Showing papers on "L band published in 2011"

Comparison of L- and C-Band Satellite-to-Indoor Broadband Wave Propagation for Navigation Applications

Abstract: In order to compare satellite-to-indoor wave propagation characteristics between L-band and C-band for satellite navigation applications, the German Aerospace Center (DLR) conducted a measurement campaign in June 2008. The measurements were performed at 1.51 GHz for L-band and at 5.2 GHz for C-band with a broadband signal of 100 MHz bandwidth. A mobile crane was used as transmitter platform. The receiving antenna was mounted on a model train which ran through various rooms in order to capture channel characteristics with a high spatial resolution. Standard statistical results are given in terms of power delay profile, received energy, mean delay, delay spread and number of paths for various transmitter heights and receiver locations. To show the impact of the satellite-to-indoor propagation channel on navigation receivers, the error of the delay-locked-loop (DLL) receiver and an experimental upper bound for multipath mitigation receivers is given. The analysis shows, that C-band is more sensitive to the building layout compared to L-band. Due to building material, C-band wave propagation is subjected to higher entry loss. In terms of positioning performance, L- and C-band show similar performances in the bias seen by the DLL estimator. For multipath mitigation receivers, L-band outperforms C-band especially for higher elevations.

3 GS/s 7 GHz BW 12 Bit MuxDAC for direct microwave signal generation over L, S or C bands

Abstract: In advanced applications such as digital radar, frequency hopping encryption data links, Micro-Wave Waveform Design Systems, Ultra Wide Bandwidth communications and software defined radio, the need for instantaneous bandwidth often drives system design decisions. The availability of powerful signal processors able to handle broadband signal vectors is not an issue anymore; the bottleneck is now the availability of high sampling rate and high linearity data converters, ADC (Analogue to Digital Converter) for reception and DAC (Digital to Analogue Converter) for transmission. Access to high speed data converters enabling up and down conversion directly in the L Band, S Band and C Band will allow system architects to operate in the digital world ever closer to the antenna, thus simplifying drastically receiver or transmitter architecture by removing costly Intermediate Frequency stages. Broadband DAC's are key enabling components which open up new design opportunities for direct digital Synthesizer systems. In this regard, this paper describes an innovative multimode 12 Bit 3GS/s MuxDAC, offering 46ps full swing rise time (that is 7.5 GHz analogue output bandwidth), based on a 200 GHz SiGeC bipolar Technology, which enables direct micro wave signal generation of up to 1.2 GHz width arbitrary waveforms directly in the high IF (L S or C Band) region closer to the Antenna. Beyond system and DAC design considerations this paper includes extended capability measurement performed on silicon. This DAC is turning Software Defined Micro-Wave or Direct Micro-Wave Synthesis (DMWS) from pure concept into proven reality up to C-Band.

A circular polarized self tracking L band array with high bandwidth and scan beamwidth for inmarsat BGAN applications

Abstract: This paper presents a 4×5 element antenna array for applications such as Inmarsat BGAN. This array addresses an important phenomenon which appears to have been little reported in the literature. This is the degradation of circular polarisation characteristics when a CP array is steered electronically. The design of this array presents significant challenges, as not only does it have to maintain a high quality of CP when scanning up to ±40°, but also has to do this over an 8.5% frequency coverage of 1.525 to 1.66 GHz. The resulting array was able to fulfil these requirements, with element sequential rotation being employed to further enhance the CP characteristics.

12 Bit 1.5 GS/s L-Band ADC on 200 GHz SiGeC Technology

Abstract: In advanced applications such as digital radar, Ultra Wide Bandwidth communications and software defined radio, the need for wide instantaneous bandwidth often drives system design decisions. Broadband 12 Bit ADC's (Analogue to Digital Converters) are key enabling components which open up new design opportunities for digital Receiver systems. In this regard, this paper describes a new 12bit true single Core 1,5 GS/s ADC with 2,3 GHz Bandwidth, based on a 200 GHz SiGeC bipolar Technology, which enables the direct digitizing of 500MHz broadband arbitrary waveforms directly in the 2nd Nyquist region closer to the Antenna (L-Band), enabling the design of flexible and simplified Radar receiver system architectures.

Characteristic of mobile satellite l-band signal in mid-latitude region:GPS approach

Abstract: Mobile satellite L-band signal that propagates from the transmitting satellite to the receiver experiences impairment mainly due to shadowing and multipath effects. In the present study, open space data has been obtained for Fukuoka, Japan (mid-latitude) using portable global positioning system (GPS) satellite receiver. The received signal performance, fading characteristic and cumulative distribution function of certain GPS satellites over the sky of Fukuoka have been observed and analysed. A general mathematical model representing the signal strength for the open space environment has been deduced based on the collected data. The outcome of this study can be used in future research to determine the effect of different mobile satellite environment on the arriving mobile satellite signal in improving the quality of service perceived by mobile satellite users.

Using e2v's high speed Space grade ADC and DAC to achieve direct conversion of L band signals

Abstract: This paper will describe the architecture and results obtained with two new e2v products designed for Space grade applications which open up new design possibilities for direct conversion of signals to and from L band.

Design of a software-defined radio for use in the IEEE L- and S-band

Abstract: This paper reports on the development and measurements of a software-defined radio front end spanning the IEEE L- and S-band [1]. Specifically, the GPS L1 and 2.4 GHz 802.11 signals are captured by the developed multi-purpose front end. Previous developments have focused on these individual frequency ranges but combining these frequency ranges can be beneficial to several types of applications, e.g. real-time location systems, cognitive radio development and low-cost development platforms. Furthermore, the front end is capable of receiving signals well outside the intended applications due to the flexibility of the design. We present the development of the front end and elaborate on our component choices. After which we discuss and interpret the captured measurements. These outcomes prove that even with modest hardware it is possible to develop and construct a working SDR front end capable of receiving a multitude of signals.

GaN transistor-based Class E power amplifier for the low L-band

Abstract: A GaN HEMT-based Class E power amplifier to work in the low L-band has been designed, built and measured. Measurements exhibit a 74% Power Added Efficiency and a 15W output power performance. The prototype has been tested under continuous wave excitation, two tone input signal and a constant envelope modulated signal used for the E5 band (1.19 GHz) of the future Galileo navigation system.

Generic prediction equation of both the in-band and out-of-band resonant frequencies of L-band and S band blade antennae

Abstract: In this research work, blade antennae operating in the L band and S band are studied to understand the electromagnetic compatibility and susceptibility of the blade antennae. Both the in-band and out-of-band performance of the antennae with varying structural parameters are analyzed based on the simulation and far-field measurement results. A generic equation has been derived to predict the in-band and out-of-band frequencies of the blade antennae with similar structures.

Design and test of an L-band phased array for maritime satcom

Abstract: In this paper a phased array antenna for maritime satellite communications is described. The antenna consists of 26 patch elements that are mounted on a soccer-like spherical aperture. The antenna allows full duplex communication via L-band satellite systems like Inmarsat BGAN or Thuraya. This design is an innovative and powerful alternative to current mechanically steered systems. Intermediate results of this antenna design were already presented in previous papers [1, 2]. This paper shows the final results in detail - after the final demonstration on a ship has been performed successfully.

Excellent polarization-independent reflector based on guided mode resonance effect

Abstract: A broad band polarization-independent reflector working in the telecommunication C+L band is proposed using the guided mode resonance effect of a periodic surface relief element deposited by a layer of silicon medium. It is shown that this structure can provide high reflection (R > 99.5%) and wide angular bandwidth (θ ≈ 20°, R > 98%) for both TE and TM polarizations over a wide spectrum band 1.5 μm~1.6 μm. Furthermore, it is found by rigorous coupled wave analysis that the polarization-independent reflector proposed here is tolerant of a deviation of grating thickness, which makes it very easy to fabricate in experiments.

L-band orthomode transducer for Shanghai 65m radio telescope

Abstract: Orthomode transducer which is the essential passive component of radio front-end constitutes a simple and compact device for splitting two perpendicular linear polarized signals and vice versa. In this paper, an L-band (1.25 to 1.75 GHz) quad-ridged orthomode transducer terminated by two orthogonal rows of shorting pins is designed and implemented with a strong concentration on assembly and suppression of higher-order modes and trapped-mode resonances. It is shown that experimental and simulated results are in good agreement which validates the proposed design procedure and approach.

A novel L band satellite beacon receiver based on Zero IF converter

Abstract: A novel kind of L band satellite beacon receiver is described in this paper. The Zero IF down convert concept is used to the receipt of the satellite beacon signal. Digital signal processing is also used in the receiver. When the input signal is −90dBm, the output of the receiver is −10dBm, thus s/n is 20dBm. When the input signal is −95dBm, the output of the receiver is also −10dBm, thus s/n is 10dBm. The output is same but s/n is different due to the use of AGC in the Zero IF concept.

Preliminary results of ground reflectivity measurements using noise radar

Abstract: The paper describes experimental L-band ground reflectivity measurement using noise radar demonstrator working as a scatterometer. The radar ground return is usually described with a scattering coefficient, a quantity that is independent from the scatterometer system. To calculate the coefficient in a function of incidence angle, range profile values obtained after range compression were used. In order to improve dynamic range of the measurement, antenna cross-path interference was removed using lattice filter. The ground return was measured at L band both for HH and VV polarizations of radar wave as well as for HV and VH crosspolarizations using log-periodic antennas placed at a 10 m high mast directed towards a meadow surface. In the paper the theoretical considerations, noise radar setup, measurement campaign and the results are described.

L Band Propagation Measurements for DAB Service Planning in INDIA

Abstract: The nature of variations of L band satellite signal strength for direct reception -both in fixed as well as in mobile reception are important technical parameters for the planning of satellite broadcast and communication services network. These parameters have been assessed through a field experiment using simulated satellite conditions. Variation of signal strength due to vegetation; urban structures; etc. as well as the building penetration loss along with the Standard Deviation of each of these variations has been assessed based on the data collected during the fixed and mobile reception. This paper gives an insight into the propagation in ‘L’ band under the simulated satellite conditions.

Independently reconfigurable multiband high impedance surface for L, C, X and Ku Radar Bands

Abstract: In this paper, a novel reconfigurable multiband high impedance surface (HIS) is introduced which is based on employing simple patch-like elements with “off the shelf” varactor diodes and PIN switching diodes in a multilayer unit cell configuration to achieve reconfigurable zero-reflection phase bands at L, C, X and Ku radar bands. The proposed HIS structure consists of three individual layers of FR4 substrates stacked up on top of each other with vacuum gap of 1mm. The bottom layer (L/X band) employs Toshiba 1SV245 varactor diodes with variable capacitance values from 4.55pF to 0.6pF. The middle layer (C band) employs Micrometrics Silicon Hyperabrupt varactor diodes with variable capacitance values from 0.8pF to 0.2pF. The top layer (Ku band) uses ON/OFF PIN switching diodes. The overall performance of the proposed reconfigurable HIS has been simulated using CST MWS and it has shown independently reconfigurable bands in L, C and Ku bands with partial reconfigurability in X band. The simulated tuneable effective bandwidth is from 0.93GHz to 2.47GHz for L band and from 5.78GHz to 7.02GHz for C band. The switchable bands for Ku band have been also observed at 12.1GHz and 14.8GHz. The overall unit cell structure has a thickness of 3.8mm and periodicity of 10mm.

Broadband non-polarizing beam splitter based on guided mode resonance effect

Abstract: A broadband non-polarizing beam splitter (NPBS) operating in the telecommunication C+L band is designed by using the guided mode resonance effect of periodic silicon-on-insulator (SOI) elements. It is shown that this double layer SOI structure can provide ~50/50 beam ratio with the maximum divergences between reflection and transmission being less than 8% over the spectrum of 1.4 μm~1.7 μm and 1% in the telecommunication band for both TE and TM polarizations. The physical basis of this broadband non-polarizing property is on the simultaneous excitation of the TE and TM strong modulation waveguide modes near the designed spectrum band. Meanwhile, the electric field distributions for both TE and TM polarizations verify the resonant origin of spectrum in the periodic SOI structure. Furthermore, it is demonstrated with our calculations that the beam splitter proposed here is tolerant to the deviations of incident angle and structure parameters, which make it very easy to be fabricated with current IC technology.

Satellite Digital Audio Radio Service Front-End

Abstract: ...................................................................................i Acknowledgements......................................................................ii Chapter

Airborne Remote Observations of L-Band Radio Frequency Interference and Implications for Satellite Missions

Abstract: Passive remote sensing of the Earth s surface and atmosphere from space has significant importance in operational and research environmental studies, in particular for the scientific understanding, monitoring and prediction of climate change and its impacts. Passive remote sensing requires the measurement of naturally occurring radiations, usually of very low power levels, which contain essential information on the physical process under investigation. As such, these sensed radio frequency bands are a unique natural resource enabling space borne passive sensing of the atmosphere and the Earth s surface that deserves adequate allocation to the Earth Exploration Satellite Service and absolute protection from interference. Unfortunately, radio frequency interference (RFI) is an increasing problem for Earth remote sensing, particularly for passive observations of natural emissions. Because these natural signals tend to be very weak, even low levels of interference received by a passive sensor may degrade the fidelity of scientific data. The characteristics of RFI (low-level interference and radar-pulse noise) are not well known because there has been no systematic surveillance, spectrum inventory or mapping of RFI. While conducting a flight experiment over central Tennessee in May 2010, RFI, a concern for any instrument operating in the passive L band frequency, was observed across 16 subbands between 1402-1427 MHz. Such a survey provides rare characterization data from which to further develop mitigation technologies as well as to identify bandwidths to avoid in future sensor formulation.