M. Huber

Three stage wakeup scheme for sensor networks

Crucial for limiting power consumption of the nodes in sensor networks is a strategy of keeping the nodes in sleep a mode most of the time. Consequently, the strategy of when and how to reactivate them is a key issue to let sensor networks become reality. This paper presents a special wakeup receiver for this task which utilizes a concept of two successive stages of different complexity and power consumption. Always on will only be a very simple stage consuming nW, this will activate a slightly more complex stage consuming some /spl mu/m, and only if this stage confirms a valid wakeup condition the main transceiver is activated.

A GaAs HBT Low Power 24 GHz Downconverter with On-Chip Local-Oscillator

In this paper, the paper presents a low-power mixer with integrated local oscillator intended for use in a 24 GHz receiver front-end. The chip is realized using HBT GaAs technology. The voltage-controlled oscillator (VCO) provides a tuning range of 18% at a mean frequency of 21 GHz, with a low DC consumption of 21 mW. DC consumption of the mixer part is about 17 mW from a 3 V supply, with a mean gain of 14 dB and a sensitivity of -70 dBm. The MMIC demonstrates interesting potential for low-power RF terminals in the 24 GHz range

Ultra low power 24 GHz HBT mixer

A K band GaAs-HBT mixer using a cascode structure is presented. Conversion gain of 4 dB can be achieved at 24 GHz with 4 dBm LO power. Power consumption is reduced to 9 mW, hence such mixers are applicable as central building blocks of highly integrated low power receiver front-ends in pico cell networks. Finally, a modification of the mixer is presented which achieves 12 dB conversion gain at a 50 /spl Omega/ output port with 12 mW DC power consumption.

System Architecture for Low Power 24 GHz Front-End

By Stefan von der Mark. Meik Huber, Mathias Wittwer, Wolfgang Heinrich and Georg Boeck Abstract This paper provides an overview of RF front-end architectures and technologies of future wireless picocellnetworks. Because of the targeted size of only 1 cm, the most critical point of such systems is the energy consumption of individual cells. Therefore, such systems can be operated only if the cells are in a deep sleep mode during most of their lifetime. Only by request of another cell via the wake-up circuit the RF front-end is activated. With regard to this issue, wake-up principles and circuits play a major role and will be discussed, especially the differences between periodical and event-driven wake-up schemes. The most energy consuming function block is the 24 GHz radio front-end. Most important for its energy balance are the antenna concept, the front-end architecture, the semiconductor technology, the modulation scheme and the data rate. The influence of the key parameters on energy consumption is discussed and realization approaches are proposed.

Design Concepts and First Implementations for 24 GHz Wireless Sensor Nodes

This paper reviews proposed realization concepts and achievements of wireless sensor nodes and focuses on new developments in the 24 GHz frequency range. The relatively high frequency offers the advantage of ultra miniaturization and therefore opens new application fields. On the other hand power consumption of the RF-front-end becomes still more challenging than at lower frequencies. It is shown that by applying very simple CMOS transceiver architectures and modulation schemes combined with innovative efficient wake-up concepts, very low energy consumption can be achieved. Technological realization concepts and first experimental results from a 24 GHz demonstrator as well as novel special purpose wakeup-circuitry are presented, too.

24 GHz Direct Conversion Transceiver for Sensor Networks

A complete low power 24 GHz transceiver chain intended for wireless sensor networks is presented. Including standard button cell batteries, the node size is only 1cm3. A specially designed PCB antenna is implemented, which is fed through the substrate from the backside. The RF components are flip chip mounted directly to the feedline to reduce losses. Data transmission at 2400 bps has been demonstrated, low complexity of the circuitry makes future system on chip (SoC) integration feasible.

Low power signal generation at 24 GHz using a frequency multiplier

A low power 24 GHz signal generator consisting of a 12 GHz VCO and a frequency doubler in GaAs HBT technology is presented. Overall power consumption is 43 mW at 0 dBm output power, tuning range is 800 MHz for 3 V tuning voltage. The doubler by itself provides 3 dB gain at 13 mW power consumption. Its design is based on harmonic termination of an HBT producing the desired harmonic frequency

Integrated Circuits and 3D-Packaging for Low-Power 24 GHz Front End

ByChafikMeliani, ProdyutTalukder, Jochen Hilsenbeck, Meik Huber, Georg Bock, and Wolfgang Heinrich Abstract Design and experimental results for a low-power monolithic 24 GHz front end are described. As basic circuits, VCO and mixer are presented. The circuits are realized on GaAs using heterobipolar transistors. The VCO reaches 19% efficiency at 4.3 dBm output power and 14.5 mW DC power consumption. The circuits are to be integrated together with a special slot antenna using flip-chip technology. Simulatbn data on this novel antenna approach demonstrate acceptable gain characteristics around 3 dB, despite of its small size.

Ultra Miniaturized 24 GHz Wireless Sensor Nodes -- A Concept Study and First Results

This paper reviews realization concepts and achievements of wireless sensor nodes and focuses on new developments in the 24 GHz frequency range. The higher frequency offers the advantage of ultra miniaturization and therefore opens new application fields. On the other hand power consumption of the RF-front-end becomes still more challenging than at lower frequencies. It is shown that by applying very simple CMOS transceiver architectures and modulation schemes combined with efficient wake-up concepts very low energy consumption can be achieved. Technological realization concepts and first experimental results from a 24 GHz demonstrator are presented, too

A Dual Stage GaAs Amplifier for a K-Band Direct Receiver

An energy efficient K-band GaAs-HBT amplifier applicable in a highly integrated direct receiver concept for sensor networks is presented. The preamplifier in a direct receiver is the most important building block and mainly determines sensitivity and energy consumption. Special issues of the amplifier design related to the receiver concept are highlighted in this paper. The presented amplifier shows gain of 14 dB and a noise figure of 6 dB using 47 mW DC supply.