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Baselmans JJA, Hajenius M, Gao JR, Baryshev A, Kooi J, Klapwijk TM, et al. NbN hot electron bolometer mixers: sensitivity, LO power, direct detection and stability. IEEE Trans Appl Supercond. 2005;15(2):484–9.
Abstract: We demonstrate that the performance of NbN lattice cooled hot electron bolometer mixers depends strongly on the interface quality between the bolometer and the contact structure. Both the receiver noise temperature and the gain bandwidth can be improved by a factor of 2 by cleaning the interface and adding an additional superconducting interlayer to the contact pad. Using this we obtain a double sideband receiver noise temperature of 950 K at 2.5 THz and 4.3 K, using a 0.4/spl times/4 /spl mu/m HEB mixer with a spiral antenna. At the same bias point, we obtain an IF gain bandwidth of 6 GHz. To comply with current demands on THz mixers for use in space based receivers we reduce the device size to 0.15/spl times/1 /spl mu/m and use a twin slot antenna. We report measurements of the noise temperature, LO power requirement, stability and the direct detection effect, using a mixer with a 1.6 THz twin slot antenna and a 1.462 THz solid state LO source with calibrated output power.
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Goltsman GN, Vachtomin YB, Antipov SV, Finkel MI, Maslennikov SN, Polyakov SL, et al. Low-noise NbN phonon-cooled hot-electron bolometer mixers for terahertz heterodyne receivers. In: Proc. 9-th WMSCI. Vol 9. International Institute of Informatics and Systemics; 2005. p. 154–9.
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Nagatsuma T, Hirata A, Sato Y, Yamaguchi R, Takahashi H, Kosugi T, et al. Sub-Terahertz Wireless Communications Technologies. In: Proc. 18th International Conference on Applied Electromagnetics and Communications (ICECom 2005).; 2005. p. 1–4.
Abstract: This paper presents a 10-Gb/s wireless link system that uses a 120-GHz-band sub-terahertz electro-magnetic waves. In the transmitter, photonic techniques are used for generation, modulation, and emission of the sub-THz signals, while the receiver is composed of all-electronic devices using InP-HEMTs.
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An Z, Chen J-C, Ueda T, Komiyama S, Hirakawa K. Infrared phototransistor using capacitively coupled two-dimensional electron gas layers. Appl Phys Lett. 2005;86:172106-3.
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Barends R, Hajenius M, Gao JR, Klapwijk TM. Current-induced vortex unbinding in bolometer mixers. Appl Phys Lett. 2005;87:263506 (1 to 3).
Abstract: We present a description of the current-voltage characteristics of hot electron bolometers in terms of the current-dependent intrinsic resistive transition of NbN films. We find that, by including this current dependence, we can correctly predict the complete current-voltage characteristics, showing excellent agreement with measurements for both low and high bias and for small as well as large devices. It is assumed that the current dependence is due to vortex-antivortex unbinding as described in the Berezinskii–Kosterlitz–Thouless theory. The presented approach will be useful in guiding device optimization for noise and bandwidth.
Keywords: HEB mixer numerical model, HEB model, IV-curves, vortex-antivortex, Berezinskii–Kosterlitz–Thouless theory, diffusion cooling channel, diffusion channel, distributed HEB model, distributed model, self-heating effect, temperature profile
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