ABSTRACT A likelihood ratio test is proposed for moving target detection in an ultra wide frequency band and wide antenna beam (wide band) SAR system. The developed method combines time domain fast backprojection SAR processing methods with moving target detection. It saves computational load when all relative speeds can be tested using the same clutter suppressed sub-aperture beams. The propos...

This study proposes a novel miniaturized circularly polarized (CP) ultrahigh frequency (UHF) quadrifilar helix antenna for spaceborne applications. The dual-band operation is realized using four inverted-U shaped helical strips (IUSHSs) that are rotated and alternately arranged on the faces of hollow polyimide cuboid in sequential rotation manner, which effectively reduces size antenna. Further...

This communication proposes a new all-dielectric broadband dual-band reflectarray with large frequency ratio using low-cost 3-D printing. In contrast to conventional reflectarrays metallic resonant cells or dielectric slabs as phasing elements full metal ground, the proposed design uses air element and stepped mirror structure ground. this way, ground is removed, which makes an one. Taking adva...

in the form of passive seismic methods, broadband seismometers have been used in hydrocarbon exploration. the frequency bandwidth typically studied is in the range of 1–6 hz. the observations on low frequency band of microtremors are used to calculate the spectral ratio of vertical and horizontal components (v/h) and power spectral density (psd). attributes based on the v/h ratio and the psd ha...

BACKGROUND The fetal heart rate (FHR) is commonly monitored during labor to detect early fetal acidosis. FHR variability is traditionally investigated using Fourier transform, often with adult predefined frequency band powers and the corresponding LF/HF ratio. However, fetal conditions differ from adults and modify spectrum repartition along frequencies. AIMS This study questions the arbitrar...

The best-fitting 2-dimensional plane within the 3-dimensional space of spiral galaxy disk observables (rotational velocity vrot, central disk surface brightness μ0 = −2.5 log I0, and disk scale-length h) has been constructed. Applying a threedimensional bisector method of regression analysis to a sample of ∼100 spiral galaxy disks that span more than four mag arcsec in central disk surface brig...

A compact printed hybrid-mode antenna for dual-band dual-sense circular polarisation (CP) has been proposed. To achieve CP, a hybrid mode produced by an L-shaped element and loop is used. In the lower frequency band, left-handed CP radiated vertical electric field from horizontal element. higher right-handed Both elements produce resonances in bands. The operational principle clarified using si...