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.

PROBLEM TO BE SOLVED: To provide an antenna whose antenna gain and whose beam width are varied depending on the situation so as to cope flexibly with the arrangement of base stations and terminal equipments SOLUTION: A horn antenna 11 being a primary radiator and a reflecting mirror 12 being a reflecting means are placed on a base 10 supported turnably by a rotary joint 15 The horn antenna 11 is connected to a frequency conversion section 13, which is connected to an external transmitter-receiver or the like via a cable 14 and the rotary joint 15 The reflecting mirror 12 composed by connecting a plane 17 and a paraboloidal plane is supported by a guide 16 and fixed at an optional position COPYRIGHT: (C)1997,JPO

Antenna and radio communication system

A local signal of a predetermined frequency is supplied to an input terminal of a local signal input section. The local signal is applied to a control input terminal of a variable current supply and, in accordance with the local signal, a current is output from a variable current supply and sent to a phase-shifting section. The phase-shifting section includes two resonance circuits each comprised of a capacitor and inductor. The two resonance circuits are connected in parallel with a linear element constituting the local signal input section to output first and second output signals of the same frequency as that of the local signal and whose phases are shifted by a predetermined amount. The respective output signals of the phase-shifting section are output to a next stage through a signal output section comprised of two sets each of a current supply and transistor.

Phase shifter and communication system using the phase shifter

A 0.13 mum CMOS Cartesian loop transmitter IC with calibration and loop setting scheme of less than 5 mus is fabricated in order to keep high efficiency in wide output power range. The proposed scheme adjusts amplitude, phase, loop gain by using TX modulated signal for fast loop setting. Adjacent channel power leakage ratio (ACPR) is improved by 18 dB. The transmitter IC without PA consumes 62 mA, in which feedback path consumes 22 mA.

0.13 μm CMOS Cartesian loop transmitter IC with fast calibration and switching scheme from opened to closed loop

A direct conversion transmitter IC including a proposed frequency doubler, a quadrature modulator, and a 3-bit variable attenuator was fabricated using BiCMOS technology with fΤ of 12 GHz. This architecture employing frequency doubler is intended for realizing wireless terminals that are low in cost and small in size. The architecture is effective for reducing serious interference between PA and VCO by making the VCO frequency different from that of PA. The proposed frequency doubler comprises a current-driven 90° phase-shifter and an ECL-EXOR circuit for both low power operation and wide input power range of local oscillator (LO). The proposed frequency doubler keeps high output power even when rectangular wave from LO is applied owing to use of the current-driven 90° phase-shifter instead of a voltage-driven 90° phase-shifter. An LO leakage of less than −25 dBc, an image rejection ratio in excess of 45 dBc, and a maximum attenuation of 21 dB were measured. The transmitter IC successfully operates at LO power above −15 dBm and consumes 68 mA from 2.7 V power supply voltage. An active die size is 1.5 mm×3 mm.

A 1.9-GHz Direct Conversion Transmitter IC with Low Power On-Chip Frequency Doubler (Special Section on Analog Circuit Techniques and Related Topics)

An amplifier circuit according to the present invention comprises: a first differential amplifier circuit including a first transistor having a gate terminal forming a first input node, a second transistor having a gate terminal forming a second input node and having a dimensional ratio with respect to the first transistor of K:M (where K>M), and a first current source that supplies a first current to a source terminal of the first transistor and a source terminal of the second transistor; a second differential amplifier circuit including a third transistor having a gate terminal forming a third input node, a fourth transistor having a gate terminal forming a fourth input node and having a dimensional ratio with respect to the third transistor of M:K, and a second current source that supplies a second current to a source terminal of the third transistor and a source terminal of the fourth transistor, the second differential amplifier circuit having a same gain as the first differential amplifier circuit; and a third differential amplifier circuit including a fifth transistor having a gate terminal forming a fifth input node, a sixth transistor having a gate terminal forming a sixth input node and having a dimensional ratio with respect to the fifth transistor of 1:1, and a variable current source that supplies a third current to a source terminal of the fifth transistor and a source terminal of the sixth transistor, wherein the third differential amplifier circuit combines the third current and the fifth transistor so that a gain of the third differential amplifier circuit is greater than a gain of the first differential amplifier circuit when the third current is a first magnitude, and the gain of the third differential amplifier circuit is lower than the gain of the first differential amplifier circuit when the third current is a second magnitude that differs from the first magnitude.

Shoji Otaka

Papers

Antenna and radio communication system

Phase shifter and communication system using the phase shifter

0.13 μm CMOS Cartesian loop transmitter IC with fast calibration and switching scheme from opened to closed loop

A 1.9-GHz Direct Conversion Transmitter IC with Low Power On-Chip Frequency Doubler (Special Section on Analog Circuit Techniques and Related Topics)

Amplifier circuit and communication device