Claudia Marschner

A novel circuit concept for PSK-demodulation in passive telemetric systems

A PSK-demodulator for a bi-directional data transmission in passive telemetric microsystems is presented in this work. These systems, which use the telemetry link for energy and data transmission, are based on identification systems, which use ASK-modulation for both data transfer directions. This leads to problems with a bi-directional data transmission in sensor applications, where the power consumption is significantly higher than in identification systems. A system that uses a PSK to transfer data into the microsystem to improve the energy transfer during data transmission is presented. The key component of this system is a novel PSK-demodulator, which works without an internal oscillator and therefore no PLL is needed. The major advantages of the presented system are the self-adaptation to the carrier frequency and the independence of the demodulator of parameter drifts.

Modeling and optimization of microcoils for telemetric transmission at frequencies up to 20 MHz

Wireless transmission of data and energy is needed e.g. in medical applications and autonomous sensor systems, where the maximum size or the use of batteries are limited by system specific restrictions. A possible solution for frequencies up to 20 Mhz is the use of a transformer which consists of an air-cored and two rectangular microcoils. For simulation and optimization of the system an accurate model of the micro coil is needed to predict the terminal impedance. The model must map the geometrical and material specific parameters into the terminal impedance to avoid the use of correction factors and to obtain a wide range of validity. An accurate model is presented and verified by measurements made with realized micro coils. The model is implemented into the system simulator SABER along with other components of a sensor system. An optimization was carried out to gain optimal coil parameters. The optimization strategy is presented and the optimization was carried out to gain optimal coil parameters. The optimization strategy is presented and the optimization results agree very well with measurements made with a realized sensor system.

Calculation of inductances and capacitances for 3D structures using Prony's method

A closed form expression for the electrical field of a line source over a multi-layered material can only be derived fro special geometries and cases. The use of the spectral domain, but this expression can normally not be transferred back into the space-domain. The solution is an approximation in the spectral domain by use of exponential terms which can easily be transferred back into the space-domain. This is done by use of Pronys method. The number of exponential terms has to be correctly estimated to avoid numerical difficulties. This paper presents a sophisticated method to determine the necessary number of exponential terms and shows how this approximation can be used to calculate inductances and capacitances for conductors with rectangular cross-sections.

Modular concept for the design of application-specific integrated telemetric systems

Modern microsystem technology generates a great variety of very small sensors and actuators. With the use of capacitive measurement or moving principles these components have a very low power consumption and with some data preprocessing they can be used in passive telemetry systems, which need no integrated battery. Instead, they use two loosely coupled coils to realize the energy transfer. To create very small systems, e.g. for the implantation inside the human body, the use of an application specific integrated circuit for the telemetry will be necessary. In this paper a design strategy for the realization of implantable telemetric microsystems and a building set with different blocks for the creation of an application specific telemetry chip is presented. In addition to the necessary main building blocks like rectifiers, voltage regualtors and blocks for the uni- or bi-directional data transmission the set also includes some supplementary blocks like an auaotmatic resonance adjust. All blocks are realized in a standard CMOS process (a 0.7 um CMOS process with some analogue add-ons) and therfore very small and cheap systems can be created.

Theoretical basis for including small as well as large deflections of quadratic membrane structures in one behavioral model

Membrane structures are one of the most common elements in microsystems. In order to be able to perform system simulations, behavioral models of their bending lines have to be developed. These models may also be used as a basis for parameter extractions which is a crucial task in the development of microsystems. But parameter extractions can only be performed, if the models used include all of the most important physical effects. Hence, the physical basis of these models has to be very profound.

Microcoil modeling: benefit and implementation of a permeable layer

Rectangular micro coils which are used in a wide range of applications are the main components of appropriate wireless transmission systems for frequencies up to 20 MHz. As shown in previous works the self inductance of micro coils has to be maximized to achieve a higher working distance. This can be done by usage of a permeable layer underneath the micro coil. The existing model of the micro coil is extended by use of the magnetic image method to include the inductance yield caused by the permeable layer. The underlying permeable layer or substrate is also modeled accurately to include eddy current phenomena and parasitic elements. To do this the layer respectively the substrate is divided into segments analog to the structure of the micro coil. Each segment is described by lumped elements. All elements are connected together to build up a 3D network which will be used to calculate the terminal impedance. The model and first results will be presented.

Novel circuit concept for PSK-demodulation in passive telemetric systems

A PSK-demodulator for a bi-directional data transmission in passive telemetric microsystems is presented in this work. These systems, which use the telemetry link for energy and data transmission, are based on identification systems, which use ASK-modulation for both data transfer directions. This leads to problems with a bi-directional data transmission in sensor applications, where the power consumption is significantly higher than in identification systems. A system which uses a PSK to transfer data into the microsystem to improve the energy transfer during data transmission is presented. The key component of this system is a novel PSK-demodulator, which works without an internal oscillator a d therefore no PLL is needed. The major advantages of the presented systems are the self adaptation to the carrier frequency and the independence of the demodulator of parameter drifts.

OPTIMIERUNG VON MIKROSPULEN ZUR VERSORGUNG AUTARKER TELEMETRISCHER MIKROSYSTEME

Wenn die Anwendung von Batterien bei autarken Mikrosystemen Restriktionen unteriiegt, erfolgt die Energieversorgung durch die induktive Kopplung zweier Spulensysteme. Die verwendeten Mikrospulen (onchip coils) haben einen entscheidenden Einfluß auf den Schreibund Leseabstand des Systems. Der Artikel beschreibt die Optimierungsparameter für Mikrospulen, die mit der 3D-Tiefenlithographie und galvanischer Abscheidung hergestellt werden. Der Einfluß von Gold und Kupfer als Spulenmaterial und die Verwendung einer geeigneten Isolationsschicht wird beschrieben. Der Einfluß des Mikrospulendesigns wird anhand eines Modells und an Messungen aufgezeigt.