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Chinchun Meng - One of the best experts on this subject based on the ideXlab platform.

  • large improvement in Image Rejection of double quadrature dual conversion low if architectures
    IEEE Transactions on Microwave Theory and Techniques, 2010
    Co-Authors: Jinsiang Syu, Chinchun Meng, Yahui Teng, Huayu Liao
    Abstract:

    The reasons for a degradation of Image-Rejection performance in double-quadrature-double-quadrature and single-quadrature-double-quadrature dual-conversion low-IF downconverters are fully discussed in this paper. Polyphase filters (PPFs) are inserted at proper positions to minimize the effects of device/signal mismatches, and thus improve the Image Rejection without calibration. Both a 0.35-μm SiGe heterojunction bipolar transistor 5.2-GHz double-quadrature-double-quadrature downconverter with an RF PPF and a 0.18-μm CMOS 2.2/4.8-GHz single-quadrature-double-quadrature downconverter with a switched-band low-noise amplifier (LNA) and a narrowband inter-stage PPF are demonstrated. Compared with our previous work, the 5.2-GHz downconverter achieves a 15-dB improvement in Image-Rejection ratio (IRR) of the first Image signal (IRR1) even without a pre-selection filter or LNA. Additionally, the dual-band downconverter has a 25-dB improvement in IRR of the second Image signal (IRR2) , which nearly reaches the theoretical limit of a four-stage PPF covering 20-40 MHz.

  • 17-GHz pHEMT gilbert single-quadrature downconverter with polyphase filters for Image Rejection
    2010
    Co-Authors: Hung-ju Wei, Chinchun Meng, Guo-wei Huang
    Abstract:

    A 17-GHz Gilbert single-quadrature down-converter (SQDC) with polyphase filters is successfully demonstrated using 0.15-µm pseudomorphic high electron mobility transistor (pHEMT) technology for the first time to the best of our knowledge. Thanks to the semi-insulating GaAs substrate and an advanced technology, the Image Rejection Gilbert mixer works well at high frequencies. A polyphase filter at the LO stage is employed to generate precisely differential quadrature signals and a four-stage polyphase filter at the IF stage can filter out the unwanted Image signal to achieve Image Rejection. From 10-MHz to 90-MHz IF frequencies, a 30-dB Image Rejection ratio is achieved when RF and LO frequencies are designed around 17 GHz. The Gilbert SQDC has a 5.5-dB conversion gain, 0-dBm IP 1dB , and 16-dBm IIP 3 .

  • 5 2 5 7 ghz 48 db Image Rejection gainp gaas hbt weaver down converter using lo frequency quadrupler
    IEEE Journal of Solid-state Circuits, 2006
    Co-Authors: Chinchun Meng
    Abstract:

    A GaInP/GaAs heterojunction bipolar transistor (HBT) down-converter using the Weaver architecture is demonstrated in this paper. The Weaver system is a double-conversion Image Rejection heterodyne system which requires no bandpass filters in the signal path and no quadrature networks. The Weaver down-converter has the Image Rejection ratios of 48 dB and 44 dB when the RF frequency is 5.2 GHz and 5.7 GHz, respectively. A new frequency quadrupler is employed in the down-converter to generate the local oscillator (LO) signals. The frequency quadrupler is designed to minimize the phase error when generating LO signals and thus the Image Rejection performance is improved. A diagrammatic explanation using the complex mixing technique to analyze the Image Rejection mechanism of the Weaver architecture is developed in this paper. From our analysis, the Image Rejection can be further improved by making the LO1 and LO2 signals coherent

  • 5.2/5.7-GHz 48-dB Image Rejection GaInP/GaAs HBT Weaver Down-Converter Using LO Frequency Quadrupler
    IEEE Journal of Solid-State Circuits, 2006
    Co-Authors: Chinchun Meng
    Abstract:

    A GaInP/GaAs heterojunction bipolar transistor (HBT) down-converter using the Weaver architecture is demonstrated in this paper. The Weaver system is a double-conversion Image Rejection heterodyne system which requires no bandpass filters in the signal path and no quadrature networks. The Weaver down-converter has the Image Rejection ratios of 48 dB and 44 dB when the RF frequency is 5.2 GHz and 5.7 GHz, respectively. A new frequency quadrupler is employed in the down-converter to generate the local oscillator (LO) signals. The frequency quadrupler is designed to minimize the phase error when generating LO signals and thus the Image Rejection performance is improved. A diagrammatic explanation using the complex mixing technique to analyze the Image Rejection mechanism of the Weaver architecture is developed in this paper. From our analysis, the Image Rejection can be further improved by making the LO1 and LO2 signals coherent

Takashi Noguchi - One of the best experts on this subject based on the ideXlab platform.

  • A Waveguide Band-Stop Filter as an Image Rejection Filter for Measurement of Stratospheric Ozone
    International Journal of Infrared and Millimeter Waves, 2003
    Co-Authors: Shin'ichiro Asayama, Hideo Ogawa, Yoshinori Yonekura, Kazuji Suzuki, Akira Mizuno, Hiroyuki Iwashita, Takashi Noguchi
    Abstract:

    In this report we present the performance and test observation results of a waveguide band-stop filter (BSF) as an Image Rejection filter for the measurement of stratospheric ozone. By using the waveguide BSF, we are able to adopt a very simple optical system and achieve a good Image Rejection ratio. Additionally, we are able to observe in both single sideband (SSB) mode and double sideband (DSB) mode by only changing the local oscillator (LO) frequency. We have installed the waveguide BSF into an atmospheric ozone-measuring system using a superconductive (SIS) receiver and have successfully observed an ozone spectrum at 110 GHz in SSB and DSB mode. The receiver noise temperature (SSB) and the Image Rejection ratio at 110 GHz are about 60 K and more than 30 dB, respectively. Because of the IF power ripple, the waveguide BSF cannot be used with a wide-band spectrometer. However, it is quite practical for narrow-band observation.

  • A Waveguide Band-Stop Filter as an Image Rejection Filter for Measurement of Stratospheric Ozone
    International Journal of Infrared and Millimeter Waves, 2003
    Co-Authors: Shin'ichiro Asayama, Hideo Ogawa, Yoshinori Yonekura, Kazuji Suzuki, Akira Mizuno, Hiroyuki Iwashita, Takashi Noguchi
    Abstract:

    In this report we present the performance and test observation results of a waveguide band-stop filter (BSF) as an Image Rejection filter for the measurement of stratospheric ozone. By using the waveguide BSF, we are able to adopt a very simple optical system and achieve a good Image Rejection ratio. Additionally, we are able to observe in both single sideband (SSB) mode and double sideband (DSB) mode by only changing the local oscillator (LO) frequency. We have installed the waveguide BSF into an atmospheric ozone-measuring system using a superconductive (SIS) receiver and have successfully observed an ozone spectrum at 110 GHz in SSB and DSB mode. The receiver noise temperature (SSB) and the Image Rejection ratio at 110 GHz are about 60 K and more than 30 dB, respectively.

Sanggug Lee - One of the best experts on this subject based on the ideXlab platform.

  • a fast and precise blind i q mismatch compensation for Image Rejection in direct conversion receiver
    Etri Journal, 2014
    Co-Authors: Suna Kim, Hyungchul Park, Daeyoung Yoon, Giwan Yoon, Sanggug Lee
    Abstract:

    In this paper, we propose a new digital blind in-phase/quadrature-phase (I/Q) mismatch compensation technique for Image Rejection in a direct-conversion receiver (DCR). The proposed Image-Rejection circuit adopts DC offset cancellation and a sign-sign least mean squares (LMS) algorithm with a unique step size adaptation both for a fast and precise I/Q mismatch estimation. In addition, several performance-optimizing design considerations related to accuracy, speed, and hardware simplicity are discussed. The implementation of the proposed circuit in an FPGA results in an Image-Rejection ratio (IRR) of 65 dB, which is the best performance with modulated signals, along with an adaptation time of 0.9 seconds, which is a tenfold increase in the compensation speed as compared to previously reported circuits. The proposed technique will be a promising solution in the area of Image Rejection to increase both the speed and accuracy of future DCRs.

  • A 5.25-GHz Image Rejection RF front-End Receiver With Polyphase filters
    IEEE Microwave and Wireless Components Letters, 2006
    Co-Authors: Chang-wan Kim, Sanggug Lee
    Abstract:

    A 5.25-GHz Image Rejection (IR) radio frequency (RF) front-end receiver is proposed, which is implemented in 0.18-/spl mu/m CMOS technology. The proposed receiver adopts both a high-intermediate frequency (IF) and the double quadrature architecture to achieve high IR at 5-GHz frequency. The measured results show a power gain of 14 dB, a minimum noise figure of 7.9dB, and IIP3 of -8dBm. The measured maximum Image Rejection ratio is 45dBc. The receiver consumes a total of 32mA from a 1.8-V supply.

  • Ultra-low-power 2.4 GHz Image-Rejection low-noise amplifier
    Electronics Letters, 2005
    Co-Authors: Thuy Nguyen, Sub Han, Sanggug Lee
    Abstract:

    An ultra-low-power Image-Rejection low-noise amplifier (IR-LNA) for 2.4 GHz ZigBee applications based on 0.18 /spl mu/m CMOS technology is presented. By using the third-order active notch filter the proposed IR-LNA can achieve high Image-Rejection ratio. Measurements show 12 dB gain, 1.8 dB noise figure, 38 dB Image-Rejection, -3 dBm input third-order intercept point, -18 and -19 dB input and output return loss while dissipating 0.6 mA from a supply voltage of 1.5 V.

  • Frequency- Controllable Image Rejection Down
    2004
    Co-Authors: Chang-wan Kim, Min-suk Kang, Sanggug Lee
    Abstract:

    This paper presents a low noise frequency controllable Image Rejection mixer in heterodyne architecture for 2 GHz applications based on 0.18 µm CMOS technology. The designed mixer uses an inductor and capacitors as a notch filter to suppress the Image signal and parasitic capacitance to improve the noise figure (NF) and conversion gain. Two small value capacitors in parallel with an inductor are used for precise tuning the desired Image frequency. An Image Rejection of 20-70 dB is obtained in a 200MHz of bandwidth around 2GHz with IF varying from 100 to 300MHz. The simulation results show single- side band (SSB) NF improved 3.7 dB, the voltage conversion gain of 14.7 dB, improved by more than 4 dB. The circuit operates at the supply voltage of 1.8V, and dissipates 11.34 mW.

  • Frequency- controllable Image Rejection down CMOS mixer
    Proceedings of the Fifth IEEE International Caracas Conference on Devices Circuits and Systems 2004., 2004
    Co-Authors: Anh Tuan Phan, Min-suk Kang, Chang-wan Kim, Sanggug Lee
    Abstract:

    This paper presents a low noise frequency controllable Image Rejection mixer in heterodyne architecture for 2 GHz applications based on 0.18 /spl mu/m CMOS technology. The designed mixer uses an inductor and capacitors as a notch filter to suppress the Image signal and parasitic capacitance to improve the noise figure (NF) and conversion gain. Two small value capacitors in parallel with an inductor are used for precise tuning the desired Image frequency. An Image Rejection of 20-70 dB is obtained in a 200MHz of bandwidth around 2GHz with IF varying from 100 to 300MHz. The simulation results show single-side band (SSB) NF improved 3.7 dB, the voltage conversion gain of 14.7 dB, unproved by more than 4 dB. The circuit operates at the supply voltage of 1.8V, and dissipates 11.34 mW.

S. Sae-ngow - One of the best experts on this subject based on the ideXlab platform.

  • ISCAS (1) - Inductorless RF amplifier with tuneable band-selection and Image Rejection
    Proceedings of the 2003 International Symposium on Circuits and Systems 2003. ISCAS '03., 1
    Co-Authors: A. Thanachayanont, S. Sae-ngow
    Abstract:

    This paper describes the design of two inductorless amplifiers that provide both band-selection and Image-Rejection, and thus can be used to perform the functions of bandpass filters, low-noise amplifier and Image-Rejection filter in the superheterodyne RF receiver front-end. Two topologies, namely the source-degeneration and bridge-T notch, are employed due to their excellent Image Rejection and independent control of the shape and depth. Simulation results using a 0.35-/spl mu/m CMOS technology demonstrate the feasibility of both circuits for operation in the low GHz frequency range with passband gain around 30 dB and maximum Image suppression of 80 dB.

Erwin H. W. Chan - One of the best experts on this subject based on the ideXlab platform.

  • Brillouin-Assisted Notch Filtering Based All-Optical Image Rejection Mixer
    IEEE Photonics Journal, 2019
    Co-Authors: Chirappanath B. Albert, Chongjia Huang, Erwin H. W. Chan
    Abstract:

    A novel approach for realizing a microwave photonic Image Rejection mixer is presented in this paper. It is based on using a widely tunable narrow-band optical notch filter implemented by stimulated Brillouin scattering (SBS) to remove the Image signal. The Image Rejection mixer has a simple structure as it only requires a single integrated dual-polarization modulator for both frequency conversion and pump wave generation for the SBS process. The absence of electrical components enables the Image Rejection mixer to be operated over a wide frequency range with a high Image Rejection ratio. A technique is also proposed to suppress the noise generated by the SBS process in the Image Rejection mixer. Experimental results demonstrate a high and constant Image Rejection ratio of over 32 dB for the Image Rejection mixer operating over an RF signal frequency range of 11.8–19.6 GHz, and around −5 dB conversion efficiency.

  • high conversion efficiency photonic microwave mixer with Image Rejection capability
    IEEE Photonics Journal, 2016
    Co-Authors: Jun Zhang, Erwin H. W. Chan, X Wang, Xinhuan Feng, Baiou Guan
    Abstract:

    A new photonic microwave Image Rejection mixer that can achieve high conversion efficiency and has a wide bandwidth is presented. It is based on an integrated dual-parallel Mach–Zehnder modulator (MZM) with a 90° polarization rotator on one branch of the modulator. The two modulators connected in parallel are biased at the minimum transmission point to generate two sets of orthogonally polarized radio frequency (RF) and local oscillator (LO) modulation sidebands with the optical carrier being suppressed. Suppressing the optical carrier enables high RF and LO modulation sidebands to be detected by a photodiode without saturation. The LO modulation index is also designed to obtain a high conversion efficiency mixing operation. Experimental results demonstrate frequency downconversion with an Image Rejection function and a high conversion efficiency of > $-$ 5 dB over a wide 3 to 20 GHz frequency range. A technique for compensating the effect of coupler amplitude and phase imbalance to obtain a high Image Rejection ratio is also experimentally demonstrated.