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.

A method of setting a wireless link is provided between a first wireless device and a second wireless device in a wireless system. The first wireless device includes an extremely low-power receiver. When the extremely low-power receiver receives a predetermined wireless signal, the receiver turns on the first wireless device, and continues broadcast transmission of a packet periodically without a transmission pause until receiving a response packet from the second wireless device.

Method of setting wireless link, wireless communication device and wireless system

PROBLEM TO BE SOLVED: To decrease the sampling speed of an A/D converter and to reduce power consumption at a radio terminal by selecting a narrow band for a channel selection filter in the radio terminal. SOLUTION: Carriers of a request number which are adjacent to each other on a frequency axis are assigned to each terminal, and moreover the assignment of the carriers to each terminal is controlled so that the assigned carrier groups of each terminal are adjacent to each other on the frequency axis. A radio terminal receiver is provided with a channel selection BPF 205, whose pass band is freely variable and with an A/D converter 206 whose sampling speed is freely variable and the passband of the channel selection BPF 205 and the sampling speed of the A/D converter 206 are controlled, depending on the carrier assigned to its own station.

Radio base station, radio terminal, radio communication system and its carrier assignment control method

A series combining transformer(SCT)-based, watt-level 1.9 GHz linear CMOS power amplifier with an on-chip linearizer is demonstrated. Proposed compact, predistortion-based linearizer is embedded in the two-stage PA to compensate AM-PM distortion of the cascode power stages, and improve ACLR of 3GPP WCDMA uplink signal by 2.6 dB at 28.0 dBm output power. The designed interstage power distributor with one tuning inductor contributes to low-loss power supply for the driver stage and high common-mode stability of the whole PA. Moreover, a newly developed PVT variation- tolerant cascode biasing circuit guarantees highly accurate bias voltages in a wide supply voltage range from 2.5 V to 3.6 V. The test chip demonstrates maximum output power of 28.3 dBm at 1.95 GHz, satisfying 3GPP WCDMA spectrum mask with die area of 5.4 mm2.

A 1.9 GHz CMOS Power Amplifier With Embedded Linearizer to Compensate AM-PM Distortion

This paper presents a novel control method for wireless power transmission (WPT). The proposed method can maximize the power efficiency only by controlling the voltage ratio between the primary and the secondary side. Experimental measurement results of the prototype system with 3 kW power transmission show the efficiency difference between the proposed control method and the available maximum value is less than 0.3 % even with a large variation of coil-to-coil distance and load voltage. The automatic controller for the proposed method provides the load-following operation, maintaining both constant power and high efficiency, using a WLAN connection.

A voltage ratio-based efficiency control method for 3 kW wireless power transmission

A linear-in-dB signal-summing Variable Gain Amplifier (VGA) is fabricated in 0.25 /spl mu/m CMOS technology. Two gain compensation techniques are proposed in order to compensate the gain deviations due to the MOSFET characteristic which has a square-law characteristic or an exponential-law characteristic determined by its current density. Temperature compensation techniques are also proposed. A gain range of 80 dB, a gain error of within /spl plusmn/3 dB, an NF of 11 dB are obtained at 380 MHz by measurement.

Shoji Otaka

Papers

Method of setting wireless link, wireless communication device and wireless system

Radio base station, radio terminal, radio communication system and its carrier assignment control method

A 1.9 GHz CMOS Power Amplifier With Embedded Linearizer to Compensate AM-PM Distortion

A voltage ratio-based efficiency control method for 3 kW wireless power transmission

A 380-MHz CMOS linear-in-dB signal-summing variable gain amplifier with gain compensation techniques for CDMA systems