Masaaki Nishijima

A 26GHz Short-Range UWB Vehicular-Radar Using 2.5Gcps Spread Spectrum Modulation

A 26 GHz short-range radar (SRR) system has been developed based on a 2.5 Gcps direct sequence spread spectrum (DSSS) technique combined with simple homodyne detection. Separate frequency-triplers have been provided with transmitter (TX) and receiver (RX) chips to cut off the carrier-leakage path from local signal. By using this configuration, carrier-leakage in TX signal can be significantly suppressed falling into the satisfactory range of the UWB regulation. The present radar system achieved the maximum detection range of 14 m with the resolution of 6 cm. TX, RX, and PN generator chipset has been developed using InGaP/GaAs HBT process, where fT/fmax of 65 GHz/ 83 GHz were attained.

A fully integrated broad-band amplifier MMIC employing a novel chip-size package

In this work, we used a novel RF chip-size package (CSP) to develop a broad-band amplifier monolithic microwave integrated circuit (MMIC), including all the matching and biasing components, for Ku- and K-band applications. By utilizing an anisotropic conductive film for the RF-CSP, the fabrication process for the packaged amplifier MMIC could be simplified and made cost effective. STO (SrTiO/sub 3/) capacitors were employed to integrate the dc biasing components on the MMIC. A novel pre-matching technique was used for the gate input and drain output of the FETs to achieve a broad-band design for the amplifier MMIC without any loss of gain. To improve the circuit stability of the amplifier MMIC in the out-of-band, a parallel RC circuit was employed at the input of the amplifier MMIC. The packaged amplifier MMIC exhibited good RF performance and stability over a wide frequency range. This work is the first report of a fully integrated CSP amplifier MMIC successfully operating in the Ku-/K-band.

A 3.5V, 1.3W GaAs power multichip IC for cellular phone

A GaAs power multichip IC (MCIC) operating at 3.5 V for cellular phone has been developed. The MCIC can deliver an output power over 1.3 W with a power-added efficiency of 60% from 890 to 950 MHz. It is comprised of two GaAs MESFETs, three GaAs passive matching chips and a printed board on which biasing networks are fabricated. These components are mounted on an aluminum nitride (AlN) package. The volume of the MCIC is only 0.4 cc, half that of conventional power hybrid ICs. This MCIC will contribute to realization of high performance and very compact cellular phones.<<ETX>>

A fully-integrated broadband amplifier MMIC employing a novel chip size package

In this work, using a novel RF-CSP, a broadband amplifier MMIC including all the matching and biasing components was developed for Ku and K band applications. To integrate DC biasing components on the MMIC, an STO (SrTiO/sub 3/) capacitor was employed. By employing an anisotropic conductive film for the RF-CSP, the MMIC fabrication process became very simple and cost effective. The packaged amplifier MMIC exhibited good RF performance in a wide frequency range. This work is the first report for fully-integrated Ku or K band MMICs which have all the biasing and matching components.

A 3.5 V, 1.3 W GaAs power multi-chip IC for cellular phones

A GaAs power multi-chip IC (MCIC) operable at a voltage of 3.5 V designed for cellular phones has been developed. The MCIC is able to deliver an output power of 1.3 W with a power-added efficiency of 60% in a frequency range from 890 to 950 MHz. This consists of two GaAs MESFETs, three GaAs passive matching chips, and a printed circuit board on which biasing networks are disposed. These are mounted on an aluminum nitride (AlN) package, occupying a half volume of conventional power hybrid ICs, i.e., only 0.4 cc. In order to improve the low voltage operation characteristics, a GaAs power MESFET operable at a low voltage of 3.5 V with an output power of 32 dBm and a power-added efficiency of 65% is developed, and microstrip lines having high impedance characteristics are incorporated also in order to minimize the conductor loss of matching network. The MCIC would be highly useful to develop compact cellular phones with advanced characteristics. >

High fmax with High Breakdown Voltage in AlGaN/GaN MIS-HFETs using In-Situ SiN as Gate Insulators

AlGaN/GaN heterojunction transistors (HFETs) with metal-insulator-semiconductor (MlS)-type gate structure is promising for high frequency and high power applications owing to the superior material properties together with the reduced gate leakage current. In this paper, we present a novel AlGaN/GaN MIS-HFET using so-called in-situ SiN as a gate insulator. The in-situ SiN with a crystalline structure is formed subsequently after the epitaxial growth in the same reactor without any exposure in the air. The formation of the in-situ SiN greatly enhanced the sheet carrier concentration, which helps the reduction of the parasitic resistances. The fabricated MIS- HFET exhibits very high maximum oscillation frequency (fmax) of 203 GHz for the device with the gate length of 100 nm. The device exhibits the off-state breakdown voltages of 190 V at highest maintaining the high fmax over 190 GHz, and is thus promising for high frequency and high power applications including future millimeter wave communication systems.

A K-band AlGaN/GaN HFET MMIC Amplifier on Sapphire using novel superlattice cap layer

We have developed a K-band AIGaN/GaN HFET MMIC amplifier by applying an AIGaN/GaN superlattice (SL) capped structure on sapphire substrate. Owing to the lowest (0.4 Ω. mm) source resistance of A1GaN/GaN HFETs, the HFETs exhibited excellent DC and RF characteristics, and sufficient ability to operate in the K-band frequency range is obtained. The fabricated MMIC with a CPW-line structure exhibited a small-signal gain higher than 10 dB with a 3-dB bandwidth of 20-24.5 GHz and that of 13 dB at 21.6GHz when biased at a supply voltage of 7 V. The 1dB compression point (P 1 d B ) referred to output of 15.4 dBm at 21.6 GHz was obtained. This work is the first report of MMIC amplifier fabricated on sapphire successfully operating in the K band.

A high performance transceiver hybrid IC for PHS hand-set operating with single positive voltage supply

A high performance transceiver hybrid IC (HIC) operating with single positive voltage supply has been developed for PHS hand-set. The HIC integrates a power amplifier (PA), a front-end (F/E) IC, a T/R SPDT switch (SW) and their peripheral circuits, which are mounted on the HIC circuit board with thick Cu metal heat-sink. In the transmitter block, the PA with a SW exhibits a low dissipation current of 190 mA, a high power gain of 39.4 dB and a low adjacent channel leakage power of -56.4 dBc at an output power of 20.5 dBm. In the receiver block, the F/E with a SW exhibits a low noise figure of 3.7 dB, a low dissipation current of 4.8 mA and a high conversion gain of 25.4 dB. The HIC needs only single positive voltage supply of 3.5 V. The HIC size is only 10 mm/spl times/13 mm/spl times/1.9 mm.

High-Power and High-Gain S-band AlGaN/GaN HFETs with Source Field Plates on Si Substrate

1. Introduction AlGaN/GaN heterojunction field-effect transistors (HFETs) have been widely investigated for high-frequency and high-power applications such as base stations of cellular phones, taking advantages of the superior material properties. Higher gain is also required in such applications, which reduces the number of amplifiers leading to smaller system in size. Introduction of field plate structures in the HFETs increases the gain by reducing gate-drain feedback capacitances (C gd) [1]. However, there has been a limitation of increasing the maximum output power keeping the high gain in the reported devices. In this paper, we present 203W output power with high gain of 16.9dB at 2.5GHz in AlGaN/GaN HFETs on Si substrates with source field plates. The detailed simulation using the device parameters at various biasing conditions reveals that shortening the field plate length achieves high output power together with the high gain, which well agrees with the experimental esults. r

A K-band AlGaN/GaN-based MMIC amplifier with microstrip lines on sapphire

We present a K-band AlGaN/GaN HFET MMIC amplifier with integrated microstrip lines on sapphire. The microstrip lines with via-holes through chemically stable sapphire are successfully formed for the first time by using a novel laser drilling technique. AlGaN/GaN HFETs with superlattice capping layers in the MMIC exhibit RF performance with ƒ max of 160GHz and NF min of 2.5dB at 28GHz. The fabricated 3-stage MMIC amplifier exhibits a small-signal gain as high as 22dB at 26GHz with a 3dB bandwidth of 4GHz. The presented K-band MMIC would be applicable to future millimeter-wave communication systems.