L band

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

Submarine optical fiber communications architectures

Abstract: Submarine optical fiber communications are described. A submarine optical fiber communications system can be configured to transmit optical signals within a first band of the electromagnetic spectrum in a first direction, and to transmit optical signals within a second band of the electromagnetic spectrum in a second direction. The bands can be C band, L band, or both bands.

Co-Site Interference Study and Mitigation Onboard a Submarine Between Communication and Positioning Systems at L Band

Abstract: This letter focuses on modeling and studying the RF interference between a civilian Inmarsat FB emitter at 1627 MHz (culprit) and a GPS L1 band maritime system at 1575 MHz (victim) on close antennas proximity onboard a submarine. Once predicted the RFI, we propose the design of an adequate mitigation for it. The chosen platform to host this study is a 3D model of the U.S. Navy retired Los Angeles SSN-688 original class submarine. The proposed methodology consists on calculating through numerical 3D electromagnetic simulation the electromagnetic decoupling between culprit and victim’s antennas on different antenna placement scenarios onboard the SSN-688’s masts; modeling a typical GPS front-end receiver simultaneously excited with both the interferer signal after decoupling, and the GPS weak signal reception; to observe the RFI effects on the modeled receiver circuit; and to finally propose and design an adequate filter to control and mitigate the interference. The result is a pre-filter, to be connected to the GPS receiver front-end before the GPS’s low noise amplifier, which attenuates the Inmarsat signal on the rejection band below the RFI threshold level and inserts a low insertion loss on GPS pass band.

Single-band Compact Asymmetric meandered patch Antenna(AMPA) with partial Ground Plane for L- band Application

Abstract: A compact planar printed partial ground plane monopole antenna with single-band operation suitable for radio navigation satellite application is submitted in this letter. The Antenna covers a total space of 30 ×15.44 mm2. The Antenna is excited by a microstrip fed line, which radiates at 1.21 GHz. By optimally choosing the antenna extents, single-band resonant modes with a narrow impedance matching are present in this Antenna. Models of the achieved optimized configuration have been simulated using a CST. The simulated outcomes inspect well single band operation with −10 dB impedance bandwidth of 83.3 MHz, which covers the 1.21 GHz for L5 (1.164-1.215)GHz Radio navigation satellite service for both federal and nonfederal operating bands and L2 (1.215-1.240)GHz for primary national government use. Decent Antenna shows, for instance, radiation patterns, Surface current patterns, Electric field, and miniaturization. The Antenna with a compact dimension of 30×15.44×1.6 mm3 is intended to take an FR4 substrate through a permittivity of 4.4.

Variations of GSM Path Loss Exponent with Propagation Distance at L-Band Frequencies in Different Microcellular Environment of Southwestern Nigeria

Abstract: Propagation path loss exponent is an important component of system design, and knowing the values helps to avoid surprises when the actual service begins. The path loss exponent is known to be critical in establishing the coverage of any new cellular network. Estimating the path loss exponent of any environment requires raising new data sets, which can be accomplished by conducting experiments. With this objective, the present study reports the L-band signal RSS level measurements of 6 GSM base stations in the urban, suburban and rural environments of Ondo and Ekiti States in the Southwestern region of Nigeria. Using a Sony Ericsson TEMS phone monitoring device—connected to a laptop equipped with TEMS software and base station cell reference—and a GPS device, RSS measurements were performed in each sector of the base station up to 1200 m, employing a single sector verification method. The values of path loss exponents were computed from the deduced values of path loss at 50 m intervals up to distances of 1200 m. Close to the base station, the following exponent values were observed—between 2.0 and 3.8 in the urban environment, 2.0 to 2.8 in the suburban environment while for the rural environment, 1.5 to 2.6 we're observed. After the breakpoint distance, higher path loss exponent values of up to 6 was recorded in the urban environment, exponent value of up to 4.3 was observed in the suburban environment and up to 3.5 exponent value in the rural environment. It was also observed that the rural environment presented the longest breakpoint distance of 500 m. The high path loss exponents observed, especially in the urban environment, could cause GSM operators to rethink the margins they have provided. This study is useful for the design of upcoming network systems in these regions and in similar regions.

A high stability L-band travelling-wave tube receiver for use in radio astronomy

Abstract: In order to facilitate fast high resolution surveys and spectral work over a large frequency range a broadband travelling-wave tube receiver has been developed. A Dicke-system employing a travelling-wave tube switch was chosen to give maximum stability. A noise figure below 5 down to 2:95 in connection with a system stability of better than 1 in 104 appears sufficient for cosmic noise work in the L-band, but interference from a number of powerful radar transmitters makes broadband measurements impossible at the present time.