After buying an aftermarket extended battery for my HTC Rezound cell phone I noticed that my reception was terrible. The battery was thicker than the original battery and came with a new back cover. I discovered that the circuits and contacts in the new back cover were just thinly applied copper colored paint. I inspected the original HTC back cover and saw that it also had conductive paint, but much thicker. This is how I improved on the cheap aftermarket back cover, resulting in greatly improved reception. The entire process took about 20 minutes.
Step 1: Materials
About 4" of foil tape. I used aluminum because it was in my shop, but I suspect copper would be better.
A hobby or craft knife.
(not shown) a fine tip pen or marker. I used a Sharpie.
A pencil with an eraser.