This paper studies implant communication in the Wireless Body Area Networks (WBAN) and presents a novel analytical electromagnetic model for galvanically coupled Intra-body Communication (IBC) for implants. The model is versatile to be applied to any part of the human body as it is based on multilayered ellipsoidal geometry. Experimental validation and Finite Difference Time Domain (FDTD) analysis show that the model is highly accurate for implant-to-implant and implant-to-surface communication. With high degree of miniaturizability, path loss at the surface of the skin is found to around 35 dB; that shows Galvanically coupled IBC implants are a good alternative compared to existing wireless implants.