Speaker
Mr
Iheanetu kelachukwu
(Rhodes University)
Description
Accurate modeling of the antenna primary beam response is important in many wireless applications, but is particularly crucial for the next generation of radio telescopes, since they offer unprecedented levels of sensitivity, at which even the most subtle instrumental effects become important. Electromagnetic and optical simulations which has often been used to model it can only provide a first-order approximation; real-life primary beam patterns differ from this due to various subtle effects such as mechanical deformation, etc. Ideally, a parameterized model is required, so that these effects can be calibrated for in a closed-loop manner. Instances of actual patterns can be measured through a process known as holography, but this is subject to noise, radio frequency interference, and other measurement effects. We present a set of holography measurements for a subset of dishes of the Karl G. Jansky Very Large Array telescope (JVLA US), and discuss the problem of using these measurements to derive parameterized models of the primary beam. We show that the beams exhibit complicated frequency behavior due to standing waves in the optics, particularly in the polarization terms. We discuss the potential application of a technique called characteristic basis function patterns (CBFPs) to these data, which offers the possibility of deriving a parameterized model that can accommodate subtle variations in the beam pattern.
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
No
Apply to be<br> considered for a student <br> award (Yes / No)?
Yes
Main supervisor (name and email)<br>and his / her institution
Oleg Smirnov, osmirnov@gmail.com, Rhodes University
Julien Girard, jgirard@ska.ac.za, AIM/CEA, Université Paris Diderot (Paris 7)
Level for award<br> (Hons, MSc, <br> PhD, N/A)?
PhD
Primary author
Mr
Iheanetu kelachukwu
(Rhodes University)
