scholarly journals Ku-Band Long Distance Site-Diversity (SD) Characteristics Using New Measuring System

2004 ◽  
Vol 52 (6) ◽  
pp. 1481-1491 ◽  
Author(s):  
T. Hatsuda ◽  
Y. Aoki ◽  
H. Echigo ◽  
F. Takahata ◽  
Y. Maekawa ◽  
...  
Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 116
Author(s):  
Julian Deuerling ◽  
Shaun Keck ◽  
Inasya Moelyadi ◽  
Jens-Uwe Repke ◽  
Matthias Rädle

This work presents a novel method for the non-invasive, in-line monitoring of mixing processes in microchannels using the Raman photometric technique. The measuring set-up distinguishes itself from other works in this field by utilizing recent state-of-the-art customized photon multiplier (CPM) detectors, bypassing the use of a spectrometer. This addresses the limiting factor of integration times by achieving measuring rates of 10 ms. The method was validated using the ternary system of toluene–water–acetone. The optical measuring system consists of two functional units: the coaxial Raman probe optimized for excitation at a laser wavelength of 532 nm and the photometric detector centered around the CPMs. The spot size of the focused laser is a defining factor of the spatial resolution of the set-up. The depth of focus is measured at approx. 85 µm with a spot size of approx. 45 µm, while still maintaining a relatively high numerical aperture of 0.42, the latter of which is also critical for coaxial detection of inelastically scattered photons. The working distance in this set-up is 20 mm. The microchannel is a T-junction mixer with a square cross section of 500 by 500 µm, a hydraulic diameter of 500 µm and 70 mm channel length. The extraction of acetone from toluene into water is tracked at an initial concentration of 25% as a function of flow rate and accordingly residence time. The investigated flow rates ranged from 0.1 mL/min to 0.006 mL/min. The residence times from the T-junction to the measuring point varies from 1.5 to 25 s. At 0.006 mL/min a constant acetone concentration of approx. 12.6% was measured, indicating that the mixing process reached the equilibrium of the system at approx. 12.5%. For prototype benchmarking, comparative measurements were carried out with a commercially available Raman spectrometer (RXN1, Kaiser Optical Systems, Ann Arbor, MI, USA). Count rates of the spectrophotometer surpassed those of the spectrometer by at least one order of magnitude at identical target concentrations and optical power output. The experimental data demonstrate the suitability and potential of the new measuring system to detect locally and time-resolved concentration profiles in moving fluids while avoiding external influence.


2010 ◽  
Vol 36 ◽  
pp. 387-394
Author(s):  
Hisashi Oohira ◽  
Serikawa Seiichi

It was reported in the previous report that the propagation constant measuring system for long distance pipelines was produced based upon the distribution constant theory for the purpose of maintenance and management of long distance pipelines buried underground and to have a system to directly measure the propagation constants and characteristic impedance of the pipeline buried underground. This time, a simulator for the signal propagation of a pipeline, referring to these actual measurement values, was constructed and various signal modes were simulated. On the prediction of accidents where heavy-construction equipment, such as backhoe or boring machine, has contact with a pipeline and damages the coating of pipeline, the damage simulations with a backhoe and boring machine were performed and the fault resistances of these heavy-construction pieces of equipment at the time of accidents were identified. As a result, it was revealed that the fault resistance generated by the metal-to-metal contact caused by the boring machine, which damages pipeline the most, was approximately 20-50Ω when water was used, and that caused by the backhoe was approximately 100Ω. In order to verify the detectable property of this system, a simulation was performed to determine how each distributed constant changed when this degree of grounding faults occurred in the monitoring section of the pipeline, and validated it with an actual pipeline.


Author(s):  
A.W. Dissanayake ◽  
D.K. McCarthy ◽  
J.E. Allnutt ◽  
B. Arbesser-Rastburg
Keyword(s):  

2021 ◽  
Vol 20 (2) ◽  
pp. 107-112
Author(s):  
Sarmistha Satrusallya ◽  
Mihir N. Mohanty

The antenna is the back bone of communication. In recent time, it needs to communicate in many ways along with different types of data such as voice, video, text etc. A long distance communication satellite needs a seamless transmission. The antenna design for satellite communication is to be array type to avoid the communication failure. This insists to work with array antenna to fulfil the seam less communication through satellite. Further the antenna design depends on the geometry of the patch, the placement of the patch for better gain and bandwidth. In this paper, authors have chosen the circular patch due to its single degree of freedom. The antenna is compact and is of 30X30mm2 where substrate thickness is considered as 1.6mm. The central patch is of rectangular shape with two slots. Slot is made because of better bandwidth. It is cut diagonally at the corner. As a result, the bandwidth is increased to 2.4GHz with a gain of 5.68dB. The substrate is considered to be FR4 Epoxy. The proposed design satisfies the compactness along with the satellite communication band with satisfactory gain. Simulation results compromise with the measured value. A 3X3 array of circular parasitic elements is considered. It is found that the antenna performs well at 14GHz that is meant for Ku band. The radius of the parasitic patch is considered as 4mm to satisfy the less space with good performance.


2012 ◽  
Vol 37 (4) ◽  
pp. 149-153
Author(s):  
Lauryna Šiaudinytė ◽  
Mindaugas Rybokas ◽  
Vytautas Giniotis

Testing and calibrating geodetic instruments is an important metrological procedure for precise instrumentation used in industry and geodesy. Electronic geodetic measuring instruments consist, among other elements, of circular scales and angular encoders for angle determination in two perpendicular horizontal and vertical planes. The accuracy of the instrument mostly depends on the accuracy of angle standards used for angle calibration in the horizontal plane. Although many methods are developed for angle calibration, the majority of those are not available for calibrating angles in the vertical plane. The method described in the International Standards of vertical angle calibration validates field testing geodetic instruments by taking precise angle readings between the calibrated points placed at long distance and height. Difficulties in creating such calibration basis and inconveniencies in proceeding with this field at long distances may appear. Also, the traceability of length and angle measurements is not ensured. The new method of calibrating the angles in the vertical plane for geodetic instruments was developed. The article describes the principle of indoor testing and the calibration of the vertical angle measuring system. Santrauka Daugelyje optinių elektroninių matavimo prietaisų yra įmontuotos apskritiminės skalės, skirtos kampinei padėčiai dviejose statmenose plokštumose – horizontaliojoje bei vertikaliojoje nustatyti. Prietaiso tikslumas daugiausia priklauso nuo sių skalių tikslumo. Rastrinių skalių metrologija yra gana specifinė sritis, būtina tam tikra metodika ir kalibravimo įranga. Trumpai apžvelgus pateikiami kai kurie būdai ir priemonės, taikytini kampų metrologijai, ypač vertikaliam plokščiajam kampui kalibruoti. Резюме Многие оптико-электронные измерительные инструменты состоят из круговых шкал для определения углов в двух перпендикулярных плоскостях – горизонтальной и вертикальной. Точность инструмента в основном зависит от точности этих угломерных шкал. Метрология угловых растровыx шкал довольно специфична и требует специфических мeтодов и приспособлений для калибрирования. В статье приводится обзор и некоторые простые способы и приспособления, которые можно использовать в метрологии углов, в частности, в калибрировании вертикального плоского угла.


Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4080 ◽  
Author(s):  
Chao-Tsung Ma ◽  
Cheng-Ling Lee ◽  
Yan-Wun You

This paper presents a novel measuring scheme for fiber interferometer (FI) based sensors. With the advantages of being small sizes, having high sensitivity, a simple structure, good durability, being easy to integrate fiber optic communication and having immunity to electromagnetic interference (EMI), FI based sensing devices are suitable for monitoring remote system states or variations in physical parameters. However, the sensing mechanism for the interference spectrum shift of FI based sensors requires expensive equipment, such as a broadband light source (BLS) and an optical spectrum analyzer (OSA). This has strongly handicapped their wide application in practice. To solve this problem, we have, for the first time, proposed a smart measuring scheme, in which a commercial laser diode (LD) and a photodetector (PD) are used to detect the equivalent changes of optical power corresponding to the variation in measuring parameters, and a signal processing system is used to analyze the optical power changes and to determine the spectrum shifts. To demonstrate the proposed scheme, a sensing device on polymer microcavity fiber Fizeau interferometer (PMCFFI) is taken as an example for constructing a measuring system capable of long-distance monitoring of the temperature and relative humidity. In this paper, theoretical analysis and fundamental tests have been carried out. Typical results are presented to verify the feasibility and effectiveness of the proposed measuring scheme, smartly converting the interference spectrum shifts of an FI sensing device into the corresponding variations of voltage signals. With many attractive features, e.g., simplicity, low cost, and reliable remote-monitoring, the proposed scheme is very suitable for practical applications.


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