A piece of wire at least 4 inches long (this can be a pipe cleaner, jewelry wire... anything you like)
2 Lucky red envelopes (any type of paper is a good substitute. such as wrapping paper or origami paper)
Red envelopes can be bought in places like Chinatown and are quite cheep (usually a pack of 20 for a dollar)
If you choose to use some form of paper, use either a square (3 x 3 inches) or a rectangle (2.5 x 3.5 inches).
The longer the wire is, the longer the antennas will be so it's up to you, but better too long than too short (you can always cut it later).