In this study, the numerical analysis and designs of microstrip implant antenna structures for MICS-band (Medical Implant Communication Systems band; 402-405 MHz) and ISM-band (Industrial, Scientific and Medical band; 2.4-2.48 GHz) medical communication applications are evaluated and simulation and measurement results of the proposed dual-band implant antenna are included. Within the scope of the study, first of all, general evaluations about operating bands allocated for medical applications, implant antennas with different radiation geometries, and specific absorption rate (SAR) were made and the features that an implant antenna should have, were presented. By comparing the real tissue and skin-mimicking gel methods used to measure microstrip implant antennas in the laboratory environment, the pros and cons were also discussed. Finally, modeling approaches, numerical analysis and measurement results of an exemplary MICS/ISM-band implant antenna were given. Simulations have been carried out with the CST-MWS, which is based on the finite integral method in time domain. Measurements of the implant antenna, fabricated using RO3210 (epsilon(r)=10.2) dielectric material, in MICS and ISM band skin mimicking liquids proposed in the literature were performed. It has been observed that the measurement and simulation results are fairly compatible, except for some frequency shifts and level differences due to fabrication and measurement tolerances. The measured implant antenna with fractional bandwidths of 77% and 15% respectively in MICS and ISM bands, compact size of 10.6x10x1.27 mm(3) and low SAR values compatible with international standards, is a good alternative that can be used in dual-band implant communication applications.