A Q-Band High Gain, Low Noise Variable Gain Amplifier Using Dual Gate AlGaAs/InGaAs Pseudomorphic HEMTs

Takayuki KATOH
Hiroyuki MINAMI
Toshiaki KITANO
Noriyuki TANINO
Tadashi TAKAGI

IEICE TRANSACTIONS on Electronics   Vol.E79-C    No.4    pp.573-579
Publication Date: 1996/04/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Semiconductor Materials and Devices
millimeter-wave,  low noise figure,  MMIC,  dual gate,  gain control,  

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A Q-band high gain and low noise Variable Gain Amplifier (VGA) module using dual gate AlGaAs/InGaAs pseudomorphic HEMTs has been developed. The dual gate HEMT can be fabricated by the same process of the single gate HEMT which has the gate length of 0.15 µm. The Q-band VGA module consists of a 1-stage low noise amplifier (LNA) MMIC using a single gate HEMT and a 2-stage VGA MMIC using dual gate HEMTs. During the design, an accurate noise modeling is introduced to achieve low noise performance. A fully passivated film is employed to achieve reliability. The VGA module has a gain of more than 20 dB from 41 GHz to 52 GHz and a maximum gain of 24.5 dB at 50 GHz. A gain control range of more than 30 dB is achieved in the same frequency range. A phase deviation is less than 10 degrees in 10 dB gain control range. A minimum noise figure of 1.8 dB with an associated gain of 22 dB is achieved at 43 GHz and the noise figure is less than 2.5 dB with associated gain of more than 20 dB from 41 GHz to 46 GHz when biased for 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.