improvement in antenna performance for wban (wireless body area network)

various antenna parameters get affected whenever the antenna is operated near the body. what are some possible methods and technique to maintain or improve the performance of the antenna when operated near body. one thing which i am already considering is the separation between antenna and body(> 2d2/lambda). can you refer any paper or book which have the required information. i searched and got to know using "ebg plane" and "changing he shape of ground plane" are one of the few techniques which are used. can you tell some others as well or anything which can be helpful for me.