Browsing by Author "Syu, J. -S."

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10 GHz dual-conversion low-IF downconverter with microwave and analogue quadrature
(2009-06-18)
Syu, J. -S.
;
Meng, C.
;
Teng, Y. -H.
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電信工程研究所
;
Institute of Communications Engineering
A 10 GHz dual-conversion low-IF downconverter using 0.18-mm CMOS technology is demonstrated. The high-frequency quadrature RF and LO(1) signals are generated by broadside-coupled quadrature couplers while a two-section polyphase filter is utilised for the low-frequency LO(2) quadrature signal generation. As a result, the demonstrated downconverter achieves a conversion gain of 7 dB, IP(1dB) of -16 dBm, IIP(3) of 25 dBm and noise figure of 26 dB at a 1.8 V supply. The image-rejection ratio of the first/second image signal is 33/42 dB for IF frequency ranging from 10 to 60 MHz, respectively.
2.4/5.7-GHz Dual-Band Dual-Conversion Low-IF Downconverter Using 0.35 mu m SiGe HBT Technology
(2010)
Syu, J. -S.
;
Meng, C. C.
;
Yu, S. -W.
;
Huang, G. -W.
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電機工程學系
A 2.4/5.7-GHz dual-band dual-conversion low-IF downconverter is demonstrated using 0.35 mu m SiGe heterojunction bipolar transistor (HBT) technology. The first image signal is shifted away from the IF band by a complex Weaver architecture while the second image signal is eliminated by a complex Hartley architecture. The downconverter achieves a 45/44-dB image-rejection ratio of the first image (IRR1) and a 50/48-dB image-rejection ratio of the second image (IRR2) for 2.4/5.7-GHz modes, respectively, when IF frequency ranges from 20 to 40 MHz.
5 GHz quadrature voltage-controlled oscillator using trifilar transformers
(2008-04-24)
Syu, J. -S.
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Meng, C.
;
Tsung, K. -C.
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Huang, G. -W.
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電信工程研究所
A 0.18 mm CMOS 5 GHz quadrature voltage-controlled oscillator (QVCO) is demonstrated by using trifilar transformer coupling. The trifilar transformers composed of one primary coil and two secondary coils are used to separate the gate and drain bias for output voltage swing optimisation and also replace a conventional transistor-coupling method for quadrature output generation simultaneously. As a result, the trifilar-coupling QVCO achieves 180.1 dBc/Hz figure of merit (FOM) at the supply voltage of 1.2 V. The on-chip passive single sideband upconversion mixer is also demonstrated to fairly measure the quadrature accuracy of the QVCO. Thus, a 33.7 dB sideband rejection ratio is achieved.
Broadband SiGe HBT Gilbert downconverter with 1.8 to 36 GHz integrated dual Marchand balun
(2008-07-03)
Syu, J. -S.
;
Meng, C.
;
Yu, S. -W.
;
電信工程研究所
;
Institute of Communications Engineering
A broadband Gilbert downconverter with an integrated dual Marchand balun (balanced to unbalanced transformer) is demonstrated by using 0.35 mu m SiGe heterojunction bipolar transistor (HBT) technology. A dual Marchand balun consisting of a lower band balun and an upper band balun is employed in the LO stage of the downconverter to maintain balanced LO signals from 1.8 to 36 GHz. The broadband downconverter has peak conversion gain of 3 dB at RF = 3 GHz and 3 dB bandwidth of 1.8 to 20 GHz at 3.3 V DC supply.
UWB Gilbert downconverter utilising a wideband LR-CR quadrature generator
(2009-05-07)
Syu, J. -S.
;
Meng, C.
;
Teng, Y. -H.
;
電信工程研究所
;
Institute of Communications Engineering
An ultra-wideband (UWB) I/Q downconverter with an LR-CR quadrature generator is demonstrated using 0.35 mu m SiGe HBT technology. The I/Q outputs of this generator are always in quadrature phase at any frequency while the BJT-type active mixer inherently tolerates much LO power difference for a. at gain response. Consequently, the amplitude imbalance and phase error of the I/Q outputs are less than 1 dB and 2 degrees in the RF frequency range 3-11 GHz.