150 V-Bias RF GaN for 1 kW UHF Radar Amplifiers

2016 ◽  
Author(s):  
Gabriele Formicone ◽  
Jeff Burger ◽  
James Custer
Keyword(s):  
Uhf Radar

VHF and UHF radar observations of the aurora at College, Alaska

1959 ◽  
Vol 64 (9) ◽  
pp. 1179-1190 ◽  
Author(s):  
R. I. Presnell ◽  
R. L. Leadabrand ◽  
A. M. Peterson ◽  
R. B. Dyce ◽  
J. C. Schlobohm ◽  
...  
Keyword(s):  
Radar Observations ◽  
Uhf Radar

scholarly journals Observations of HF-induced instability in the auroral E region

2013 ◽  
Vol 31 (6) ◽  
pp. 1103-1108 ◽  
Author(s):  
N. M. Schlatter ◽  
N. Ivchenko ◽  
B. Gustavsson ◽  
T. Leyser ◽  
M. Rietveld
Keyword(s):  
Lower Layer ◽  
Central Feature ◽  
Ionospheric Heating ◽  
E Region ◽  
Uhf Radar

Abstract. Enhancements were observed in backscattered radar power during an ionospheric heating experiment from two distinct altitude regions in the auroral E region above Tromsø. For the experiment the EISCAT Tromsø heater was operated with O mode and X mode alternated at 4.04 MHz, close to the 3rd electron gyroharmonic. Ion-line data recorded with the EISCAT UHF radar reveal different temporal evolutions as well as different ion-line characteristics for the enhancements from the two altitude regions. The upper layer is dominated by a strong central feature, whereas the lower layer has three peaks corresponding to the central feature and the two ion lines. The altitude region of the two closely spaced (altitude separation ~ 5 km) but distinct enhancements is close to the critical altitude for the heater wave.

Some further results on long term mesospheric and lower thermospheric wind observations by the Arecibo UHF radar

1987 ◽  
Vol 49 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Yasuyuki Maekawa ◽  
Shoichiro Fukao ◽  
Isamu Hirota ◽  
Michael P. Sulzer ◽  
Susumu Kato
Keyword(s):  
Thermospheric Wind ◽  
Uhf Radar

scholarly journals Measurements and simulation of ionospheric scattering on VHF and UHF radar signals: Channel scattering function

Radio Science ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Neil C. Rogers ◽  
Paul S. Cannon ◽  
Keith M. Groves
Keyword(s):  
Scattering Function ◽  
Radar Signals ◽  
Uhf Radar

Some findings on correlation between the stratospheric echo power and the wind shear observed by the Arecibo UHF radar

Radio Science ◽  
1985 ◽  
Vol 20 (6) ◽  
pp. 1503-1508 ◽  
Author(s):  
T. Tsuda ◽  
K. Hirose ◽  
S. Kato ◽  
M. P. Sulzer
Keyword(s):  
Wind Shear ◽  
Uhf Radar

Ion composition in sporadicElayers measured by the EISCAT UHF radar

1988 ◽  
Vol 93 (A12) ◽  
pp. 14603 ◽  
Author(s):  
A. Huuskonen ◽  
T. Nygrén ◽  
L. Jalonen ◽  
N. Bjørnå ◽  
T. L. Hansen ◽  
...  
Keyword(s):  
Ion Composition ◽  
Uhf Radar

scholarly journals Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths

2007 ◽  
Vol 25 (12) ◽  
pp. 2487-2496 ◽  
Author(s):  
E. Belova ◽  
P. Dalin ◽  
S. Kirkwood
Keyword(s):  
Short Interval ◽  
Beam Width ◽  
Turbulent Energy ◽  
Energy Dissipation Rate ◽  
Theory Model ◽  
Turbulence Theory ◽  
Vhf Radar ◽  
Summer Echoes ◽  
Polar Mesosphere Summer Echoes ◽  
Uhf Radar

Abstract. On 5 July 2005, simultaneous observations of Polar Mesosphere Summer Echoes (PMSE) were made using the EISCAT VHF (224 MHz) and UHF (933 MHz) radars located near Tromsø, Norway and the ALWIN VHF radar (53.5 MHz) situated on Andøya, 120 km SW of the EISCAT site. During the short interval from 12:20 UT until 12:26 UT strong echoes at about 84 km altitude were detected with all three radars. The radar volume reflectivities were found to be 4×10−13 m−1, 1.5×10−14 m−1 and 1.5×10−18 m−1 for the ALWIN, EISCAT-VHF and UHF radars, respectively. We have calculated the reflectivity ratios for each pair of radars and have compared them to ratios obtained from the turbulence-theory model proposed by Hill (1978a). We have tested different values of the turbulent energy dissipation rate ε and Schmidt number Sc, which are free parameters in the model, to try to fit theoretical reflectivity ratios to the experimental ones. No single combination of the parameters ε and Sc could be found to give a good fit. Spectral widths for the EISCAT radars were estimated from the spectra computed from the autocorrelation functions obtained in the experiment. After correction for beam-width broadening, the spectral widths are about 4 m/s for the EISCAT-VHF and 1.5–2 m/s for the UHF radar. However, according to the turbulence theory, the spectral widths in m/s should be the same for both radars. We also tested an incoherent scatter (IS) model developed by Cho et al. (1998), which takes into account the presence of charged aerosols/dust at the summer mesopause. It required very different sizes of particles for the EISCAT-VHF and UHF cases, to be able to fit the experimental spectra with model spectra. This implies that the IS model cannot explain PMSE spectra, at least not for monodisperse distributions of particles.

scholarly journals Electron heating by HF pumping of high-latitude ionospheric F-region plasma near magnetic zenith

2020 ◽  
Vol 38 (2) ◽  
pp. 297-307 ◽  
Author(s):  
Thomas B. Leyser ◽  
Björn Gustavsson ◽  
Theresa Rexer ◽  
Michael T. Rietveld
Keyword(s):  
Electron Temperature ◽  
Pump Beam ◽  
Electron Heating ◽  
Incoherent Scatter ◽  
F Region ◽  
Left Handed ◽  
Parameter Values ◽  
Uhf Radar ◽  
Region Plasma ◽  
Magnetic Zenith

Abstract. High-frequency electromagnetic pumping of ionospheric F-region plasma at high and mid latitudes gives the strongest plasma response in magnetic zenith, antiparallel to the geomagnetic field in the Northern Hemisphere. This has been observed in optical emissions from the pumped plasma turbulence, electron temperature enhancements, filamentary magnetic field-aligned plasma density irregularities, and in self-focusing of the pump beam in magnetic zenith. We present results of EISCAT (European Incoherent SCATter association) Heating-induced magnetic-zenith effects observed with the EISCAT UHF incoherent scatter radar. With heating transmitting a left-handed circularly polarized pump beam towards magnetic zenith, the UHF radar was scanned in elevation in steps of 1.0 and 1.5∘ around magnetic zenith. The electron energy equation was integrated to model the electron temperature and associated electron heating rate and optimized to fit the plasma parameter values measured with the radar. The experimental and modelling results are consistent with pump wave propagation in the L mode in magnetic zenith, rather than in the O mode.

scholarly journals Combined radar observations of equatorial electrojet irregularities at Jicamarca

2007 ◽  
Vol 25 (2) ◽  
pp. 457-473 ◽  
Author(s):  
D. L. Hysell ◽  
J. Drexler ◽  
E. B. Shume ◽  
J. L. Chau ◽  
D. E. Scipion ◽  
...  
Keyword(s):  
Thermal Effects ◽  
Equatorial Electrojet ◽  
Radar Data ◽  
Multiple Frequency ◽  
Radar Observations ◽  
Plasma Irregularities ◽  
Doppler Shifts ◽  
Uhf Radar ◽  
East West

Abstract. Daytime equatorial electrojet plasma irregularities were investigated using five distinct radar diagnostics at Jicamarca including range-time-intensity (RTI) mapping, Faraday rotation, radar imaging, oblique scattering, and multiple-frequency scattering using the new AMISR prototype UHF radar. Data suggest the existence of plasma density striations separated by 3–5 km and propagating slowly downward. The striations may be caused by neutral atmospheric turbulence, and a possible scenario for their formation is discussed. The Doppler shifts of type 1 echoes observed at VHF and UHF frequencies are compared and interpreted in light of a model of Farley Buneman waves based on kinetic ions and fluid electrons with thermal effects included. Finally, the up-down and east-west asymmetries evident in the radar observations are described and quantified.

scholarly journals Observations of time dependence and aspect sensitivity of regions of enhanced UHF backscatter associated with RF heating

2005 ◽  
Vol 23 (1) ◽  
pp. 75-85 ◽  
Author(s):  
R. S. Dhillon ◽  
T. R. Robinson
Keyword(s):  
Elevation Angle ◽  
High Amplitude ◽  
Radar System ◽  
Heating Facility ◽  
Subsequent Decrease ◽  
Time Histories ◽  
Constant Altitude ◽  
Coherent Radar ◽  
Uhf Radar ◽  
Field Aligned Irregularities

Abstract. The EISCAT incoherent radar system, which is collocated with the EISCAT heating facility, is used to diagnose the ionosphere while heating experiments are conducted. In late September 2002, an experiment was performed in which the heater transmitted a 2-min-on/2-min-off cycle while its pointing direction was kept fixed and the UHF beam was cycled through five pointing directions. This UHF cycle was used for three heater beam-pointing directions. For field-aligned heater beam and UHF pointing, UHF data indicated a gradual decrease, with time, in the altitude at which enhanced ion-line scatter occurred. This was accompanied by a reduction in the intensity of the scatter. For field-aligned heater pointing and the UHF elevation angle of 6° in the field-aligned direction, a persistent high-amplitude signature was observed, which remained at a fairly constant altitude throughout the period that the heater remained switched on. Different time histories of the backscatter amplitude were observed in other UHF pointing directions, including the "ion-line overshoot", which is characterized by an increase and subsequent decrease in the heater-enhanced backscatter just after heater switch-on. It is suggested that these signatures may be caused by the presence or absence of field-aligned irregularities and reduced recombination caused by heating. The CUTLASS coherent radar system, which operated simultaneously with the UHF radar and the heater, observed backscatter from field-aligned irregularities created by the heater. The intensity of this backscatter was highest from the regions of the ionosphere that were excited by the central part of the heater beam.

Sign in / Sign up

Export Citation Format

Share Document