Numerical simulation of a full-scale human body model on radiation characteristics of rectangular loop antennas at the wrist position for watch-type radiophone applications is presented. The loop antenna with a superquadric curve is used to model the rectangular loop antenna with rounded corners. The loop antenna may have different position and orientation relative to the wrist. A 3-D realistically shaped man model with homogeneous muscle phantom is constructed. The coupled integral equation (CIE's) and the method of moments (MoM) are employed for numerical simulation. Numerical results of detail antenna radiation characteristics in free space and mounted on the wrist of the body with different position and orientation at 900 MHz and 1800 are presented and discussed.