International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

An RF-DC power conversion system is designed to efficiently convert far-field RF energy to DC voltages at very low received power and voltages. Passive rectifier circuits are designed in a 0.25 mum CMOS technology using floating gate transistors as rectifying diodes. The 36-stage rectifier can rectify input voltages as low as 50 mV with a voltage gain of 6.4 and operates with received power as low as 5.5 muW(22.6 dBm). Optimized for far field, the circuit operates at a distance of 44 m from a 4 W EIRP source. The high voltage range achieved at low load current make it ideal for use in passively powered sensor networks.

Efficient Far-Field Radio Frequency Energy Harvesting for Passively Powered Sensor Networks

The idea of wireless power transfer (WPT) has been around since the inception of electricity. In the late 19th century, Nikola Tesla described the freedom to transfer energy between two points without the need for a physical connection to a power source as an ?all-surpassing importance to man? [1]. A truly wireless device, capable of being remotely powered, not only allows the obvious freedom of movement but also enables devices to be more compact by removing the necessity of a large battery. Applications could leverage this reduction in size and weight to increase the feasibility of concepts such as paper-thin, flexible displays [2], contact-lens-based augmented reality [3], and smart dust [4], among traditional point-to-point power transfer applications. While several methods of wireless power have been introduced since Tesla?s work, including near-field magnetic resonance and inductive coupling, laser-based optical power transmission, and far-field RF/microwave energy transmission, only RF/microwave and laser-based systems are truly long-range methods. While optical power transmission certainly has merit, its mechanisms are outside of the scope of this article and will not be discussed.

Harvesting Wireless Power: Survey of Energy-Harvester Conversion Efficiency in Far-Field, Wireless Power Transfer Systems

More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC–DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

/pdf/micropower-energy-harvesting-1l9ase94z1.pdf

Micropower energy harvesting

More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC-DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

This control device includes: a rectifier to rectify a received signal; an amplifier having an amplifying element to amplify the signal rectified by the rectifier and an assisting element being connected to the amplifying element to assist the amplifying element; a determination unit to determine presence or absence of the signal amplified by the amplifier; and a controller to control the connection of the assisting element with the amplifying element at a predetermined timing.

Control device and control method

PROBLEM TO BE SOLVED: To reduce a temperature change in the gain characteristic of a variable gain amplifier employing a MOS transistor (TR). SOLUTION: This invention provides the temperature compensation circuit that corrects a 1st signal current supplied externally in order to control the gain of the variable gain amplifier for the temperature compensation of the gain characteristic of the variable gain amplifier employing the MOS TR, is characterized in the provision of a current source (101) that provides an output of a 2nd signal current depending on a temperature change between the ambient temperature and a prescribed temperature and with a multiplier (104) that receives the 1st and 2nd signal currents and provides an output of a 3rd output current in proportion to the temperature change and the 1st signal current, and the temperature compensation circuit supplies the 3rd signal current to the variable gain amplifier in place of the 1st signal current. COPYRIGHT: (C)2002,JPO

Temperature compensation circuit and variable gain amplifier circuit

PROBLEM TO BE SOLVED: To reduce the size and cost by promoting common use of components furthermore in a radio communication apparatus capable of dealing with a plurality of radio systems. SOLUTION: The radio communication apparatus comprises a local signal generator 110 generating a first local signal, a frequency divider 111 for dividing the frequency of the first local signal to generate a second local signal, and frequency converters 107 and 108 for converting a first RF received signal having frequency f RF1 corresponding a first radio system and a second RF received signal having frequency f RF2 corresponding a second radio system into IF signals of the same frequency f IF using the first local signal 110 and the second local signal 111, respectively, wherein the frequency f LO11 of the first local signal and the frequency division ratio M are set to satisfy a relation; |f LO11 -f RF1 |=|f LO11 /M-f RF2 |=f IF . COPYRIGHT: (C)2005,JPO&NCIPI

Radio communication apparatus capable of dealing with a plurality of radio systems

A MOS resistance controlling device includes: a plurality of MOS transistors having a first MOS transistor to N-th (the integer N is larger than 1) MOS transistor being serially connected, the source of the first MOS transistor being set to a first reference potential, the drain the N-th MOS transistor being set to a second reference potential, and the drain of an I-th MOS transistor being connected to the source of an I+1-th MOS transistor, where I is an integer from 1 to N−1; a current source which is electrically disposed at connection node between the drain of the N-th MOS transistors and the second reference potential; and an operational amplifier having a first input terminal being supplied with a third reference potential, a second input terminal connected with the connection node and an output terminal being connected with gates of the MOS transistors.

Mos resistance controlling device, mos attenuator and radio transmitter

We have developed a GaAs direct-conversion 1/4/spl pi/ shifted QPSK modulator IC equipped with variable attenuators for controlling the output power level of the 1.9 GHz personal handy phone system (PHS). The IC was successfully demonstrated showing state-of-the-art performance with the image rejection ratio of more than 36 dB at a low input power of -10 dBm in the 1.9 GHz frequency range. By using the "Gate Current Control method by Pull-down FET's" (GCCPF), the equipped attenuators vary the output power from 0 dB to -28 dB by 4 dB step. The IC operates at a 2.7 V supply with the power dissipation of 259 mW. The 2.6/spl times/4.6 mm/sup 2/ chip with about 400 elements was fabricated by a 0.5 /spl mu/m WNx-gate BPLDD GaAs MESFET process.

Shoji Otaka

Papers

Control device and control method

Temperature compensation circuit and variable gain amplifier circuit

Radio communication apparatus capable of dealing with a plurality of radio systems

Mos resistance controlling device, mos attenuator and radio transmitter

A GaAs direct-conversion 1/4/spl pi/ shifted QPSK modulator IC with 0-28 dB variable attenuator for 1.9 GHz personal handy phone system