When we are working with PCB fabrication systems, "Gerber" files are widely used as the input to the fabrication device from the CAD drawing. So, It is very useful to have a Gerber viewer on your mobile phone. Recenlty, I had to work with some microstrip designs and I had to check and compare the finished product at the fabrication facility. So, I found this free Gerber viewer at "Google Play" and you can find this at here. Here are some screeshots from this application showing a microstrip patch antenna in my mobile phone.