Heterodyne detection at 216, 432, and 648 GHz based on bilayer graphene field-effect transistor with quasi-optical coupling. (September 2017)

• Record Type: Journal Article
• Authors: Qin, Hua; Sun, Jiandong; He, Zezhao; Li, Xingxin; Li, Xiang; Liang, Shixiong; Yu, Cui; Feng, Zhihong; Tu, Xuecou; Jin, Biaobing; Chen, Jian; Wu, Peiheng
• Is Part Of: Carbon. Volume 121(2017)
• Page Start: 235
• Page End: 241
• Publication Date: 2017-09
• Subjects: Graphene -- Millimeter-wave -- Terahertz -- Heterodyne -- Self-mixing -- Field-effect transistor; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2017.05.080
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Graphene field-effect transistors (G-FETs) are being developed with ever increasing sensitivity as terahertz direct detectors at room temperature. The noise-equivalent power is being reduced towards the order of 1 pW / Hz with frequency about 650 GHz. G-FET-based frequency multipliers and subharmonic mixers are becoming new active components for both millimeter and terahertz wave technologies. We report a 650-GHz G-FET coupled with terahertz antennas and a quasi-optical silicon lens for heterodyne/subharmonic detection. Heterodyne detection at 216 and 648 GHz, second-subharmonic detection at 432 GHz, and third-subharmonic detection at 648 GHz were demonstrated and characterized. Self-mixing/homodyne detection was used as a calibration tool for the power levels of the local pump source and the source to be detected. The conversion losses of heterodyne mixing at 216 GHz (off-resonant) and 648 GHz (resonant) were 38.4 dB and 57.9 dB with 12.8 dBm and −14 dBm of local pump power, respectively. The conversion loss of the second-harmonic mixing at 432 GHz is about 8 dB higher than that of the heterodyne mixing at 216 GHz. Calculations based on our quasi-static mixing model agree well with the measured conversion losses. To improve the conversion loss, more details on the G-FET noise, the optimal pump power, and the antenna should be examined. Graphical abstract: