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Shitov, S. V., Inatani, J., Shan, W. - L., Takeda, M., Wang, Z., Uvarov, A. V., et al. (2008). Measurement of emissivity of the ALMA antenna panel at 840 GHz using NbN-based heterodyne SIS receiver. In Proc. 19th Int. Symp. Space Terahertz Technol. (pp. 263–266).
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Uzawa, Y., Kojima, T., Kroug, M., Takeda, M., Candotti, M., Fujii, Y., et al. (2009). Development of the 787-950 GHz ALMA band 10 cartridge. In Proc. 20th Int. Symp. Space Terahertz Technol. (p. 12).
Abstract: We are developing the Atacama Large Millimeter/Submillimeter Array (ALMA) Band 10 (787-950 GHz) receiver cartridge. The incoming beam from the 12-m antenna is reflected by a pair of two ellipsoidal mirrors placed in the cartridge, and then split into two orthogonal polarizations by a free-standing wire-grid. Each beam enters a corrugated feed horn attached to a double-side-band (DSB) mixer block. The mixer uses a full-height waveguide and an NbTiN- or NbN-based superconductor-insulator-superconductor (SIS) mixer chip. We are testing the following three types of mixer chips: 1) Nb SIS junctions + NbTiN/SiO2/Al tuning circuits on a quartz substrate, 2) Nb SIS junctions + NbN/SiO2/Al tuning circuits on an MgO substrate, and 3) NbN SIS junctions + NbN or NbTiN tuning circuits on an MgO substrate. The IF system uses a 4-12-GHz cooled low-noise InP-based MMIC amplifier developed by Caltech. So far, the type 1) has shown the best performance. At LO frequencies from 800 to 940 GHz, the mixer noise temperatures measured by using the standard Y-factor method were below 240 K at an operating physical temperature of 4 K. The lowest noise temperature, 169 K, was obtained at the center frequency of the band 10, as designed. These well-developed technologies will be implemented in the band 10 cartridge to achieve the ALMA specifications.
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Li, C. - T., Chen, T. - J., Ni, T. - L., Lu, W. - C., Chiu, C. - P., Chen, C. - W., et al. (2009). Development of SIS mixers for SMA 400-520 GHz band. In Proc. 20th Int. Symp. Space Terahertz Technol. (pp. 24–30).
Abstract: SIS junction mixers were developed for SMA 400-520 GHz band. The results show receiver noise temperature around 100 K across the band, with noise contribution from RF loss and IF estimated to be around 50 K and 20K, respectively. Two schemes were used to tune out junction's parasitic capacitance. When a parallel inductor is employed, the input impedance is close to Rn, which facilitates impedance matching between the junction and the waveguide probe. Waveguide probes were designed to achieve a low feed-point impedance to match to the junction resistance. Optimum embedding impedances for lower receiver noise temperature were investigated. Performances of two schemes and composition of receiver noise were also discussed.
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Huebers, H. - W., Pavlov, S., Semenov, A., Köhler, R., Mahler, L., Tredicucci, A., et al. (2005). Terahertz quantum cascade laser as local oscillator in a heterodyne receiver. Optics Express, 13(15), 5890–5896.
Abstract: Terahertz quantum cascade lasers have been investigated with respect to their performance as a local oscillator in a heterodyne receiver. The beam profile has been measured and transformed in to a close to Gaussian profile resulting in a good matching between the field patterns of the quantum cascade laser and the antenna of a superconducting hot electron bolometric mixer. Noise temperature measurements with the hot electron bolometer and a 2.5 THz quantum cascade laser yielded the same result as with a gas laser as local oscillator.
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de Lange, G., Krieg, J. - M., Honingh, N., Karpov, A., & Cherednichenko, S. (2008). Performance of the HIFI flight mixers. In Proc. 19th Int. Symp. Space Terahertz Technol. (pp. 98–105).
Abstract: We summarize the technology and final results of the superconducting heterodyne SIS and HEB mixers that are developed for the HIFI instrument. Within HIFI 7 frequency bands cover the frequency range from 480 GHz to 1910 GHz. We describe the different device technologies and optical coupling schemes that are used to cover the frequency bands. The efforts of the different mixer teams that participate in HIFI have contributed to an instrument that will have unprecedented sensitivity and frequency coverage.
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