In this paper, an implantable microstrip antenna design is introduced to cover the Medical Implant Communications Service (MICS, 402-405 MHz) band for biomedical telemetry systems. The radiating layer of the antenna comprises two concentric square split-ring elements and a metallic pad placed between them. A shorting pin is also used for miniaturization purposes, directly connecting the outer ring element to the ground plane. It is numerically demonstrated that the proposed antenna offers approximately 7% impedance bandwidth and gains of 1.9 dBi at the designated frequency band. In addition, effects of some critical design parameters on the antenna performance are numerically examined in the paper, noting that the full-wave analysis of the implant antenna is carried out using CST Microwave Studio.