Cyber Physical & Medical Systems

New types of antennas are able to establish a connection to a satellite from an airplane and maintain it during the flight. Thanks to their extremely flat design, installation in the outer skin of the aircraft can save a significant amount of fuel compared to conventional solutions.

On closer inspection, airplanes have a hump at the top of the fuselage. The antennas for communication via the satellites in space are concealed under this bulge. This protective cover is called a radome. Using satellites from an airplane is no easy matter, as the plane moves and still has to maintain contact with the satellite. Until now, this has been done with antennas that are tracked mechanically. This is done in the same way as with movable satellite antennas, whose round dishes are installed on millions of houses to receive radio and television stations. The Institute of High-Frequency Technology (IHF) at Hamburg University of Technology is now breaking new ground and conducting research on the BANG (Broadband in Aviation - Next Generation) antenna project, which is being developed with the support of Lufthansa Technik. The supervising professor Arne Jacob explains how it works: "We are building the antennas from many very flat individual antennas. The modular design of the antenna makes it possible to replace individual modules and simplifies maintenance."

Fast internet while flying

In future, it should be possible to use them to make phone calls and be online during a flight. "This takes place on board via electromagnetic waves, at frequencies of several tens of gigahertz, at which the waves are not visible," says Prof. Jacob. "The task of antennas is to bundle these waves. You can think of it like the beam of a flashlight. And this beam - also known as the antenna lobe - is no longer directed mechanically, but electronically at the satellite." Such antennas (phased arrays) no longer have anything in common with conventional antennas. They consist of many small individual antennas, which in turn are assembled into modules about one centimeter thick. And they also work completely differently: each of these small antennas transmits or receives the same signal, but with a tiny time delay to its neighbors. This time delay is now set so that the waves constructively overlap in the desired direction. Because this is done electronically, the antenna lobe generated in this way can be tracked quickly and flexibly. Continuous transmission and reception is now possible without moving the antenna mechanically.

New technology saves fuel

"We want to carry out the first measurements on our demonstrator at our project partner Lufthansa Technik soon," says Prof. Jacob. The demonstrator is still much smaller than the real antenna that will one day be installed in the aircraft. It initially only consists of a single five by five centimeter module. Overall, however, the entire electronic antenna will be no larger than 0.25 square meters and particularly flat - so that the hump on top of the aircraft's outer skin will no longer be 35 centimeters high, but only a few centimeters. That doesn't sound like much, but it means considerably less air resistance for an aircraft. And therefore significantly lower fuel consumption. With the same aim, the transmitting and receiving antenna are to be integrated into an aperture in order to reduce the footprint and weight. For the demonstrator module, this means that eight of its antenna elements can transmit and receive and eight others only transmit. The modular design also makes the antennas safer to operate. With electronically controlled antennas in the aircraft, the frequent statement: "Unfortunately, I have no reception at the moment" should no longer occur.

More information

More information is avalaible on the website of the Institute of High-Frequency Technology

Contactless detection of epilepsy

Epilepsy is a regulatory disorder of the brain. If it is not treated, it manifests itself in adults, for example, in the form of seizures or even unconsciousness. In newborns and young children, however, epilepsy is often overlooked because they do not exhibit seizures, and can therefore be fatal.

Epilepsy research is usually done only at specialized centers. This involves measuring and analyzing brain waves using an EEG (electroencephalography). This can only take place over short periods of a few hours and severely restricts the subjects during the measurements, as they are wired and not allowed to move. There is also the question of how meaningful the measurements are, since measurements are not taken under real conditions, but only under artificial conditions and over a short period of time.

Detecting danger at an early stage

For this reason, Prof. Alexander Kölpin from the Institute of High Frequency Technology (IHF) at the Technical University of Hamburg is investigating a method as part of the publicly funded BrainEpP project that enables non-contact and continuous monitoring of cardiovascular functions in young adults, infants and even premature babies. The activation of the autonomic nervous system can be inferred from the measured parameters. It is controlled by two systems with opposing effects: the sympathetic and parasympathetic nervous systems. Together they regulate vital bodily functions such as respiration, heartbeat or digestion. The fine structure of extracted cardiac signals provides information about how well this regulation takes place. Not only can epileptic seizures be estimated from this without an EEG, but incipient disturbances should also be detected before a seizure occurs. In case of such an alarm, the seizure could be suppressed with medication and the quality of life of many affected persons could be increased as well as the risk of dying in case of a seizure could be reduced. After all, it is suspected that up to 20 percent of all sudden infant deaths are related to an undiagnosed epileptic condition.

Measuring the smallest vibrations

The monitoring takes place without any contact from a short distance of up to one meter through clothing or bed covers. A so-called high-frequency interferometer is used, which transmits electromagnetic waves at minimum power, which are reflected by the body surface and received by the sensor. From this, the smallest vibrations of the body surface of only a few micrometers deflection can be recorded, as they are caused by heartbeat and breathing. This distance measurement data can be continuously collected and automatically segmented and classified using machine learning. The BrainEpP project searches the measurement data for specific markers, i.e. measurable indicators, of an impending epileptic seizure.

The contactless recording of vital data thus allows continuous monitoring of vulnerable groups of people without restricting their quality of life. Medical changes can thus be detected at an early stage, before health crises arise. This is all the more important in the case of children because epilepsy, a disease that is difficult to recognize, can lead to death if left untreated.

Project partners in the BrainEpP project, which is funded by the German Federal Ministry of Education and Research (BMBF), are the University Hospital Erlangen and the companies Geratherm Respiratory, Silicon Radar, DeMeTec and Voigtmann.