Signal-Conditioning Block of a 1 × 200 CMOS Detector Array for a Terahertz Real-Time Imaging System

Yang, Jong‐Ryul; Lee, Woo‐Jae; Han, Sang‐Min

doi:10.3390/s16030319

Cited by 14 publications

(8 citation statements)

References 21 publications

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“…In addition, the overall noise level of the detector increases because the noise generated in the SCB is added to that of the overall detector. In addition, the detector becomes sensitive to interference from the interconnection lines between the detector and SCB [ 12 , 14 ]. Therefore, improving the SNR for a THz imaging system is difficult, even though the responsivity was shown to increase in the detectors reviewed in previous studies.…”

Section: Introductionmentioning

confidence: 99%

Differential CMOS Sub-Terahertz Detector with Subthreshold Amplifier

Yang

Han

Baek

2017

Sensors

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We propose a differential-type complementary metal-oxide-semiconductor (CMOS) sub-terahertz (THz) detector with a subthreshold preamplifier. The proposed detector improves the voltage responsivity and effective signal-to-noise ratio (SNR) using the subthreshold preamplifier, which is located between the differential detector device and main amplifier. The overall noise of the detector for the THz imaging system is reduced by the preamplifier because it diminishes the noise contribution of the main amplifier. The subthreshold preamplifier is self-biased by the output DC voltage of the detector core and has a dummy structure that cancels the DC offsets generated by the preamplifier itself. The 200 GHz detector fabricated using 0.25 μm CMOS technology includes a low drop-out regulator, current reference blocks, and an integrated antenna. A voltage responsivity of 2020 kV/W and noise equivalent power of 76 pW/√Hz are achieved using the detector at a gate bias of 0.5 V, respectively. The effective SNR at a 103 Hz chopping frequency is 70.9 dB with a 0.7 W/m2 input signal power density. The dynamic range of the raster-scanned THz image is 44.59 dB.

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Section: Introductionmentioning

confidence: 99%

Differential CMOS Sub-Terahertz Detector with Subthreshold Amplifier

Yang

Han

Baek

2017

Sensors

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“…The 200-GHz signal generated by the gyrotron is focused on the detector by off-axis parabolic (OAP) mirrors [28]. An optical chopper operating at a frequency of 100 Hz is used to mechanically modulate the input signal to reduce the effect of the 1/f noise [5]. The linearly polarized signal generated from the gyrotron is transmitted to the integrated antenna of the detector by adjusting the power level based on the cosine value of the angle determined by the polarizer.…”

Section: Methodsmentioning

confidence: 99%

“…Since Dyakonov and Shur first introduced the mechanism of plasma-wave detection in a field-effect transistor, plasmon detectors have been an attractive technology for measuring the magnitude of high-frequency signals above the cut-off frequency of the transistor when implemented using a low-cost semiconductor process [1]− [5].…”

Section: Introductionmentioning

confidence: 99%

CMOS Plasmon Detector With Three Different Body-Biasing MOSFETs

Han

Yang

2020

IEEE Access

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A complementary metal-oxide-semiconductor (CMOS) plasmon detector using metaloxide-semiconductor field-effect transistors (MOSFETs) biased at three different body voltages is proposed for high sensitivity and a wide dynamic range. The detection core consists of three differential MOSFET detectors biased at different body voltages based on the photoresponse variation depending on the body potential. The sensitivity of the proposed detector is improved through an increase in the nonlinearity owing to the uses of transistors biased by negative body voltages, and the dynamic range of the detector is widened through the parallel-connected detectors individually biased at different body voltages. A 200-GHz signal is simultaneously incident to the detection cores configured in-parallel through the integrated differential antenna, and DC voltages converted using the different photoresponsivity of the cores are current-combined at the preamplifier and amplified with a three-stage folded-cascode operational amplifier. Simulation and measurement results of the proposed detector designed using TSMC 0.25-µm CMOS technology show that the negative body-biasing (set to 0, −0.2, and −0.4 V), in the MOSFET can improve the voltage responsivity of 2.63 times, the sensitivity by 2.9-fold compared to zero body-biasing, reaching a dynamic range of 11.1% in the CMOS plasmon detector. Raster-scanned imaging for 60-µm thick copper tapes with a line width of 6−12 mm attached to 10-mm thick Styrofoam demonstrates that the signal-to-noise ratio of 200-GHz images can be improved from 25.5 dB to 30.6 dB when using the proposed detector with three different body-biased MOSFETs.

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“…The terahertz signal was received through the integrated antenna and transmitted to the gate of the detector device. The detector gate was also provided with an external gate bias voltage to control the modulation of the internal channel of the transistor [23]. The input signal vIN of the plasmon detector can be expressed with a terahertz input signal vTHz and an external gate bias VG at high frequency as follows: vIN=vTHz+VG.…”

Section: Quasi-static Analysis Using the Proposed Equivalent Circumentioning

confidence: 99%

Quasi-static Analysis Based on an Equivalent Circuit Model for a CMOS Terahertz Plasmon Detector in the Subthreshold Region

Son¹,

Yang²

2019

Sensors

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An analytic method for a complementary metal-oxide-semiconductor (CMOS) terahertz plasmon detector operating in the subthreshold region is presented using the equivalent circuit model. With respect to design optimization of the detector, the signal transmission from the antenna port to the output of the detector is described by using the proposed circuit model, which does not include a complicated physical operating principle and mathematical expressions. Characteristics from the antenna port to the input gate node of the detector are analyzed through the superposition method by using the characteristic impedance of transmission lines. The superposition method shows that the effect of interconnection lines at the input is simplified with the optimum bias point. The characteristics of the plasmon detection are expressed by using small-signal analysis of the single transistor at the sub-threshold operation. The results of the small-signal analysis show that the unity gain preamplifier located between the detector core and the main amplifier can improve the detection performances such as the voltage responsivity and the noise equivalent power. The measurement results using the fabricated CMOS plasmon detector at 200 GHz suggest that the unity gain preamplifier improves the detector performances, which are the same results as we received from the proposed analytic method.

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Signal-Conditioning Block of a 1 × 200 CMOS Detector Array for a Terahertz Real-Time Imaging System

Cited by 14 publications

References 21 publications

Differential CMOS Sub-Terahertz Detector with Subthreshold Amplifier

Differential CMOS Sub-Terahertz Detector with Subthreshold Amplifier

CMOS Plasmon Detector With Three Different Body-Biasing MOSFETs

Quasi-static Analysis Based on an Equivalent Circuit Model for a CMOS Terahertz Plasmon Detector in the Subthreshold Region

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