High Efficiency Wideband Refractive Optics for ALMA Band-1 (35-52 GHz)

Tapia, Valeria; González, Álvaro; Finger, Ricardo; Mena, F. P.; Monasterio, David; Reyes, Nicolás; Sánchez, Manuel García; Bronfman, L.

doi:10.1007/s10762-016-0331-4

Cited by 12 publications

(13 citation statements)

References 9 publications

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“…2. The GRASP simulation model based on a corrugated horn at 35 GHz [13]; the sampling interval on the measurement plane is equal to λ/2, which is smaller than the Nyquist sampling interval (λ/2u, λ/2v).…”

Section: A Near-field-to-far-field Transformation (Nft) and Fourier T...mentioning

confidence: 99%

“…The most important procedure is to transform the beam patterns of probe and AUT into the same coordinate system. Following the same principle, we derived the coupling equation of our measurement system as stated in ( 13), (13) where P1 and P2 are the near-field measurement results after NFT; and Gx and Gy are the x and y components of the probe far-field beam patterns. The details of the measurement system will be explained in the Section IV.…”

Section: B Probe Compensationmentioning

confidence: 99%

“…It is rotated 90 degrees for XsP measurements. Based on the measurement procedure, we derived the coupling equation as stated in (13).…”

Section: Application To Measurementsmentioning

confidence: 99%

“…We also derive the relation between different Efield components based on the far-field boundary condition, which is more straightforward than derivations in previous literature. In section III, we create a simulation model based on a corrugated horn designed for an astronomical receiver [13] to verify the basic equations and estimate the systematic errors introduced by FT. Additionally, we analyze the effect of the probe antenna patterns on measurement results. In section IV, we apply our method to actual near-field measurements.…”

Section: Introductionmentioning

confidence: 99%

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Accurate Reconstruction of Far-Field Polarization Beam Patterns from Planar Near-Field Measurements

Kang¹,

González²,

Sakai³

et al. 2022

Preprint

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Planar near-field measurements are a common method to characterize antenna performance at millimeter and submillimeter wavelengths. Far-field beam patterns are then calculated from those measurements. However, different approximations have been traditionally used for this calculation without careful analysis. In this paper, we derive a Near-field-to-Far-field Transformation (NFT) based on diffraction theory and the full components of electrical fields based on the boundary condition in the far-field region. We analyze the systematic errors introduced by Fourier Transformation (FT) and the probe antenna by comparison with simulations. We further apply our data analysis procedures in the near-field measurement of a corrugated horn. Measurement and simulation results suggest that when all the procedures are conducted accurately, we are able to reconstruct far-field beam patterns from planar near-field measurements with high accuracy. <br>

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Section: A Near-field-to-far-field Transformation (Nft) and Fourier T...mentioning

confidence: 99%

Section: B Probe Compensationmentioning

confidence: 99%

“…It is rotated 90 degrees for XsP measurements. Based on the measurement procedure, we derived the coupling equation as stated in (13).…”

Section: Application To Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Accurate Reconstruction of Far-Field Polarization Beam Patterns from Planar Near-Field Measurements

Kang¹,

González²,

Sakai³

et al. 2022

Preprint

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“…The next element in the optics is the feedhorn, which is placed on the 15K stage of the receiver. Three prototypes have been developed and tested by University of Chile (UCh) [3], INAF [4] and NAOJ [5]. All the designs are based on corrugated horns with different profiles and have been optimised to achieve low cross-polarisation (<-30 dB), high reflection loss (>30 dB), good beam symmetry and appropriate beam size and phase centre location (PCL) as a function of frequency.…”

Section: Opticsmentioning

confidence: 99%

Wideband 67−116 GHz receiver development for ALMA Band 2

Yagoubov

Mroczkowski

Belitsky

et al. 2020

A&A

Self Cite

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Context. The Atacama Large Millimeter/submillimeter Array (ALMA) has been in operation since 2011, but it has not yet been populated with the full suite of its planned frequency bands. In particular, ALMA Band 2 (67-90 GHz) is the final band in the original ALMA band definition to be approved for production. Aims. We aim to produce a wideband, tuneable, sideband-separating receiver with 28 GHz of instantaneous bandwidth per polarisation operating in the sky frequency range of 67-116 GHz. Our design anticipates new ALMA requirements following the recommendations of the 2030 ALMA Development Roadmap. Methods. The cryogenic cartridge is designed to be compatible with the ALMA Band 2 cartridge slot, where the coldest components -the feedhorns, orthomode transducers, and cryogenic low noise amplifiers -operate at a temperature of 15 K. We use multiple simulation methods and tools to optimise our designs for both the passive optics and the active components. The cryogenic cartridge is interfaced with a room-temperature (warm) cartridge hosting the local oscillator and the downconverter module. This warm cartridge is largely based on GaAs semiconductor technology and is optimised to match the cryogenic receiver bandwidth with the required instantaneous local oscillator frequency tuning range. Results. Our collaboration has resulted in the design, fabrication, and testing of multiple technical solutions for each of the receiver components, producing a state-of-the-art receiver covering the full ALMA Band 2 and 3 atmospheric window. The receiver is suitable for deployment on ALMA in the coming years and it is capable of dual-polarisation, sideband-separating observations in intermediate frequency bands spanning 4-18 GHz for a total of 28 GHz on-sky bandwidth per polarisation channel. Conclusions. We conclude that the 67-116 GHz wideband implementation for ALMA Band 2 is now feasible and that this receiver provides a compelling instrumental upgrade for ALMA that will enhance observational capabilities and scientific reach. 1 https://www.almaobservatory.org of construction. Recent technological developments in cryogenic monolithic microwave integrated circuits (MMICs) and optical components, such as wide bandwidth feedhorns, orthomode transducers (OMT), and lens designs -have opened up the opportunity to extend the originally-planned radio-frequency (RF) bandwidth of this receiver, to cover the 67-116 GHz frequency range on-sky with a single receiver. This holds the potential for combining ALMA Band 2 (67-90 GHz) with ALMA Band 3 (84-116 GHz), serving as an upgrade that paves the way for wider bandwidth ALMA operations. As discussed in Mroczkowski et al. 2019a, this approach offers several opera-Article number, page 1 of 23

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