© The Institution of Engineering and Technology
A broadband monolithic microwave integrated circuit (MMIC) quadrature phase shift keying (QPSK) modulator with low amplitude and phase errors is proposed. The presented modulator adopts two wideband reflection-type binary BPSK modulators, each consisting of a modified Lange coupler with additional λ/4 transmission lines, varactor diodes, inductors and resistors. The proposed QPSK modulator is implemented in 0.15 μm GaAs low-noise pHEMT process. The measurements show an error vector magnitude and a demodulated I/Q offset <5.8% root-mean-square and −16.1 dB, respectively, from 18 to 26.5 GHz.
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J.-H. Tsai ,
T.-W. Huang
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35-65-GHz CMOS broadband modulator and demodulator with sub-harmonic pumping for MMW wireless gigabit applications.
IEEE Trans. Microw. Theory Tech.
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10 ,
2075 -
2085
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2. Chang, H.-Y., Wu, P.-S., Huang, T.-W., Wang, H., Chang, C.-L., Chern, C.J.: ‘Design and analysis of CMOS broad-band compact high-linearity modulators for gigabit microwave/millimetre-wave applications’, IEEE Trans. Microw. Theory Tech., 2006, 54, (1), pp. 20–30 (doi: 10.1109/TMTT.2005.860900).
http://iet.metastore.ingenta.com/content/journals/10.1049/el.2013.2444
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content/journals/10.1049/el.2013.2444
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Balanced MMIC QPSK modulator with low amplitude and phase errors