ALMA Band-1 Receiver

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ALMA Band-1 Receiver

• Chau-Ching CHIONG ???

Institute of Astronomy and Astrophysics, Academia
Sinica (ASIAA)
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Contributions from

• ASIAA
• Microwave Group Dr. Y.-J. Hwang, Dr. Y.-F. Kuo,
  Dr. C.-C. Lin, C.-C. Chuang, C.-T. Ho.
• Receiver Group Dr. M.-T. Chen, T.-S. Wei.
• National Taiwan University EE
• Prof. H. Wang Dr. Z.-M. Tsai, Dr. B.-J. Huang,
  W.-J. Tzeng, Y.-C. Wu, B.-H. Tsai, C.-C. Hung.
• National Central University EE
• Prof. H.-Y. Chang S.-H. Weng.
• Prof. Y.-S. Lin Y.-S. Hsieh.

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Science of ALMA Band 1 (30-45 GHz)

• High resolution Sunyaev-Zeldovich effect imaging
• Anisotropy of cosmic microwave background
  radiation
• High-redshifted CO lines
• Probing magnetic field strength via Zeeman
  measurement

Transistion Frequency (GHz) Zeeman splitting (Hz/uG)
CCS JN 32-21 33.75 0.70
CCS JN 43-32 45.38 0.63
SO JN 10-01 30.00 1.74
SiO v1, J 1-0 43.12 Very small
Transistion Redshift range
CO J1-0 1.55 2.67
CO J2-1 4.11 6.35
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Band-1 Development Plan

• International cooperation of Taiwan (ASIAA),
  Canada (HIA) and Chile (Uni. of Chile).
• ASIAA deliver key components, mostly in MMIC
  technologies (LNA, mixer, filter, IF amp.), while
  HIA focuses on optics, LNA (hybrid) and system
  integration.
• Proto-type receiver will be assembling in Chile.

HIA Band-1 cartridge layout

• Main challenges
• Longest wavelength, thus largest component size.
• LNA Noise lt 7 K.
• More than 60 copies required.

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Band 1 System Requirements

• Observation frequency 31.3-45 GHz (36)
• Operation mode single side band (USB), dual
  linear polarization feed
• Image suppression gt 20 dB
• Aperture efficiency gt 78
• IF bandwidth 4-12 GHz
• IF output power -31 to -18 dBm. IF power
  variation 6dB peak-to-peak in any 2GHz BW. 10 dB
  peak to peak across the complete IF band.
• Receiver noise temperature
• 17 K (80 bandwidth) and 28 K (full bandwidth)
  when operating at 15 K.
• LO tuning range 27.3-33 GHz (18.9). No
  mechanical tuning
• RMS LO phase noise in jitter 53 fs (short-term),
  17.7 fs (long-term)
• LO output power 10 mW
• Front-end cartridge size diameter 170mm, length
  500mm

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ALMA Band 1 Front-end System
15K

• Optics design Feedhorn
• OrthoMode Transducor (OMT)
• Cryogenic Low Noise Amplifier (LNA)
• Bandpass Filter Mixer
• Intermediate Frequency (IF) Amplifier
• Local Oscillator (LO) PLL

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Reasons for MMIC Approach

• Easy integration
• High reliability
• Mass production (gt 200 pcs.)
• Low cost (?)
• But still high noise.

Hybrid IC MMIC
Design Time Fast Slow
Noise Low High
Assembling Mass Production Hard Easy
Circuit Density Large Small
Integration Hard Easy
Experts No Yes
Hybrid X-band LNA from JPL, Weinreb (2007)
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MMICs for Front End
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Q-band Cascode PHEMT Mixer

• The cascode mixer using WIN 0.15 um pHEMT shows
• Good conversion gain flatness over 4-12GHz IF
  frequency.
• Low LO power drive.

Z.-M. Tsai et. al, EuMIC, 2009
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31-45 GHz 0.15 um MHEMT LNA
2f100mm 2-stage mHEMT LNA
S (dB)
Both with 2 mm x 1 mm
Vd2V, Id_dev37mA, Id_mea30, 33mA
2f50mm 3-stage mHEMT LNA
S (dB)
December 01-03, 2010
Vd1Vd2Vd31V, Id1Id2Id310mA
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Cryogenic Measurements
Packaging
Test Dewar
Weng et al., EuMIC, 2011
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Balanced LNA as Second Stage

• The same design of the 3-stage version.
• Better input/output matching.

December 01-03, 2010
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IF Amplifier
Chiong et al., EuMIC, 2009
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Integrated LNA-Mixer-Filter-IFA Chip
LO Input
Bandpass filter (Lin et al. 09)
IF amplifier
cascode HEMT mixer
LNA
2nd-stage LNA
Total DC power lt 150mW

• Highly integrated design of the module.
• Saving space inside the cryogenic section of the
  front-end cartridge.
• Reducing the possibility of failure in assembling.

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LO System YTO or VCO
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YIG-Tuned Oscillator (YTO) in Current ALMA System

• Coarse/fine tune
• 30 MHz ref.
• Excellent phase noise

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YTO Doubler Phase Noise

• Jitter (1 kHz to 1MHz) 45 fs
• ALMA spec 53 fs

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VCO Approach

• VCO has almost all advantages over YTO except
  phase noise.
• PLL board for YTO has to be modified for VCO
  operation, because single-tuned VCO has large
  gain and large gain variation.
• Frequency divider is added so that VCO-based PLL
  can be used in ALMA environment (using 30 MHz
  reference).

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Differential VCO layout
Tuning Voltage
PN -100 dBc/Hz _at_ 1MHz offset
RF out
-0.6 V
-2.5 V
RF out
WIN 0.15 um HBT Total dc power consumption 85 mW
Chiong et al., EuMIC, 2008
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Adaptive Loop Bandwidth Technique

• The VCO gain variation is large. For osc. Freq. gt
  33GHz, Kvco 200MHz/V, with Filter 1, PLL BW
  200 kHz.
• By switching to Filter 2, the PLL BW can be
  increased from 200kHz to 1MHz.
• The phase noise can be improved more than 22dB at
  the offset frequency of 250kHz under such
  adaptive loop bandwidth.

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Phase Locked Spectra of VCO
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Phase Noise Comparison between Phase-locked YTO
and VCO

• RMS Jitter/Degree of YTO (_at_1kHz to 1MHz) is
  44.6fs/0.59o
• RMS Jitter/Degree of VCO (_at_1kHz to 1MHz) is
  63.8fs/0.77o

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YIG vs. VCO

• Using adaptive loop bandwidth technique, the
  whole tuning range of VCO can be locked by single
  PLL board.
• Phase noise within the loop bandwidth ( 100 kHz)
  is compatible.
• Worse VCO phase noise at larger offset frequency
  contribute a lot of noise.
• Need more advanced InP HBT to meet ALMA spec.

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Possible Timeline for Band-1

• 2012 Proposal to ALMA
• 2013 Preliminary Design Review. First prototype
  front-end
• 2014 Critical Design Review. Production starts
• 2018 Project finishes

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Thank you.