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.

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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.

Abstruct- A 1.9 GHz quadrature modulator with an onchip 90" phase-shifter was fabricated using a silicon bipolar technology. This paper investigates error factors caused by a limiter amplifier. It is found that a gain enhancement technique in a phase-shifter circuit is effective in realizing an adjustmentfree quadrature modulator; we propose a new high-gain phaseshifter circuit for this purpose. This technique employs a current mode interface and an on-chip inductor. An image-rejection ratio of over 45 dBc and a carrier feedthrough of below -40 dBc were attained at -15 dBm local oscillator power. This quadrature modulator operates at 2.7 V supply voltage. The operating frequency ranges from 1.2 GHz to 2.3 GHz. The die size of the quadrature modulator IC is 2.49 mm x 2.14 m.

Low Local Input 1.9 GHz S olar adrature Modulator with No Adjustment

A wireless communication apparatus for performing communication using a first communication scheme which transmits a signal using amplitude shift keying and a second communication scheme which suppresses communication with others except a communication counterpart by transmitting a transmission suppression signal before communication is started. The apparatus includes: a first signal generation unit configured to generate transmission data; a modulation unit configured to generate first and second signals having different amplitudes by amplitude-shift keying the transmission data; a second signal generation unit configured to generate the transmission suppression signal having a signal length corresponding to that of the first signal; and a transmission unit configured to transmit the transmission suppression signal at the timing when the first signal is transmitted.

Wireless communication apparatus for suppressing interference while reducing transmission delay

Due to requirements for large-capacity data communication, the bandwidth of wireless communication systems such as cellular phones and wireless LAN has been increased. In this paper, the recent trends of wireless communication systems are reviewed with an emphasis on the receiver analog front end. In addition, a design technique for wide-band circuits is described, with the mixer in the receiver as an example. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(4): 1–10, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20146

Trend of wireless communication systems and wide‐band circuits

PROBLEM TO BE SOLVED: To improve the polarization efficiency by employing an equipment provided with a portable radio equipment antenna consisting of a rectangular conductor ground plate, a radio unit, a monopole antenna, a conductor linear element, a variable reactance element and a control unit for the diversity radio equipment. SOLUTION: An inverted-F antenna 12 is used for this radio equipment and placed at one side of an end of a short-side A of a conductor ground plate 11. A linear element 13 is formed to be the same shape as that of the inverted-F antenna 12. The antenna 12 is fed from a radio circuit unit 14 on the conductor ground plate 11 via a high frequency line 21. Furthermore, the linear element 13 is connected to a variable reactance element 15 inserted to a connecting point of the conductor ground plate 11. The element 15 is connected to a control circuit unit 16 via a control signal line 22 and a control signal is fed to the element 15 via an element that has a high impedance for high frequencies and a low impedance for low frequencies such as an inductor 17.

Diversity radio equipment

A receiving apparatus includes a variable gain unit to change between a first gain and a smaller second gain, and to amplify a received signal to obtain an amplified signal; a comparator to compare a power of the amplified signal with a reference value; and a controller to set a gain to the first gain while in a standby state, to reset a gain to a third gain between the first and second gains if in a standby state the power of the received signal is larger than the reference value, and then to set a gain to the first gain and return to the standby state if the power is equal to or lower than the reference value, or if not, to a fourth gain between the first and third gains

Wireless communicatoin method and apparatus for reducing reception error by performing automatic gain control (AGC) based on a comparison between the received signal and a reference value

Shoji Otaka

Papers

Low Local Input 1.9 GHz S olar adrature Modulator with No Adjustment

Wireless communication apparatus for suppressing interference while reducing transmission delay

Trend of wireless communication systems and wide‐band circuits

Diversity radio equipment

Wireless communicatoin method and apparatus for reducing reception error by performing automatic gain control (AGC) based on a comparison between the received signal and a reference value