Takuo Kashiwa

V-band high-power low phase-noise monolithic oscillators and investigation of low phase-noise performance high drain bias

This paper reports on the excellent performance of V-band monolithic high electron-mobility transistor (HEMT) oscillators, and discusses oscillation characteristics on drain bias. With regard to output characteristics, double-hetero (DH) HEMT (especially with a high-density Si-planar doped layer) are superior to single-hetero (SH) HEMTs. A monolithic microwave integrated circuit (MMIC) oscillator has been developed with a planar doped DH HEMT and has achieved the peak output power of 11.1 dBm at a 55.9-GHz oscillation frequency. Phase noise of -85 dBc/Hz at 100-kHz offset and -103 dBc/Hz at 1-MHz offset have been achieved at a drain voltage of 5.5 V and a gate voltage of 0 V. These characteristics have been achieved without any buffer amplifiers of dielectric resonators. This study has revealed that the phase noise decreases as drain voltage increases. This phenomenon is caused by lower pushing figure and lower noise level at a low-frequency range obtained under a high drain voltage. It is because the depletion layer in the channel is extended to the drain electrode with increase of drain voltage, resulting in the small fluctuation of the gate-to-source capacitance. We also investigate low-frequency noise spectra of AlGaAs-InGaAs-GaAs DH HEMTs with different bias conditions. The low-frequency noise decreases for more than 3 V of the drain voltage. A unique mechanism is proposed to explain this phase noise reduction at high drain voltage.

A high-performance Ka-band monolithic variable-gain amplifier using dual-gate HEMTs

The author describes the excellent performance of a Ka-band monolithic variable-gain amplifier monolithic microwave integrated circuit (VGA MMIC) using dual-gate AlGaAs-InGaAs pseudomorphic high electron mobility transistors (HEMTs). The dual-gate HEMT can be fabricated by the same process as a single-gate HEMT. To achieve low-noise performance, a single-gate HEMT is employed in the first stage of the VGA MMIC. However, in the second and third stages, dual-gate HEMTs are used for gain control performance with higher gain. The VGA MMIC achieves more than 30-dB gain with more than 50-dB gain control range from 30 to 35 GHz. A noise figure of 1.4 dB with an associated gain of 29.2 dB is achieved at 33 GHz when biased for a low-noise performance.

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.

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 V-band monolithic InP HEMT resistive mixer with low LO-power requirement

We report on a 60 GHz-band InP HEMT resistive mixer that can be operated with very low LO-power. The mixer is fabricated using Coplanar Waveguide (CPW) techniques to reduce production costs. A narrow source-to-drain space and a short length gate (0.15 /spl mu/m) are employed in order to reduce the LO-power requirement. The minimum conversion loss of 8.4 dB is achieved at a 55 GHz RF frequency with LO power of -2 dBm. This low LO-power is comparable with the best data ever reported for millimeter-wave passive mixers. In addition, the mixer has an excellent IF output linearity that indicates capability to provide good intermodulation performance.

A super low noise AlInAs/InGaAs HEMT processed by selective wet gate recess etching

A 0.15 /spl mu/m T-shaped gate AlInAs/InGaAs high electron mobility transistor (HEMT) with excellent RF performance has been developed using a selective wet gate recess etching. The etching condition for recess formation is optimized and an extremely low minimum noise figure (F/sub min/) of 0.9 dB with an associated gain (G/sub a/) of 7.0 dB has been achieved at 60 GHz for a SiON-passivated device.

Low noise HEMTs with multi-feed gate configurations

A novel multifeed gate configuration using air-bridge metallization is demonstrated for low-noise high electron mobility transistors (HEMTs). The configuration is designed according to the detailed analysis of parasitic gate capacitances. Very low noise figures of 0.55 and 1.6 dB have been achieved at 12 and 40 GHz for 0.25 mu m gate AlGaAs/InGaAs pseudomorphic HEMT respectively. A noise figure of 4.1 dB and a gain of 12.2 dB at 40 GHz were obtained for two-stage HEMT monolithic microwave integrated circuits.<<ETX>>