By a News Reporter-Staff News Editor at Journal of Technology -- Investigators discuss new findings in Microwave Research. According to news reporting from Gyeonggi Do, South Korea, by VerticalNews journalists, research stated, "This paper presents a gallium nitride (GaN)-based hybrid current-mode class-S (CMCS) power amplifier (PA) using a bandpass delta-sigma modulator (BPDSM) for a 955-MHz LTE signal. To enhance the drain efficiency of the CMCS PA, the chip-on-board (COB) technique, which can reduce the external parasitic components of the packaged transistor and allow fast switching operation at high frequencies by minimizing distortion of the pulse waveform, is adopted."
The news correspondents obtained a quote from the research from Korea Electronics Technology Institute, "Also, GaN Schottky barrier diodes are fabricated in-house to protect the switching transistor against the high negative voltage swing. The differential output filter and balun composed of lumped resonators are integrated at the back of the switching transistor to extract amplified LTE signal from the output rectangular waveform, and the fabricated CMCS PA is measured and analyzed at four different states of BPDSM according to the coding efficiency from different input power level to obtain higher power and efficiency. Finally, a cavity bandpass filter (BPF) is added to the output circuit for a more accurate reduction of the harmonics and out-of-band noise signals to enhance system efficiency."
According to the news reporters, the research concluded: "From the measured results for an 8.5-dB PAPR 3 G LTE 10-MHz input signal, the proposed CMCS PA has a maximum average output power of 37.61 and 30.78 dBm, and the resulting drain efficiencies of 33.3% and 38.6% with the drain voltage of 19 and 7 V, respectively."
For more information on this research see: Hybrid Current-Mode Class-S Power Amplifier With GaN Schottky Diode Using Chip-On-Board Technique for 955 MHz LTE Signal. IEEE Transactions on Microwave Theory and Techniques, 2013;61(12):4168-4178. IEEE Transactions on Microwave Theory and Techniques can be contacted at: Ieee-Inst Electrical Electronics Engineers Inc, 445 Hoes Lane, Piscataway, NJ 08855-4141, USA. (Institute of Electrical and Electronics Engineers - www.ieee.org/; IEEE Transactions on Microwave Theory and Techniques - ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=22)
Our news journalists report that additional information may be obtained by contacting J.C. Park, Korea Elect Technol Inst, Packaging Res Center, Gyeonggi Do 463816, South Korea. Additional authors for this research include J.G. Yook, B.H. Park, N. Jeon, K.S. Seo, D. Kim, W.S. Lee and C.S. Yoo.
Keywords for this news article include: Asia, Gyeonggi Do, South Korea, Microwave Research
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