A Wireless Passive LC Resonant Sensor Based on LTCC under High-Temperature/Pressure Environments

In this work, a wireless passive LC resonant sensor based on DuPont 951 ceramic is proposed and tested in a developed high-temperature/pressure complex environment. The test results show that the measured resonant frequency varies approximately linearly with the applied pressure; simultaneously, high temperature causes pressure signal drift and changes the response sensitivity. Through the theoretical analysis of the sensor structure model, it is found that the increase in the dielectric constant and the decrease in the Young’s modulus of DuPont 951 ceramic are the main causes that affect the pressure signal in high-temperature measurement. Through calculations, the Young’s modulus of DuPont 951 ceramic is found to decrease rapidly from 120 GPa to 65 GPa within 400 °C. Therefore, the LC resonant pressure sensor needs a temperature compensation structure to eliminate the impact of temperature on pressure measurement. Finally, a temperature compensation structure is proposed and fabricated, and the pressure response after temperature compensation illustrates that temperature drift is significantly reduced compared with that without the temperature compensation structure, which verifies the feasibility the proposed temperature compensation structure

Automotive Inductive Position Sensor

Inductive angular position sensors (IAPS) are widely used for high accuracy and low cost angular position sensing in harsh automotive environments, such as suspension height sensor and throttle body position sensor. These sensors ensure high resolution and long lifetime due to their contactless sensing mode and their simple structure. Furthermore, they are suitable for wider application areas. For instance, they can be miniaturized to fit into a compact packaging space, or be adopted to measure the relative angle of multiple rotating targets for the purposes of torque sensing. In this work, a detailed SIMULINK model of an IAPS is first proposed in order to study and characterize the sensor performance. The model is validated by finite element analysis and circuit simulation, which provides a powerful design tool for sensor performance analysis. The sensor error introduced by geometry imperfection is thoroughly investigated for two-phase and three-phase configurations, and a corresponding correction method to improve the accuracy is proposed. A design optimization method based on the response surface methodology is also developed and used in the sensor development. Three types of sensors are developed to demonstrate the inductive sensor technology. The first type is the miniaturized inductive sensor. To compensate for the weak signal strength and the reduced quality (Q) factor due to the scaling down effect, a resonant rotor is developed for this type of sensor. This sensor is fabricated by using the electrodeposition technique. The prototype shows an 8mm diameter sensor can function well at 1.5mm air gap. The second type is a steering torque sensor, which is designed to detect the relative torsional angle of a rotating torsional shaft. It demonstrates the mutual coupling of multiple inductive sensors. By selecting a proper layout and compensation algorithm, the torque sensor can achieve 0.1 degree accuracy. The third type is a passive inductive sensor, which is designed to reduce power consumption and electromagnetic emissions. The realization and excellent performance of these three types of sensors have shown the robustness of the inductive sensor technology and its potential applications. The research conducted in this dissertation is expected to improve understanding of the performance analysis of IAPS and provide useful guidelines for the design and performance optimization of inductive sensors

Methods for Improvement of RF Performances of Micro- Inductor and Transformer Structures

Tematika disertacije obuhvata projektovanje, izradu i karakterizaciju pasivnih induktivnih RF komponenti u PCB i LTCC tehnologiji, kao i poboljšanje njihovih performansi. Izvršena je i karakterizacijarazličitih tipova dielektričnih i feritnih  LTCC materijala koji su korišćeni za izradu komponenti. Ukupno je projektovano i izrađeno 37 struktura, 14 induktora i 23 transformatora. Na poboljšanje karakteristika projektovanih struktura, koje se ogleda prvenstveno u povećanju induktivnosti zavojaka, uticalo se izradom projektovanih struktura na supstratima izrađenih od različitih materijala, supstratima formiranih od kombinacije materijala različitih karakteristika, redizajnom osnovnih (polaznih) geometrija struktura i optimizcijom parametara LTCC postupka izrade.Topic of this theases focuses on design, fabrication and characterization of industive passive RF components in PCB and LTCC technology, as well as on improvement of their performances. Characterization of different types ofdielectric and ferrite LTCC materials that were implemented for component fabrication was also performed. In total, 37 structures were designed and fabricated, of those 14 are inductor structures and 23 are transformers. Performance improvement of designed structures that is manifested through increase of inductance value of structures windings implied fabrication of designed components on substrates formed from different materials, or from combination of two or more materials with different properties, redesign of original design and optimization of LTCC fabrication process parameters

Research and Development of 2D/3D Deformable Structures LTCC for Optoelectronic Applications

Disertační práce je zaměřena na výzkum, vývoj a výrobu deformačních elementů vyrobených technologií LTCC, určených pro použití v optoelektronických aplikacích. Je zde provedeno studium technologických postupů, přičemž je kladen důraz na dosažení přesné a opakovatelné výroby mechanických komponent tak, aby tyto byly využitelné na standardních LTCC substrátech v komerční sféře. Proto jsou využívány dostupné standardní tlustovrstvé materiály. Součástí práce je také nezbytné testování vhodnosti použití standardních LTCC materiálů pro vybrané senzorické aplikace, v nichž je používána vláknová optika, aby byla potvrzena využitelnost dosažených výsledků v praxi. Disertabilní jádro práce představuje výzkum a vývoj technologie využívající nové principy a možnosti skryté v mechanických parametrech LTCC struktur, které jsou určeny a využívány pro realizaci deformačních prvků. Součástí práce je také nezbytné testování vhodnosti použití standardních LTCC materiálů pro vybrané senzorické aplikace, v nichž je používána vláknová optika, aby byly potvrzena využitelnost dosažených výsledků v praxi.The doctoral thesis is focused on the research, development and production of deformation elements produced by LTCC technology for use in optoelectronic applications. A study of technological processes is carried out, with the emphasis on achieving accurate and reproducible mechanical component manufacturing so that these can be used on standard LTCC substrates in the commercial sphere. Therefore, available standard thick-film materials are used. The work also involves testing the suitability of the use of standard LTCC materials for selected sensory applications in which fiber optics are used to confirm the usefulness of the results achieved in practice. The dissertable core of the work is research and development of a technology using new principles and possibilities hidden in the mechanical parameters of LTCC structures, which are designed and used for the realization of deformation elements. The work also involves testing the suitability of the use of standard LTCC materials for selected sensory applications in which fiber optics are used to confirm the usefulness of the results achieved in practice.