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Sun M.,University of Electronic Science and Technology of China | Ning N.,University of Electronic Science and Technology of China | Li J.,University of Electronic Science and Technology of China | Yu Q.,University of Electronic Science and Technology of China | And 3 more authors.
Microwave and Optical Technology Letters | Year: 2016

In this letter, a two-stage low-noise amplifier (LNA) with continuously variable gain for 3-10 GHz Ultra-wideband (UWB) application has been realized in 65 nm CMOS technology. A self-biased shunt resistive feedback with source inductive degeneration topology is used to achieve wideband input matching in the first stage; the inductive-peaking technique is introduced to make the gain smooth; and common source amplifier structure is used to realize variable gain in the second stage. The LNA exhibits a continuously variable gain ranging from -13.2 dB to 16.4 dB, a minimum NF of 3.7 dB and power consumption between 11.1 mW and 16.2 mW under a 1.2 V supply voltage. Moreover, the LNA occupies silicon area of 0.12 mm2. © 2016 Wiley Periodicals, Inc. Source


Guo J.,Sun Yat Sen University | Lu G.G.,Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory | He G.Y.,Sun Yat Sen University | Jiao Z.X.,Sun Yat Sen University | Wang B.,Sun Yat Sen University
Laser Physics Letters | Year: 2013

We report a high-brightness and high-efficiency degenerate periodically poled MgO:LiNbO3 (PPMgLN) optical parametric oscillator (OPO), configured with a four-mirror standing-wave cavity and pumped by a Q-switched Nd:YVO4 laser. Attributed to the successful mode matching of four-mirror standing-wave cavity, we have obtained good beam qualities both in single-pass and double-pass geometry. The beam qualities of single-pass pump geometry are M2 ∼ 1.6 and 1.7 in the horizontal and vertical directions, and the beam qualities of double-pass pump geometry are M 2 ∼ 1.8 and 1.9. Optical to optical conversion efficiencies of 38% and 55% are achieved, respectively. With a volume Bragg grating used as the output coupler, we achieved a narrow linewidth of less than 2 nm. © 2013 Astro Ltd. Source


Cheng L.X.,South China University of Technology | Li G.Y.,South China University of Technology | Li Z.L.,South China University of Technology | Wu Z.Z.,South China University of Technology | Zhou B.,Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory
Journal of Materials Science: Materials in Electronics | Year: 2015

The role of active element titanium for the bonding alumina substrates using Sn3.5Ag4Ti(Ce,Ga) alloy filler at 250 °C in air was studied. The influence of soldering time on the microstructure and element distribution was investigated. It was observed that the Sn3.5Ag4Ti(Ce,Ga) solder could wet the alumina well under the agitation of external force. No continuous reaction products could be detected at the alumina/solder interface by using scanning electron microscopy and X-ray diffractometer. It might be inferred that the joining could be accomplished by chemical adsorption of Ti on the alumina/solder interface, regardless of whether or not an interfacial reaction layer is formed. The theoretical analysis of the Ti element adsorption at the alumina/solder interface was tried. Results can further explain the adsorption phenomenon of Ti at the interface prior to bond formation. In the case of environmental temperature has yet to meet the chemical reaction conditions, the chemical adsorption between active elements and alumina can get good bond as well. The shear strengths of the soldered Al2O3/Al2O3 substrates with the soldering time of 15 min, 30 min, and 1 h were measured to be 15.46, 16.15, and 17.39 MPa respectively. © 2015, Springer Science+Business Media New York. Source


Jiao Z.,Sun Yat Sen University | Guo J.,Sun Yat Sen University | He G.,Sun Yat Sen University | Lu G.,Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory | Wang B.,Sun Yat Sen University
Optics and Laser Technology | Year: 2014

We report a narrow-bandwidth near-degenerate MgO:PPLN optical parametric oscillator (OPO) based on a volume Bragg grating (VBG) output coupler (OC) intracavity pumped by a linearly polarized Q-switched Nd:YAG laser. Maximum 2.1 μm output power of 7.1 W with beam quality factor M2 of 2.0 and 2.3 in horizontal and vertical directions is achieved. 23.5 W of 1 μm radiation with fundamental mode is obtained simultaneously. © 2013 Elsevier Ltd. Source


Tang Y.,South China University of Technology | Tang Y.,Zhongkai University of Agriculture and Engineering | Li G.Y.,South China University of Technology | Luo S.M.,Zhongkai University of Agriculture and Engineering | And 2 more authors.
Journal of Electronic Materials | Year: 2015

The creep behavior of 95.8Sn–3.5Ag–0.7Cu shear-lap solder joints was investigated at different shear stresses ranging from 2–26 MPa and test temperatures of 25, 75, and 125°C. The stress exponent can be clearly defined in the low-stress (τ < 12 MPa) and high stress (τ > 15 MPa) ranges. The stress exponent is larger in the high-stress range, and decreases with increasing temperature in both low and high-stress ranges. The average modulus compensated shear stress transition point and the average activation energy were determined to be 1.08 × 10−3 and 90.59 kJ/mol, respectively. A creep constitutive model with internal stress incorporated into the Garofalo hyperbolic sine law model was used to describe the creep behavior of 95.8Sn–3.5Ag–0.7Cu shear-lap solder joints. In this model, the relationship between creep strain rate and shear stress was determined by introducing internal stress that is a function of the shear stress in the low-stress range and a function of particle size and volume fraction of intermetallic particles in the high-stress range. The internal stress was calculated on the basis of the different creep mechanisms in the low and high-stress ranges. Results showed that the modified creep constitutive model was consistent with experimental data, which indicates that the model can be used to predict the creep behavior of 95.8Sn–3.5Ag–0.7Cu shear-lap solder joints. © 2015, The Minerals, Metals & Materials Society. Source

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