Topic
L band
About: L band is a research topic. Over the lifetime, 674 publications have been published within this topic receiving 4570 citations.
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09 Jun 2007
TL;DR: An L-band circularly polarized antenna was designed using genetic algorithms in this paper, which has an impedance bandwidth of 12.5% at 1.6 GHz with a remarkably constant 4.2 dBi gain.
Abstract: An L-band circularly polarized antenna is designed using genetic algorithms. The design has an impedance bandwidth of 12.5% at 1.6 GHz with a remarkably constant 4.2 dBi gain. Further, it is very thin (
2 citations
TL;DR: In this article, the sensitivity of L-band (1.41GHz) polarimetric brightness temperature signatures to oriented permittivity patterns, which can occur for example in the case of row and interrow soil moisture differences in agricultural fields, was investigated.
Abstract: This study investigates the sensitivity of L-band (1.41GHz) polarimetric brightness temperature signatures to oriented permittivity patterns, which can occur for example in the case of row and interrow soil moisture differences in agricultural fields. A field experiment and model simulations are conducted to verify the effects of such patterns on all four Stokes parameters. We find that for an artificial target resembling idealized model conditions, permittivity patterns lead to systematic brightness temperature modulations in dependency of the azimuthal look angle. For the specific field setup, modulations reach amplitudes of ∼ 4K and mostly affect h-polarized brightness temperatures as well as the first, second, and third Stokes parameters. Simulations of soil moisture patterns under idealized model conditions indicate even higher amplitudes (up to 60K for extreme cases). However, the effects occur only for permittivity layer widths of up to 8 cm (given the observing wavelength of 21 cm), which is lower than the row and interrow widths typically observed in agricultural settings. For this reason, and due to the idealized model geometry investigated here, future studies are needed to transfer the findings of this study to potential applications such as the sensing of oriented soil moisture patterns. Particular interest might lie in radiometry and reflectometry in lower frequency ranges such as P-band, where according to the threshold established here (8/21 wavelengths), permittivity layer widths of up to ∼ 45 cm could be observed.
2 citations
Patent•
06 Nov 2018
TL;DR: In this paper, a VHF/L dual-band common-caliber antenna with a single-point feeding common-antenna structure form is presented, which consists of a reflection plate, a spiral belt, a support rod, support cylinder, a coaxial feeder, an SMA connector and an impedance matching segment.
Abstract: The invention discloses a novel VHF/L dual-band common-caliber antenna. A single-point feeding common-antenna structure form is employed, and the novel VHF/L dual-band common-caliber antenna comprisesa reflection plate, a spiral belt, a support rod, a support cylinder, a coaxial feeder, an SMA connector and an impedance matching segment. By the antenna, on one hand, the antenna can simultaneouslywork at a VHF band and an L band, different polarization modes and wave beam characteristics are shown, and on the other hand, the miniature design of the VHF-band omnibearing antenna can be achieved.
2 citations
Patent•
23 Oct 2013
TL;DR: In this article, a four-array L band omnidirectional satellite positioning antenna is presented, which comprises a substrate, a number of circular polarization patch antennas and microstrip lines used as power dividers.
Abstract: The utility model discloses a four array L band omnidirectional satellite positioning antenna which comprises a substrate, a number of circular polarization patch antennas and microstrip lines used as power dividers. The substrate surface is provided with grooves into which the patch antennas can be embedded. A number of patch antennas are connected through the microstrip lines. The substrate is provided with a through hole which can penetrate the substrate along the thickness direction of the substrate. The four array L band omnidirectional satellite positioning antenna provided by the utility model can reduce the antenna size on the premise that signal receiving is not affected.
2 citations
01 Feb 2018
TL;DR: In this paper, a dual band FSS (Frequency Selective Surface) reflector antenna that operates in the S and L-bands with gains of 8 dBi and 11 dBi at 1 GHz and 2.5 GHz respectively is demonstrated.
Abstract: A dual band FSS (Frequency Selective Surface) reflector antenna that operates in the S- and L-bands with gains of 8 dBi and 11 dBi at 1 GHz and 2.5 GHz respectively is demonstrated. The antenna has been simulated successfully showing good results in CST MWS (Microwave Studio) EM (Electromagnetic) simulation software. The reflector antenna consists of a dual band trap dipole antenna situated over an FSS upper parabolic reflector and a PEC (Perfect Electrical Conductor) lower parabolic reflector. The convoluted design of the FSS gives it angular and polarisation stability with a stop band centred at 2.5 GHz.
2 citations