Masashi Nakatsugawa

An L-band ultra-low-power-consumption monolithic low-noise amplifier

A low-power consumption variable-gain low-noise amplifier (LNA) is demonstrated. To achieve low noise, low distortion, and low power consumption simultaneously, a cascode connection between an enhancement-mode GaAs MESFET (EFET) and a depletion-mode GaAs MESFET (DFET) is employed. The EFET is superior to the DFET in its gain and noise figure performance while the DFET offers good intermodulation distortion performance. The advantages of both types of FETs are combined in the developed LNA. It shows excellent performance with an NF of 2.0 dB, a gain of 12.2 dB, and an IP/sub 3/ of 5.1 dBm at 1.9 GHz. The demonstrated performance satisfies the specifications of the Japanese Personal Handyphone System even at the ultra-low power consumption of 2.0 mW. >

Quasi-linear amplification using self-phase distortion compensation technique

This paper demonstrates a self-phase distortion compensation technique to realize linear power amplifiers, in which the positive phase deviation from a common-source FET and the negative phase deviation from a common-gate FET cancel each other. It is confirmed both theoretically and experimentally that increasing the drain-to-source conductance, G/sub d/, causes the self-phase distortion compensation effect. An experimental power amplifier for L-band personal communications systems, which employs the cascode connection, shows good phase deviation performance. More than 20-dB gain, 21-dBm output power, and 50% power added efficiency are obtained along with the adjacent channel interference of -52 dBc in 192-kHz bands at 600-kHz offset frequency from 1.9 GHz at the operating voltage of only 3 V. The demonstrated performances satisfy the specifications for the 1.9-GHz Japanese Personal Handy-phone System (PHS) utilizing the /spl pi//4-shift QPSK modulation scheme. The proposed technique is suitable for MMIC design, and allows the design of handsets that are small, lightweight, and have long operating times. >

A 1.9 GHz-band ultra low power consumption amplifier chip set for personal communications

An ultra low power consumption amplifier chip set for the 1.9 GHz Japanese Personal Handy-phone System (PHS) is presented. The chip set includes a linear power amplifier, a driver amplifier, and an LO switch amplifier. These amplifiers use Cascode FETs that provide low phase distortion, high gain, and low current operation. The power amplifier uses a new concept of a self-phase distortion compensation to achieve a record performance of 45% power added efficiency with sufficient linearity. The driver amplifier has a gain of 13.5 dB with a low power consumption of 3 mW (1 mA, 3 V). The LO switch amplifier is a new MMIC that has both switch and buffer amplifier functions. The switch amplifier has an output power of 3 dBm, a forward gain of 15 dB, and a reverse isolation of 35 dB with a low power consumption of 6 mW (2 mA, 3 V).<<ETX>>An ultra low power consumption amplifier chip set for the 1.9 GHz Japanese Personal Handy-phone System (PHS) is presented. The chip set includes a linear power amplifier, a driver amplifier, and an LO switch amplifier. These amplifiers use Cascode FETs that provide low phase distortion, high gain, and low current operation. The power amplifier uses a new concept of a self-phase distortion compensation to achieve a record performance of 45 % power added efficiency with sufficient linearity. The driver amplifier has a gain of 13.5 dB with a low power consumption of 3 mW (1 mA, 3 V). The LO switch amplifier is a new MMIC that has both switch and buffer amplifier functions. The switch amplifier has an output power of 3 dBm, a forward gain of 15 dB, and a reverse isolation of 35 dB with a low power consumption of 6 mW (2 mA, 3 V).<<ETX>>

A novel MMIC power amplifier for pocket-size cellular telephones

A novel MMIC (monolithic microwave integrated circuit) power amplifier for cellular telephones is proposed. The amplifier, called UBIC-PA (unbalanced bias cascode power amplifier), makes very compact monolithic integration possible in spite of the considerably low frequency of 900 MHz. The UBIC-PA has more than 40 dB gain, 29 dBm output power, and 62% power added efficiency at the supplied voltage of 6 V. The chip size of the MMIC without an output matching circuit is 2.4*2.4 mm. The size and cost of the UBIC-PA module is estimated at about 1/6 (0.2 cc) and 1/2 that of the former hybrid PA module. Moreover, the UBIC-PA improves power dissipation by more than 50% under medium and low output power conditions. This is very important for cellular telephones using adaptive transmitter power control for battery saving.<<ETX>>

A 15-GHz monolithic low-phase-noise VCO using AlGaAs/GaAs HBT technology

A 15-GHz fully monolithic low-phase-noise VCO MMIC fabricated without an external tuning element using an AlGaAs/GaAs HBT technology was developed. An HBT and a variable capacitance diode or varactor were fabricated in an MMIC chip using-standard HBT IC process. A tuning range of about 600 MHz was obtained with varying control voltage from 0 to 4 V with an output power of more than -4 dBm. The low phase noise for an offset frequency of 100 kHz of -85 dBc/Hz was measured at a frequency of 15.6 GHz. >

A high-accuracy pedestrian positioning information system using pico cell techniques

We have developed a high-accuracy pedestrian positioning information system named P-POINTS (Personal Positioning INformaTion System). This system is characterized by highly accurate position detection and seamless indoor/outdoor utilization, these benefits not offered by conventional position detection systems. P-POINTS employs pico cells to improve its accuracy. Owing to the small coverage area of each cell, the resolution of position detection can be increased. It is also suitable in extending the service area such as inside of buildings or underground areas. These features make it attractive to realize pedestrian support in an ITS service.

1.9 GHz-band low voltage and low power consumption RF IC chip-set for personal communications

New RF circuit techniques have overcome the distortion problems for low supply voltages. The RF IC chip-set for the 1.9 GHz Japanese personal handy phone (PHP) system includes a low noise amplifier (GaAs MMIC), a mixer (GaAs MMIC), a linear power amplifier (GaAs MMIC), a T/R switch (GaAs MMIC), a 1.9 GHz direct-conversion quadrature modulator (Si LSI), and a frequency synthesizer (Si LSI). These components achieve very low power consumption at very low supply voltages such as 2.0 to 2.4 V.<<ETX>>

Service Area Expansion of Quasi-Millimeter FWA Systems Through Site Diversity Based on Detailed Rainfall Intensity Data

Two years of high temporal- and spatial-resolution radar data is used to quantify the rain-attenuation diversity gain available in 26 GHz fixed wireless access systems having sight of the second transmitter. The service area defined by attenuation contours on the least-faded link is determined; the results show that an expansion of the service area is possible even over short paths. Service area contours with and without diversity are derived from radar observations of rainfall rate. Good agreement is obtained with similar results for a statistical model based on a gamma probability distribution and a negative-exponential spatial correlation function for rain rate (which are shown to fit observed data). For the service area defined by a bit error rate of 10-4 and availability of 4 times 10-1, site diversity expands the service area by up to 20% with a 10 km access point spacing.

Line-loss and size-reduction techniques for millimeter-wave rf front-end boards by using a polyimide/alumina-ceramic multilayer configuration

This paper proposes a concept for constructing low- loss and small-size millimeter-wave RF front-end boards by using a polyimide/alumina-ceramic multilayer configuration. The thick polyimide layer enables us to design low-loss wide microstrip lines (MSs). Moreover, the board size can be reduced by compactly arranging all RF and dc lines in the intermediate layers of the polyimide/alumina-ceramic substrate. The size of a prototype board designed for the quasi-millimeter-wave region is 30 mm 30 mm. In experiments, it showed 23.2-dB linear gain and 7.4-dBm RF output power in transmitter (TX) mode, and 3.1-dB linear gain and 20.1-dBm IF output power in receiver (RX) mode. These performance levels agree well with predicted values. This paper further discusses applications to the integration of passive circuits fabricated in the substrate. The proposed configuration has enough potential to integrate all monolithic microwave integrated circuit (MMIC) chips, dc-bias integrated circuits (ICs), and passive circuits, and can improve the total performance in terms of the RF characteristics, board size, and fabrication cost. conductor wafers and lead to cost reduction. They adopt thin polyimide layers to form thin film microstrip lines (TFMSs). Their patterning flexibility on the semiconductor chip makes it possible to design various kinds of functional circuits and to connect them within a small area, and results in fabrication of multifunctional one-chip MMICs (3). Nevertheless, it is difficult to integrate circuits fabricated by different device processes into one circuit module because all unit circuits in a 3-D MMIC share the same semiconductor substrate. The ability to integrate different types of active devices improves the total circuit performance and increases the field of 3-D

Inter-cluster interference canceller for multiuser MIMO distributed antenna systems

We propose a co-channel inter-cluster interference canceller for distributed antenna systems (DAS) that utilize the multiuser Multiple Input Multiple Output (MU-MIMO) technique in the downlink. We first define the cluster as a virtual cell that consists of a few remote antennas and subscriber stations which communicate cooperatively by MU-MIMO. Multiuser beamforming is applied to each cluster, so the proposed method can decrease the computational complexity of spatial division multiplexing processes compared to MIMO systems with large number of antennas. Though clustering causes co-channel inter-cluster interference, it can be cancelled simply by linear processing of the downlink transmission signals. Computer simulations show that the proposed method enables denser cluster configurations. The method contributes to the practical realization of distributed antenna systems through its effective frequency reuse.