Toshihiko Yoshimasu

An HBT MMIC power amplifier with an integrated diode linearizer for low-voltage portable phone applications

This paper gives a detailed description of a novel linearization technique using a transistor base-collector junction diode. The novel linearization technique effectively improves the gain compression and phase distortion of the heterojunction bipolar transistor (HBT) with no additional dc consumption, leading to highly efficient linear amplification of the /spl pi//4 DQPSK modulation signals. An AlGaAs/GaAs HBT monolithic microwave integrated circuit (MMIC) linear power amplifier was fabricated using the novel linearization technique for the handsets used in the 1.9 GHz Japanese Personal Handy Phone System (PHS). The fabricated HBT MMIC power amplifier exhibits an output power of 21 dBm and a power-added efficiency as high as 37% at an operation voltage of 2.7 V. At this rated output power, the adjacent channel power rejection in /spl plusmn/600 kHz offset frequency bands is -55 dBc and the error vector magnitude is 4.3%. This measured linearity is well within the PHS standard.

A 3.5 W HBT MMIC power amplifier module for mobile communications

A 900 MHz-band GaAs/GaAlAs HBT MMIC power amplifier module has been developed for mobile communications by using a novel assembly technique called BHS and an AlN package as the MMIC chip carrier. The power module gave a peak output power of 3.7 W and a power-added efficiency of 54.5% with a +6 V single supply voltage.<<ETX>>

An HBT MMIC linear power amplifier for 1.9 GHz personal communications

This paper describes a special circuit design concept for high efficiency linear amplification of /spl pi4 DQPSK modulation signals. A fabricated HBT MMIC linear power amplifier exhibited an output power of 21.2 dBm and a power added efficiency of 36% along with an adjacent channel interference of -55 dBc in +/- 600 kHz offset frequency bands.<<ETX>>

Miniaturized low noise variable MMIC amplifiers with low power consumption for L-band portable communication applications

Miniaturized L-band low-noise variable gain amplifiers for portable mobile communication equipment applications are discussed. The fabricated monolithic microwave integrated circuits (MMICs) use D-mode GaAs MESFETs and need only positive bias. The amplifier has a noise figure of 3 dB and a gain of 14 dB. The chip size is approximately 1 mm*1 mm and the current dissipation is only 1.8 mA.<<ETX>>

High-efficiency HBT MMIC linear power amplifier for L-band personal communications systems

A heterojunction bipolar transistor (HBT) MMIC linear power amplifier is demonstrated for the 1.9 GHz Japanese Personal Handy Phone utilizing the /spl pi//4 DQPSK modulation technique. At an operating voltage of only 3 V, an output power of 21 dBm and a power added efficiency of 35% are obtained along with a modulation vector error of 4.5% and an adjacent channel interference of /spl minus/60 dBc in +//spl minus/600 kHz offset frequency bands.<<ETX>>

High power AlGaAs/GaAs HBTs and their application to mobile communications systems

This paper addresses the power application of AlGaAs/GaAs heterojunction bipolar transistors (HBTs) to L-band mobile communications systems. From points of view of circuit and systems design, features of HBT technology are discussed and compared with those of GaAs MESFET technology.

A low distortion and high efficiency HBT MMIC power amplifier with a novel linearization technique for /spl pi//4 DPSK modulation

A novel linearization technique which improves the phase distortion and gain compression of a power amplifier is proposed in this paper. Moreover, a low distortion and high efficiency AlGaAs/GaAs HBT MMIC power amplifier for the 1.9 GHz PHS system has been demonstrated using the novel linearization technique. The HBT MMIC power amplifier exhibits an output power of 21 dBm and a power added efficiency as high as 37% at an operation voltage of 2.7 V with linearity well within the PHS standard.

High-efficiency AlGaAs/GaAs HBT power amplifier MMIC for 1.9 GHz Japanese digital cordless phone

A highly efficient personal hand phone (PHP) power amplifier monolithic microwave integrated circuit (MMIC) based on AlGaAs/GaAs heterojunction bipolar transistor (HBT) technology is discussed. The amplifier operates at a supply voltage of only 3 V, and yet a power-added efficiency as high as 40% is achieved at a 1-dB compression point of 24 dBm. This is the highest power-added efficiency ever reported for such an amplifier operating at any voltage. The amplifier also has high linearity.<<ETX>>

A low current GaAs monolithic image rejection downconverter for X-band broadcast satellite applications

The design, fabrication, and performance of a fully integrated X-band monolithic image rejection downconverter are described. The downconverter consists of a low-noise amplifier, an image rejection mixer, and an IF amplifier. The downconverter receives RF signals between 11.7 and 12.3 GHz and converts them down to IF frequency between 1.0 and 1.6 GHz. A conversion gain of 46+or-1 dB, a noise figure of less than 3.3 dB, and an image rejection of 30 dB have been achieved over the RF frequency range. The chip size of the downconverter is 1.9 mm*2.2 mm, and its current dissipation is only 43 mA. Since the downconverter has sufficient image rejection due to an on-chip bandstop filter, it requires no off-chip circuits. Therefore, the use of this downconverter in X-band broadcast satellite applications will lead to a great reduction in size and current dissipation. >

A miniature low current GaAs MMIC downconverter for Ku-band broadcast satellite applications

A miniature low-current GaAs monolithic microwave integrated circuit (MMIC) downconverter with a novel image rejection filter was developed for commercial Ku-band broadcast satellite receivers. The low-noise RF amplifier, image rejection filter mixer, and intermediate-frequency amplifier were integrated on this MMIC. This MMIC used 0.3- mu m-gate ion-implanted GaAs MESFETs. The individual circuit designs and performance are described. The current consumption of the MMIC downconverter was only 40 mA. The chip size of the MMIC downconverter with the image rejection filter was 1.7 mm*2.05 mm.<<ETX>>