High-frequency (HF) radars have been used since 20 years for remotely sensing ocean surface currents and ocean waves. Backscattered Doppler spectra contain two discrete lines, the frequencies of which (Bragg frequency) determine the current speed, and four continuous side bands, which allow to apply inversion techniques for retrieving ocean wave spectra. Recently, a new HF radar has been develo...

Wind direction measurements collected at 4 in-situ anemometers were compared with the WERA HF radar over a 20 month period to assess the accuracy of the radar system. The radar data was interpolated onto the less frequent in-situ time series. An unexpectedly large RMS error of 58.9° was calculated over all stations. A complex correlation coefficient of 0.65 was obtained. An improved correlation...

In this paper, a semi-empirical algorithm for significant wave height (Hs) and mean wave period (Tmw) retrieval from C-band VV-polarization Sentinel-1 synthetic aperture radar (SAR) imagery is presented. We develop a semi-empirical function for Hs retrieval, which describes the relation between Hs and cutoff wavelength, radar incidence angle, and wave propagation direction relative to radar loo...

Frequency-Modulated Continuous-Wave (FMCW) Radar has traditionally been used in short range applications. Conventional FMCW radar requires the use of expensive microwave mixers and low noise amplifiers. A uniquely inexpensive solution was created, using inexpensive Gunn oscillator based microwave transceiver modules that consist of 3 diodes inside of a resonant cavity. However these transceiver...

In lunar exploration, spaceborne high frequency (HF) radar sounder is an effective tool for investigation of lunar subsurface structure in lunar exploration [1] [2]. The primary strategy for radar sounder detection of subsurface structure is through the time delay and intensity difference of the lunar surface and subsurface nadir echoes (Figure 1). It is important to fully understand electromag...

Milan et al. (2001) identified a class of narrow, slow-moving HF radar backscatter echoes which originate between altitudes of 80 and 100 km, the ionospheric Dand lower E-regions. These echoes appeared to be associated with the occurrence of pulsating aurora, which are known to be created by energetic electrons capable of penetrating to D region altitudes. In this study we show that these echoe...

Synthetic aperture radar (SAR) based on frequency modulated continuous wave (FM-CW) transmission is a viable option for producing high resolution microwave imagery at low heights. In this paper, we show detailed analytical simulation for stripmap mode of FM-CW SAR imaging alongwith SAR images generated from actual airborne FM-CW radar video data collection. Key words—FM-CW, SAR, Range-Doppler, UAV

In the realm of materials science, terahertz frequency measurement systems provide significant utility in the characterization of material properties. With support primarily from the U.S. Army National Ground Intelligence Center (NGIC), Submillimeter Technology Laboratory (STL) researchers have been advancing the field of terahertz technology to the application of modeling millimeter-wave and m...

In this paper the benefits of using highly integrated millimeter-wave FMCW radar systems for industrial and security imaging applications are discussed. A 240 GHz wideband transceiver MMIC with on-chip antennas is presented and first non destructive testing measurements of packed hazelnut chocolate are shown. The radar system covers the frequency band from 204GHz to 265GHz.