Radio frequency circuits design techniques

LT Spice is a free powerful simulator that is quite intuitive, less complex to use than Cadence. It's a good alternative to get quick hints on simpler circuits. 
Install the SW using the link provided. Then copy the source files provided below at the location indicated when you do open file. Open the file from the tool and press > to run the sim. Then go to View->visible trace to select what you want to plot!