scispace - formally typeset
Search or ask a question
Topic

L band

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


Papers
More filters
01 Jan 2015
TL;DR: In this paper, a low-noise amplifier for GNSS applications is proposed, which is powered by a single positive supply of +5 V and has very low DC power consumption of 15 mW.
Abstract: Abstract This thesis work was performed at RUAG Space AB, Goteborg, Sweden. The aim of this thesis is to test the performance boundaries of SiGe based heterojunction bipolar transistor in designing a low noise amplifier meant for GNSS applications. After careful consideration of different alternatives for active components in SiGe HBT process, BFY640-04 from Infineon was selected as the active component for the design. Later, different topologies have been evaluated in Advanced Design System (ADS) software and finally a common emitter topology is selected considering cost-effectiveness, performance and simplicity. Apart from this, the functionality of a limiter component namely, GG-77015-01 from Microsemi has been tested by placing it in front of the LNA. The purpose of this is to know if it can prevent the LNA from high power levels and to study its overall effect on noise figure, gain and linearity. The prototypes were fabricated on a hardback PCB consisting of Roger Duroid 6002 substrate. The designed LNA has less than 1 dB (excluding limiter) noise figure, gain of 17-13 dB and input return loss of 6 dB. It is powered by a single positive supply of +5 V and has very low DC power consumption of 15 mW. Also, the noise figure is fairly low in the entire L-band apart from current GNSS bands, which provides possibility of this design to be useful in future GNSS applications too. (Less)

1 citations

01 Jan 2005
TL;DR: In this paper, the phase center of the feed at mid-band needs to be at or near the secondary focus and the larger feeds do not cause blockage for the adjacent feeds.
Abstract: A primary goal of the Very Large Array Expansion (EVLA – Phase 1) Project is to provide continuous frequency coverage with increased sensitivity from 1 to 50 GHz from the secondary focus. Eight receiver bands were chosen to cover the above range. The lower three bands cover the 1-8 GHz range, with each receiver covering an octave band (1-2, 2-4 and 4-8 GHz). A new feed cone has been designed for the EVLA antenna to accommodate the eight receivers and feeds. The feeds for the lower three bands use the compact feed design [1], [2], which is relatively small compared to the linear taper design for the same illumination taper. The design of the L-band feed was critical as its size dictated the layout of the feeds on the feed cone. The feed layout was driven by two factors: (i) the phase center of the feed at mid-band needs to be at or near the secondary focus and (ii) the larger feeds do not cause blockage for the adjacent feeds. In order to achieve these goals, a compromise was made on the size of the L-band feed, resulting in a small loss in efficiency. The calculated aperture efficiency varied between 0.46 and 0.62. Spillover temperatures at 1.4 GHz and 2.0 GHz were 12.3 K and 12 K, respectively. However, measurements on the antenna gave lower efficiencies and spillover temperatures. The cause of this discrepancy has been analyzed and is presented here.

1 citations

Journal Article
Fu Bin1
TL;DR: In this article, the relationship between the frequency and SAR image of internal wave was discussed based on the SIR-C/X-SAR multi-frequency data, and the simulated SAR image was given under the given program of M4S.
Abstract: The relationship between the frequency and SAR image of internal wave is discussed based on the SIR-C/X-SAR multi-frequency data.For both elevation internal waves and depression internal waves,the feature of internal wave is significantly distinct in both X band and C band,while L band is the least.Also,the reason for the similarity between C band and L band but above both bands different from L band is explained by Bragg resonant scattering theory.Subsequently,we give the simulated SAR image of internal wave under the given program of M4S,and the result is also coincident with the analysis.

1 citations

Network Information
Related Topics (5)
Radar
91.6K papers, 1M citations
89% related
Pixel
136.5K papers, 1.5M citations
83% related
Antenna (radio)
208K papers, 1.8M citations
76% related
Optical fiber
167K papers, 1.8M citations
76% related
Amplifier
163.9K papers, 1.3M citations
76% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232
202222
202134
202036
201944
201838