Search Results - kwang-jin+koh

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90 Degree Hybrid-Coupler Based Phase-Interpolation Phase-Shifter for Phase-Array Applications at W-Band and Beyond
In the proposed phase shifter, a 90 degree-hybrid performs I/Q phase splitting and phase interpolation to synthesize all four quadrant phases after amplitude weighting made by VGAs. In such way, by designing the weighting amplifiers with a matched impedance, the I/Q accuracy and thereby accuracy of phase interpolation is not sensitive to the amplifier...
Published: 1/4/2016   |   Inventor(s): Sadia Afroz, Kwang-Jin Koh
Category(s): Electrical, Engineering
?/4-Transformer Based Harmonic Filter for Optimal Harmonic Impedance Modulation at Millimeter-Wave for High Efficiency Class-F^-1 Power Amplifiers
The proposed λ/4-transformer based Class-F^-1 load network effectively shapes the voltage and current waveform of the active device and increases the efficiency of the PA. The simple load structure makes it effective at millimeter-wave regime despite low quality (low-Q) of passive components. The effectiveness of the load network is verified...
Published: 12/17/2015   |   Inventor(s): Seyed Mortazavi, Kwang-Jin Koh
Category(s): Electrical