Antennas and Receivers in Radio Astronomy
|
|
- Cecilia Dorsey
- 5 years ago
- Views:
Transcription
1 Antennas and Receivers in Radio Astronomy Mark McKinnon Eleventh Synthesis Imaging Workshop Socorro, June 10-17, 2008
2 Outline 2 Context Types of antennas Antenna fundamentals Reflector antennas Mounts Optics Antenna performance Aperture efficiency Pointing Polarization Receivers
3 Importance of the Antenna Elements 3 Antenna amplitude pattern causes amplitude to vary across the source. Antenna phase pattern causes phase to vary across the source. Polarization properties of the antenna modify the apparent polarization of the source. Antenna pointing errors can cause time varying amplitude and phase errors. Variation in noise pickup from the ground can cause time variable amplitude errors. Deformations of the antenna surface can cause amplitude and phase errors, especially at short wavelengths.
4 4.8 GHz (C-band) Interferometer Block Diagram 4 Antenna Front End Key X Amplifier Mixer Correlator IF Back End Correlator
5 Types of Antennas 5 Wire antennas ( λ >1m) Dipole Yagi Helix Small arrays of the above Reflector antennas ( λ <1m) Hybrid antennas ( λ 1m) Wire reflectors Reflectors with dipole feeds Yagi Helix
6 Basic Antenna Formulas 6 Effective collecting area A(ν,θ,φ) m 2 P( θ, φ, ν ) = A( θ, φ, ν ) I( θ, φ, ν ) ΔνΔΩ On-axis response A 0 = ηa η = aperture efficiency Normalized pattern (primary beam) A(ν,θ,φ) = A(ν,θ,φ)/A 0 Beam solid angle Ω A = A(ν,θ,φ) dω all sky A 0 Ω A = λ 2 λ = wavelength, ν = frequency
7 Aperture-Beam Fourier Transform Relationship 7 What determines the beam shape? f(u,v) = complex aperture field distribution u,v = aperture coordinates (wavelengths) F(l,m) = complex far-field voltage pattern l = sinθcosφ, m = sinθsinφ F(l,m) = aperture f(u,v)exp(2πi(ul+vm))dudv f(u,v) = hemisphere F(l,m)exp(-2πi(ul+vm))dldm For VLA: θ 3dB = 1.02/D, First null = 1.22/D, D = reflector diameter in wavelengths
8 Antenna Mounts: Altitude over Azimuth 8 Advantages Cost Gravity performance Disadvantages Zone of avoidance Beam rotates on sky
9 Beam Rotation on the Sky 9 Parallactic angle
10 Antenna Mounts: Equatorial 10 Advantages Tracking accuracy Beam doesn t rotate Disadvantages Cost Gravity performance Sources on horizon at pole
11 Reflector Optics 11 Prime focus Cassegrain focus Offset Cassegrain Naysmith Beam Waveguide Dual Offset
12 Reflector Optics: Limitations 12 Prime focus Over-illumination (spillover) can increase system temperature due to ground pick-up Number of receivers, and access to them, is limited Subreflector systems Can limit low frequency capability. Feed horn too large. Over-illumination by feed horn can exceed gain of reflector s diffraction limited sidelobes Strong sources a few degrees away may limit image dynamic range Offset optics Support structure of offset feed is complex and expensive
13 Reflector Optics: Examples 13 Prime focus (GMRT) Cassegrain focus (AT) Offset Cassegrain (VLA) Naysmith (OVRO) Beam Waveguide (NRO) Dual Offset (GBT)
14 Feed Systems 14 GBT VLA EVLA
15 Antenna Performance: Aperture Efficiency 15 On axis response: A 0 = ηa Efficiency: η = η sf η bl η s η t η misc η sf = Reflector surface efficiency Due to imperfections in reflector surface η sf = exp( (4πσ/λ) 2 ) e.g., σ = λ/16, η sf = 0.5 rms error σ η bl = Blockage efficiency Caused by subreflector and its support structure η s = Feed spillover efficiency Fraction of power radiated by feed intercepted by subreflector η t = Feed illumination efficiency Outer parts of reflector illuminated at lower level than inner part η misc = Reflector diffraction, feed position phase errors, feed match and loss
16 Antenna Performance: Aperture Efficiency 16 Primary Beam πdl l=sin(θ), D = antenna diameter in contours: 3, 6, 10, 15, 20, 25, wavelengths 30, 35, 40 db db = 10log(power ratio) = 20log(voltage ratio) VLA: θ 3dB = 1.02/D, First null = 1.22/D Voltage radiation pattern, F(l,m)
17 Antenna Pointing: Practical Considerations 17 Reflector structure Subreflector mount Quadrupod El encoder Alidade structure Rail flatness Foundation Az encoder
18 Antenna Performance: Pointing 18 Pointing Accuracy Δθ = rms pointing error Δθ Often Δθ < θ 3dB /10 acceptable, because A(θ 3dB /10) ~ 0.97 BUT, at half power point in beam A(θ 3dB /2 ± θ 3dB /10)/A(θ 3dB /2) = ±0.3 θ 3dB Primary beam A(θ) For best VLA pointing use Reference Pointing. Δθ = 3 arcsec = θ 3dB 50 GHz
19 Antenna Performance: Polarization 19 Antenna can modify the apparent polarization properties of the source: Antenna structure Symmetry of the optics Reflections in the optics Curvature of the reflectors Quality of feed polarization splitter Constant across the beam Circularity of feed radiation patterns No instrumental polarization on-axis, But cross-polarization varies across the beam
20 Off-Axis Cross Polarization 20 Cross-polarized aperture distribution Cross-polarized primary beam Field distribution in aperture of paraboloid fed by electric dipole VLA 4.8 GHz cross-polarized primary beam
21 Receivers: Noise Temperature 21 Reference received power to the equivalent temperature of a matched load at the input to the receiver Rayleigh-Jeans approximation to Planck radiation law for a blackbody P in = k B T Δν (W) Matched temp T ( o K) k B = Boltzman s constant (1.38*10-23 J/ o K) P in Gain G B/W Δν Receiver P out =G*P in When observing a radio source, T total = T A + T sys Tsys = system noise when not looking at a discrete radio source T A = source antenna temperature
22 Receivers: SEFD 22 EVLA Sensitivities T A = ηas/(2k B ) = KS Band (GHz) 1-2 η.50 T sys 21 SEFD 236 S = source flux (Jy) SEFD = system equivalent flux density SEFD = Tsys/K (Jy)
23 23 EVLA Q-Band (40-50 GHz) Receiver Dewar Integrated Remove Dorado 4IWC45-1 NRAO CDL Isolator Dorado 4IWN45-1A (UG38 UG599) Post-AmpModule Caltech 3XM L/R RF=40-50 GHz Tripler/Mixer Assembly Spacek 3XM L/R RF=40-50 GHz DC-Block Inmet 8055H GHz Isolator MICA T-708S GHz RCP IF Out 8-18 GHz GHz RCP Pol T Cal Atlantic Microwave AMC 1233 Septum Polarizer & Cal Coupler T Cal 35dB LNA LNA Variable Attenuator NRAO GHz Magic-T MDL 22TH12B 24dB Noise/COM NC 5222 ENR > 20 db Noise Diode x3 18 dbm x3 LO Splitter MAC Tech PA8207-2F GHz Limiting LO Amplifier Norden N GHz P Out = 21.0 ± 0.5 dbm for ±6 dbm input Isolator Mica T-610S GHz GHz LO Ref 0 3 dbm 35dB LCP 24dB Old Some New New Pamtech KYG2121-K2 (w/g) NRAO CDL Isolator Dorado 4IWN45-1A (UG38 UG599) Post-AmpModule Caltech 3XM L/R RF=40-50 GHz Tripler/Mixer Assembly Spacek 3XM L/R RF=40-50 GHz DC-Block Inmet 8055H GHz Isolator MICA T-708S GHz LCP IF Out 8-18 GHz Isolator Ditom D3I GHz
24 Corrections to Chapter 3 of Synthesis Imaging in Radio Astronomy II 24 Equation 3-8: replace u,v with l,m Figure 3-7: abscissa title should be πdl
Antennas & Receivers in Radio Astronomy Mark McKinnon. Twelfth Synthesis Imaging Workshop 2010 June 8-15
Antennas & Receivers in Radio Astronomy Mark McKinnon 2010 June 8-15 Outline Context Types of antennas Antenna fundamentals Reflector antennas Mounts Optics Antenna performance Aperture efficiency Pointing
More informationAntennas. Greg Taylor. University of New Mexico Spring Astronomy 423 at UNM Radio Astronomy
Antennas Greg Taylor University of New Mexico Spring 2011 Astronomy 423 at UNM Radio Astronomy Radio Window 2 spans a wide range of λ and ν from λ ~ 0.33 mm to ~ 20 m! (ν = 1300 GHz to 15 MHz ) Outline
More informationAntennas. Greg Taylor. University of New Mexico Spring Astronomy 423 at UNM Radio Astronomy
Antennas Greg Taylor University of New Mexico Spring 2017 Astronomy 423 at UNM Radio Astronomy Outline 2 Fourier Transforms Interferometer block diagram Antenna fundamentals Types of antennas Antenna performance
More informationAntennas & Receivers in Radio Astronomy
Antennas & Receivers in Radio Astronomy Mark McKinnon Fifteenth Synthesis Imaging Workshop 1-8 June 2016 Purpose & Outline Purpose: describe how antenna elements can affect the quality of images produced
More informationIntroduction to Radio Astronomy!
Introduction to Radio Astronomy! Sources of radio emission! Radio telescopes - collecting the radiation! Processing the radio signal! Radio telescope characteristics! Observing radio sources Sources of
More informationSignal Flow & Radiometer Equation. Aletha de Witt AVN-Newton Fund/DARA 2018 Observational & Technical Training HartRAO
Signal Flow & Radiometer Equation Aletha de Witt AVN-Newton Fund/DARA 2018 Observational & Technical Training HartRAO Understanding Radio Waves The meaning of radio waves How radio waves are created -
More informationA Crash Course in Radio Astronomy and Interferometry: 1. Basic Radio/mm Astronomy
A Crash Course in Radio Astronomy and Interferometry: 1. Basic Radio/mm Astronomy James Di Francesco National Research Council of Canada North American ALMA Regional Center Victoria (thanks to S. Dougherty,
More informationEVLA Scientific Commissioning and Antenna Performance Test Check List
EVLA Scientific Commissioning and Antenna Performance Test Check List C. J. Chandler, C. L. Carilli, R. Perley, October 17, 2005 The following requirements come from Chapter 2 of the EVLA Project Book.
More informationWhat does reciprocity mean
Antennas Definition of antenna: A device for converting electromagnetic radiation in space into electrical currents in conductors or vice-versa. Radio telescopes are antennas Reciprocity says we can treat
More informationRichard Dodson 1/28/2014 NARIT-KASI Winter School
Goals: Technical introduction very short So what to cover? Things which are essential: How radio power is received - I How an interferometer works -II Antenna Fundamentals Black Body Radiation Brightness
More informationAperture Antennas. Reflectors, horns. High Gain Nearly real input impedance. Huygens Principle
Antennas 97 Aperture Antennas Reflectors, horns. High Gain Nearly real input impedance Huygens Principle Each point of a wave front is a secondary source of spherical waves. 97 Antennas 98 Equivalence
More informationSchool of Electrical Engineering. EI2400 Applied Antenna Theory Lecture 8: Reflector antennas
School of Electrical Engineering EI2400 Applied Antenna Theory Lecture 8: Reflector antennas Reflector antennas Reflectors are widely used in communications, radar and radio astronomy. The largest reflector
More informationEVLA Front-End CDR. EVLA Ka-Band (26-40 GHz) Receiver
EVLA Front-End CDR EVLA Ka-Band (26-40 GHz) Receiver 1 EVLA Ka-Band Receiver Overview 1) General Description 2) Block Diagram 3) Noise & Headroom Model 4) Feed & Thermal Gap 5) RF Tree - Phase-Shifter
More informationREPORT ITU-R SA.2098
Rep. ITU-R SA.2098 1 REPORT ITU-R SA.2098 Mathematical gain models of large-aperture space research service earth station antennas for compatibility analysis involving a large number of distributed interference
More informationSubmillimeter (continued)
Submillimeter (continued) Dual Polarization, Sideband Separating Receiver Dual Mixer Unit The 12-m Receiver Here is where the receiver lives, at the telescope focus Receiver Performance T N (noise temperature)
More informationFundamentals of the GBT and Single-Dish Radio Telescopes Dr. Ron Maddalena
Fundamentals of the GB and Single-Dish Radio elescopes Dr. Ron Maddalena March 2016 Associated Universities, Inc., 2016 National Radio Astronomy Observatory Green Bank, WV National Radio Astronomy Observatory
More informationReceiver Performance and Comparison of Incoherent (bolometer) and Coherent (receiver) detection
At ev gap /h the photons have sufficient energy to break the Cooper pairs and the SIS performance degrades. Receiver Performance and Comparison of Incoherent (bolometer) and Coherent (receiver) detection
More informationThe magnetic surface current density is defined in terms of the electric field at an aperture as follows: 2E n (6.1)
Chapter 6. Aperture antennas Antennas where radiation occurs from an open aperture are called aperture antennas. xamples include slot antennas, open-ended waveguides, rectangular and circular horn antennas,
More informationEvaluation of Suitable Feed Systemes
Evaluation of Suitable Feed Systemes Review of the Ring Focus Antenna Quadridge Horn Eleven Feed Coaxial Horn and Multiband Corrugated Horn Conclusion MIRAD Microwave AG Broadband Feedsystems IVS VLBI21
More informationG. Serra.
G. Serra gserra@oa-cagliari.inaf.it on behalf of Metrology team* *T. Pisanu, S. Poppi, F.Buffa, P. Marongiu, R. Concu, G. Vargiu, P. Bolli, A. Saba, M.Pili, E.Urru Astronomical Observatory of Cagliari
More informationIntroduction to DSTV Dish Observations. Alet de Witt AVN Technical Training 2016
Introduction to DSTV Dish Observations Alet de Witt AVN Technical Training 2016 Outline Theory: - Radio Waves - Radio Telescope Antennas - Angular Sizes - Brightness Temperature and Antenna Temperature
More informationReflector antennas and their feeds
Reflector antennas and their feeds P. Hazdra, M. Mazanek,. hazdrap@fel.cvut.cz Department of Electromagnetic Field Czech Technical University in Prague, FEE www.elmag.org v. 23.4.2015 Outline Simple reflector
More informationProgress Towards Coherent Multibeam Arrays
Progress Towards Coherent Multibeam Arrays Doug Henke NRC Herzberg Astronomy and Astrophysics, Victoria, Canada August 2016 ALMA Band 3 Receiver (84 116 GHz) Dual linear, 2SB Feed horn OMT (two linear
More informationANTENNA INTRODUCTION / BASICS
ANTENNA INTRODUCTION / BASICS RULES OF THUMB: 1. The Gain of an antenna with losses is given by: 2. Gain of rectangular X-Band Aperture G = 1.4 LW L = length of aperture in cm Where: W = width of aperture
More informationSources classification
Sources classification Radiometry relates to the measurement of the energy radiated by one or more sources in any region of the electromagnetic spectrum. As an antenna, a source, whose largest dimension
More informationEC ANTENNA AND WAVE PROPAGATION
EC6602 - ANTENNA AND WAVE PROPAGATION FUNDAMENTALS PART-B QUESTION BANK UNIT 1 1. Define the following parameters w.r.t antenna: i. Radiation resistance. ii. Beam area. iii. Radiation intensity. iv. Directivity.
More informationLE/ESSE Payload Design
LE/ESSE4360 - Payload Design 4.3 Communications Satellite Payload - Hardware Elements Earth, Moon, Mars, and Beyond Dr. Jinjun Shan, Professor of Space Engineering Department of Earth and Space Science
More informationEVLA Memo #119 Wide-Band Sensitivity and Frequency Coverage of the EVLA and VLA L-Band Receivers
EVLA Memo #119 Wide-Band Sensitivity and Frequency Coverage of the EVLA and VLA L-Band Receivers Rick Perley and Bob Hayward January 17, 8 Abstract We determine the sensitivities of the EVLA and VLA antennas
More informationOPTICS OF SINGLE BEAM, DUAL BEAM & ARRAY RECEIVERS ON LARGE TELESCOPES J A M E S W L A M B, C A L T E C H
OPTICS OF SINGLE BEAM, DUAL BEAM & ARRAY RECEIVERS ON LARGE TELESCOPES J A M E S W L A M B, C A L T E C H OUTLINE Antenna optics Aberrations Diffraction Single feeds Types of feed Bandwidth Imaging feeds
More informationNewsletter 4.4. Antenna Magus version 4.4 released! Array synthesis reflective ground plane addition. July 2013
Newsletter 4.4 July 2013 Antenna Magus version 4.4 released! We are pleased to announce the new release of Antenna Magus Version 4.4. This release sees the addition of 5 new antennas: Horn-fed truncated
More informationEVLA Antenna and Array Performance. Rick Perley
EVLA Antenna and Array Performance System Requirements EVLA Project Book, Chapter 2, contains the EVLA system requirements. For most, astronomical tests are necessary to determine if the array meets requirements.
More informationATCA Antenna Beam Patterns and Aperture Illumination
1 AT 39.3/116 ATCA Antenna Beam Patterns and Aperture Illumination Jared Cole and Ravi Subrahmanyan July 2002 Detailed here is a method and results from measurements of the beam characteristics of the
More informationIntroduction to Radio Astronomy. Richard Porcas Max-Planck-Institut fuer Radioastronomie, Bonn
Introduction to Radio Astronomy Richard Porcas Max-Planck-Institut fuer Radioastronomie, Bonn 1 Contents Radio Waves Radio Emission Processes Radio Noise Radio source names and catalogues Radio telescopes
More informationEVLA Memo 137 Performance Tests of the EVLA K, Ka, and Q-Band Receivers
EVLA Memo 137 Performance Tests of the EVLA K, Ka, and Q-Band Receivers Rick Perley, Bob Hayward and Bryan Butler NRAO August 4, 2009 Abstract Efficiency observations performed in January and February
More informationFinal Feed Selection Study For the Multi Beam Array System
National Astronomy and Ionosphere Center Arecibo Observatory Focal Array Memo Series Final Feed Selection Study For the Multi Beam Array System By: Germán Cortés-Medellín CORNELL July/19/2002 U n i v e
More informationALMA Sensitivity Metric for Science Sustainability Projects
ALMA Memo 602 ALMA Sensitivity Metric for Science Sustainability ALMA-35.00.101.666-A-SPE 2017 01 23 Description Document Jeff Mangum (NRAO) Page 2 Change Record Revision Date Author Section/ Remarks Page
More informationA new K-band (18-26 GHz) 7-horn multi-feed receiver: Calibration campaign at Medicina 32 m dish
A new K-band (18-26 GHz) 7-horn multi-feed receiver: Calibration campaign at Medicina 32 m dish R.Verma, G.Maccaferri, A.Orfei I.Prandoni, L.Gregorini IRA 430/09 Contents 1 6 1.1 Goals............................................
More informationANTENNA INTRODUCTION / BASICS
Rules of Thumb: 1. The Gain of an antenna with losses is given by: G 0A 8 Where 0 ' Efficiency A ' Physical aperture area 8 ' wavelength ANTENNA INTRODUCTION / BASICS another is:. Gain of rectangular X-Band
More informationAntennas & wave Propagation ASSIGNMENT-I
Shri Vishnu Engineering College for Women :: Bhimavaram Department of Electronics & Communication Engineering Antennas & wave Propagation 1. Define the terms: i. Antenna Aperture ii. Beam Width iii. Aperture
More informationAperture antennas. Ahmed FACHAR, Universidad Politécnica de Madrid (Technical University of Madrid, UPM)
Aperture antennas Ahmed FACHAR, ahmedfach@gr.ssr.upm.es Universidad Politécnica de Madrid (Technical University of Madrid, UPM) Outline Introduction Horn antennas Introduction Rectangular horns Conical
More informationBHARATHIDASAN ENGINEERING COLLEGE NATTARAMPALLI Frequently Asked Questions (FAQ) Unit 1
BHARATHIDASAN ENGINEERING COLLEGE NATTARAMPALLI 635854 Frequently Asked Questions (FAQ) Unit 1 Degree / Branch : B.E / ECE Sem / Year : 3 rd / 6 th Sub Name : Antennas & Wave Propagation Sub Code : EC6602
More informationEVLA Receivers PDR. (4m, P,) L, S, C BAND RECEIVERS. AuthorDaniel (Mert) Mertely
EVLA Receivers PDR (4m, P,) L, S, C BAND RECEIVERS Daniel (Mert) Mertely 1 Trx Projections EVLA RX FREQ RANGES AND OP TEMPS: REQUIRED vs. PROJECTED BND FRQ REQ CURNT CURNT CALC IDR RANGE Tsys (2) Tsys
More informationAntenna Fundamentals. Microwave Engineering EE 172. Dr. Ray Kwok
Antenna Fundamentals Microwave Engineering EE 172 Dr. Ray Kwok Reference Antenna Theory and Design Warran Stutzman, Gary Thiele, Wiley & Sons (1981) Microstrip Antennas Bahl & Bhartia, Artech House (1980)
More informationAperture antennas. Andrés García, Francico José Cano, Alfonso Muñoz. (Technical University of Madrid, UPM)
Aperture antennas Andrés García, Francico José Cano, Alfonso Muñoz andresg@gr.ssr.upm.es, ssr francisco@gr.ssr.upm.es, ssr alfonso@gr.ssr.upm.esssr Universidad Politécnica de Madrid (Technical University
More informationNMA Antenna and Receiver Concepts
EVLA Planning Workshop NRAO, Socorro, NM August 23, 2001 NMA Antenna and Receiver Concepts 1. Station Cost Equation 2. Hydroformed Antennas 3. Wideband Receivers Sander Weinreb, Caltech/JPL sweinreb@caltech.edu
More informationA Quick Review. Spectral Line Calibration Techniques with Single Dish Telescopes. The Rayleigh-Jeans Approximation. Antenna Temperature
Spectral Line Calibration Techniques with Single Dish Telescopes A Quick Review K. O Neil NRAO - GB A Quick Review A Quick Review The Rayleigh-Jeans Approximation Antenna Temperature Planck Law for Blackbody
More information5 RECEIVERS TABLE TBD: EVLA RECEIVER FREQUENCY RANGES AND OPERATING TEMPERATURES
EVLA Project Book, Chapter 5. 5 RECEIVERS Robert Hayward, Ed Szpindor, and Daniel J. Mertely Last changed 2001-Oct-30 Revision History 2001-July-01: Initial release. 2001-Oct-01: Sys-def & detail added.
More informationPhased Array Feeds A new technology for multi-beam radio astronomy
Phased Array Feeds A new technology for multi-beam radio astronomy Aidan Hotan ASKAP Deputy Project Scientist 2 nd October 2015 CSIRO ASTRONOMY AND SPACE SCIENCE Outline Review of radio astronomy concepts.
More informationFundamentals of Radio Astronomy. Lyle Hoffman, Lafayette College ALFALFA Undergraduate Workshop Arecibo Observatory, 2008 Jan. 13
Fundamentals of Radio Astronomy Lyle Hoffman, Lafayette College ALFALFA Undergraduate Workshop Arecibo Observatory, 2008 Jan. 13 Outline Sources in brief Radiotelescope components Radiotelescope characteristics
More informationEVLA Front-End CDR. Overview & System Requirements
EVLA Front-End CDR Overview & System Requirements 1 Overview & System Requirements Introduction to the EVLA Front-End Task EVLA vs. VLA Feeds Receivers System Requirements, including: System Temperatures
More informationTHEORY OF MEASUREMENTS
THEORY OF MEASUREMENTS Brian Mason Fifth NAIC-NRAO School on Single-Dish Radio Astronomy Arecibo, PR July 2009 OUTLINE Antenna-Sky Coupling Noise the Radiometer Equation Minimum Tsys Performance measures
More informationC-band Circular Corrugated horn for the SRT. Beam Waveguide Focus. L. Cresci, P. Curioni, V. Natale, R. Nesti, A.Orfei, D. Panella, J.
C-band Circular Corrugated horn for the SRT Beam Waveguide Focus GAI4 Memo Series I.N.A.F GAI4-TM-13.1 7/5/211 Abstract In this report the authors present the design of a circular corrugated horn for
More informationEVLA System Commissioning Results
EVLA System Commissioning Results EVLA Advisory Committee Meeting, March 19-20, 2009 Rick Perley EVLA Project Scientist t 1 Project Requirements EVLA Project Book, Chapter 2, contains the EVLA Project
More informationRADIATION PATTERNS. The half-power (-3 db) beamwidth is a measure of the directivity of the antenna.
RADIATION PATTERNS The radiation pattern is a graphical depiction of the relative field strength transmitted from or received by the antenna. Antenna radiation patterns are taken at one frequency, one
More informationIntroduction to interferometry with bolometers: Bob Watson and Lucio Piccirillo
Introduction to interferometry with bolometers: Bob Watson and Lucio Piccirillo Paris, 19 June 2008 Interferometry (heterodyne) In general we have i=1,...,n single dishes (with a single or dual receiver)
More informationThe 4mm (68-92 GHz) Receiver
Chapter 18 The 4mm (68-92 GHz) Receiver 18.1 Overview The 4 mm receiver ( W-band ) is a dual-beam, dual-polarization receiver which covers the frequency range of approximately 67-93 GHz. The performance
More informationPhased Array Feeds A new technology for wide-field radio astronomy
Phased Array Feeds A new technology for wide-field radio astronomy Aidan Hotan ASKAP Project Scientist 29 th September 2017 CSIRO ASTRONOMY AND SPACE SCIENCE Outline Review of radio astronomy concepts
More informationThe WVR at Effelsberg. Thomas Krichbaum
The WVR at Effelsberg Alan Roy Ute Teuber Helge Rottmann Thomas Krichbaum Reinhard Keller Dave Graham Walter Alef The Scanning 18-26 GHz WVR for Effelsberg ν = 18.5 GHz to 26.0 GHz Δν = 900 MHz Channels
More informationFinal Examination. 22 April 2013, 9:30 12:00. Examiner: Prof. Sean V. Hum. All non-programmable electronic calculators are allowed.
UNIVERSITY OF TORONTO FACULTY OF APPLIED SCIENCE AND ENGINEERING The Edward S. Rogers Sr. Department of Electrical and Computer Engineering ECE 422H1S RADIO AND MICROWAVE WIRELESS SYSTEMS Final Examination
More informationINSTITUTE OF AERONAUTICAL ENGINEERING Dundigal, Hyderabad ELECTRONICS AND COMMUNIACTION ENGINEERING QUESTION BANK
INSTITUTE OF AERONAUTICAL ENGINEERING Dundigal, Hyderabad - 500 04 ELECTRONICS AND COMMUNIACTION ENGINEERING QUESTION BANK Course Name : Antennas and Wave Propagation (AWP) Course Code : A50418 Class :
More informationTelescope, Receiver, and Radiometry
Chapter 2 Telescope, Receiver, and Radiometry In this chapter, we discuss the telescope, optics, and receiver used to carry out the blazar monitoring program. We also describe the radiometry and calibration
More informationHigh Fidelity Imaging of Extended Sources. Rick Perley NRAO Socorro, NM
High Fidelity Imaging of Extended Sources Rick Perley NRAO Socorro, NM A Brief History of Calibration (VLA) An Amazing Fact: The VLA was proposed, and funded, without any real concept of how to calibrate
More informationNATIONAL RADIO ASTRONOMY OBSERVATORY CHARLOTTESVILLE, VIRGINIA. ELECTRONICS DIVISION INTERNAL REPORT No. 275 CRYOGENIC, HEMT, LOW-NOISE RECEIVERS
NATIONAL RADIO ASTRONOMY OBSERVATORY CHARLOTTESVILLE, VIRGINIA ELECTRONICS DIVISION INTERNAL REPORT No. 275 CRYOGENIC, HEMT, LOW-NOISE RECEIVERS FOR 1.3 TO 43 GHz RANGE S. WEINREB M. W. POSPIESZALSKI R.
More informationAntenna Engineering Lecture 3: Basic Antenna Parameters
Antenna Engineering Lecture 3: Basic Antenna Parameters ELC 405a Fall 2011 Department of Electronics and Communications Engineering Faculty of Engineering Cairo University 2 Outline 1 Radiation Pattern
More informationReceivers for. FFRF Tutorial by Tom Clark, NASA/GSFC & NVI Wettzell, March 19, 2009
Receivers for VLBI2010 FFRF Tutorial by Tom Clark, NASA/GSFC & NVI Wettzell, March 19, 2009 There is no fundamental difference between the receivers for PRIME FOCUS & CASSEGRAIN Except for: the beamwidth
More informationAn Introduction to Antennas
May 11, 010 An Introduction to Antennas 1 Outline Antenna definition Main parameters of an antenna Types of antennas Antenna radiation (oynting vector) Radiation pattern Far-field distance, directivity,
More informationThe TWIN-Radiotelescopes Wettzell;
The TWIN-Radiotelescopes Wettzell Critical Design Points G. Kronschnabl, BKG; Dr. A. Neidhardt, TUM; Dr. K. Pausch, Vertex GmbH; W. Göldi, Mirad; R. Rayet, Callisto; A. Emrich, Omnisys; 1 VLBI 2010 VLBI
More informationDr. John S. Seybold. November 9, IEEE Melbourne COM/SP AP/MTT Chapters
Antennas Dr. John S. Seybold November 9, 004 IEEE Melbourne COM/SP AP/MTT Chapters Introduction The antenna is the air interface of a communication system An antenna is an electrical conductor or system
More informationSingle Dish Observing Techniques and Calibration
Single Dish Observing Techniques and Calibration David Frayer (NRAO) {some slides taken from past presentations of Ron Maddalena and Karen O Neil} What does the telescope measure: Ta = antenna temperature
More informationIntroduction to Interferometry. Michelson Interferometer. Fourier Transforms. Optics: holes in a mask. Two ways of understanding interferometry
Introduction to Interferometry P.J.Diamond MERLIN/VLBI National Facility Jodrell Bank Observatory University of Manchester ERIS: 5 Sept 005 Aim to lay the groundwork for following talks Discuss: General
More informationRadio Interferometry. Xuening Bai. AST 542 Observational Seminar May 4, 2011
Radio Interferometry Xuening Bai AST 542 Observational Seminar May 4, 2011 Outline Single-dish radio telescope Two-element interferometer Interferometer arrays and aperture synthesis Very-long base line
More informationRECOMMENDATION ITU-R S.1512
Rec. ITU-R S.151 1 RECOMMENDATION ITU-R S.151 Measurement procedure for determining non-geostationary satellite orbit satellite equivalent isotropically radiated power and antenna discrimination The ITU
More informationW1GHZ W1GHZ W1GHZ W1GHZ W1GHZ W1GHZ W1GHZ W1GHZ
Online Online Online Online Online Online (ex-n1bwt) (ex-n1bwt) (ex-n1bwt) (ex-n1bwt) (ex-n1bwt) (ex-n1bwt) (ex-n1bwt) Online (ex-n1bwt) W1GHZ W1GHZ Microwave Antenna Book Antenna BookOnline W1GHZ W1GHZ
More informationHandbook of Reflector Antennas
Handbook of Reflector Antennas and Feed Systems Volume I Theory and Design of Reflectors Satish K. Sharma Sudhakar Rao Lotfollah Shafai Preface Acknowledgments ix x Introduction 1 1.1 Introduction 1 1.2
More informationRECOMMENDATION ITU-R S.733-1* (Question ITU-R 42/4 (1990))**
Rec. ITU-R S.733-1 1 RECOMMENDATION ITU-R S.733-1* DETERMINATION OF THE G/T RATIO FOR EARTH STATIONS OPERATING IN THE FIXED-SATELLITE SERVICE (Question ITU-R 42/4 (1990))** Rec. ITU-R S.733-1 (1992-1993)
More informationBroadband and High Efficiency Single-Layer Reflectarray Using Circular Ring Attached Two Sets of Phase-Delay Lines
Progress In Electromagnetics Research M, Vol. 66, 193 202, 2018 Broadband and High Efficiency Single-Layer Reflectarray Using Circular Ring Attached Two Sets of Phase-Delay Lines Fei Xue 1, *, Hongjian
More informationFocal Plane Receiver Architecture for ASTE and Total Power Array of ALMA. Jung-Won Lee
Focal Plane Receiver Architecture for ASTE and Total Power Array of ALMA Jung-Won Lee Korea Astronomy and Space Science Institute ASTE-ALMA Development Workshop, June 17, 2014 Focal Plane Array: Sampling
More informationNotes 21 Introduction to Antennas
ECE 3317 Applied Electromagnetic Waves Prof. David R. Jackson Fall 018 Notes 1 Introduction to Antennas 1 Introduction to Antennas Antennas An antenna is a device that is used to transmit and/or receive
More informationNew Trends on Receivers Development" May 30, 2005, Medicina. RECEIVING SYSTEMs for the ANTENNAS OPERATED by the INSTITUTE of RADIOASTRONOMY in ITALY
New Trends on Receivers Development" May 30, 2005, Medicina RECEIVING SYSTEMs for the ANTENNAS OPERATED by the INSTITUTE of RADIOASTRONOMY in ITALY Alessandro Orfei IRA-INAF, Medicina station (Italy) RADIONET
More informationMore Radio Astronomy
More Radio Astronomy Radio Telescopes - Basic Design A radio telescope is composed of: - a radio reflector (the dish) - an antenna referred to as the feed on to which the radiation is focused - a radio
More informationL-Band and X-Band Antenna Design and Development for NeXtRAD
L-Band and X-Band Antenna Design and Development for NeXtRAD S. T. Paine, P. Cheng, D. W. O Hagan, M. R. Inggs, H. D. Griffiths* Department of Electrical Engineering Radar Remote Sensing Group University
More informationADVANCED 14/12 AND 30/20 GHz MULTIPLE BEAM ANTENNA TECHNOLOGY FOR COMMUNICATIONS SATELLITES
ADVANCED 14/12 AND 30/20 GHz MULTIPLE BEAM ANTENNA TECHNOLOGY FOR COMMUNICATIONS SATELLITES C.C. Chen TRW Defense and Space Systems Group Redondo Beach, CA 90278 ABSTRACT This paper discusses recent TRW
More informationChapter 41 Deep Space Station 13: Venus
Chapter 41 Deep Space Station 13: Venus The Venus site began operation in Goldstone, California, in 1962 as the Deep Space Network (DSN) research and development (R&D) station and is named for its first
More informationPhased Array Feeds & Primary Beams
Phased Array Feeds & Primary Beams Aidan Hotan ASKAP Deputy Project Scientist 3 rd October 2014 CSIRO ASTRONOMY AND SPACE SCIENCE Outline Review of parabolic (dish) antennas. Focal plane response to a
More informationPhased Array Feed Design. Stuart Hay 23 October 2009
Phased Array Feed Design Stuart Hay 23 October 29 Outline Why phased array feeds (PAFs) for radioastronomy? General features and issues of PAF approach Connected-array PAF approach in ASKAP Why PAFs? High
More informationAtonnm. Lincoln Laboratory MASSACH1 SETTS INSTITUTE OF TECHNOLOGY. Technical Report TR A.J. Fenn S. Srikanth. 29 November 2004 ESC-TR
ESC-TR-2004-090 Technical Report TR-1099 Radiation Pattern Measurements of the Expanded Very Large Array (EVLA) C-Band Feed Horn in the MIT Lincoln Laboratory New Compact Range: Range Validation at 4 GHz
More informationKULLIYYAH OF ENGINEERING
KULLIYYAH OF ENGINEERING DEPARTMENT OF ELECTRICAL & COMPUTER ENGINEERING ANTENNA AND WAVE PROPAGATION LABORATORY (ECE 4103) EXPERIMENT NO 3 RADIATION PATTERN AND GAIN CHARACTERISTICS OF THE DISH (PARABOLIC)
More informationFundamentals of Radio Interferometry. Robert Laing (ESO)
Fundamentals of Radio Interferometry Robert Laing (ESO) 1 ERIS 2015 Objectives A more formal approach to radio interferometry using coherence functions A complementary way of looking at the technique Simplifying
More informationCHAPTER 5 THEORY AND TYPES OF ANTENNAS. 5.1 Introduction
CHAPTER 5 THEORY AND TYPES OF ANTENNAS 5.1 Introduction Antenna is an integral part of wireless communication systems, considered as an interface between transmission line and free space [16]. Antenna
More informationDetector Systems. Graeme Carrad
Detector Systems Graeme Carrad November 2011 The Basic Structure of a typical Radio Telescope Antenna Receiver Conversion Digitiser Signal Processing / Correlator They are much the same CSIRO. Radiotelescope
More informationCOMPARATIVE ANALYSIS BETWEEN CONICAL AND GAUSSIAN PROFILED HORN ANTENNAS
Progress In Electromagnetics Research, PIER 38, 147 166, 22 COMPARATIVE ANALYSIS BETWEEN CONICAL AND GAUSSIAN PROFILED HORN ANTENNAS A. A. Kishk and C.-S. Lim Department of Electrical Engineering The University
More informationPRIME FOCUS FEEDS FOR THE COMPACT RANGE
PRIME FOCUS FEEDS FOR THE COMPACT RANGE John R. Jones Prime focus fed paraboloidal reflector compact ranges are used to provide plane wave illumination indoors at small range lengths for antenna and radar
More informationW1GHZ W1GHZ W1GHZ W1GHZ W1GHZ W1GHZ W1GHZ W1GHZ
Section 6.0 Introduction Chapter 6 Feeds for Parabolic Dish Antennas Paul Wade 1994,1997,1998,1999 The key to good parabolic dish antenna performance is the feed antenna, the source of radiated energy
More informationA NEW WIDEBAND DUAL LINEAR FEED FOR PRIME FOCUS COMPACT RANGES
A NEW WIDEBAND DUAL LINEAR FEED FOR PRIME FOCUS COMPACT RANGES by Ray Lewis and James H. Cook, Jr. ABSTRACT Performance trade-offs are Investigated between the use of clustered waveguide bandwidth feeds
More informationarxiv:astro-ph/ v1 21 Jun 2006
Ð Ú Ø ÓÒ Ò Ð Ô Ò Ò Ó Ø ËÅ ÒØ ÒÒ ÓÙ ÔÓ Ø ÓÒ Satoki Matsushita a,c, Masao Saito b,c, Kazushi Sakamoto b,c, Todd R. Hunter c, Nimesh A. Patel c, Tirupati K. Sridharan c, and Robert W. Wilson c a Academia
More informationRVRUSA - DATA DE REFERENCIA PARA INGENIEROS
Useful formulae Electrical formulae Electrical power in KW: DC power [KW]: YROW DPSHUH YROW DPSHUH AC power (single phase) [KW]: AC power (three-phase) [KW]: where: cos( j ) YROW DPSHUH 73. cos( j) Volt:
More informationVLBI2010 Current status of the TWIN radio telescope project at Wettzell, Germany
VLBI2010 Current status of the TWIN radio telescope project at Wettzell, Germany Alexander Neidhardt, FESG/TU München (on behalf of the BKG) G. Kronschnabl, (BKG); Hase, H. (BKG); Schreiber, U. (BKG);
More informationNoise generators. Spatial Combining of Multiple Microwave Noise Radiators NOISE ARRAY. This article reports on. experiments to increase the
From April 2008 High Frequency Electronics Copyright 2008 Summit Technical Media LLC Spatial Combining of Multiple Microwave Noise Radiators By Jiri Polivka Spacek Labs Inc. Noise generators This article
More informationEVLA Memo 103 Performance Tests of the EVLA K- and Q-Band Systems
EVLA Memo 103 Performance Tests of the EVLA K- and Q-Band Systems Rick Perley, Bob Hayward, Bryan Butler, Vivek Dhawan NRAO March 1, 2006 Abstract Sensitivity measurements performed on EVLA antenna #14
More information