# Diagram Correlation

In this section the user can calculate the correlation between two radiation pattern files. The pattern file format must be 3DE DIA File.

Select the DIA Files with the browse buttons and click on calculate.

The formula below is used to calculate the correlation parameters.

$$\begin{array}{l}{R}_{12}={\displaystyle \sum _{j=1}^{{N}_{\varphi}}{\displaystyle \sum _{i=1}^{{N}_{\theta}}\left(XPR\cdot E\theta {1}_{i,j}\cdot E\theta {2}_{{}_{i,j}}^{*}\cdot P{\theta}_{i}+E\varphi {1}_{i,j}\cdot E\varphi {2}_{{}_{i,j}}^{*}\cdot P{\varphi}_{j}\right)\cdot \mathrm{sin}{\theta}_{i}\cdot \Delta \theta \cdot \Delta \varphi}}\\ {\sigma}_{1}={\displaystyle \sum _{j=1}^{{N}_{\varphi}}{\displaystyle \sum _{i=1}^{{N}_{\theta}}\left(XPR\cdot E\theta {1}_{i,j}\cdot E\theta {1}_{{}_{i,j}}^{*}\cdot P{\theta}_{i}+E\varphi {1}_{i,j}\cdot E\varphi {1}_{{}_{i,j}}^{*}\cdot P{\varphi}_{j}\right)\cdot \mathrm{sin}{\theta}_{i}\cdot \Delta \theta \cdot \Delta \varphi}}\\ {\sigma}_{2}={\displaystyle \sum _{j=1}^{{N}_{\varphi}}{\displaystyle \sum _{i=1}^{{N}_{\theta}}\left(XPR\cdot E\theta {2}_{i,j}\cdot E\theta {2}_{{}_{i,j}}^{*}\cdot P{\theta}_{i}+E\varphi {2}_{i,j}\cdot E\varphi {2}_{{}_{i,j}}^{*}\cdot P{\varphi}_{j}\right)\cdot \mathrm{sin}{\theta}_{i}\cdot \Delta \theta \cdot \Delta \varphi}}\\ {\rho}_{\epsilon}=\frac{{\left|{R}_{12}\right|}^{2}}{{\sigma}_{1}\cdot {\sigma}_{2}}\end{array}$$