.

The extent to which a material can be penetrated by electrical fields is referred to as its 'electrical permittivity'. 'Prior to the acid treatment, the permittivity measures between seven and eight but the nanopores reduce it by up to 30%. Not only that, but this can be achieved with a minimum of technological effort and using conventional tape systems that were not even produced with this etching process in mind. That is impressive,' exclaims Dr. Achim Bittner.

Bittner studied this effect several years ago and now his colleague Frank Steinhäußer has managed to develop the technique further in conjunction with Happy Plating (an electroplating company based in Austria) with very promising results. The remaining steps required to manufacture the antenna circuit board were carried out by partners in Germany. For instance, the glass ceramics were sintered by MSE using material supplied by Kerafol. The high-frequency simulations were performed and the antenna was designed at the University of Erlangen-Nuremberg and by Astyx.

The new etching technique can be used with pinpoint accuracy to imbue different parts of the glass ceramics with different properties. This may – for example – prove extremely useful in the context of multi-antenna arrays that are connected for the purpose of transmitting an electromagnetic wave in a very specific direction. There are also plans to use the technique as a diagnostic method in the future to find out more about the behaviour of the glass ceramic material with a view to improving it further at a fundamental level.

Weitere Informationen:

http://www.tuwien.ac.at/en/news/news_detail/article/9551/

Dr. Florian Aigner | Technische Universität Wien

More articles from Power and Electrical Engineering:

nachricht Researchers pave the way for ionotronic nanodevices
23.02.2017 | Aalto University

nachricht Microhotplates for a smart gas sensor
22.02.2017 | Toyohashi University of Technology

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>