Xiaobing Mei

California Institute of Technology, Pasadena, CA, United States

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Publications (11)5.29 Total impact

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    ABSTRACT: This paper reports on the process and technology of the sub-50nm InP HEMT MMIC process which has enabled signal amplification up to 670 GHz. In particular, considerations not commonly addressed such as the related processing requirements and uniformity of transistors to establish working chipsets are discussed. Finally, initial burn in data is presented as the technology evolves from a research and development process to production.
    Indium Phosphide and Related Materials (IPRM), 2013 International Conference on; 01/2013
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    ABSTRACT: In this paper, progress toward developing solid-state power-amplifier modules at 0.65 THz is reported. This work is enabled by a $>$1 THz ${ f}_{\rm MAX}$ InP HEMT transistor with a 30-nm gate and an integrated circuit process specifically tailored for circuits operating at frequencies approaching 1 THz. The building block of the reported amplifier modules is an eight-stage terahertz monolithic integrated circuit (TMIC) amplifier. The first six stages of the TMIC use 20- $\mu{\hbox {m}}$ transistors, while the final two output stages rely on two power-combined 20- $\mu{\hbox {m}}$ transistors to increase the output power. For operation at 0.65 THz, the TMIC also relies on integrated electromagnetic transitions for direct coupling with the WR1.5 waveguide of the amplifier package. Two modules are reported, with the first module containing a single TMIC and demonstrating a peak saturated output power of 1.7 mW at 640 GHz with a measured small-signal gain $\geq$10 dB from 629 to 638 GHz. The second module features two power-combined TMICs to increase output power. This is done using a waveguide Y-junction as both the combiner and splitter. In test, this power-combined module reached a peak output power of 3 mW at 650 GHz and measured small-signal gain $\geq$ 10 dB from 625 to 640 GHz.
    IEEE Transactions on Microwave Theory and Techniques 03/2012; 60(3):724-729. · 2.23 Impact Factor
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    ABSTRACT: This paper reports on several solid-state power amplifier (PA) modules operating at frequencies around the 220-GHz propagation window. Included is a single module demonstrating saturated output power ≥60 mW from 205 to 225 GHz and peak output power of 75 mW at 210 GHz using eight-way on-chip power combining. The output power is further increased by using waveguide power combining with WR-4 waveguide. Results include a single two-way combined module achieving >; 100 mW of power from 210 to 225 GHz and four-way combining using two two-way combiners to reach 185 mW of output power at 210 GHz. The amplifier MMICs uses sub-50-nm InP HEMT transistors, coplanar waveguide (CPW) technology, and on-chip electromagnetic transitions to waveguide. Finally, preliminary burn-in and initial room-temperature lifetest data is shown.
    IEEE Journal of Solid-State Circuits 01/2012; 47(10):2291-2297. · 3.06 Impact Factor
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    ABSTRACT: In this paper, a 220 GHz solid-state power amplifier (SSPA) module is presented. Eight-way on-chip power combining is used to achieve a saturated output power ≥ 50 mW over a 217.5 to 220 GHz bandwidth, representing a significant increase in SSPA output power at this frequency compared to prior state of the art. The amplifier MMIC is implemented in coplanar waveguide (CPW) technology and uses sub 50 nm InP HEMT transistors. Two levels of power combining, a 2:1 tandem coupler and a 4:1 Dolph-Chebychev transformer, are realized in CPW. The module demonstrates ≥ 11.5 dB small signal gain from 207 to 230 GHz. Saturated output power ≥ 40 mW was measured from 216 to 222.5 GHz.
    Microwave Symposium Digest (MTT), 2010 IEEE MTT-S International; 06/2010
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    ABSTRACT: Weather forecasting, hurricane tracking and atmospheric science applications depend on humidity sounding of atmosphere. Current instruments provide these measurements from ground based, airborne and LEO satellites by measuring radiometric temperature on the flanks of the 183 GHz water vapor line. We have developed miniature low noise receivers that will enable these measurements from a geostationary thinned array sounder. This geostationary instrument is based on hundreds of low noise receivers that convert the 180 GHz signal directly to baseband in-phase and quadrature signals for digitization and correlation. The developed receivers provided a noise temperature of 450 K from 165 to 183 GHz (NF = 4.1 dB) and had a mass of 3 g while consuming 24 mW of power. These are the most sensitive broadband I-Q receivers at this frequency range that operate at room temperature, and are significantly lower in mass and power consumption than previously reported receivers.
    Microwave Symposium Digest (MTT), 2010 IEEE MTT-S International; 06/2010
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    ABSTRACT: A W-band MMIC low-noise amplifier (LNA) was designed and fabricated using NGST's 35 nm InP HEMT process. It was packaged in a WR-12 module and tested at 297K and 17.5K ambient temperatures. At room temperature, the WR-12 LNA module has 26-30 dB gain from 70 to 92 GHz and less than 300K noise temperature from 65-86 GHz. At 17.5K ambient temperature, the WR-12 LNA module has a minimum noise temperature of 22K at 85 GHz and less than 40K noise temperature from 70-96 GHz (below 30K noise temperature from 78-95 GHz). Gain at 17.5K is 27-31 dB from 70 to 94 GHz. Power dissipation cold is 2.1 mW. Analysis is also included to investigate the observed frequency shift with ambient temperature. It is believed that these are the lowest noise temperature measured for a packaged W-band amplifier at both room and cryogenic temperatures.
    Microwave Symposium Digest, 2009. MTT '09. IEEE MTT-S International; 07/2009
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    ABSTRACT: Measurement of the humidity profile of the atmosphere is highly important for atmospheric science and weather forecasting. This sounding measurement is obtained at frequencies close to the resonance frequency of water molecules (183 GHz). We have designed and characterized a MMIC low noise amplifier that will increase the sensitivity of sounding instruments at these frequencies. This study demonstrated a factor of two improvement in MMIC LNA noise temperature at this frequency band. The measured packaged InP monolithic millimeter-wave integrated circuit (MMIC) amplifier had a noise temperature of NT=390 K (NF=3.7 dB). The circuit was fabricated in 35 nm InP high electron mobility transistor (HEMT) process.
    Microwave Symposium Digest, 2008 IEEE MTT-S International; 07/2008
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    ABSTRACT: 35 nm gate InP HEMT devices were fabricated with S-MMIC amplifier designs at Northrop Grumman Space Technology (NGST). A 3-stage, grounded coplanar, 2-mil substrate LNA design exhibited a peak gain of 12 dB at 340GHz, the highest gain above 300 GHz reported to date. There are three core areas for the success of product fabrication, epitaxial material growth using Molecular Beam Epitaxy (MBE), frontside processing with a 35nm gate and backside processing with final wafer thickness of 50 μm. In this paper, we focus on the advanced InP backside process and the evaluation of device performance before and after backside processing.
    ECS Transactions 09/2007; 11(5).
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    ABSTRACT: NGST is developing advanced high frequency HEMT device and MMIC technologies to address imminent applications at MMW frequencies above 80 GHz through 300 GHz. The improved device transport characteristics, high transconductance, and gain at very high frequencies will benefit next generation communications, radar, imaging and radiometer systems. In this paper, we status the development and production of 0.1 mum GaAs HEMT, 0.1 mum InP HEMT and sub 0.1 mum InP HEMT technologies for high frequency mmW circuits.
    Device Research Conference, 2007 65th Annual; 07/2007
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    ABSTRACT: Uniform millimeter wave 0.1 mum InP HEMT MMICs (Ka-band, Q-band, W-band, and distributed amplifiers) on 100 mm InP substrates have been demonstrated. Moreover, high performance and high reliability have been achieved. The results indicate that the readiness of 100 mm InP HEMT technology for insertion to support military/space applications.
    Indium Phosphide & Related Materials, 2007. IPRM '07. IEEE 19th International Conference on; 06/2007
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    ABSTRACT: We have developed and demonstrated miniature 180 GHz Monolithic Microwave Integrated Circuit (MMIC) radiometer modules that have low noise temperature, low mass and low power consumption. These modules will enable the Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) of the Precipitation and All-weather Temperature and Humidity (PATH) Mission for atmospheric temperature and humidity profiling. The GeoSTAR instrument has an array of hundreds of receivers. Technology that was developed included Indium Phosphide (InP) MMIC Low Noise Amplifiers (LNAs) and second harmonic MMIC mixers and I-Q mixers, surface mount Multi-Chip Module (MCM) packages at 180 GHz, and interferometric array at 180 GHz. A complete MMIC chip set for the 180 GHz receiver modules (LNAs and I-Q Second harmonic mixer) was developed. The MMIC LNAs had more than 50% lower noise temperature (NT=300K) than previous state-of-art and MMIC I-Q mixers demonstrated low LO power (3 dBm). Two lots of MMIC wafers were processed with very high DC transconductance of up to 2800 mS/mm for the 35 nm gate length devices. Based on these MMICs a 180 GHz Multichip Module was developed that had a factor of 100 lower mass/volume (16x18x4.5 mm 3 , 3g) than previous generation 180 GHz receivers. Index Terms — high electron mobility transistors (HEMTs), indium phosphide, millimeter wave field-effect transistor (FET) amplifiers, monolithic millimeter wave integrated low noise amplifier, MMIC receiver, I-Q receiver.