Your SlideShare is downloading. ×
Phased-Array Radar Talk Jorge Salazar
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Phased-Array Radar Talk Jorge Salazar

1,448
views

Published on

This talk will give an overview of the current phased array radar systems and its requirements for weather observations, performance in sensitivity, antenna design requirement for dual-polarized …

This talk will give an overview of the current phased array radar systems and its requirements for weather observations, performance in sensitivity, antenna design requirement for dual-polarized weather radars.


0 Comments
3 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
1,448
On Slideshare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
0
Comments
0
Likes
3
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. PHASED ARRAY RADAR SYSTEMS FOR WEATHER OBSERVATION National Center For Atmosphere Research (NCAR) EOL Seminar Presented by Jorge L. Salazar-Cerreno University of Massachusetts, Amherst, MA, USA R e-mail: jlsalaza@engin.umass.educasa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere April 23, 2011 1
  • 2. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere Outline • Introduction • Overview of phased-array antenna for weather radars • Phased-array antenna requirements for weather radars • Phased-array antenna design considerations for weather radar • CASA phased array radar
  • 3. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Introduction • 1905: Phased array transmission was originally developed in 1905 by Nobel Laureate Karl Ferdinand Braun who demonstrated enhanced transmission of radio waves in one direction. • 1941: At the MIT Rad Lab , Luis Alvarez invented a new type of phased array antenna having excellent radiation F-16 characteristics at 48MHz. Later the B1 US fighter uses AN/APQ-164 design was used AN/APQ-7 EAGLE 3 cm passive electronically scanned radar • 1960-1980 : A rapid evolution of passive phased-array antennas for detection of ballistic missile attacks. The most famous radars are the SPY-1 developed during the 1970’s and the AN/APQ-164 Patriot AN/MPQ-53/65 fitted in the B1B and similar ones in the Radar Set is a passive Lockheed Martin, The Soviet MIG-31. AN/TPS-77 is an L-Band, electronically phased array
  • 4. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Introduction (cont) • >1980: Enabling technology Gallium Arsenic Microwave Monolithic Integrated Circuit (GaAs MMIC) permitted the integration of low cost-phases shifters and power amplifiers permitting the mass production of AESAS (Active Electronic Phased-array antennas). • 2006: NSSL is collaborating with the federal agencies to explore Ways to transition from maintaining a number of single-function radar systems, used for aircraft surveillance and AESA to field will be the weather observations, to a single Northrop-Grumman multimission, phased array radar network AN/APG-77 radar (MPAR) • Today, several efforts to incorporate SiGe, Si RF CMOS in the panel Array . A 128 T/R channel, Low Power Density Panel Array has been designed at X-Band that integrates the A 128 T/R channel, Low following components and circuits. MPAR Power Density Panel Array has been designed at X-Band
  • 5. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Phased-array weather research projects CIRPAS-MWR-05XP (Mobile Weather Radar, 2005, X-Band, Phased-array) (Center for Interdisciplinary Remotely-Piloted Aircraft Studies) • Designed for military application in 1980 Courtesy: Chad Baldi NPS and ProSensing Inc • X-band Freq-Phase-Mechanically, • Single polarization (H) • Scanning time : ~42 sec • Scan volume: for 360: azim. x 40: elev. • Cost: ~10 million Goshen County Wyoming tornado that was interceptedAnalysis of Performance Characteristics of the Naval Postgraduate SchoolMWR-05XP Mobile Weather Radar By: Jeffrey B. Knorr , December 2005 during VORTEX 2 (June 5th 2010)
  • 6. casacasa Engineering Research Center for Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Phased-Array weather research projects NWRT-PAR (phase-phase) (National Weather Radar Testbed-PAR) 19 August 2007 - Phase-phase, S-band, V-polarization. - Scanning time (~26 sec for 90: azim. x 40 : elev.) - Only single polarization and BW=1MHZ -Cost: ~ $27 millions and single polarization Agile-Beam Phased Array Radar Weather Observations PAR (VCP 12 BMX) By: D.S Zrink, J.K Kimpel, D.E Forsyth, A.Shapiro, G. Crain, AMS, 60 sector November 2007 0.5 oversampling in azimuth Images ~ 43 s WSR-88D (VCP 12 ) Images ~ 4.1 min SPY-1 NWRT From: Rapid Sampling of Severe Storms with the National Weather Radar Testbed Phased Array Radar, OU Seminar Series, October 2007, Pam
  • 7. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Multi Function Phased Array Antenna (MPAR) Progress Current challenges: • Ultra-low cost array (~ $50k / m2) and Low cost in operations and maintenance • Dual polarization (Xpol better than -40dB) Modest HPA power (8W peak) base on ATSR polarization mode LRU Low cost (<$20k ea) • Cooling subsystem and antenna calibration Panel: 78 LRU (~$1.5M) Douglas Carlson, Jeffrey Herd, Sean Duffy, mark Weber, Glenn Brigham, Michael Rachlin, Daniel Curcio, Cheryl Liss, Chris Weigand,. "Low cost Phased Array Radar: The Multifunction Phased Array radar (MPAR) for Air Traffic Control and Weather Surveillance". M/A-COM Technology Solutions Inc. Lowell, MA.
  • 8. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Phased-array radar weather requirements • Inertial free beam steering • Dual-polarized radars • High scanning performance • Flexible scan strategy • Efficient use of the radiated energy • Low profile and low weight radars • Modular architecture • High reliability and maintainability • Low cost and low life-cycle cost • Capability to work in network
  • 9. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar What kind of phased-array antenna architecture we can use? Quasi optical phased-array Frequency-scan array antennas reflector Phased-array antennas Digital beam forming Lens antennas/Rotman Lens
  • 10. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Phased-array antenna types Frequency scanning arrays Advantages: • Series feed arrays are frequency-sensitive • Simple architecture, simple design • Low cost, low profile, low weight. • Implemented using MS patch antennas Disadvantages: • Limited scanning range ( <30 deg) CIRPAS-MWR-05XP • Lead to bandwidth restrictions (10deg/200MHz) • 1D scanning • Single polarization ( H or V) • Use common power source • Low efficiency (ferrite phase shifters) Examples: • IWRAP, MWR-05XP
  • 11. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Phased-array antenna types Phased-array antenna Advantages: • Improve noise behavior since the TR modules contain itself low noise amplifiers • Permit ultra low sidelobe levels (<-30dB) • Improves the efficiency since power is distributed across thousand of elements. • Higher levels of reliability , permitting a failure up to 10% of the elements, without affect the antenna performance. • Dual-polarized and 2D-scanning up to 45deg. 0.3-3GHz Vivaldi EASA Canadian SKA Technology Research • Low profile, low weight. Disadvantages: • Cost (>$1M/m2 at X-band) • Polarization isolation • Examples: • SKA, MPAR, CASA Phased-array S-band MPAR AESA X-band CASA M-AESA
  • 12. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Design considerations for phased-array antennas in weather radars • Scanning performance • Gain loss vs. scan angle • Beam broadening beam effect vs. scan angle • Antenna mismatch vs. scan angle • Polarization distortion vs. scan angle • TR module architecture and technology • Reliability and graceful degradation • Production cost and life cycle cost
  • 13. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Scanning performance: Gain loss vs. beam position Measured Active Element Pattern Port H/V stick 10 0 -5 10HH Active Element Pattern in dB -10 10HV 10VH -15 10VV Composition of the array pattern M=32, d=0.5, Uniform distribution Active Element Pattern and Reflection Coefficient (mag) Gain scan loss vs. scan angle 1 0 -20 -25 • Element pattern roll -off 0.9 -2 -30 -4 0.8 AF s • Reflection coefficient -6 -35 AF Element AF 0.7 -40 Element TotalElement -80 -60 -40 -20 Total Theta in deg 0 Total 40 20 c 60 80 4d x d y N x N y -8 E-Patterns Pattern dB 0.6 Gθ, φ   [1  Γθ, φ  ]cosθ 2 -10 λ2 0.5 1 ACR CASE4:0.54,with Backplane -12 0.9 E-Patternc 0.4 cos 1.2 Active Reflection Coefficient (Magnitude) • -14 0.8 The mutual coupling in elements 0.3 0.7 E-plane( =0) H-plane( =90) -16 can affect the scanning 0.6 0.2 -18 performance of the array 0.5 0.1 -20 0.4 -80 0.3 -60 -40 -20 0 20 40 60 80 0 Theta (deg) 0 10 0.2 20 30 40 50 60 70 80 0.1 Scan: 30 deg,ScanLoss: 0dB,Δθ33:0 º º º Scan: deg, Loss: -3dB, Δθ :3.16 Loss: -0.63dB, Δθ3:1.31 Scan: 600 deg, angle (deg) 0 0 10 20 30 40 50 60 70 80 90 theta (deg) 13
  • 14. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Scanning performance: Beam broadening vs. scan beam position Broadside Aele ( )  Aele (o ) cos( ) ø 3  3o B f / cos( ) Antenna 0.95 0.78 1.34 1.1 -25dB -40dB Phased Array Antenna Handbook Second Edition, Robert J. Mailloux 14
  • 15. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Phased array radar performance for a single node Azimuth resolution (Azr) Azimuth Resolution Vs.Range 54x46 Phased Array Antenna H:0.05km Azr-max: 1km, Azr-med: 0.7km Mechanically Steered km Azimuth Resolution Vs.Range Azimuth Resolution Vs.Range 54x46 Phased Array Antenna H:0.05km 54x46 Phased Array Antenna H:3.2km C(6x60º) Azr-max: 1.1km, Azr-med: 0.74km km Azr R, ,    R sin(3 ) Azr-max: 1.2km, Azr-med: 0.83km Mechanically Steered km C(6x60º) km -30 -30 -30 -20 2.5 2.5 -20 -20 2.5 2.5 60o 60o Range in km Range in km Range in km Range in km -10 22 -10 -10 22 R: Maximum radar range 0 360oo 360 1.5 00 1.5 1.5 1.5 3  3o B f / cos  Ø : Scan angle 10 11 10 10 11 Ø3: 3dB Beamwidth 20 0.5 20 20 0.5 0.5 Bf: Broadening factor 1.2 for Taylor -25dB 0.5 30 30 30 -20 -20 00 2020 -20 -20 00 20 20 Range in km in km Range Range in km Range in km Az(worst): 11.0 km Az(worst): km Az(worst): 1.21.1 km (10%) Az(worst): km (20%) Az(med): 0.7 km H=50m H=3.2km Az(med): 0.74 km (6%) Az(med): 0.83 km (4%) Az(med): 0.8 km Azimuth Resolution Vs.Range Azimuth Resolution Vs.Range Azimuth Resolution Vs.Range Azimuth Resolution Vs.Range Elevation coverage at maximum scanning range 12 deg (± 6 deg ) 60x46 Phased Array Antenna H:0.05km 60x46 Phased Array Antenna H:3.2km Azr-max: 1.4km, Azr-med: 0.79km B(4x90º) Azr-max: 1.4km, Azr-med: 0.88km B(4x90º) km km 64x46 Phased Array Antenna H:0.05km 64x46 Phased Array Antenna H:3.2km Azr-max: 2km, Azr-med: 0.84km A(3x120º) Azr-max: 2km, Azr-med: 0.94km A(3x120º) km km -30 -30 -30 -30 Hight Single node -20 -20 2.5 2.5 -20 -20 2.5 2.5 90o 90o Range in km Range in km Range in km Range in km -10 -10 22 -10 -10 120o 22 120o Cone of silence 00 1.5 1.5 00 1.5 1.5 3 km 6% 6% 10 10 11 10 10 11 2km1.38km 12º 0.5km 20 20 0.5 0.5 20 20 0.5 0.5 N2 30 30 30 30 R=30 km R=30 km -20 -20 00 20 20 -20 -20 00 20 20 Range in km Range in km Range in km Range in km R=6.25 km Az(worst): 1.4 km (40%) Az(worst): 1.4 km (40%) Az(worst): 2 km (100%) Az(worst): 2.0 km (100%) 0.8 km (14%) Az(med): 0.88 km (10%) Az(med): 0.94 km (18%) Az(med): 0.84 (20%) 15
  • 16. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Phased array radar performance for a single node Minimum Radar sensitivity (Zmin) Minimum Radar Sensitivity (Ze) Radar Parameters CPmin R 2 L2 SNR Z min  Parameter Symb Units Value Pt G 23 3 K w 2 Frequency f GHz 9.41 Wavelength λ m 0.032 Peak transmitter power Pt W 432 E-Plane beamwidth (at broadside) θ3 deg 1.83 H-Plane beamwidth (at broadside) ø3 deg 1.83 31 km E-Plane scan range Δθ deg 12 6.25 km H-Plane scan range Δø deg 60-90-120 Signal to noise ratio SNR dB 0 0.625 km Noise figure NF dB 4.5 Gain (at broadside) G dB 39 Maximun radar range R km 31 Range resolution ΔR m 25 Bandwidth BW MHz 6 Pulse repetition frequency PRF kHz 3.399 Radar Pulse Scheme System loss L dB 2 Pulse width т us 4.16-41.67 4.16us 41.67us 4.16us 41.67us Pulse compression gain PCG dB 14-24 Minimum detectable signal P min dBm -103.6 Duty cycle D % 18 Dielectric constant of water K - 0.93 Radar constant C 2.5x1016 Time (us) 41.67us 207 us References: [6] 16
  • 17. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Phased array radar performance for a single node Minimum Radar sensitivity (Zmin) Minimum Radar Sensitivity (Ze) Minimun Sensitivity Vs.Range Minimun Sensitivity Vs.Range Radar Parameters Minimun Sensitivity Vs.Range 54x46 Phased Array Antenna 54x46 Phased Array Antenna 54x46 Phased Array Antenna Tx Pow er: 603mW/elem 432W/secPmin: -104 SNR: 0dB NF:4.5dB Tx Pow er: 603mW/elem 432W/secPmin: -104 SNR: 0dB NF:4.5dB Tx Pow er: 603mW/elem 432W/secPmin: -104 SNR: 0dB NF:4.5dB t1: 4.17us BW1: 6MHz PRF1: 3.399KHz dBm PCG1:25mag CPmin R 2 L2 SNR t1: 4.17us BW1: 6MHz PRF1: 3.399KHz dBm PCG1:25mag t1: 4.17us BW1: 6MHz PRF1: 3.399KHz dBm PCG1:25mag t2: 41.7us BW2: 6MHz PRF2: 3.399KHz dBm PCG2:250mag H:3.2km t2: 41.7us BW2: 6MHz PRF2: 3.399KHz dBm PCG2:250mag H:0.05km t2: 41.7us BW2: 6MHz PRF2: 3.399KHz dBm PCG2:250mag H:3.2km t2: 41.7us BW2: 6MHz PRF2: 3.399KHz dBm PCG2:250mag H:0.05km Zemax: 5.43dBZ, Ze med: 3.33dBZ Z min  Mechanically2.22dBZ Zemax: 5.23dBZ, Ze med: Steered Mechanically Steered dBZ dBZ Zemax: 6.08dBZ, Ze med: 3.47dBZ C(6x60º) 6.03dBZ, C(6x60º) 2.47dBZ dBZ -30 -30 -30 Pt G 23 3 K w 2 -20 -20 15 15 10 -20 15 10 10 Range in km Range in km Range in km -10 -10 5 -10 5 5 0 0 0 0 0 0 G ,   r A D(1   ,   ) cos  2 -5 10 10 -5 10 -5 -10 -10 -10 20 20 20 -15 -15 -15 30 30 30 -20 -20 0 0 20 20 -20 0 20 Range in km Range in km Range in km Elevation coverage at maximum scanning range 12 deg (± 6 deg ) Ze(worst): 5.43 dBZ Ze(worst): 5.23 dBZ Minimun Sensitivity Vs.Range H=50m H=3.2km 6.03 Ze(worst): 6.08 dBZ (Δ: 0.7dB) Minimun Sensitivity Vs.Range 0.8dB) Ze(med):Array Antenna dBZ 60x46 Phased 3.33 64x46 Phased Array Antenna Ze(med): 2.22 dBZ Tx Pow er: 543mW/elem 432W/secPmin: -104 SNR: 0dB NF:4.5dB TxZe(med): 2.47 dBZ 0dB NF:4.5dB Pow er: 512mW/elem 432W/secPmin: -104 SNR: (Δ: 0.3dB) 3.47 0.1dB) Hight Single node t1: 4.17us BW1: 6MHz PRF1: 3.399KHz dBm PCG1:25mag t2: 41.7us BW2: 6MHz PRF2: 3.399KHz dBm PCG2:250mag H:0.05km t2: 41.7us BW2: 6MHz PRF2: 3.399KHz dBm PCG2:250mag H:3.2km t1: 4.17us BW1: 6MHz PRF1: 3.399KHz dBm PCG1:25mag t2: 41.7us BW2: 6MHz PRF2: 3.399KHz dBm PCG2:250mag H:0.05km t2: 41.7us BW2: 6MHz PRF2: 3.399KHz dBm PCG2:250mag H:3.2km 7.18dBZ, 2.81dBZ Zemax: 7.22dBZ, Ze med: 3.79dBZ Zemax: 9.37dBZ, Ze med: 3.35dBZ 9.42dBZ, 4.32dBZ B(4x90º) B(4x90º) dBZ A(3x120º) A(3x120º) dBZ No covered Area: -30 -30 ~23% 15 15 -20 -20 Cone of silence 10 10 Range in km Range in km 3 km -10 5 -10 5 2km 6% 6% 1.38km 12º 0 0 0 0 0.5km 10 -5 10 -5 N2 -10 -10 R=30 km R=30 km 20 20 -15 -15 R=6.25 km 30 30 -20 0 20 -20 0 20 Range in km Range in km Ze(worst): 7.18 dBZ (Δ: 2 dB) 7.22 1.8dB) References: [6]4.1dB) 9.37 Ze(worst): 9.42 dBZ (Δ: 4.0dB) 17 2.81 0.6dB) Ze(med): 3.79 dBZ (Δ: 0.5dB) 3.35 1.1dB) Ze(med): 4.32 dBZ (Δ: 1.0dB)
  • 18. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Scanning performance: Polarization losses vs. scan beam position Cross-polarization level vs. Scan angle in azimuth and elevation Size: 64x46 elements, dx:1.6cm, dy=2.2cm Co-polar and cross-polar patterns for embedded Element: Aperture coupled patch antenna patch antenna in array 18x32 elements Er: 2.17 h=20mil 30.0 0 25.0 Co-polar H -10 Amplitude of AEP(dB) Co-polar V X-polar H 20.0 Broadside ~13dB -20 X-polar V ~20dBX-pol (dB) 15.0 -30 10.0 X-pol (port-v) at elev=7.5deg -40 X-pol (port-v) at elev= 0deg 5.0 -50 ~29dB ~13dB 0.0 -60 -80 -60 -40 -20 0 20 40 60 80 0 30 45 60 Theta(deg) Scan angle (deg) Cross-polarization level planar array of 64x46 elements, dx=1.6cm, dy=2.2cm using HFSS (Finite Array Tool) 18
  • 19. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Antenna requirements for dual-polarized weather radars 0 Co-polar and Cross-polar patterns of Chill Radar (at 90deg. Plane) fhh -10 fvv fhv -20 fvh • Figure for merit to evaluate -30 Pattern (dB) the polarimetric performance -40 -50 of any antenna: ZbDR and -60 ICPR2 -70 Mismatch patterns -80 -4 -3 -2 -1 0 1 2 3 4 Theta (deg)  f 2  f 2 2 cos d  P Z DR  10 log10  hh   Assuming b Z DR  10 log10   hh hv  P   f 2  f 2 2 cos d    vh homogeneous  vv  spherical scatters vv  P   G 2 f f cos d  hh  hh vh LDR  10 log 10  hv  P  ICPR2  10 log10    hh   G f cos d   vv  hh 2 2 2  where, fhh, fvv, are the co-polar patterns for H and V and fhv, fvh,Yanting Wang , V Chandrasekar and David McLaughlin, “Polarization isolation requirements for linear dual- 19polarization weather Radar in simultaneous transmission mode of operation”, IEEE Trans. On Geoscience and represents the cross-polar patterns for H and V, both in transmissionRemote Sensing, Volume 44, Issue 8, pp. 2019 – 2028, Aug. 2006. and reception, respectively
  • 20. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Polarimetric biases for STSR Antenna requirements for dual- Standard Deviation in ZDR <0.2dB polarized weather radars Cross-polarization Level (CPL): <-40dB The bias ZDR is very sensitive to the polarization deviation for STSR than in ATAR polarization H-Transmitter Duplexer mode H-receiver H STSR CPL<-40dB V-Receiver V V-Transmitter Duplexer Polarizer Switch Polarimetric biases for ATAR H H-receiver Transmitter V-Receiver ATAR Standard Deviation in ZDR <0.2dB V Cross-polarization Level (CPL): <-20dB CPL<-20dBYanting Wang , V Chandrasekar and David McLaughlin, “Polarization isolation requirements for linear dual- 20polarization weather Radar in simultaneous transmission mode of operation”, IEEE Trans. On Geoscience andRemote Sensing, Volume 44, Issue 8, pp. 2019 – 2028, Aug. 2006.
  • 21. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar TR modules polarization architectures • TR module must provide flexible Rx-H PS ATT LNA architecture to permit calibration of the PS ATT PA PC/D polarization distortion Tx-H/V PS ATT PA STSR • Polarization modes is one of the PS ATT LNA important drivers in the cost on the Rx-V phased array system. • ATAR requires 1 Phase-shifter Tx • STSR requires 3-4 Phase shifters AT LN A H-Pol T PS V-Pol • COTS MMIC in GaAs chip phase-shifters Rx PA ATAR price at X-band : $100-$150. ATAR: for 4,000 elements $0.4 M/m2 PS ATT LNA Rx-H STSR: for 4,000 elements $1.6 M/m2 PS ATT PA H-Pol Tx-H/V ATSR • Trade-off of cost and performance is PS ATT LNA V-Pol required. Rx-V 21
  • 22. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar T/R module –Technology and cost • GaNi provides high RF power densities ( x3 to x5) on small chip sizes than GaAs. • GaNi provides PAE up to 65% • Technology is not • Current X-Band T/R modules of the 10 Watt class are still in the cost range of $1K-$3k base on GaAs. PAE<40% Parameter Units GaAs SiGe CMOS Wafer size mm 150 300 300 Node technology um 0.15 0.5 0.18 Power max @10GHz W 10 0.3 0.1 NF @ 10Ghz dB 1.8 2.7 5.0 Switch IL dB 1.5 2.2 3.0 Relative Cost $/mm2 0.235 0.037 0.051 22Current Status of Active Phased Array Antennas and Future Trends, Heinz-Peter Feldle. IRS 2009, Hamburg 10 Sept. 2009
  • 23. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Reliability Technology: • Wide band-gap in GaN and SiC MMIC chips offers major power density (2X, 4X) in comparison with GaAs. • Life time and MTTF is driving by power and temperature. Wide band gap offer better MTTF. MTTF  e Ea / kT Ea: activation energy in electron-volts (eV) k: Boltzmann’s constant (k = 8.617 x 10-5 eV/Tk)n electron-volts (eV) T: Reference junction temperature, in degrees Kelvin (K = C + 273) 23
  • 24. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Reliability • The reliability of the system is determined by the number of components in each subsystem and the failure rate of each one. MTBF  N PS (1 / FRPS )  NCM (1 / FRCM )  NTR (1 / FRTR ) sys P. Supply (PS) Cont. Mod. (CM) T/R Mod. (TR) STSR ATAR Rx-H PS ATT LNA Tx PS ATT PA LN H-Pol PC/D AT A T Tx-H/V PS ATT PA PS V-Pol Rx PS ATT LNA PA Rx-V 24
  • 25. casacasa Engineering Research Center for Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere Collaborative Adaptive Sensing of the Atmosphere FR_TX (10-6 hrs) FR_RX (10-6 hrs) 4 4 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar rms_amp 0.08 0.72 dB 5. CASA phased-array radar rms_pha 0.09 5.16 deg Graceful degradation and life cycle cost N elements 2048 N act_elements 2048 Dcycle 30% • Assuming : # Failure # Failure Performance Elements Elements (%) o TR failure rate: 4x10-6 hrs -1 LC ΔSLLave Cost (%) o N:2048 elements Operational time (yrs) RX Tx RX Tx Ze Loss (dB) (dB) o Duty cycle: 30% 1.0 50 22 2% 1% -0.44 0.00 1% o Phase shifter/Attenuator: 6 bits 2.5 126 54 6% 3% -0.81 -2.15 3% • The radar can operate up to 10 yrs, 5.0 251 108 12% 5% -1.46 -3.95 6% 7.5 377 161 18% 8% -2.14 -5.14 9% after that 25% of TR need be (10-6 FR_TX 10.0 hrs) 502 0.1 215 25% 11% -2.86 -6.10 12% replaced and the cost incurred will FR_RX 12.5 hrs) (10-6 628 0.1 269 31% 13% -3.62 -6.94 15% 15.0 754 0.72 dB 37% 323 16% -4.42 -7.73 18% represent 12% of the production rms_amp 17.5 0.08 879 5.16 deg43% 377 18% -5.27 -8.50 21% rms_pha 0.09 cost. 20.0 N elements 1005 2048 431 49% 21% -6.19 -9.27 25% N act_elements 2048 Dcycle 30%• Assuming : o TR failure rate: 10x10-6 hrs -1 # Failure # Failure Performance o N:2048 elements Elements Elements (%) LC Cost (%) o Duty cycle: 30% Operational time RX Tx RX Tx Ze Loss ΔSLLave (yrs) (dB) (dB) o Phase shifter/Attenuator: 6 bits 1.0 126 54 6% 3% -0.81 0.00 3%• The radar can operate up to 5 yrs, 2.5 314 135 15% 7% -1.80 -2.43 8% after that 31% of TR need be 5.0 628 269 31% 13% -3.62 -4.79 15% 7.5 942 404 46% 20% -5.73 -6.73 23% replaced and the cost incurred will 10.0 1256 538 61% 26% -8.29 -8.76 31% represent 15% of the production 12.5 1570 673 77% 33% -11.70 -11.33 38% cost. 15.0 1884 807 92% 39% -17.68 -15.91 46%
  • 26. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA dense radar network“There is insufficient knowledge about what is actually happening (or is likely to happen) at the Earth’s surface where people live.” [National Academy of Sciences, 1998] 10,000 ft 4 km 3.05 km 2 km 1 km 5.4 km snow wind tornado gap Horz. Scale: 1” = 50 km 3 km Vert. Scale: 1” = 2 km 1 km AGL AGL 0 40 80 120 160 200 240 RANGE (km) • Earth curvature effects prevent 72% of the troposphere below 1 km from being observed • 250 km average spacing between ground radars • 1-4 km resolution of storms in the upper troposphere Maddox, Robert A., Jian Zhang, Jonathan J. Gourley, Kenneth W. Howard, 2002: Weather Radar Coverage over the Contiguous United States. Wea. Forecasting, 17, 927–934.
  • 27. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA dense radar network OFF THE GRID NETWORK 100000 CELL TOWER 10000 Sensors 1000 NEXRAD 100 10 20 50 100 200 500 Grid spacing [km] D. McLaughlin, E. Knapp, Y. Wang, V. Chandrasekar, "Distributed Weather Radar Using X-Band Active Arrays", Proceedings of IEEE Radar conference 2007, Waltham, MA, April 17-20, 2007
  • 28. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere IP1-radar test bed • Successfully demonstration of the IP1 testbed using short range radar in X-band, over a triangular grid of 30 km • Significant improvements in coverage, spatial resolution and temporal resolution, improving the scanning update times 5 times WSR-88D. CASA IP1• Cost: ~$203 k ( radar equipment per node)• Pedestals about 59% of the equipment cost NEXRAD• Next: Low-cost Phased-array antennaBrotzge, J., D. Andra, K. Hondl, and L. Lemon, 2008: A case study evaluating Distributed,Collaborative, Adaptive Scanning: Analysis of the May 8th, 2007, minisupercell event.Preprints, Symposium on Recent Developments in Atmospheric Applications of Radar andLidar, AMS Conf., New Orleans, LA.Salazar, J.L. et al., “Coverage Comparison Of Short Range Radar Networks Vs.Conventional Weather Radars: Case Study In The Northwestern United States”,Proceedings of IGARSS 2009, South Africa.
  • 29. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA phased radar system requirements System Requirements Heigth • Dual polarized with high 0 4.0 km cross-polarization level 0.05 km Ѳt=1 • Radar range: 30 km N1 R=41 • Low-power : Pt=100W d=30 km • Scan volume: 360 deg x 12 Heigth d=30 km deg 4.0 km • Low cost : < $40K per panel 0 0.05 km Ѳt=15o RB • Low cost in O&M (Using N1 N2 N3 R=31km R=41 km existent wireless Distance infrastructure) d=30 km 29
  • 30. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phased-Array radar architecture LRU ARRAY ANTENNA Phase-tilt array antenna LRU LRU LRU LRU 32 elements in series-fed configuration Elev. Array Formatter Board Board (AFB) Transceiver (XCVR) and Up/Down Converter Host Computer MC&C • Phased-array antenna architecture based on 1-D e-scan • Uses only 64 TR modules based on COTS components • Dual-polarized based on ATAR mode • Low cost : Prototype $74K, Prod. volume $40K •Salazar, J., R. Medina, E. Knapp and D. J. McLaughlin. 18 columns "Phase-Tilt Array Antennae Design for Dense Distributed Radar Network for Weather Sensing", Proceedings of IGARSS 2008, Boston, US.
  • 31. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radarPower and radar sensitivity of CASA phased-array in a network environment Parameter Solid state IP1 Center Frequency 9.36 ±50 MHz 9.41 ±30 MHz Peak power output 50 W 5 KW Pulse width 3.33 μs-40 μs 0.66 μs Max duty cycle 7% 0.16 % Average power output 3.5 W 8W Polarization Dual linear, H and V Dual linear, H and V Antenna gain 36 dB 38 dB 3dB Beam width 1.8º -2.5 º (H-plane) 1.8 º x 1.8 º 3.6 º (E-plane) Noise Figure 4.5 dB 5.5 dB Range resolution 50 m -100 m 100 m Minimum detectable signal -103.6 dBm@BW:3 MHz -103.6dBm@BW:1.5 MHz
  • 32. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radarTransmit/Receive Modules TR Module cost ~$450@64 TR Module cost ~$340@1000
  • 33. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phased-array antenna LRU elevation patterns Measured patterns of 32x1 linear array in LRU (32X18) V-port H-Port Parameter Value@9.36GHz Parameter Value@9.36GHz BW 3.81 deg BW 3.62 deg SLL1(L/R) -29/-26.5 dB SLL1(L/R) -23.2/-22.5 dB Emax(dB) -43.83 dB Emax(dB) -43.30 dB Xpol_brodside -34 dB (rel) Xpol_brodside -38.7 dB (rel) ICPR2 -34.4 ICPR2 -34.0 • RL better than -13 dB at Resonant frequencies for H and VPatch layer Foam layer • Impedance bandwidth: 200 MHz at RL of -10 GHz • Beam pattern bandwidth: 100 MHz Fed layer • Isolation port -27 dB Reflector layer
  • 34. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar NF measured antenna patterns in azimuth plane 1 LRU (16x32) , Ѳs: 0⁰-50 ⁰, Standard Calibration UNIFORM Azimuth Pattern LRU (18x32), Uniform, SC, ss:50deg Azimuth Pattern LRU (18x32), Uniform, SC,  :40 deg :10 :20 :30 :0 0 MP:-1% MP:3.6% MP:-0.2% MP:3.3% MP:0.8% MP:-36% V V -5 H H V -10 H -15 Amplitude(dB) -20 -25 -30 -35 -40 -45 -50 -60 -40 -20 0 20 40 60 Azimuth(deg) TAYLOR -25 dB Azimuth Pattern LRU (18x32), Taylor-25dB n=2, SC, ss :0 deg Azimuth Pattern LRU (18x32), Taylor-25dB n=2, SC,  :50 deg :10 :20 :30 :40 0 MP:1.9% MP:3.8% MP:-1.2% MP:1.6% MP:-2.2% MP:-51% V V V -5 H H H -10 -15 Amplitude(dB) -20 -25 -30 -35 -40 -45 -50 -60 -40 -20 0 20 40 60 34 Azimuth(deg)
  • 35. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar NF measured antenna patterns in azimuth plane 1 LRU (16x32) , Ѳs: 0⁰-50 ⁰, Standard Calibration UNIFORM AMPLITUDE DISTRIBUTION Azimuth Pattern LRU (18x32), Uniform, SC, s :0 deg Azimuth Pattern LRU (18x32), Uniform, SC, s :10 deg Azimuth Pattern LRU (18x32), Uniform, SC, s :20 deg 0 0 0 MP:-1% V MP:3.6% V MP:-0.2% V -5 H -5 H -5 H -10 -10 -10 -15 -15 -15Amplitude(dB) Amplitude(dB) Amplitude(dB) -20 -20 -20 -25 -25 -25 -30 -30 -30 -35 -35 -35 -40 -40 -40 -45 -45 -45 -50 -50 -50 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 Azimuth(deg) Azimuth(deg) Azimuth(deg) Azimuth Pattern LRU (18x32), Uniform, SC, s :30 deg Azimuth Pattern LRU (18x32), Uniform, SC, s :40 deg Azimuth Pattern LRU (18x32), Uniform, SC, s :50 deg 0 0 0 MP:3.3% V MP:0.8% MP:-36% V -5 H -5 -5 H V -10 -10 H -10 -15 -15 -15Amplitude(dB) Amplitude(dB) Amplitude(dB) -20 -20 -20 -25 -25 -25 -30 -30 -30 -35 -35 -35 -40 -40 -40 -45 -45 -45 -50 -50 -50 35 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 Azimuth(deg) Azimuth(deg) Azimuth(deg)
  • 36. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar NF measured antenna patterns in azimuth plane 1 LRU (16x32) , Ѳs: 0⁰-50 ⁰, Standard Calibration TAYLOR -25dB AMPLITUDE DISTRIBUTION Azimuth Pattern LRU (18x32), Taylor-25dB n=2, SC, s :0 deg Azimuth Pattern LRU (18x32), Taylor-25dB n=2, SC, s :10 deg Azimuth Pattern LRU (18x32), Taylor-25dB n=2, SC, s :20 deg 0 0 0 MP:1.9% V MP:3.8% V MP:-1.2% V -5 H -5 H -5 H -10 -10 -10 -15 -15 -15Amplitude(dB) Amplitude(dB) Amplitude(dB) -20 -20 -20 -25 -25 -25 -30 -30 -30 -35 -35 -35 -40 -40 -40 -45 -45 -45 -50 -50 -50 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 Azimuth(deg) Azimuth(deg) Azimuth(deg) Azimuth Pattern LRU (18x32), Taylor-25dB n=2, SC, s :30 deg Azimuth Pattern LRU (18x32), Taylor-25dB n=2, SC, s :40 deg Azimuth Pattern LRU (18x32), Taylor-25dB n=2, SC, s :50 deg 0 0 0 MP:1.6% V MP:-2.2% V MP:-51% V -5 H -5 -5 H H -10 -10 -10 -15 -15 -15Amplitude(dB) Amplitude(dB) Amplitude(dB) -20 -20 -20 -25 -25 -25 -30 -30 -30 -35 -35 -35 -40 -40 -40 -45 -45 -45 -50 -50 -50 36 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 Azimuth(deg) Azimuth(deg) Azimuth(deg)
  • 37. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuthMeasured Patterns V-pol 37
  • 38. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuthMeasured Patterns V-pol 38
  • 39. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuthMeasured Patterns V-pol 39
  • 40. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuthMeasured Patterns V-pol 40
  • 41. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuthMeasured Patterns V-pol 41
  • 42. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuthMeasured Patterns H-pol 42
  • 43. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuthMeasured Patterns H-pol 43
  • 44. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuth Patterns H-pol 44
  • 45. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuth Patterns H-pol 45
  • 46. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar CASA Phase-tilt antenna azimuthMeasured Patterns H-pol 46
  • 47. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Polarization performance of CASA phased array radar ICPR ICPR2 and Z DRb 2 Azimuth patterns for Tx and Rx in V ZbDR 6 Azimuth patterns for Tx and Rx in H H:cos(),V:cos()1.2 5 Array:18x32 (meas.) Array:64x32 (calc.) 4 3 Zb (dB) 2 DR 1 0 -1 -2 47 -50 -40 -30 -20 -10 0 10 20 30 40 50
  • 48. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere 1. 2. 3. 4. Introduction Overview of phased-array antenna for weather radars Phased-array antenna requirements for weather radars Phased-array antenna design considerations for weather radar 5. CASA phased-array radar Uncertainty ZbDR of CASA phased-array radar Azimuth patterns for Tx and Rx inin V Azimuth patterns for Tx and Rx V Std (ZbDR ) for Unif-Unif and Unif-Tay25 0.16 0.14 standar deviation of bias Z (deg) Unif-Unif (a) 0.12 Unif-Tay25dBT (a) dr 0.1 0.4 0.08 SLLp=-13dB 0.06 SLLi=-8.75dB 0.3 Phase errors RMS (rad) 0.04 13.7o c 0.02 -60 -40 -20 0 20 40 60 SLLp=-20dB 0.2  (deg) SLLi=-14.4dB b Azimuth patterns for Tx and Rx in H Std (ZbDR ) for Unif-Unif and Unif-Tay20 6.8o Azimuth patterns for Tx and Rx in H Unif-Unif (b) 0.16 0.1 4.6o a -2.4 dB Unif-Tay20dBT (b) SLLp=-25dB -1.1 dB 0.14 standar deviation of bias Z (deg) SLLi=-17.7dB 0.12 dr 0 0.1 0.2 0.3 0.4 -0.7dBAmplitude errors RMS (mag) 0.1 0.08 Tolerance of the antenna based on residual sidelobe level (relative to 0.06 isotropic radiation) for CASA the Phased- array antenna. 0.04 0.02 -60 -40 -20 0 20 40 60  (deg) Dual-Polarization Performance of the Phase-Tilt Antenna Array in a CASA Dense Network Radar Geoscience and Remote Sensing Symposium (IGARSS), 2010 IEEE International December 3, 2010 48 Authors: Jorge Luis Salazar-Cerreno, Eric Knapp, , David McLaughlin
  • 49. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere Phase-Tilt Polarization performance in Azimuth plane Measured AEP (in 1 LRU) Calculated ICPR2 for one single panel 0 Co-polar H -10 Amplitude of AEP(dB) Co-polar V X-polar H X-polar V -20 -30 -40 -50 -60 -80 -60 -40 -20 0 20 40 60 80 Theta(deg) Dual-Polarization Performance of the Phase-Tilt Antenna Array in a CASA Dense Network Radar Geoscience and Remote Sensing Symposium (IGARSS), 2010 IEEE International December 3, 2010 49 Authors: Jorge Luis Salazar-Cerreno, Eric Knapp, , David McLaughlin
  • 50. casa Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere CASA Team Anthony Hopf, Rafael Medina, Jorge Salazar, Charlotte De Vries, Eric Knap and Stephen Fraiser. 50

×