OK, got the idea.
Antennas measure the distance your hand is from the antenna, not where you touch them. Google [i]ribbon controller[/i].
Alternatively, if you really want an antenna, here's a suggestion. Take a theremin with a plate antenna, such as the Art Harrison Minimum I notice you're asking about on another thread (the answer is, it's a major mod - better to start with a 2 antenna design) and attach a long, non-conductive pole (a rigid plastic cylinder) of the desired length to it, sticking straight up from the centre of the plate. To make it wearable, attach a belt to both sides of the enclosure and wear it as one might wear a sporran, with the pole projecting upwards at a convenient angle for sliding one's hand along the length of it to play the instrument.
I look forward to seeing it demonstrated on youTube.