Takayuki Katoh

A 38/77 GHz MMIC transmitter chip set for automotive applications

This paper describes the successful development of 38/77 GHz transmit MMICs for automotive applications. They consist of a 38 GHz amplifier, a frequency doubler, and a 77 GHz power amplifier. These amplifiers achieve output powers of 16 dBm at 38 GHz and 15 dBm at 76.5 GHz at 1 dB gain compression point. The output power of the 77 GHz amplifier is one of the highest delivered by a single chip MMIC at 76.5 GHz. The frequency doubler delivers an output power of 5.7 dBm at 76.5 GHz. These results are promising for automotive applications in the W-band.

A 12 GHz-band monolithic HEMT low-noise amplifier

A 12-GHz-band two-stage monolithic HEMT (high-electron-mobility transistor) low-noise amplifier has been developed. The HEMT used in the amplifier has a gate length of 0.5 mu m and shows a typical noise figure of 1.0 dB at 12-GHz. The noise figure of the amplifier is less than 1.7 dB with an associated gain over 15.0 dB in the frequency range from 11.7 to 12.7 GHz. The input VSWR (voltage standing-wave ratio) is less than 1.9 and the output VSWR is less than 1.5. These results suggest that the HEMT MMIC (monolithic microwave integrated circuit) has promising applicability for microwave low-noise amplification.<<ETX>>

Millimeter-wave MMIC switches with pHEMT cells reduced parasitic inductance

High isolation millimeter-wave switches have been successfully developed using a newly developed line unified shunt pHEMT structure, which is effective to reduce parasitic inductance of its short circuit. The developed V-band SPDT switch shows an isolation of greater than 40 dB and an insertion loss of 1.8 dB at 60 GHz, and the W-band SP3T switch shows an isolation of greater than 35 dB and an insertion loss of 2.5 dB at 77 GHz. Input and output return losses are better than 12 dB in ON-state. These performances of high isolation and low insertion loss are the best among V-band and W-band pHEMT MMIC switches. The switches consume no DC power, and require no complex off-chip bias circuitry.

1 watt compact Ka-band MMIC power amplifiers using lumped element matching circuits

A compact MMIC chip set for Ka-band communication systems has been developed. A two stage power MMIC amplifier using only lumped elements and narrowly spaced lines for the matching circuit delivers 1.44 watt at 30 GHz with a very small die size of 1.94 mm/spl times/2.0 mm. The designing scheme is confirmed to be useful for cost reduction.

A Q-band high gain and low noise variable gain amplifier using dual gate HEMTs

A Q-band high gain and low noise Variable Gain Amplifier (VGA) using dual gate AlGaAs/InGaAs pseudomorphic HEMTs has been developed. The dual gate HEMT can be fabricated using the same process as the single gate HEMT with a gate length of 0.15 /spl mu/m. The Q-band VGA consists of a 1-stage low noise amplifier MMIC using a single gate HEMT and a 2-stage VGA MMIC using dual gate HEMTs. The VGA has a gain of more than 20 dB from 41 GHz to 52 GHz. A gain control range of more than 30 dB is obtained in the same frequency range. A minimum noise figure of 1.8 dB with an associated gain of 22 dB is achieved at 43 GHz when biased for a low noise figure. This performance is comparable with the best data ever reported for LNAs at Q-band including both GaAs based HEMTs and InP based HEMTs.

A 40 GHz-band fully monolithic VCO with a one-wave length microstrip resonator for accurate oscillation frequency

A 40 GHz-band fully monolithic VCO with a one-wavelength microstrip resonator (MSR) associated with a dumping resistor is presented. Employing a one-wavelength MSR, high setting accuracy of oscillation frequency can be obtained, and it is a very effective method to improve yield of millimeter wave MMIC oscillator. Also the one-wavelength MSR with a dumping resistor is proposed for suppression of parasitic oscillation. In analytical approach, variation of oscillation frequency is less than 150 MHz over C/sub gs//C/sub ds//C/sub dg/ variation of /spl plusmn/10% in worst case. The measured VCO tuning range is 493 MHz and it is much wider than the variation of oscillation frequency caused by process variations.

Design of W-band monolithic low noise amplifiers using accurate HEMT modeling

A W-band monolithic two-stage low noise amplifiers have been developed using new accurate HEMT modeling. The modeling includes intrinsic FET noise parameters that are independent of frequency. A noise figure of 5.5 dB with an associated gain of 8.7 dB is achieved at 91 GHz when biased for low noise figure, and a small signal gain of 10.4 dB with noise figure of 5.9 dB is obtained when biased for high gain. Good agreement between measured and simulated data of the low noise amplifier verifies the HEMT modeling.<<ETX>>

A W-band monolithic low noise AlGaAs/InGaAs pseudomorphic HEMT amplifier mounted on a small hermetically-sealed package with waveguide interface

A W-band monolithic low noise AlGaAs/InGaAs/GaAs pseudomorphic HEMT amplifier mounted on a small hermetically-sealed package has been developed for use in Advanced Microwave Scanning Radiometer. A six-stage amplifier cascading three two-stage MMIC amplifier chips is assembled on a small hermetically-sealed package with waveguide interface and has achieved a noise figure of 4.3 dB with a gain of 28.1 dB at 91 GHz. The overall amplifier measures 12/spl times/32.8/spl times/5.4 mm/sup 3/. This is the first W-band multi-stage monolithic low noise amplifier mounted on a hermetically-sealed package.<<ETX>>

A V-band drain injected/resistive dual-mode monolithic mixer

This paper is the first to report on a V-band dual-mode MMIC mixer that provides a drain injected mode and a resistive mode with the same MMIC design. This design allows the devices impedances of a drain injected mode and a resistive mode to approach each other at a higher LO-power. The developed GaAs MMIC delivers excellent mixer performances in both modes at 60 GHz. It provides a 3.7 dB conversion gain and a 7.8 dB noise figure under 10 dBm LO power for the drain injection mode at a 61 GHz RF frequency, while providing a 7.7 dB conversion loss and a 9.8 dB noise figure under 0 dBm LO power for the resistive mode at a 60.6 GHz RF frequency.

A high electron mobility transistor with a mushroom gate fabricated by focused ion beam lithography

A superlow-noise HEMT (high-electron-mobility transistor) with a mushroom-shaped quarter-micrometer gate was fabricated using focused ion-beam lithography. The mixed exposure of Be/sup ++/ and Si/sup ++/ focused ion beams was used to form T-shaped resist profiles. This method has the advantages of a high reproducibility and controllability of resist profiles. The gate resistance was extremely reduced by producing this mushroom-shaped gate. As a result, the fabricated HEMT showed a minimum noise figure (NF/sub min/) of 0.68 dB, with an associated gain (G/sub a/) of 9.7 dB at 12 GHz. This device also showed an NF/sub min/ of 0.83 dB with a G/sub a/ of 7.7 dB at 18 GHz.<<ETX>>