The RF Design and Analysis app is included in RF Toolbox. You can find it, along with the rest of the apps for your installed products, by clicking the Apps tab in the MATLAB Toolstrip.
The RF Design and Analysis app creates and analyzes RF circuits. Components and networks can be created in the app, imported from the MATLAB workspace, or from RF data files. You can set parameters, analyze a circuit in the frequency domain, and display its S-parameters in both tabular and graphical form using X-Y plots, polar plots, and Smith charts.
Apps are interactive MATLAB programs you can use without writing any code. Most toolboxes come with apps, and you can download more for free from the MATLAB File Exchange. You can also package and share your own apps.