A systematic, extensive and in-depth study of channel characteristics for both static and dynamic human body model is reported in this thesis. The work involves design, fabrication and testing of various printed and dielectric antennas with very high gain for the proposed applications. A significant part of the thesis deals with human model which features the critical body segments such as head, shoulder, torso, upper arm, lower arm, thighs and calf for the study of double arm swing activity. Two cross-slot antennas (CSA) are designed and fabricated, for investigation of the double arm swing activity using the newly introduced twelve cylinder body model. The same CSA is used for creeping wave analysis on cylindrical single layered phantom. Simulations are done in CST Microwave studio suite and experiments are carried out using container filled with distilled water as phantom. The work reported in the thesis are published in very high quality journals such as IEEE Antennas and Wireless Propagation Letters, Wiley RFMICAE, Journal of Electronics Materials and so on.