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.
Step 2: Make a template.
Using your marker, outline the painted areas on the tape. You don't have to be exact, just get the general pattern traced onto the tape.
Lay your foil tape flat, with the shiny side up. It will help to secure the edges with transparent tape so the foil tape won't slide around while you are cutting it.
Carefully remove the transparent tape from the back cover. You want to keep the pattern intact, so try not to tear the tape when you peel it off.
Stick the transparent tape, along with the outlined patterns, onto the foil tape. Make sure the pattern is flat, with no wrinkles.
Step 3: Cut the foil.
You don't have to perfectly match the pattern painted on the back cover. Close is good enough.
Once your pattern is cut from the foil tape, remove the transparent tape you used as a template. Your hobby knife can be used to lift an edge and peel it off. This is the most difficult part of the process, because the foil tape will peel away from the backing. Just stick it back down and keep peeling the transparent tape.
Step 4: Apply the foil.
Step 5: Finishing.
The finished product will not look exactly like the original, but it will work just as good. Maybe better. When I first tried the aftermarket back cover I could barely get a signal in areas where the original back cover gave me four bars of 4G reception. My messy foil job now equals the reception of the original back cover. An unexpected bonus is that the phone seems to use less power with this modified back cover. The reason I purchased the extended life battery (3800 mAh) was because the original battery (1620 mAh) would die about halfway through my work day. I can now use the original battery with the foil enhanced back cover and get through an entire work day. The extended life battery will now last over 24 hours.