Nyquist Sampling at K band

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Airy Pattern K band:First null Diameter

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KPAF Horn Design Consideration

Single Horn

• = 1.27 cm
• Pyramidal Horn
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  • Requires four feeds to cover Airy Pattern
  • 16x16 array ~ 225 beams @

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• 23.4 GHz Farfield Hplane:
• 23.4 GHz Farfield Eplane
• S11
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Dual Horn

• Dual Polarization with symmetrical beam shapes can be achieved with the dual horn configuration, E plane excited farfield at 23.4 GHz ; and H plane excited farfield at 23.4 GHz.

• Difficult to obtain proper match in the E plane, compared to a reasonable match in the H plane

• Dual Horn: H sectoral rectangular horn with Length:
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Commercial MMIC at K band

• cmd163_ver_2.3_0516Kband.pdf: F = 1.3 dB, Te= 290(F-1) = 102 K; @ 15 K: ~ 102/10 = 10.2 K comparable to Cryo3 devices. 120 mA of current probably too high.
• cmd160_ver_3.5_0516.pdf: F = 1.4 dB, Te= 290(F-1) = 110 K; @ 15 K: ~ 110/10 = 11.0 K comparable to Cryo3 devices. 26 mA but gain rolls off but still > 20 dB at 26.5 GHz. Two 1020 could cool ~ 300 devices.
• Getting two samples to test July 7, 2016.

IF system

• The KFPA IF system IDM1_block_diagram.pdf as an example.
  • Note: This module is dual polarization, only one polarization is required for this design.
  • Note: This module has a waveguide input, a coaxial input may be required instead.
  • Note: The Kband Phased Array Feed IF System requires a much smaller bandwidth, 400 MHz, and an output frequency range of 400 to 800 MHz.
  • The rejection level and input power level must be specified, which will determine the filter specifications and the total module gain required.
• WVU CAPSTONE Project
• cmd163_ver_2.3_0516Kband.pdf: Possible input amplifier
• cmd160_ver_3.5_0516.pdf: Possible input amplifier

Backend Notes from Kevin Bandura

• Backend Notes by Kevin Bandura

Previous AST/ATI Funding

• AST ATI/MRI Awards 2012 onwards

Some Notes from the Old KFPA Internal NRAO Proposal

The old KFPA internal proposal is here: KFPA Proposal. The proposed, total cost in 2007 dollars, was $1.7M. Steve may have an estimate of the actual cost.

The old proposal was based around the capabilities of the GBT spectrometer, but it was noted that the GBT spectrometer provided a reasonable match to the required capabilities. A useful, if somewhat dated overview of ammonia is available in this AARA review paper. The principal lines are NH3 (1,1), (2,2) and (3,3) at 23.6945, 23.7226 and 23.8701 GHz (separation 176 MHz). Many o

The configurations discussed in the old proposal were:

• 50 MHz total width and 16384 channels, giving, at 22 GHZ, a total velocity coverage of 680 km/s at a channel spacing of 0.04 km/s. This is a good match to surveys in the Galactic plane and allows in-band frequency switching as well.
• 12.5 Mhz bandwidth and 16384 channels which gives, at 22 GHz, a total velocity coverage of 170 km/s at 0.01 km/s channel spacing. This is likely to be the main mode for study of individual molecular clouds.
• 200 MHz total bandwidth with 8k channels or 800 MHz total bandwidth with 2k channels. At 22 GHz these modes give 2700 km/s at 1.3 km/s channel spacing, and 11,000 km/s at 5.3 km/s channel spacing, respectively. The broad band modes are well matched to observations of extragalactic molecular clouds, galactic nucleii, and high-redshift molecular lines.