this is for holding javascript data
Demian Arancibia edited untitled.tex
almost 9 years ago
Commit id: 7c3377b4b1109661ed90fca419315b526eea65bb
deletions | additions
diff --git a/untitled.tex b/untitled.tex
index 9c36f4d..d7bb445 100644
--- a/untitled.tex
+++ b/untitled.tex
...
This section aims to include all relevant design parameters that might influence the selected performance objectives in section 4.
\subsection{Antenna Aspects}
\subsubsection{Collecting Area}
\subsubsection{Temperature}
\subsubsection{Efficiency}
An overall antenna efficiency measure is the System Equivalent Flux Density, $SEFD$, defined as the flux density of a source that would deliver the same amount of power (see \cite{sensitivity2}):
\begin{equation}\label{eq:system_equivalent_flux_density}
SEFD = {\frac{T_{sys}}{\frac{\eta_a A}{2k_B}}}
\end{equation}
in units of Janskys where $T_{sys}$ is the system temperature including contributions from receiver noise, feed losses, spillover, atmospheric emission, galactic background and cosmic background, $k_B = 1.380 \times 10^{-23}$ Joule $K^{-1}$ is the Boltzmann constant, $A$ is the antenna collecting area (thus we could also write $\pi \cdot D^2$), and $\eta_a$ is the antenna efficiency with $\eta_a = \eta_{\text{surface efficiency}} \cdot \eta_{\text{aperture blockage}} \cdot \eta_{\text{feed spillover efficiency}} \cdot \eta_{\text{illumination taper efficiency}}$ (see \cite{antenna}).
\subsection{Pad Aspects}
\subsubsection{Quantity}
\subsubsection{Position}
...
\section{Objectives}
This section aims to include array performance objectives that might be influenced by design choices.
\subsection{Minimize Brightness Sensitivity Limit}
An overall measure of performance is the System Equivalent Flux Density, $SEFD$, defined as the flux density of a source that would deliver the same amount of power (see \cite{sensitivity2}):
\begin{equation}\label{eq:system_equivalent_flux_density}
SEFD = {\frac{T_{sys}}{\frac{\eta_a A}{2k_B}}}
\end{equation}
in units of Janskys where $T_{sys}$ is the system temperature including contributions from receiver noise, feed losses, spillover, atmospheric emission, galactic background and cosmic background, $k_B = 1.380 \times 10^{-23}$ Joule $K^{-1}$ is the Boltzmann constant, $A$ is the antenna collecting area (thus we could also write $\pi \cdot D^2$), and $\eta_a$ is the antenna efficiency with $\eta_a = \eta_{\text{surface efficiency}} \cdot \eta_{\text{aperture blockage}} \cdot \eta_{\text{feed spillover efficiency}} \cdot \eta_{\text{illumination taper efficiency}}$ (see \cite{antenna}).
If we assume N apertures with the same $SEFD$, observing the same bandwidth $\Delta\nu$, during the same integration time $t_{int}$, then the weak-source limit in the sensitivity of a synthesis image of a single polarization is
\begin{equation}\label{eq:sens}
\Delta I_m = {\frac{1}{\eta_s }}{\frac{SEFD}{\sqrt{(N(N-1) \Delta \nu t_{int}}}}
...