Michel Declercq - Böcker

Radio Frequency IDentification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is a small object that can be attached toor incorporated into a product, animal or person. An RFID tag contains an antenna to enable it to receive and respond to Radio-Frequency (RF) queries from an RFID reader or interrogator. Passive tags require no internal power source, whereas active tags require a power source.As of today (2006), the concepts of ubiquitous computing and ambient intelligence are becoming widespread. In order for these to become a reality, a number of key technologies are required. In brief, these technologies need to be sensitive, responsive, interconnected, contextualised, transparent and intelligent. RFID, and in particular passive RFID tags, are such a technology. In order to deliver the necessary characteristics that could lead to ambient intelligence, however, there are some challenges that need to be addressed.Remote powering of the tags is probably the most important challenge. Issues concerning the antenna-tag interface and the rectifier design, that allow the RF signal to be converted to Direct Current (DC) are top priorities. Secondly, the communication link and the reader should be optimized. The RF signal that contains the tag data suffers from a power of four decay with the distance between tag and reader. As a result, both the reader sensitivity and the tag backscattered power efficiency have to be maximized. Long-range powering, as well as sufficient communication quality, are the guidelines of this work.This work proposes a linear two-port model for an N-stage modified-Greinacher full wave rectifier. It predicts the overall conversion efficiency at low power levels where the diodes are operating near their threshold voltage. The output electrical behavior of the rectifier is calculated as a function of the received power and the antenna parameters. Moreover, the two-port parameter values are computed for particular input voltages and output currents for the complete N-stage rectifier circuit, using only the measured I-V and C-V characteristics of a single diode.Also presented in this work is an experimental procedure to measure how the impedance modulation at the tag side affects the signal at the reader. The method allows the tag designer to efficiently predict the effect of a modulator design at the system level and gives a useful instrument to choose the most appropriate impedances.Finally, the design of a fully-integrated, remotely powered and addressable RFID tag working at 2.45GHz is described. The achieved operating range at a 4W Effective Isotropically Radiated Power (EIRP) reader transmit power is at most 12 m. The Integrated Circuit (IC) is implemented in a 0.5 um silicon-on-sapphire technology. A state-of-the-art rectifier design is embedded to supply energy to the transponder. Inductive matching and a folded-dipole antenna are key elements for achieving this performance.

Standard voltages used in modern ICs may vary from about 1.3V to more than 100V, depending on the technology and the application. High voltage is therefore a relative notion. This text is mainly focused on standard CMOS technologies, where high voltage (HV) is defined as any voltage higher than the nominal (low) voltage, that is 5V, 3.3V, or even lower. In this standard CMOS environment, IC designers are more and more frequently confronted with HV problems, particularly at the I/O level of the circuit. In the first group of applications, a large range of industrial or consumer circuits either require HV driving capabilities, or are supposed to work in a high-voltage environment. This includes ultrasonic drivers, flat panel displays, robotics, automotive, etc. On the other hand, in the emerging field of integrated microsystems, MEMS actuators mainly make use of electrostatic forces involving voltages in the typical range of 30 to 60V. Last but not least, with the advent of deep sub-micron and/or low-power technologies, the operating voltage tends towards levels ranging from 1V to 2.5V, while the interface needs to be compatible with higher voltages, such as 5V.For all these categories of applications, it is usually preferable to perform most of the signal processing at low voltage, while the resulting output rises to a higher voltage level. Solving this problem requires some special actions at three levels: technology, circuit design and layout.

Features contributions on developments and challenges in research and education on microelectronics, microsystems and related areas. This book is intended for professors, researchers and PhDs involved in microelectronics and/or in electrical engineering, microsystems and material sciences.

Radio Frequency IDentification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is a small object that can be attached toor incorporated into a product, animal or person. An RFID tag contains an antenna to enable it to receive and respond to Radio-Frequency (RF) queries from an RFID reader or interrogator. Passive tags require no internal power source, whereas active tags require a power source.As of today (2006), the concepts of ubiquitous computing and ambient intelligence are becoming widespread. In order for these to become a reality, a number of key technologies are required. In brief, these technologies need to be sensitive, responsive, interconnected, contextualised, transparent and intelligent. RFID, and in particular passive RFID tags, are such a technology. In order to deliver the necessary characteristics that could lead to ambient intelligence, however, there are some challenges that need to be addressed.Remote powering of the tags is probably the most important challenge. Issues concerning the antenna-tag interface and the rectifier design, that allow the RF signal to be converted to Direct Current (DC) are top priorities. Secondly, the communication link and the reader should be optimized. The RF signal that contains the tag data suffers from a power of four decay with the distance between tag and reader. As a result, both the reader sensitivity and the tag backscattered power efficiency have to be maximized. Long-range powering, as well as sufficient communication quality, are the guidelines of this work.This work proposes a linear two-port model for an N-stage modified-Greinacher full wave rectifier. It predicts the overall conversion efficiency at low power levels where the diodes are operating near their threshold voltage. The output electrical behavior of the rectifier is calculated as a function of the received power and the antenna parameters. Moreover, the two-port parameter values are computed for particular input voltages and output currents for the complete N-stage rectifier circuit, using only the measured I-V and C-V characteristics of a single diode.Also presented in this work is an experimental procedure to measure how the impedance modulation at the tag side affects the signal at the reader. The method allows the tag designer to efficiently predict the effect of a modulator design at the system level and gives a useful instrument to choose the most appropriate impedances.Finally, the design of a fully-integrated, remotely powered and addressable RFID tag working at 2.45GHz is described. The achieved operating range at a 4W Effective Isotropically Radiated Power (EIRP) reader transmit power is at most 12 m. The Integrated Circuit (IC) is implemented in a 0.5 um silicon-on-sapphire technology. A state-of-the-art rectifier design is embedded to supply energy to the transponder. Inductive matching and a folded-dipole antenna are key elements for achieving this performance.

Standard voltages used in today's ICs may vary from about 1.3V to more than 100V, depending on the technology and the application. High voltage is therefore a relative notion. High Voltage Devices and Circuits in Standard CMOS Technologies is mainly focused on standard CMOS technologies, where high voltage (HV) is defined as any voltage higher than the nominal (low) voltage, i.e. 5V, 3.3V, or even lower. In this standard CMOS environment, IC designers are more and more frequently confronted with HV problems, particularly at the I/O level of the circuit. In the first group of applications, a large range of industrial or consumer circuits either require HV driving capabilities, or are supposed to work in a high-voltage environment. This includes ultrasonic drivers, flat panel displays, robotics, automotive, etc. On the other hand, in the emerging field of integrated microsystems, MEMS actuators mainly make use of electrostatic forces involving voltages in the typical range of 30 to 60V. Last but not least, with the advent of deep sub-micron and/or low-power technologies, the operating voltage tends towards levels ranging from 1V to 2.5V, while the interface needs to be compatible with higher voltages, such as 5V. For all these categories of applications, it is usually preferable to perform most of the signal processing at low voltage, while the resulting output rises to a higher voltage level. Solving this problem requires some special actions at three levels: technology, circuit design and layout. High Voltage Devices and Circuits in Standard CMOS Technologies addresses these topics in a clear and organized way. The theoretical background is supported by practical information and design examples. It is an invaluable reference for researchers and professionals in both the design and device communities.