The material used is a thick copper wire. Take copper wire about 20cm and bend at 5cm. make 5 turns of the wire on a screw or any thing that make the winding looks good. Ok then stretch the turns about 3mm wide. now make few turns on the other end.Place it on your EVDO antenna as shown in the figure. see the difference in Signal strength.
You can use this trick to get good signal in indoor from any mobile broadband networks like BSNL, MTS MBlaze etc.