Shigekazu Hori

GaAs Monolithic MIC's for Direct Broadcast Satellite Receivers

A 12-GHz low-noise amplifier (LNA), a 1-GHz IF amplifier (IFA), and an 11-GHz dielectric resonator oscillator (DRO) have been developed for DBS home receiver applications by using GaAs monolithic microwave integrated circuit (MMIC) technology. Each MMIC chip contains FETs as active elements and self-biasing source resistors and bypass capacitors for a single power supply operation. It also contains dc-block and RF-bypass capacitors. The three-stage LNA exhibits a 3.4-dB noise figure and a 19.5-dB gain over 11.7-12.2 GHz. The negative-feedback-type three-stage IFA shows a 3.9-dB noise figure and a 23-dB gain over 0.5-1.5 GHz. The DRO gives 10-mW output power at 10.67 GHz, with a frequency stability of 1.5 MHz over a temperature range from -40-80° C. A direct broadcast satellite (DBS) receiver incorporating these MMICs exhibits an overall noise figure of ≤ 4.0 dB for frequencies from 11.7-12.2 GHz.

Broadband HEMT and GaAs FET Amplifiers for 18 - 26.5 GHz

Two types of broadband amplifiers operating over 18 to 26.5 GHz have been developed by using newly developed 0.4-µm gate HEMTs and conventional 0.25-µm gate GaAs FETs. The four-stage EEMT amplifier exhibits a noise figure of <= 7.2 d.B and a gain of 19.3 +- 1.8 dB and the five-stage GaAs FET amplifier exhibits a noise figure of <= 12 dB and a gain of 22.7 +- 2.2 dB over 18 to 26.5 GHz. The minimum noise figures in the measured frequency ranqe are 5.0 dB and 7.5 dB for the HEMT and GaAs FET amplifiers, respectively. No essential difference is found between the amplifiers in input/output VSWR, output power and temperature variation of noise figure and gain.

X and Ku band high power GaAs FETs

Internally matched GaAs FETs, with output powers of more than 10 W have been developed for the 10.7-11.7- and 14.0-14.5-GHz bands. These devices, with a total gate width of 32 mm, consist of two chips that are fabricated by direct ion implantation and chemical dry etching. At 14.25 GHz, the Ku-band device has achieved an output power of 41 dBm, a power gain of 5 dB and a power-added efficiency of 21%. At 11.2 GHz, the X-band device has delivered 41.2 dBm, 5.8 dB and 25%, respectively, at the 1-dB gain compression point.<<ETX>>

Direct-Coupled GaAs Monolithic IC Amplifiers

A two-stage GaAs FET monolithic amplifier has been developed that exhibits a noise figure of 2dB and a gain of 20dB at frequencies from 0.3 to 1.5 GHz. The FET gate width is optimized to 1mm to lower the noise figure for a 50 Omega signal source impedance. A direct-coupled scheme is used for chip size reduction. All the circuit elements such as FETs, Schottky diodes and resistors are fabricated by using selective ion-implantation for realizing a planar structure.

20 GHz-Band Low-Noise HEMT Amplifier

A 20 GHz-band low-noise amplifier has been developed by using newly developed 0.25-µm gate HEMTs. The amplifier has been fabricated by cascading six single-ended unit amplifiers without any isolators at the interstages. The HEMT amplifier exhibits a noise temperature of 170 K (NF = 2.0 dB) and a gain of 47 dB over 17.5 to 19.5 GHz in an uncooled operation. Noise temperatures of 130 K (NF = 1.6 dB) and 110 K (NF = 1.4 dB) have been obtained at -20°C and -50°C, respectively.

Broadband HEMT Amplifier for 26.5 - 40.0 GHz

A broadband amplifier operating over 26.5 to 40 GHz has been developed by using 0.25-µm gate HEMTs. The amplifier has been fabricated by cascading five unit amplifiers. Two balanced-type unit amplifiers are used in an input and an output stages to realize good input/output VSWRs . Three single-ended unit amplifiers are installed in the intermediate stages to achieve higher gain. The developed amplifier shows a noise figure of <= 7.0 dB, a gain of 18.2 +- 1.6 dB and inputfoutput VSWRs of <= 2.0 over 26.5 to 40 GHz.

Ka-band 1 watt power GaAs MMICs

High-power and high-gain Ka-band GaAs monolithic microwave integrated circuits (MMICs) were developed using a Be coimplantation technique. At 29.5 GHz, an output power of 1 W with 4.2 dB gain was obtained for a 4.8-mm width MMIC. An intercept point of +42 dBm has been obtained from the third-order intermodulation distortion measurement.<<ETX>>

GaAs Monolithic MIC Mixer-IF Amplifiers for Direct Broadcast Satellite Receivers

An MMIC mixer-IF amplifier (MIX-IFA) and a band-pass filter (BPF) have been developed for DBS receiver applications. The MIX-IFA chip with a size of 2.0 x 2.25 mm/sup 2/contains a balanced-type diode mixer using a newly designed 3-dB hybrid circuit and a resistive feedback-type single-stage IF amplifier. The MIX-IFA shows a noise figure of = 10 dB for images. With the previously developed LNA, IFA and local oscillator, all MMIC components for DBS receiver are prepared.

3-GHz 15-W Silicon Bipolar Transistors

Silicon bipolar transistors delivering 15W output power with 4.8dB gain and 38% collector efficiency have been developed at 3GHz. The transistors have been fabricated by boron ion-implantation for base region and As diffusion from doped poly silicon for emitter region. Chemical dry etching techniques for fine patterning, and internal matching-techniques have been applied.

Millimeter-Wave MIC and MMIC Amplifiers using Pseudomorphic HEMT

This paper reviews the recent works at Toshiba millimeter-wave amplifiers based on the pseudomorphic HEMTs. The HEMT devices used is 0.1 ¿ m-gate planar doped pseudomorphic HEMT with a gate width of 50 or 100 ¿ m. Structures, performances and applications of 43 GHz- and 60 GHz-bands amplifiers and 40-60 GHz amplifier have been presented with emphasis on their practicability as well as their low noise performance. Monolithic gain blocks which are essentially HEMT chips with monolithically integrated matching circuits are also described.