Eduardo Artal (1) Francisco Casas (2)
(1) Departamento de Ingeniería de Comunicaciones (DICOM) Universidad de Cantabria. Santander.
(2) Instituto de Física de Cantabria (IFCA). CSIC-Universidad de Cantabria. Santander.
! SKA Dish Array ! Description
! Our projects in radio astronomy ! ESA Planck mission
! Microwave polarimeters in “El Teide”
! Low noise receivers for radio astronomy ! Cryogenic Low Noise Amplifiers (LNA)
! Feed-horns, polarizers, Orthomode Transducers (OMT) ! Microwave correlators and detectors
! Conclusions
SKA Dish Array - Description
Dishes:
Receptors of the astronomical signal for frequencies from 450 MHz to 10 GHz
Feeds and
Low Noise Amplifiers (LNAs):
• Single Pixel Feeds (part of the SKA1)"
"
• Phased Array Feeds
(part of Advanced Instrumentation) Receivers:
SKA Dish Array - Description
SKA phases
SKA1 • 250 antennas (15 m) • Single-pixel feeds • Frequency range of 0.45 - 3 GHz SKA2• Depending on the Advanced Instrumentation Program results
• Inclusion of Phased Array or Ultra-Wide Band Feeds on the dishes
• Frequency range up to 10 GHz
Proposed work on Feed antennas and Receivers
• Wideband single-pixel feeds
• Octave-band single-pixel feeds (current default)
ESA Planck-LFI radiometers (30 and 44 GHz) Radiometer metro Radiometer WG BEM FEM WG Channel 1 Channel 2 Channel 4 Channel 3 to D A E 4 K load reference Feed-horn Feed-horn OMT 4 K load reference Feed-horn 20K 20K 300K 300K
Back End Module: BEM
LNA
(MMIC) Filter Detector
Detector output
DC amplifier
One branch of the 30 GHz BEM EBB
Size: 3x1 mm2 LNA (HEMT-Depletion) LNA (HEMT-Enhancement) PHEMT OMMIC ED02AH Gate Width : 90 µm (6x15µm) Gate Length : 0.18 µm
MMIC amplifiers (LNA) at 44 GHz
30
GHz BEM. Qualification Model (QM)
3 Back End Modules at 44 GHz
2 Back End Modules at 30 GHz
First telescope installation
Microwave polarimeters in “El Teide”
QUIJOTE 1st Instrument – 30 GHz pixel
LNA LNA Feedhorn 180º Hybrid Cryostat (T = 20 K) LNA LNA DC DC FEM F F Ph.Switch 180º F F Ph.Switch 90º Ph.Switch 180º Ph.Switch 90º φ 90º Ph.Shift φ 0º Ph.Shift DC DC 180º Hybrid Gain&Filtering Modules Phase Switches Module Correlation&Detection Module Polarizer OMT Cryo-LNA (Room Temperature, T = 298 K) Back-End Module Vd1 Vd2 Vd3 Vd4
Polarimeter receiver (26-36 GHz) (2nd instrument)
Cryogenic Low Noise Amplifiers
4-12 GHz MMIC LNA
Chip size: 3 x 1 mm2 100 nm mHEMT (IAF-Fraunhofer)
3-stage (Gate width: 4 × 30 µm)
Cryogenic Low Noise Amplifiers
Gain = 31.5 ± 1.8 dB
Feedhorn measurements 26 – 36 GHz band 25 26 27 28 29 30 31 32 33 34 35 36 37 -50 -40 -30 -20 -10 0 10 20 30 40 50 Frecuencia (GHz) (d B ) -180 -135 -90 -45 0 45 90 135 180 -60 -50 -40 -30 -20 -10 0 10 20 30 θ (deg) (d B ) φ = 0º φ = 90º Directivity
Input Matching X-polarization Radiation pattern at f = 32 GHz
Polarizer
Measured performance 26 – 36 GHz band -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 Re fle x ió n ( d B ) -108 -106 -104 -102 -100 -98 -96 -94 -92 -90 -88 -86 Di fe re n c ia d e F a s e (d e g ) -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 Tr a n s m is ió n ( d B )Units: 10-14 GHz 14-22 GHz 26-36 GHz
Facilities at Universidad de Cantabria
Test equipment from DC to 50 GHz: Gain, Noise temperature, Signal analysis, Spectrum analysis, 1/f noise, …
at Room temperature (300 K) and at cryogenic temperature (20 K)
Conclusions
-
Expertise in broadband low noise receivers for
radio astronomy
-
We are able to contribute to SKA preconstruction
phase in collaboration with the industry
Acknowledgment: QUIJOTE receivers are funded by the Ministerio de Ciencia e Innovación under Astronomy and Astrophysics research program,
