In this paper, a novel defected ground structure (DGS), connected in parallel to two periodic structures with different center frequencies of the stopband, is proposed for increasing the output power of a voltage‐controlled oscillator (VCO) in microstrip circuits. To evaluate the effects of DGS on the output power, two GaAs field‐effect transistor (FET) VCOs have been designed and fabricated. One of them has a 50Ω microstrip line with DGS at the output section, while the other has only a 50Ω straight line. Measured results show that DGS rejects the second harmonic at the output and yields improved output power by 1–5%. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 279–281, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11038

Synthesis and characterization of phase change memory cells Science in China Series E-Technological Sciences 52, 2724 (2009); Study of phase change materials for phase change random access memory

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In integrated circuit (IC) burn-in, it is desirable to produce efficient input patterns to assist heating for circuit under test. This study proposes and demonstrates an approach which uses the genetic algorithm incorporating with a BACK-like procedure to generate the patterns which produce the maximal and/or uniform node transition as well as power dissipation for burn-in application. A multi-step strategy is applied in the algorithm, and a transition measure is defined to guide the backtracing of the BACK-like procedure, improving the efficiency in searching the target patterns. Experimental results show that the approach generates better pattern pairs which produce either the maximal transition count or the maximal power dissipation than that of all the other published results. It is also able to generate the pattern sequence which achieves more uniformly stressing, by 30% improvement statistically, for each gate of the circuit under test. The computation time, because of using a divide-and-conquer strategy in this approach, is also reasonable, making it useful in the practical IC burn-in application.