Efficient algorithms for optimising the optical performance of profiled smooth walled horns for future CMB and Far-IR missions

McCarthy, D.; Trappe, Neil; Murphy, J. Anthony; O'Sullivan, Créidhe M.; Grądziel, M.; Doherty, Stephen; Bracken, Colm; Tynan, Niall; Polegre, Arturo Martin; Huggard, P. G.

doi:10.1117/12.2056336

Cited by 5 publications

(4 citation statements)

References 1 publication

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“…An overview of the measured field patterns can be found in [13], however a thorough analysis of the measurement campaign will now be given here. Figs.…”

Section: Measurement Of Fabricated Hornmentioning

confidence: 99%

The optimisation, design and verification of feed horn structures for future Cosmic Microwave Background missions

McCarthy

Trappe

Murphy

et al. 2016

Infrared Physics & Technology

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h i g h l i g h t sEfficient mode-matching based optimisation process for feed horns is presented. Allows design of high performance smooth-walled feed horns using desktop computers. Horn designed for future CMB missions with rigorous performance requirements. Horn meets all requirements across the band, only taking 6.5 h to design. Horn was manufactured and measurements agreed excellently with simulations. a b s t r a c tIn order to investigate the origins of the Universe, it is necessary to carry out full sky surveys of the temperature and polarisation of the Cosmic Microwave Background (CMB) radiation, the remnant of the Big Bang. Missions such as COBE and Planck have previously mapped the CMB temperature, however in order to further constrain evolutionary and inflationary models, it is necessary to measure the polarisation of the CMB with greater accuracy and sensitivity than before.Missions undertaking such observations require large arrays of feed horn antennas to feed the detector arrays. Corrugated horns provide the best performance, however owing to the large number required (circa 5000 in the case of the proposed COrE+ mission), such horns are prohibitive in terms of thermal, mechanical and cost limitations.In this paper we consider the optimisation of an alternative smooth-walled piecewise conical profiled horn, using the mode-matching technique alongside a genetic algorithm. The technique is optimised to return a suitable design using efficient modelling software and standard desktop computing power. A design is presented showing a directional beam pattern and low levels of return loss, cross-polar power and sidelobes, as required by future CMB missions. This design is manufactured and the measured results compared with simulation, showing excellent agreement and meeting the required performance criteria.The optimisation process described here is robust and can be applied to many other applications where specific performance characteristics are required, with the user simply defining the beam requirements.

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“…An overview of the measured field patterns can be found in [13], however a thorough analysis of the measurement campaign will now be given here. Figs.…”

Section: Measurement Of Fabricated Hornmentioning

confidence: 99%

The optimisation, design and verification of feed horn structures for future Cosmic Microwave Background missions

McCarthy

Trappe

Murphy

et al. 2016

Infrared Physics & Technology

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“…The example HUT chosen was a non-standard smooth-walled profiled horn, especially designed for application in future generations of cosmic microwave background (CMB) polarization experiments [20]. Such experiments must be sensitive to extremely low-level polarized signals, in order to enable inflationary theories in cosmology to be further constrained, thus providing a better understanding of the formation and evolution of the Universe.…”

Section: Recovering the Phase Center For An Example Horn Antennamentioning

confidence: 99%

“…While corrugated horns can provide the necessary performance in terms of cross-polar power, main beam symmetry, return loss and sidelobe levels across the 10% relative bandwidths of interest for such missions (for example, the proposed CorE+ mission to the European Space Agency, ESA, [21]), they do carry thermal, mechanical, and financial penalties, which when many thousands are required, become overwhelming. Thus, possible alternatives to corrugated horns have been investigated, and in this regard, the optimization of shaped smooth-walled horns to meet the performance demands of such missions across the band was considered as in [20]. Such smooth-walled horns can provide the necessary levels of performance in the areas of interest (e.g., cross polarization levels), but with lower penalties than those associated with corrugated horns.…”

Section: Recovering the Phase Center For An Example Horn Antennamentioning

confidence: 99%

Determination of the Phase Centers of Millimeter-Wave Horn Antennas Using a Holographic Interference Technique

McAuley

Murphy

McCarthy

et al. 2016

J Infrared Milli Terahz Waves

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In this paper, we discuss how a holographic interference technique can be applied in the experimental determination of the phase centers of non-standard horn antennas in the millimeter-waveband. The phase center is the point inside the horn from which the radiation appears to emanate when viewed from the far-field, and knowing its location is necessary for optimizing coupling efficiencies to quasi-optical systems. For non-standard horn designs, and other feed structures, the phase center may be difficult to reliably predict by simulation, in which case, before committing to antenna manufacture, there is a requirement for it to be determined experimentally. Although the phase center can be recovered by direct phase measurement of the far-field beam pattern, this usually involves expensive instrumentation such as a vector network analyzer for millimeter wave horn antennas. In this paper, we describe one inexpensive alternative, which is based on measuring the interference pattern in intensity between the radiation from the horn of interest and a reference beam derived from the same coherent source in an off-axis holography setup. The accuracy of the approach is improved by comparison with the interference pattern of a well-understood standard horn (such as a corrugated conical horn) in the same experimental setup. We present an example of the technique applied to a profiled smooth-walled horn antenna, which has been especially designed for cosmic microwave background (CMB) polarization experiments.

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“…The smoothed-walled variable profile horn appeared as a viable alternative to the diagonal horn, in which the cutting tool does not follow a continuous profile when passing through the split-block. Instead, cutting depth variations are present which were proven to achieve high gaussicities [5], [6]. In [6] a spline-profiled diagonal horn was proposed and gaussicities of approximately 97 % were obtained at the centre frequency, through an optimization process.…”

Section: Introductionmentioning

confidence: 99%

Scalable High-Gaussicity Split-Block Diagonal Horn Antenna for Integration with Sub-THz Devices

Santos

Lima

Pinho

et al. 2019

2019 49th European Microwave Conference (EuMC)

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In this paper we propose a high-gaussicity spline-profiled horn antenna, which is scalable in length and aperture to achieve higher gains whilst retaining a high Gaussian efficiency. A novel approach is used where a PSO is used for optimizing the spline, using the gaussicities at the operating frequencies as the objective function, which further improves side-lobe level and cross-polarization when compared to the state-of-the-art. With the proposed method, which was validated through FEM simulations in HFSS, reflection coefficients below -15 dB, gains greater than 25 dBi and gaussicities above 91% were obtained in the entire WR-3 band.

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Efficient algorithms for optimising the optical performance of profiled smooth walled horns for future CMB and Far-IR missions

Cited by 5 publications

References 1 publication

The optimisation, design and verification of feed horn structures for future Cosmic Microwave Background missions

The optimisation, design and verification of feed horn structures for future Cosmic Microwave Background missions

Determination of the Phase Centers of Millimeter-Wave Horn Antennas Using a Holographic Interference Technique

Scalable High-Gaussicity Split-Block Diagonal Horn Antenna for Integration with Sub-THz Devices

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