Achievements in reporting period: 1) Summary of APRICOT Project Meeting at MPIfR Bonn November 17

1.1) Essential points from “Science at Q-band” meeting in Manchester September 2009

1) Meeting remit: science and technical status/plans for EVLA, ALMA, ATCA/Mopra, GBT and APRICOT. All presentations available (http://www.alma.ac.uk/documents/science-at-q-band)
2) EVLA compatibility: Q-band camera data from dishes will certainly be combined with data from EVLA.
3) Continuum receiver: is simpler if the internal switching schemes can be avoided. With a multi-pixel array one can recognise common-modes and this makes the analysis is easier. The specificationis dominated by continuum requirements. HEMTs have fknee of 10s of Hz – this is a major challenge.
4) Spectroscopy: the CSIRO Q-band (single pixel) system at Mopra observes when PWV <30mm –This gives a “green light “ for Q-band spectroscopy on large European telescopes. Although not strictly APRICOT the design should take into account the spectrometer back-end with the capability For flexible (“zoom” modes) as at CSIRO and APEX.
5) Polarisation specifications: Preference expressed for RCP/LCP for single dishes if a major goal is linear polarisation. Circular is also needed for VLBI (inc. orbiting VSOP-2). APRICOT has now adopted RCP/LCP as the baseline
6) APRICOT can learn from CSIRO 7-mm receiver design for ATCA and Mopra (single dish). They have developed a noise-injection calibration coupler and generate LOs via GaAs MMIC frequency tripler

1.2 Strategic outcomes:
1) Validated APRICOT scientific aims
2) Validated APRICOT technical goals – 17-GHz instantaneous bandwidth with 8 x ~2 GHz subbands sent to spectrometer
3) Validated need a very well-developed observing strategy

• fast data acquisition and fast telescope motion
• spectroscopic flexibility with zoom modes

1.3 Essential points from FP7 Engineering Forum “Multi-Pixel Camera Receivers” 16/11/2009

NRAO K-band FPA: 7 dual-polarised pixels
o Funding $1.2M – used current GBT IF system and spectrometer.
o Independent noise cal. injection for each pixel- noise source is a resistor-terminated LNA
o Bias electronics in separate (vacuum) pod – few bias wires into the cryostat – using (commercial) I2C-based scheme instead.
o Data collection/analysis pipeline was a bigger issue than anticipated
QUIET
o Q and W-band horn arrays made from 100 platelets by diffusion bonding – results good
o QUIET MMIC-modules illustrate advantages of integration
AMSTAR+
o W-band MMIC radiometer implemented by IAF Freiburg for non-astronomy - like to have this technology at cryogenic temperatures
o “Why does it all need to be on one chip/module?”
o Harder to characterize.
o Harder to fault-find
o What about power dissipation issues?
o Make a split after the LNA?

1.4 APRICOT All-Project Discussion

Task 1: Receiver architecture (MPIfR et al)
o R. Keller has developed a preferred scheme involving 8 x 2 GHz continuum channels via dual down-conversion with a minimum of different filters; both LOs are fixed.
o No decisions taken on LO & down-conversion details
o Interesting option: separate PLL LOs distributed in the system with the LO power generated independently at each mixer. This scheme will be tested on a dual-horn precursor Q-band receiver being built in MPIfR using classical approach to RF design.

o Task 1 “Architecture” crosses-over with Task 3 “MMICs”
o What can be integrated?
o How much would it cost to have an integrated down-conversion chip from IAF?

Task2: Passive components (INAF/IRA et al)
o IRA/Arcetri group have made a complete a classical waveguide chain (forming the basic “reference” concept)
o The phase shifter performance rolls off at the ends of the band (currently 36-50 GHz). G.Pisano (Manchester) has a design with a significantly flatter phase characteristics which can be implemented.
o IRA/Arcetri interested to explore the platelet horn technique

Task 3&4 European MMICs & testing (Manchester/MPIfR/CAY et al)

i ) Associated with the IAF programme (initial programme almost entirely funded through MPIfR/IRAM & CAY “precursor” programmes not funded by APRICOT or AMSTAR+)
o Single transistor-based investigations: 1) devices put into existing amplifiers; 2) characterising devices at cryo. temperatures
o not yet tested 50-nm or 35-nm gate width devices
o not enough testing to tell how big is the issue of potential oscillation with 100-nm devices
o a hybrid LNA at 18-26 GHz with 100-nm IAF devices showed excellent results – noise does not change much with gate length.
o Work on 1/f noise characterisation is ongoing in CAY

o MMICs: Many 50-nm MMIC LNAs at 1-4, 4-12 and 20-25 GHz delivered via MPIfR/IRAM precursor contract now available for testing.
o Passives: low-frequency MMIC LNA performance not as good as single transistor LNA - imperfect passive models?
o Need at least 6 months more testing before in a position to design a successful APRICOT MMIC set.
o Next step: design/build a Q-band hybrid amp – this is of great interest to N. Reyes (U. Chile) who is currently working on an ALMA band-1 MIC LNA in Manchester.
o Need to begin planning on how to use APRICOT funding to add to MPIfR and CAY/Cantabria funding to secure wafer space.
o Have to go for one-shot design given our limited available money
o W-band for AMSTAR+ is in a similar situation.

ii) Associated with OMMIC (led by University of Rome Tor Vergata)
o Will use 70nm mHEMT technology. OMMIC not interested to develop cryogenic models.
o From FP6 “PHAROS”: Q-Band (35-50 GHz) and W-band MMIC LNAs available for testing.
o Packaged W-band MMICs have been measured at RT (promising) - not at cryo temps.
o No Q-band MMIC tests – could be measured in MPIfR at cryo temps
o Down-converter and harmonic mixers (at ambient) are potential interests for UTV.

iii) Associated with NGST (not to be funded in APRICOT)
o From FP5 “FARADAY”: have NGST 100-nm InP 35-50 GHz MMIC LNA circuits - could be measured in MPIfR at cryo temperatures. Excellent opportunity immediately to compare OMMIC mHEMT and NGST pHEMT performances (and later IAF).

iv) Associated with Manchester: o Awaiting recruitment to start “closer to the quantum limit” transistor investigation with InP

Task 5 Software & simulations (TCfA, Manchester et al) o Major progress made towards a complete sky-telescope-receiver output model. o More details on atmosphere can be provided from the MPIfR WV radiometer data base. o Concentrate in first instance on continuum mapping – spectroscopy later (what about baseline ripples?) o Start OTF mapping tests with CSIRO Livedata software – TCfA contributed in FP5 FARADAY. o Kick-off meeting scheduled for TCfA – 13 January 2010

• List of working documents

• Main Activities during 2009 Q3 and Q4 and Work Plan for Q1 and Q2:

2) Task Status Summary

All aspects of the project are being affected by the funding delay – nevertheless significant progress can be reported on all tasks.

Task 1) Receiver Architecture: A design options paper has been produced – with a favoured scheme emerging. Experience from other FPAs has been assimilated from the RadioNet FP7 Engineering Forum “Multi-pixel Arrays” and the “Science at Q-band” Meetings held in Q3 & Q4.

Task 2): Innovative passive components; a “classic” passive chain has been constructed by IRA/Arcetri to provide a performance baseline. Manchester has identified alternative options and awaits final funding release inside UMAN to start procurement from outside contractor.

Tasks 3) and 4): Procurement and testing of Active Devices: Even without APRICOT funding much progress with the IAF in Freiburg has been made due to the contribution of the MPIfR/IRAM/CAY- Cantabria precursor programmes and people (e.g. Beatriz Aja, Cantabria/Santander) actually working within IAF. IAF remains very keen to establish Cryogenic component models. The link with the AMSTAR+ W-band MMIC looks like it will be strong with the many cross links between the two JRAs (MPIfR, Frank Schafer,CAY, Juan Daniel Gallego, IAF, Matthias Seelman-Eggebert). On the other hand the OMMIC programme (commercial and hence awaits availability of funds) and the Manchester Programme (depends on recruitment of a post-doc) have not yet started

Task 5) Software simulations – significant progress towards a working end-to-end model can be reported. The TCfA post-doc B. Lew is now in post. A kick-off meeting will be held in Torun 13 January 2010.

• Meetings attended by people involved

Problems / Issues

• Issues - organisational, administrative or other problems foreseen

• Red flags - major problems

Forward Look

• Plan for next quarter/half year– 3 and 6 month outlook, more detail in first 3 months (including budget)

• Expected milestones/deliverables

Deliverable/Milestone 8.01: We can soon declare success on the atmospheric model – see also discussion on Task 5. Fractal atmosphere (Manchester) + Cernicharo et al.‘s world-leading analytic calculation of atmospheric opacity as a function of altitude and precipitable water vapour content (available via Yebes) + MPIfR water vapour monitoring programme (available from A. Roy MPIfR). Final discussion in kick-off meeting for Task 5.

Deliverable/Milestone 8.02: the draft architecture document circulated for the meeting can fulfil this deliverable even though we have not yet decided on the finally preferred concept. The document proposes a series of options with a degree of preference from R.Keller (see below) for that in Figure 4a. Needs final comments before final version is posted.

Milestone 8.03: Although not funded by APRICOT several of the partners have independent but linked programmes with IAF Freiburg. Results of these on MICs could properly be presented as meeting this milestone.

• Expenditures - equipment, material and services

• Person month spent/to be spent until next EC Report

• Number of Persons working in JRA