L band

About: L band is a research topic. Over the lifetime, 674 publications have been published within this topic receiving 4570 citations.

Omni-Directional Zeroth Order Resonator (ZOR) Antenna for L-Band Applications

Abstract: In this paper, Omni-directional ZOR antenna is presented which finds its application for L-Band. L-band covers frequency range from 1–2 GHz and is used for various applications such as radar, satellite, Global Positioning Systems (GPS), telecommunication use, and terrestrial communications. The proposed antenna design is based on one of the applications of Composite Right Left-Handed Transmission Line (CRLH-TL). Antenna design is a combination of two Split Ring Resonators (SRR) in which outer ring combination are of circular shape and inner ring combination is a square shape. The unit cell of proposed structure comprises of metallic patch at the top of dielectric substrate FR4. The overall dimension of proposed antenna is 12 mm \(\times \) 12 mm. The -10 dB bandwidth achieved is 20 MHz ranging from 1810 to 1830 MHz with respect to the center frequency of 1820 MHz. The results obtained in this paper is simulated using Ansys-HFSS 19.1v which is based on Finite Element Method (FEM). To prove the Omni-directional radiation pattern, uniform current distribution and 2-D plots are plotted. Beta versus frequency plot is portrayed which confirms the ZOR behavior of the antenna. Mesh size is kept at λ/20 mm so that results obtained are much pre-sized. The proposed antenna is fabricated and tested inside the Anechoic-Chamber, and the measured and the simulated results are almost similar to each other.

Propagation degradation for mobile satellite systems

Abstract: The results of four propagation tests for mobile satellite systems, which used remotely piloted vehicles and helicopters to simulate a transmitter satellite source platform, are presented. The signal degradation by individual trees, attenuation caused by roadside trees when the vehicle was moving, and multipath effects in hilly and mountainous terrain were studied. Three tests were conducted at UHF (870 MHz) and one test was performed at UHF and L band (1500 MHz). It was found that attenuation by roadside trees is the dominant cause of signal fading. The signal degradation may amount to 7 dB or more for 10 percent of the traveling time along tree-lined roads, with attenuations of 15 dB or more 1 percent of the time. The signal degradation caused by multipath effects amounted to only about 2 dB for 10 percent of the time and 9 dB for 1 percent of the time.

Fast Determination of Phase Advance, Path Delay and Ray Path Curvature between Satellites Through a 3D Ionosphere for L-band Transmissions

Abstract: A fast and accurate method of determining path delay and phase advance and range error between any two satellites for L-band frequencies has been determined. The method takes into account the bending of the ray path due to refraction by both vertical and horizontal gradients as well as the effect of the geomagnetic field and the actual profile of the electron density and its gradients along the path. The method has been validated against both analytical and precise numerical calculations. Results are presented of first and higher order ionosphere errors and path displacements from the LOS for satellite to ground and satellite to satellite paths. (5 pages)

MSK-BCS Modulation for GNSS Radio Frequency Compatibility in C Band

Abstract: Due to insufficient Radio Navigation Satellite Service (RNSS) portion of Radio Frequency (RF) spectrum for many services that are being planned for the future on L band where has come up a frequency overlapping situation, C band as an alternative spectral allocation has already been proposed in the previous years. The future C band signals could make use of the frequency band between 5010MHz and 5030MHz, offering a narrow bandwidth of 20 MHz. The main goal of C band signal design aims at having band limited signals. Consequently, it should be designed with a view to compatibility in band and the power emissions out of band. The Minimum Shift Keying(MSK) modulation is investigated to provide constant envelope and a good spectrum confinement, furthermore, a Binary Coded Symbol (BCS) modulation based on MSK pulse that has sharper autocorrelation, larger Gabor bandwidth, smaller CramerRao Lower Bound and less multipath error has been presented by Liu. Suppose spread interoperability signals employing the BCS modulation based on MSK pulse for Global Navigation Satellite System (GNSS) in C band with only a narrow bandwidth of 20MHz. Simulation results reveal the interference for the receiver prompt correlator channel processing and code tracking induced by navigation satellite system to each other. The result can be significant for the future signal design in C band

Feasibility Study on Tropospheric Attenuation Effect of Ku/V Band Signal for Korean Satellite Navigation System

Abstract: For next generation global navigation satellite systems, new carrier frequencies in Ku/V band are expected to emerge as a promising alternative to the current frequency windows in L band as they get severely congestive. In the case of higher frequency bands, signal attenuation phenomenon through the atmosphere is significantly different from the L band signal propagation. In this paper, a fundamental investigation is carried out to explore the Ku/V band as a candidate frequency band for a new global satellite navigation carrier signal, wherein specific attention is given to the effects of the dominant attenuation factors through the tropospheric propagation path. For a specific application, a candidate orbit preliminarily designed for the Korean regional satellite navigation system is adapted. Simulation results summarize that the Ku band can provide a promising satellite navigation implementation considering the present satellite’s power budget, while the V band still requires technical advances in satellite transceiver system implementations.