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Christmas card 2021

Our Christmas card for 2021 shows our WiFi Channel State Information (CSI) analysis while the song “Jingle Bells” was being played with a trumpet.

The CSI is available in the received packet preamble of the OFDM (Orthogonal Frequency Division Multiplexing) based WiFi standards such as IEEE 802.11a/n/ac/ax. Typically, the receiver uses it for channel equalization to recover data and then discards it. But the WiFi CSI is very sensitive to the changes in wireless environment and by processing it over time, it is possible to use the WiFi chip as a sensor. This technology is called WiFi Sensing and its typical applications areas are human presence detection, gesture recognition, intrusion detection and contactless vital signal (breathing and heart rate) monitoring. These applications can be implemented on consumer devices and run parallelly with existing connections, without limiting the data transfer.

For our Christmas card, we created IEEE 802.11ax PHY (Physical Layer) baseband waveform using MATLAB. This waveform is then upconverted, transmitted and received over-the-air using Ettus X300 Software-Defined-Radios (SDRs) in 2.4 GHz band. The received signal was converted back to baseband and analyzed in MATLAB. The WiFi CSI amplitude was plotted in a spectrogram. In the spectrogram we can see the effect of finger movements of our colleague while he was playing “Jingle Bells” with a trumpet. Our WiFi CSI analysis framework uses signal processing algorithms and can perform more tasks, such as detecting and counting breathing movements of a person.

As we see on our Christmas card, the WiFi CSI can even track very small movements in the environment. Currently, access to the WiFi CSI is implemented only on small number of devices, which also limits the number of available applications basing on it. This situation is expected to be change with the upcoming WiFi Sensing standard IEEE 802.11bf and WiFi is expected to become a full sensing paradigm and change the way we interact with devices. Once the WiFi CSI becomes available on customer devices, processing it correctly for the target application will gain high importance.

More information about CSI sensing can be found in our publication “In-Vehicle Breathing Rate Monitoring Based on WiFi Signals” from the European Microwave Week (EuMW2020). Download here.

 

Specification of the Christmas card

  • Measurement system:
    Ettus X300 Software-Defined-Radios and Laptop with MATLAB WLAN Toolbox
  • Center frequency: 2.385 GHz
  • Signal bandwidth: 40 MHz
  • Packet format: IEEE 802.11ax Single User SISO (Single Input Single Output)
  • Antennas: Stub antenna with 3 dBi gain
  • Antenna polarization: Vertical

Here you can find our Christmas cards of the last years.

(Feldkirchen, 13th December 2021)

Probably the most radar visible Christmas decoration in the World

What the candles are for the human eye, the corner reflectors are for the radar sensor. Due to their retroreflective character, corner reflectors are strongly visible for the radar.
Retroreflectivity describes the ability of a target to reflect the radiation back to the direction of the source (radar sensor).

Specification of shown corner reflector:

  • Edge length 60mm
  • Radar Cross Section (RCS) @76.5GHz: 1m²
    (= the average size of a motorcycle)

(Feldkirchen, the 29th Nov. 2021)

The story behind our Logo

Our logo represents a Trihedral Corner Reflector which is often used as a reference target for radar measurements. But it can also be used to make targets more visible for automotive radar sensors. Already small-sized corner reflectors can increase the detection range of small radar targets (such as bicycles or motorcycles) significantly and thus improve the safety of these vulnerable road users.

In this context, we have worked with the Technical University of Munich (TUM) in a research project on dielectric corner reflectors that can be easily and inexpensively integrated into delineators or motorcycles. Learn more.

Specification of shown corner reflector:

  • Edge length 60mm
  • Radar Cross Section (RCS) @76.5GHz: 1m²
    (= the average size of a motorcycle)

(Feldkirchen, 12th July 2021)

Merry Christmas and a Happy New Year

We thank our customers and partners for the confidence and the collaboration on the same wavelength.

For 2021 we wish you nothing but the best and many innovative ideas in all frequency ranges. Have a peaceful, relaxing holiday season and a prosperous New Year!

Our this year’s christmas card was measured with our product the Radome Measurement System (RMS-77/79G) equipped with a scanning positioning unit.
It shows a spatially resolved transmission image of a christmas tree sprayed onto a PET foil in amplitude and phase. The tree is sprayed in uni green and the balls in metallic silber.  The 100um thick uni paint gives an additional phase shift of ~6 degree with minimal impact on the attenuation. The metallic paint of only 20um gives a phase shift of 10 degrees and increases the 1way attenuation by 0.7dB. Due to the increasing demands of highly automated driving functions, it is important to investigate the influence of painted surfaces (e.g. bumpers) on automotive radar sensors. The RMS enables materials characterization of automotive paint and measurement of painted radar covers (as bumpers). Here you find more information about the RMS.

Specification of the christmas card:

  • Frequency 76.5GHz
  • Transmission image with 51 x 84 pixel of each 3mm size
  • PET foil with Dk=3.22 and d=350um
  • Uni gree paint with Dk=2.3 and d=100um
  • Metallic silber paint with Dk=31 and d=20um

All electrical properties measured with RMS-77/79G, perisens.

Here you can find our Christmas cards of the last years.

(Feldkirchen, the 04th Dec. 2020)

Radar Workshop

Our CEO Dr. Florian Pfeiffer gives you insights about automotive radar technology covering the following topics:

  • Radar as key technology for automotive sensing
  • Basics in radar technology (electromagnetic wave properties and propagation effects)
  • Measurement principles for distance, velocity (Doppler) and direction of arrival (DoA)
  • Automotive sensor performance (24/77/79GHz radar vs. other sensor technologies)
  • Radar signal processing (from raw data to high-level object data)
  • Future trends in automotive radar
  • Design priciples of radar covers (radome) and influrence on the radar performance
  • Relevant material properties (plastic and paint) of radar covers
  • Radar calibration and radome measurement techniques

Contact us for further information.

New Office

In May 2019  we moved to a new office in Feldkirchen b. München (10min from Munich Trade Fair). Our team is growing and the space at our old location was tight. With 400 square meters, the new premises offer us plenty of space for laboratory and office use.

Thanks for everyone’s support through the years!

Here you find our new adress and telephone number.

(Feldkirchen, 20th May 2019)

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