Centimeter-wave low-noise amplifiers for satellite communications

1976 ◽  
Author(s):  
R. LEVIN
2020 ◽  
Vol 96 (3s) ◽  
pp. 347-352
Author(s):  
Д.Г. Алипа ◽  
В.В. Краснов ◽  
В.М. Минненбаев ◽  
А.В. Редька ◽  
Ю.В. Федоров

В статье представлены результаты исследования возможности применения при криогенных температурах водородного уровня дискретных приборов и монолитных схем на основе нитрида галлия в составе малошумящих усилителей сантиметрового и миллиметрового диапазона длин волн для приемных устройств систем дистанционного зондирования Земли из космоса и в составе криогенных комплексов наблюдения космического пространства. The article presents the results of the research on the possibility of using discrete devices and gallium nitride monolithic circuits at the cryogenic temperatures of hydrogen level as part of low-noise amplifiers of centimeter and millimeter-wave bands used in receivers of Earth remote sensing space systems and in cryogenic systems for space observation.


Author(s):  
J. Grahn ◽  
E. Cha ◽  
A. Pourkabirian ◽  
J. Stenarson ◽  
N. Wadefalk

2021 ◽  
Vol 13 (5) ◽  
pp. 919
Author(s):  
Marco Gabella

A previous study has used the stable and peculiar echoes backscattered by a single “bright scatterer” (BS) during five winter days to characterize the hardware of C-band, the dual-polarization radar located at Monte Lema (1625 m altitude) in Southern Switzerland. The BS is the 90 m tall metallic tower on Cimetta (1633 m altitude, 18 km range). In this note, the statistics of the echoes from the BS were derived from other ten dry days with normal propagation conditions in winter 2015 and January 2019. The study confirms that spectral signatures, such as spectrum width, wideband noise and Doppler velocity, were persistently stable. Regarding the polarimetric signatures, the large values (with small dispersion) of the copolar correlation coefficient between horizontal and vertical polarization were also confirmed: the average value was 0.9961 (0.9982) in winter 2015 (January 2019); the daily standard deviations were very small, ranging from 0.0007 to 0.0030. The dispersion of the differential phase shift was also confirmed to be quite small: the daily standard deviation ranged from a minimum of 2.5° to a maximum of 5.3°. Radar reflectivities in both polarizations were typically around 80 dBz and were confirmed to be among the largest values observed in the surveillance volume of the Monte Lema radar. Finally, another recent 5-day data set from January 2020 was analyzed after the replacement of the radar calibration unit that includes low noise amplifiers: these five days show poorer characteristics of the polarimetric signatures and a few outliers affecting the spectral signatures. It was shown that the “historical” polarimetric and spectral signatures of a bright scatterer could represent a benchmark for an in-depth comparison after hardware replacements.


2021 ◽  
Author(s):  
K. Lova Raju ◽  
V. Vijayaraghavan

Abstract Internet of Things (IoT) based automation has provided sophisticated research and developments in the field of agriculture. In agriculture field production, using environmental and deployment sensors like DHT11, soil moisture, soil temperature, and so on, IoT has been utilised to monitor field conditions and automation in precision agriculture. The environmental parameters, field evaluation, deployment parameters, and shortage of water has become an unresolved task for agriculture monitoring. All of this leads to insufficient production of the agricultural crop. To eradicate the above-mentioned problems, we proposed a system in the using an architectural manner. This system uses an NRF24L01 module with in-built power and low noise amplifiers to enable a long-distance communication for transmission of the field information about the current crop situation to the farmers. This work is investigating an appropriate, reasonable, and applied IoT technology for precision agriculture by considering various applications of agriculture and experiments. The proposed system reduces power consumption, and improves operational efficiency. The proposed system reduces human efforts and also evaluates heat index measurement to monitor the environment. Based on the experiments, the current consumption and life expectancy of the AWMU are determined to be 0.02819 A and 3 days 20 hours 13 minutes and 47 seconds, respectively. Furthermore, the maximum transmission of AWMU is in an environmental location is 200 meters line of sight from the router.


Author(s):  
Eunjung Cha ◽  
Niklas Wadefalk ◽  
Per-Ake Nilsson ◽  
Joel Schleeh ◽  
Giuseppe Moschetti ◽  
...  

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