Abstract Details
| Name: K. Sasikumar Raja Affiliation: Indian Institute of Astrophysics Conference ID: ASI2015_489 Title : Design and performance study of a meter wavelength narrow band cross-polarized log-periodic dipole antenna to observe the polarized radio emission Authors and Co-Authors : K. Sasikumar Raja1, C. Kathiravan1, R. Ramesh1, M. Rajalingam1, and Indrajit V. Barve1 1Indian Institute of Astrophysics, II Block, Koramangala, Bangalore-560 034. Abstract Type : Oral Abstract Category : Instrumentation and Techniques Abstract : We designed and fabricated a cross-polarized log-periodic dipole (CLPD) antenna at Gauribidanur Radio Observatory, India to observe the circularly polarized radio emissions from the solar corona at meter-wavelengths. The CLPD consists of a two log-periodic dipole (LPD) antennas which are arranged in orthogonal fashion with a common axis. Since the commercially available CLPD has the isolation is approximately -20 dBm, We planned to design antenna which has the isolation as low as possible. The performance study of designed CLPD was carried out and measured isolation between the two mutually orthogonal LPD antennas was as low as ≈ – 43 dBm in the 65-95 MHz range. By making use of such CLPD antennas, two element interferometric polarimeter was build and successfully recorded polarized emissions in both Stokes I and V at 80 MHz. Note that such observations gives the information about the magnetic field strengths of the solar corona. Since the structure of the antenna is compact and rigid it can be used as a feed of dish antennas. This antenna also can be used to transmit/receive circularly polarized radio waves through the Earth's ionosphere, which in general washout the linear polarization at low frequencies. We intend to build broad band CLPD antenna so that different layers of the solar corona can be observed by building a interferometric polarimeter array. |