Greetings,

I'm currently developing a project which requires a specialized
antenna. The system consists in a sensor equipped suit that delivers
the data to a server. I'm having problems findind a suitable antenna
for the suit, since it requires to be integrated on the suit or in a
backpack (whip antennas are out of the question, since the suit can't
have any holes). The main problem is the human body effect and the
size constraints. Gain is also a major requirement since the range of
the operations will be 400 meters with line of sight.
(Server side: 10 dBm Tx Power and a 6 dB whip antenna, Suit side: -96
dBm sensibility- freq:433 MHz)

I've tried a patch antenna (similar to the one provided by linx
technologies) but it didn't perform well. I've also tried a small whip
antenna but the ground plane dimensions aren't suitable for
integrating this type of antennas in the backpack. I've also found a
dipole body worn antenna ( http://www.panorama.co.uk )., but I'm not
sure of its performance. Currently I'm trying to develop my own
antenna, which consists of a pcb small loop antenna. I'm asking for
sugestions and maybe antenna references for this type of application.

Thanks in advance.