Solar Radio Spectro-polarimeter (50–500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole Antenna
The Zeeman effect has been routinely used to image and quantify the solar photospheric magnetic field (B). Such a direct measuring technique is not yet available for the corona (Lin et al. 2004). Since almost all transient nonthermal radio emissions from the corona are either partially or fully circ...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acff58 |
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| author | Anshu Kumari G. V. S. Gireesh C. Kathiravan V. Mugundhan Indrajit V. Barve R. Ramesh C. Monstein |
| author_facet | Anshu Kumari G. V. S. Gireesh C. Kathiravan V. Mugundhan Indrajit V. Barve R. Ramesh C. Monstein |
| author_sort | Anshu Kumari |
| collection | DOAJ |
| description | The Zeeman effect has been routinely used to image and quantify the solar photospheric magnetic field (B). Such a direct measuring technique is not yet available for the corona (Lin et al. 2004). Since almost all transient nonthermal radio emissions from the corona are either partially or fully circularly polarized, observing their polarization signatures over broad frequency ranges would be of help to estimate B as a function of heliocentric height. This article aims to describe the design and development of a Cross-polarized Log-Periodic Dipole Antenna (CLPDA), an integral part of a radio spectro-polarimeter, which works in the 50–500 MHz frequency-range and to explain the tests that were carried out to characterize it. The above frequency range corresponds to a heliocentric height range ≈1.03 < r < 2.5 R _⊙ ( R _⊙ = photospheric radius ), wherein the numerous coronal nonthermal transients associated with space-weather effects are observed to originate. The CLPDA is used to determine the strength and sense of polarization of the received radio signal. The uncertainty involved in the determination depends on the polarization-isolation (PI) between the two orthogonal components of a CLPDA. Some of the recent advancements made in the antenna design concepts at high frequencies (∼GHz) were adopted to reduce the PI at low frequencies (∼MHz). Throughout the above frequency range, the CLPDA has a gain, return loss, and PI of ≈6.6 dBi, ≲−10 dB, and ≲−27 dB, respectively. The average PI of the CLPDA varies from −30 to −24 dB over an azimuthal angle range 0° to ±45° within which the observations are performed regularly. |
| first_indexed | 2024-03-09T14:44:22Z |
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| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-09T14:44:22Z |
| publishDate | 2023-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj.art-4221d8ed941f43c3a6ec29c5eb1192f02023-11-27T09:49:42ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01958218110.3847/1538-4357/acff58Solar Radio Spectro-polarimeter (50–500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole AntennaAnshu Kumari0https://orcid.org/0000-0001-5742-9033G. V. S. Gireesh1C. Kathiravan2https://orcid.org/0000-0002-6126-8962V. Mugundhan3Indrajit V. Barve4R. Ramesh5https://orcid.org/0000-0003-2651-0204C. Monstein6NASA Postdoctoral Program Fellow, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USAIndian Institute of Astrophysics , II Block, Koramangala, Bangalore 560034, India ; kathir@iiap.res.inIndian Institute of Astrophysics , II Block, Koramangala, Bangalore 560034, India ; kathir@iiap.res.inDepartment of Earth and Space Sciences, Chalmers University of Technology , Onsala Space Observatory, SE-439 92 Onsala, SwedenIndian Institute of Astrophysics , II Block, Koramangala, Bangalore 560034, India ; kathir@iiap.res.inIndian Institute of Astrophysics , II Block, Koramangala, Bangalore 560034, India ; kathir@iiap.res.inIstituto ricerche solari Aldo e Cele Daccò (IRSOL) , Università della Svizzera italiana (USI), CH-6605 Locarno, SwitzerlandThe Zeeman effect has been routinely used to image and quantify the solar photospheric magnetic field (B). Such a direct measuring technique is not yet available for the corona (Lin et al. 2004). Since almost all transient nonthermal radio emissions from the corona are either partially or fully circularly polarized, observing their polarization signatures over broad frequency ranges would be of help to estimate B as a function of heliocentric height. This article aims to describe the design and development of a Cross-polarized Log-Periodic Dipole Antenna (CLPDA), an integral part of a radio spectro-polarimeter, which works in the 50–500 MHz frequency-range and to explain the tests that were carried out to characterize it. The above frequency range corresponds to a heliocentric height range ≈1.03 < r < 2.5 R _⊙ ( R _⊙ = photospheric radius ), wherein the numerous coronal nonthermal transients associated with space-weather effects are observed to originate. The CLPDA is used to determine the strength and sense of polarization of the received radio signal. The uncertainty involved in the determination depends on the polarization-isolation (PI) between the two orthogonal components of a CLPDA. Some of the recent advancements made in the antenna design concepts at high frequencies (∼GHz) were adopted to reduce the PI at low frequencies (∼MHz). Throughout the above frequency range, the CLPDA has a gain, return loss, and PI of ≈6.6 dBi, ≲−10 dB, and ≲−27 dB, respectively. The average PI of the CLPDA varies from −30 to −24 dB over an azimuthal angle range 0° to ±45° within which the observations are performed regularly.https://doi.org/10.3847/1538-4357/acff58Solar radio emissionSolar radio telescopesRadio spectroscopySpectropolarimetrySolar-terrestrial interactionsSolar magnetic fields |
| spellingShingle | Anshu Kumari G. V. S. Gireesh C. Kathiravan V. Mugundhan Indrajit V. Barve R. Ramesh C. Monstein Solar Radio Spectro-polarimeter (50–500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole Antenna The Astrophysical Journal Solar radio emission Solar radio telescopes Radio spectroscopy Spectropolarimetry Solar-terrestrial interactions Solar magnetic fields |
| title | Solar Radio Spectro-polarimeter (50–500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole Antenna |
| title_full | Solar Radio Spectro-polarimeter (50–500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole Antenna |
| title_fullStr | Solar Radio Spectro-polarimeter (50–500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole Antenna |
| title_full_unstemmed | Solar Radio Spectro-polarimeter (50–500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole Antenna |
| title_short | Solar Radio Spectro-polarimeter (50–500 MHz). I. Design, Development, and Characterization of a Cross-polarized, Log-periodic Dipole Antenna |
| title_sort | solar radio spectro polarimeter 50 500 mhz i design development and characterization of a cross polarized log periodic dipole antenna |
| topic | Solar radio emission Solar radio telescopes Radio spectroscopy Spectropolarimetry Solar-terrestrial interactions Solar magnetic fields |
| url | https://doi.org/10.3847/1538-4357/acff58 |
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