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Leonhard M. Reindl  - - - 
Top co-authors See all
Jürgen Wilde

11 shared publications

Laboratory for Assemblyand Packaging Technology,Department of Microsystems Engineering,University of Freiburg,Freiburg, Germany

Elena Zukowski

10 shared publications

Laboratory for Assemblyand Packaging Technology,Department of Microsystems Engineering,University of Freiburg,Freiburg, Germany

Antwi Nimo

9 shared publications

Dept. of Microsyst. Eng., Univ. of Freiburg - IMTEK, Freiburg, Germany

Michael Berndt

8 shared publications

Laboratory for Assemblyand Packaging Technology,Department of Microsystems Engineering,University of Freiburg,Freiburg, Germany

Jochen Hempel

7 shared publications

Laboratory for Electrical Instrumentation,Department of Microsystems Engineering,University of Freiburg,Freiburg, Germany

Publication Record
Distribution of Articles published per year 
(1998 - 2018)
Total number of journals
published in
Publications See all
Article 0 Reads 0 Citations Inertial Sensor-Based Respiration Analysis Gurkan Karacocuk, Fabian Hoflinger, Rui Zhang, Leonhard M. R... Published: 01 January 2019
IEEE Transactions on Instrumentation and Measurement, doi: 10.1109/tim.2018.2889363
DOI See at publisher website
PROCEEDINGS-ARTICLE 0 Reads 0 Citations Using Bluetooth Low Energy to trigger an ultra-low power FSK wake-up receiver Paul Gavrikov, Pascal E. Verboket, Tolgay Ungan, Markus Mull... Published: 01 December 2018
2018 25th IEEE International Conference on Electronics, Circuits and Systems (ICECS), doi: 10.1109/icecs.2018.8618031
DOI See at publisher website
Article 1 Read 0 Citations Electromagnetic Analysis, Characterization and Discussion of Inductive Transmission Parameters for Titanium Based Housin... Waldemar Gruenwald, Mayukh Bhattacharrya, Dirk Jansen, Leonh... Published: 25 October 2018
Materials, doi: 10.3390/ma11112089
DOI See at publisher website ABS Show/hide abstract
The growing demand for active medical implantable devices requires data and or power links between the implant and the outside world. Every implant has to be encapsulated from the body by a specific housing and one of the most common materials used is titanium or titanium alloy. Titanium thas the necessary properties in terms of mechanical and chemical stability and biocompatibility. However, its electrical conductivity presents a challenge for the electromagnetic transmission of data and power. The proposed paper presents a fast and practical method to determine the necessary transmission parameters for titanium encapsulated implants. Therefore, the basic transformer-transmission-model is used with measured or calculated key values for the inductances. Those are then expanded with correction factors to determine the behavior with the encapsulation. The correction factors are extracted from finite element method simulations. These also enable the analysis of the magnetic field distribution inside of the housing. The simulated transmission properties are very close to the measured values. Additionally, based on lumped elements and magnetic field distribution, the influential parameters are discussed in the paper. The parameter discussion describes how to enhance the transmitted power, data-rate or distance, or to reduce the size of the necessary coils. Finally, an example application demonstrates the usage of the methods.
Article 1 Read 1 Citation An Ultra-Low-Power RFID/NFC Frontend IC Using 0.18 μm CMOS Technology for Passive Tag Applications. Mayukh Bhattacharyya, Waldemar Gruenwald, Dirk Jansen, Leonh... Published: 07 May 2018
PubMed View at PubMed ABS Show/hide abstract
Battery-less passive sensor tags based on RFID or NFC technology have achieved much popularity in recent times. Passive tags are widely used for various applications like inventory control or in biotelemetry. In this paper, we present a new RFID/NFC frontend IC (integrated circuit) for 13.56 MHz passive tag applications. The design of the frontend IC is compatible with the standard ISO 15693/NFC 5. The paper discusses the analog design part in details with a brief overview of the digital interface and some of the critical measured parameters. A novel approach is adopted for the demodulator design, to demodulate the 10% ASK (amplitude shift keying) signal. The demodulator circuit consists of a comparator designed with a preset offset voltage. The comparator circuit design is discussed in detail. The power consumption of the bandgap reference circuit is used as the load for the envelope detection of the ASK modulated signal. The sub-threshold operation and low-supply-voltage are used extensively in the analog design—to keep the power consumption low. The IC was fabricated using 0.18 μ m CMOS technology in a die area of 1.5 mm × 1.5 mm and an effective area of 0.7 m m 2 . The minimum supply voltage desired is 1.2 V, for which the total power consumption is 107 μ W. The analog part of the design consumes only 36 μ W, which is low in comparison to other contemporary passive tags ICs. Eventually, a passive tag is developed using the frontend IC, a microcontroller, a temperature and a pressure sensor. A smart NFC device is used to readout the sensor data from the tag employing an Android-based application software. The measurement results demonstrate the full passive operational capability. The IC is suitable for low-power and low-cost industrial or biomedical battery-less sensor applications. A figure-of-merit (FOM) is proposed in this paper which is taken as a reference for comparison with other related state-of-the-art researches.
Article 2 Reads 0 Citations Wake-Up Receiver with Equal-Gain Antenna Diversity Timo Kumberg, Robert Tannhaeuser, Leonhard M. Reindl Published: 25 August 2017
Sensors, doi: 10.3390/s17091961
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Small scale fading signals resulting from multipath propagation can cause signal strength variations in the range of several dB. Resulting from the fluctuating signal strengths, the wake-up packet reception rate can decrease significantly. Using antenna diversity can greatly mitigate these effects. This article presents a novel wireless sensor node with wake-up receiver that uses an equal-gain diversity method with two antennas in the wake-up path. Summation of the two diversity branch signals is done after the passive demodulation of the incoming signals. As a result, the wireless sensor node requires almost no additional active parts that would increase power consumption. Furthermore, we demonstrate experimentally the improved wake-up robustness and reliability achieved by this diversity technique in a multipath environment.
Article 0 Reads 0 Citations Ultrasonic Coupled Passive Wireless Oscillating Sensor System Taimur Aftab, Thomas Schaechtle, Joachim Hoppe, Di Shi, Domi... Published: 12 August 2017
Proceedings, doi: 10.3390/proceedings1040574
DOI See at publisher website ABS Show/hide abstract
This paper presents, for the first time, an instrumentation technique for passively extracting a resonance frequency of a high-Q resonator across a wireless ultrasonic channel. As a first application, passive wireless measurement of temperature is presented along with a proof of concept of the wireless and passive operation of the device. Temperature resolution of 0.17 °C and a measurement range of 350 mm has been demonstrated.