  The Next Generation Arecibo Telescope (NGAT) was a concept presented in a
white paper Roshi et al. (2021) developed by members of the Arecibo staff and
user community immediately after the collapse of the 305 m legacy telescope. A
phased array of small parabolic antennas placed on a tiltable plate-like
structure forms the basis of the NGAT concept. The phased array would function
both as a transmitter and as a receiver. This envisioned state of the art
instrument would offer capabilities for three research fields, viz. radio
astronomy, planetary and space & atmospheric sciences. The proposed structure
could be a single plate or a set of closely spaced segments, and in either case
it would have an equivalent collecting area of a parabolic dish of size 300 m.
In this study we investigate the feasibility of realizing the structure. Our
analysis shows that, although a single structure ~300 m in size is achievable,
a scientifically competitive instrument 130 to 175 m in size can be developed
in a more cost effective manner. We then present an antenna configuration
consisting of one hundred and two 13 m diameter dishes. The diameter of an
equivalent collecting area single dish would be ~130 m, and the size of the
structure would be ~146 m. The weight of the structure is estimated to be 4300
tons which would be 53% of the weight of the Green Bank Telescope. We refer to
this configuration as NGAT-130. We present the performance of the NGAT-130 and
show that it surpasses all other radar and single dish facilities. Finally, we
briefly discuss its competitiveness for radio astronomy, planetary and space &
atmospheric science applications.
