This paper presents a methodology for the preparation of a phantom arm model to be used for evaluating the performance of intra-body communications specifically and body area networks (BANs) in general. This paper describes the basic procedures for preparing tissue mimicking materials for each of the five basic tissue layers: Skin, fat, muscle, cortical bone, and bone marrow. Matching materials for mimicking the dielectric properties of each tissue, with a mimic accuracy of at least 90%, were finally selected, after carrying out experimental testing on more than 50 different test samples that were prepared using different techniques and mixture concentrations. The final arm phantom is then fabricated and tested. The experimental results, mainly the gain/attenuation profile, are then displayed and compared with those obtained from the real subjects with similar experimental setup conditions showing very close to perfect match, proving the high accuracy of the fabricated arm phantom model in mimicking the dielectric behavior of real body parts, over the frequency range of interests for intra-body communications (100 kHz to 100 MHz). To date, this is the first accurate physical five-layer phantom arm model fabricated for intra-body communication applications covering this frequency range and with such high accuracy.