共查询到5条相似文献,搜索用时 0 毫秒
1.
V. I. Piddyachiy A. M. Korolev V. M. Shulga 《International Journal of Infrared and Millimeter Waves》2005,26(10):1381-1388
An integrated 3mm-wave Schottky diode mixer and pseudomorphic high-electron-mobility transistor (PHEMT) IF amplifier with
record noise performance at room temperature is described. The design has shown the room-temperature double-sideband (DSB)
receiver noise temperature TRDSB of 190 K at 100 GHz due to a very low conversion loss in the full-height waveguide mixer and an ultra-low noise of the PHEMT
IF amplifier. The receiver noise temperature has been reduced by a factor of 1.5 in comparison with the best previously reported
3mm-wave Schottky diode mixer receiver. 相似文献
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3.
J. W. Kooi G. Chattopadhyay S. Withington F. Rice J. Zmuidzinas C. Walker G. Yassin 《International Journal of Infrared and Millimeter Waves》2003,24(3):261-284
We describe a waveguide to thin-film microstrip transition for high-performance submillimetre wave and teraherz applications. The proposed constant-radius probe couples thin-film microstrip line, to full-height rectangular waveguide with better than 99% efficiency (VSWR 1.20) and 45% fractional bandwidth. Extensive HFSS simulations, backed by scale-model measurements, are presented in the paper. By selecting the substrate material and probe radius, any real impedance between 15-60 can be achieved. The radial probe gives significantly improved performance over other designs discussed in the literature. Although our primary application is submillimetre wave superconducting mixers, we show that membrane techniques should allow broad-band waveguide components to be constructed for the THz frequency range. 相似文献
4.
Shin''ichiro Asayama Takashi Noguchi Hideo Ogawa 《International Journal of Infrared and Millimeter Waves》2003,24(7):1091-1099
The design and performance of a fixed-tuned W-band SIS mixer with a wide band IF of 4.0-7.5 GHz is presented. Waveguide-to-stripline transition of the SIS mixer is designed using the lumped-gap-source port provided by HFSSTM. Measured receiver noise temperature is less than 25 K in the frequency range of 95-120 GHz, with a minimum value of around 19 K achieved. Mixer noise temperature is determined to be about 8.5 K, which is around twice the quantum limit (i.e., 2hw/k). In spite of the high IF frequencies (f
0 = 6 GHz), the performance of the SIS receiver is comparable or even superior to those of the best mechanically-tunable waveguide SIS receivers at low IF frequencies (f
0 = 1.5 GHz). This result suggests that it is easy to design waveguide-to-stripline transitions without scale-model measurements. 相似文献
5.
A. I. Harris J. Stutzki U. U. Graf R. Genzel 《International Journal of Infrared and Millimeter Waves》1989,10(11):1371-1376
We accurately measured the noise temperature and conversion loss of a cryogenically cooled Schottky diode operating near 800 GHz, using the UCB/MPE Submillimeter Receiver at the James Clerk Maxwell Telescope. The receiver temperature was in the range of the best we now routinely measure, 3150 K (DSB). Without correcting for optical loss or IF mismatch, the raw measurements set upper limits ofT
M=2850 K andL
M=9.1 dB (DSB), constant over at least a 1 GHz IF band centered at 6.4 GHz with an LO frequency of 803 GHz. Correction for estimated optical coupling and mismatch effects yieldsT
M=1600 K andL
M=5.5 dB (DSB) for the mixer diode itself. These values indicate that our receiver noise temperature is dominated by the corner cube antenna's optical efficiency and by mixer noise, but not by conversion loss or IF mismatch. The small fractional IF bandwidth, measured mixer IF band flatness from 2 to 8 GHz, and similarly good receiver temperatures at other IF frequencies imply that these values are representative over a range of frequencies near 800 GHz. 相似文献