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Kazuo SHIRAKAWA Yoshihiro KAWASAKI Masahiko SHIMIZU Yoji OHASHI Tamio SAITO Naofumi OKUBO Yashimasa DAIDO
We studied a 0.15-µm InGaP/InGaAs/GaAs pseudomorphic HEMT operating under a negative drain bias, using a parameter extraction technique based on an analytical parameter transformation. The bias-dependent data of smallsignal equivalent circuit elements was obtained from Sparameters measured at up to 62.5 GHz at various bias settings. We then described the intrinsic part of the device using a new empirical large-signal model in which charge conservation and dispersion effects were taken into consideration. As far as we know, this is the first report to clarify the behavior of a HEMT operating under negative drain bias. We included our largesignal model in a commercially-available harmonic-balance simulator as a user-defined model, and designed a 60 GHz MMIC oscillator. The fabricated oscillator's characteristics agreed well with the design calculations.
Tamio SAITO Norio HIDAKA Yoji OHASHI Kazuo SHIRAKAWA Yoshihiro KAWASAKI Toshihiro SHIMURA Hideyuki OIKAWA Yoshio AOKI
This paper presents the fabrication and evaluation of a 60 GHz fully integrated MMIC one-chip receiver based on pseudomorphic InGaP/InGaAs/GaAs HEMT technology. The receiver consists of two 2-stage low-noise amplifiers (LNAs), a single-balanced active-gate mixer, a local oscillator (LO), and a buffer amplifier for the LO. The receiver has a conversion gain of greater than 17 dB from 60.2 GHz to 62.3 GHz, and the maximum conversion gain is 20 dB at 62.2 GHz. The noise figure of receiver is less than 6 dB in the IF range between 100 MHz and 1 GHz for a 61.536 GHz LO frequency, and the minimum noise figure is 4.9 dB at 1 GHz IF.
Tamio SAITO Yoji OHASHI Yoshihiro KAWASAKI Naofumi OKUBO Yutaka MIMINO
This paper describes millimeter-wave HEMT oscillators developed to operate at 50 GHz and above. To determine the feasibility of using HEMTs for millimeter-wave oscillators, we measured and compared the low-frequency noise characteristics of both HEMT and GaAs MESFET devices and found them to have nearly identical characteristics. We also estimated the S parameters of a HEMT biased at Vds-3V and Ids5 mA for an equivalent circuit study. The oscillators consisted of a microstrip line resonator, a matching circuit, and a bias circuit. The output power and oscillation efficiency for the 60-GHz HEMT oscillator was 2.6dBm and 9.5%, and 2.8dBm and 6.4% for the 50-GHz oscillator. The efficiencies of these HEMT oscillators are higher than that of GaAs MESFET oscillators at millimeter-wave frequencies.