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ABSTRACT: A C-Ku band GaN monolithic microwave integrated circuit (MMIC) transmitter/receiver (T/R) frontend module with a novel RF interface structure has been successfully developed by using multilayer ceramics technology. This interface improves the insertion loss with wideband characteristics operating up to 40 GHz. The module contains a GaN power amplifier (PA) with output power higher than 10 W over 6-18 GHz and a GaN low-noise amplifier (LNA) with a gain of 15.9 dB over 3.2-20.4 GHz and noise figure (NF) of 2.3-3.7 dB over 4-18 GHz. A fabricated T/R module occupying only 12 × 30 mm<sup>2</sup> delivers an output power of 10 W up to the Ku-band. To our knowledge, this is the first demonstration of a C-Ku band T/R frontend module using GaN MMICs with wide bandwidth, 10W output power, and small size operating up to the Ku-band.
Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International; 07/2011
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Y. Nakasha,
S. Masuda,
K. Makiyama,
T. Ohki,
M. Kanamura,
N. Okamoto,
T. Tajima,
T. Seino,
H. Shigematsu,
K. Imanishi, T. Kikkawa,
K. Joshin,
N. Hara
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ABSTRACT: This paper presents two oscillators (OSCs) and a high power amplifier (PA) for millimeter-wave transceivers. The circuits were designed with a grounded coplanar waveguide (GCPW) and 0.12-μm GaN HEMT technology. One OSC, which was based on a simple series source feedback topology, oscillated at a frequency of 74.5 GHz with an output power of 2.2 mW (3.38 dBm). This oscillation frequency was the highest ever reported for GaN HEMT OSCs. Another OSC with a buffer delivered a record power of 85 mW (19.28 dBm) at 70.75 GHz. In addition, a single-chip PA with a 3-stage common source scheme delivered an output power of 1.3 W (31.13 dBm) at 75 GHz with a CW source module. The 3-dB bandwidth of the PA was 13 GHz from 67 to 80 GHz. The performance of these devices is sufficient for use in E-band fixed wireless access systems and automotive radar systems. The results demonstrate that the GaN HEMTs represent a feasible means of addressing the stringent demands imposed by various millimeter-wave applications.
Compound Semiconductor Integrated Circuit Symposium (CSICS), 2010 IEEE; 11/2010
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ABSTRACT: In this paper, we present the current status of GaN-high electron mobility transistor (HEMT) for power-supply-applications. Advantages of GaN HEMT are summarized with discussing required characteristics applying for power supplies. Then, we introduce our Enhancement-mode (E-mode) GaN MIS-HEMT technology. We focused on realizing both normally-off operation and high current density with high breakdown voltage. Detailed results are discussed in this paper. In particular, we developed a unique device structure called triple layer cap structure. High current density with normally-off mode was successfully achieved, which is preferable for power-supply application. We also demonstrated high speed performance with low on-resistance.
Power Electronics Conference (IPEC), 2010 International; 07/2010
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ABSTRACT: A 6-18 GHz monolithic microwave integrated circuit (MMIC) power amplifier (PA) was successfully developed using a quarter wavelength short stub and a monolithic broadband coupler for a non-uniform distributed power amplifier (NDPA) topology. This topology improved the output power at 18 GHz and attained a flat output power profile over 6-18 GHz. It also achieved filtering characteristics for both lower and higher cut-off frequencies. A fabricated MMIC PA with 0.25μm GaN HEMTs delivered an output power of more than 10 W with average power added efficiency (PAE) of 18% over 6 to 18 GHz. To the best of our knowledge, this is the best combination of output power and bandwidth for any solid-state MMIC amplifier operating up to the full Ku-band.
Microwave Symposium Digest (MTT), 2010 IEEE MTT-S International; 06/2010
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ABSTRACT: This letter presents details of high-performance enhancement-mode GaN MIS high-electron-mobility transistor (MIS-HEMT) devices. Devices with an n-GaN/i-AlN/n-GaN triple cap layer, a recessed-gate structure, and high- k gate dielectrics show high drain current and complete enhancement-mode operation. The maximum drain current and threshold voltage ( V <sub>th</sub>) are 800 mA/mm and +3 V, respectively. These results indicate that a recessed AlGaN/GaN MIS-HEMT with the triple cap could be a promising new technology for future device applications.
IEEE Electron Device Letters 04/2010; · 2.85 Impact Factor
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ABSTRACT: Carbon nanotubes (CNTs) have been successfully used as source bumps for flip-chip high power amplifiers (HPAs). We have fabricated fine pitch CNT bumps with metal coating, which have been connected to electrodes close to the active areas of AlGaN/GaN HEMTs. A flip-chip AlGaN/GaN HEMT HPA with a gate width of 28.8 mm utilizing CNT bumps and an operating voltage of 50 V exhibits an output power of 49.3 dBm at a frequency of 2.4 GHz.
Radio-Frequency Integration Technology, 2009. RFIT 2009. IEEE International Symposium on; 01/2010
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ABSTRACT: This paper presents W-band monolithic microwave integrated circuit (MMIC) amplifiers with grounded coplanar waveguide (GCPW) in 0.12 μm GaN HEMT technology. A fabricated four-stage low-noise amplifier (LNA) exhibited a record gain of 23 dB at 76.5 GHz and a first reported noise figure (NF) of 3.8 dB at 80 GHz for any W-band GaN MMIC. Another MMIC power amplifier (PA) delivered an output power of 25.4 dBm at 76.5 GHz with continuous wave (CW) operation. To our knowledge, this is the first demonstration of GaN LNA as well as GaN MMICs with GCPW in the W-band. In addition, a practical design technique to prevent instability of the W-band MMIC is described.
Microwave Conference, 2009. EuMC 2009. European; 11/2009
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ABSTRACT: In summary, we dem onstrated AlGaN/GaN enhancement-mode MIS-HEMTs that exhibited a high maximum drain current of 860 mA/mm and high off-state breakdown voltage of 320 V with threshold voltage of 3 V by introducing a piezoelectric-induced cap and a recessed ALD-MIS-gate structure. This is the highest Lja¿with the breakdown voltage of over 300 V for enhancement -mode HEMTs. The 1 mm gate width device showed the output power of 4.8 W/mm and high drain efficiency of 61% at the Vgs= 3.8 V. These results suggest that the recessed AlGaN/GaN MIS-HEMT with the triple layer cap could be a promising technique for the Enhancement-mode transistors with a high breakdown voltage.
Device Research Conference, 2009. DRC 2009; 07/2009
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H. Shigematsu,
Y. Inoue,
A. Akasegawa,
M. Yamada,
S. Masuda,
Y. Kamada,
A. Yamada,
M. Kanamura,
T. Ohki,
K. Makiyama,
N. Okamoto,
K. Imanishi, T. Kikkawa,
K. Joshin,
N. Hara
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ABSTRACT: In this paper, we report a C-band power amplifier with over 340-W output power using 0.8-mum GaN-HEMTs and an X-band power amplifier with over 100-W output power using 0.25-mum GaN-HEMTs. We used two-chip configurations and the three-stage impedance transformers to extend the bandwidth for both circuits. The input and output lines adjacent to each chip are divided by four to suppress the non-uniform heat distribution in a chip at high frequencies. As a result, we obtained 343-W output power and 53-% power added efficiency (PAE) at 4.8 GHz. This is the highest output power ever reported C-band power amplifiers. We also obtained 101-W output power and 53-% PAE at 9.8 GHz. This is also the highest PAE ever reported X-band power amplifiers with over 50-W output power.
Microwave Symposium Digest, 2009. MTT '09. IEEE MTT-S International; 07/2009
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ABSTRACT: In this paper, we describe highly reliable GaN high electron mobility transistors (HEMTs) for high-power and high-efficiency amplifiers. First, we present the reliability mechanisms and progress on the previously reported GaN HEMTs. Next, we introduce our specific device structure for GaN HEMTs for improving reliability. An n-GaN cap and optimized buffer layer are used to realize high efficiency and high reliability by suppressing current collapse and quiescent current (I<sub>dsq</sub>)-drift. Finally, we propose a new device process around the gate electrode for further improvement of reliability. Preventing gate edge silicidation leads to reduced gate leakage current and suppression of initial degradation in a DC-stress test under high-temperature and high-voltage conditions. Gate edge engineering plays a key role in reducing the gate leakage current and improving reliability.
Reliability Physics Symposium, 2009 IEEE International; 05/2009
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ABSTRACT: In this paper, we demonstrated a broadband GaN power amplifier hybrid IC with high power added efficiency (PAE) under CW operation using load-impedance change compensation technique. The external output matching circuit is composed of a transmission line, an open stub and a short stub with chip capacitors to realize both wide bandwidth and high voltage operation. As a result, we developed 7-12 GHz broadband medium power amplifier and demonstrated a CW output power of 6.5 W with the PAE of 40% using 0.5-mum GaN-HEMT technology at 7 GHz. The output power also exceeded 4.9 W with PAE of over 31% up to 11 GHz. At 12 GHz, the output power was 4.1 W with PAE of 26%.
Compound Semiconductor Integrated Circuits Symposium, 2008. CSIC '08. IEEE; 11/2008
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H. Shigematsu,
Y. Inoue,
S. Masuda,
M. Yamada,
M. Kanamura,
T. Ohki,
K. Makiyama,
N. Okamoto,
K. Imanishi, T. Kikkawa,
K. Joshin,
N. Hara
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ABSTRACT: In this paper, we report a C-band power amplifier with over 300-W output power using 0.8-mum GaN-HEMTs. We used two-chip configuration and the three-stage impedance transformer to extend the bandwidth. The input and output lines adjacent to each chip are divided by four to suppress the non-uniform heat distribution in a chip at high frequencies. We confirmed that the uniform heat distribution in each chip under RF operation at 4.8 GHz. As a result, we obtained over 320-W output power and 57 % drain efficiency at 4.8 GHz. This is the highest output power of the one-package power amplifiers at C-band. We also obtained over 250-W output power and over 44-% drain efficiency between 4.7 GHz and 5.3 GHz.
Compound Semiconductor Integrated Circuits Symposium, 2008. CSIC '08. IEEE; 11/2008
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ABSTRACT: High power n-GaN/n-AlGaN/GaN metal-insulator-semi-conductor high electron mobility transistors (MIS-HEMTs) with high-k Ta2O5 dielectric layer were fabricated on a 3-inch S.I.-SiC substrate, for the first time. An n-GaN/n-AlGaN/GaN MIS-HEMTs with 400 V breakdown voltage were obtained by using Ta2O5 insulating layer/n-GaN capstructure. The single-chip GaN MIS-HEMTs amplifier with a Ta2O5 layer operated at 50 V achieve a high output power of 113 W with a linear gain of 16.3 dB at 2.5 GHz. We also investigated the RF stress reliability under the P3dB condition. The fluctuation of output power and drain current was lower than 5% even after 150 h stress test. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
physica status solidi (c) 04/2008; 5(6):2037 - 2040.
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ABSTRACT: We report a current status of high-power GaN HEMTs for high-power and high-efficiency amplifiers with higher efficiency by 5% especially at a backed-off region than the conventional GaN HEMTs. First, we introduce our specific device structure GaN HEMT with dispersion-free I-V characteristics, low Idsq-drift and high reliability. Record average drain efficiency of over 50% and linear gain of 17.2 dB were obtained at an output power of 45 dBm and 2.5 GHz. Next, we discuss their reliability with high-temperature life tests resulting in their estimated life of over 1 times 10<sup>6</sup> hours at Tj of 200degC. Finally, we describe the next generation GaN HEMTs for millimeter-wave applications.
Radio and Wireless Symposium, 2008 IEEE; 02/2008
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Compound Semiconductor Integrated Circuit Symposium, 2007. CSIC 2007. IEEE; 11/2007
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Y. Inoue,
S. Masuda,
M. Kanamura,
T. Ohki,
K. Makiyama,
N. Okamoto,
K. Imanishi, T. Kikkawa,
N. Hara,
H. Shigematsu,
K. Joshin
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ABSTRACT: We analyzed the degradation mode of GaN-HEMTs. We observed the sudden degradation to make serious influence on the reliability. In this paper, we proposed a new approach to eliminate sudden-degradation devices. By measuring the gate leakage current before stress test, we can predict the sudden degradation. We also discussed the gate leakage current factor, for example, the surface hexagonal pits. Using this eliminating method, we could select the reliable devices with a life of over 1 times 10<sup>6</sup> hours at high-temperature of 200degC.
Microwave Symposium, 2007. IEEE/MTT-S International; 07/2007
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ABSTRACT: In this paper, we describe the recent progress of high power GaN high electron mobility transistors (GaN HEMTs) for wireless base station application. First we introduce device technology and RF power performance of GaN HEMTs. Next, we discuss their reliability and cost issues which are great important for practical applications. As an example, GaN HEMTs on a low-cost conductive 3-inch SiC substrate are discussed. In addition, next generation wireless base station system will require extremely high efficiency power amplifiers when GaN HEMTs will be used at near saturation region. To suppress a forward gate leakage current at the saturation region, we developed a metal-insulator-semiconductor (MIS) gate GaN HEMT with an output power of over 100 W.
Microwave Conference, 2006. APMC 2006. Asia-Pacific; 01/2007
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ABSTRACT: Novel n-GaN/n-AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) with Si<sub>3</sub>N<sub>4 </sub> film were fabricated on a semi-insulating (S.I.) SiC substrate. An n-GaN/n-AlGaN/GaN MIS-HEMT with a breakdown voltage of 400 V was obtained by using SiN/n-GaN cap structure. The single-chip GaN MIS-HEMT amplifier operated at 60 V achieves a high output power of 110 W with a linear gain of 13 dB at 2.14 GHz. This is the first report of an AlGaN/GaN MIS-HEMT with an over 100 W output power. The MIS-HEMT amplifier, combined with a digital pre-distortion (DPD) system, also demonstrates an adjacent channel leakage power ratio (ACLR) of less than -50 dBc for 4-carrier W-CDMA signals
Electron Devices Meeting, 2005. IEDM Technical Digest. IEEE International; 01/2006
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T. Iwai,
H. Shioya,
D. Kondo,
S. Hirose,
A. Kawabata,
S. Sato,
M. Nihei, T. Kikkawa,
K. Joshin,
Y. Awano,
N. Yokoyama
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ABSTRACT: Carbon nanotubes (CNTs) have been successfully developed as thermal and source bumps for flip-chip high power amplifiers (HPAs). The newly developed 15 mum long CNT bumps exhibit thermal conductivity of 1400 W/m-K. A flip-chip AlGaN/GaN HEMT HPA with a gate width of 2.4 mm utilizing CNT bumps, operating voltage of 40 V, exhibits an output power of 39 dBm at, a frequency of 2.1 GHz without any degradation due to heat-up. To our knowledge, this is the first report about, a practical application of CNTs using their high thermal conductivity
Electron Devices Meeting, 2005. IEDM Technical Digest. IEEE International; 01/2006
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Device Research Conference Digest, 2005. DRC '05. 63rd; 02/2005
