This work represents a circularly polarized implantable patch antenna operating at the ISM band (2.4–2.48 GHz) for biomedical applications. The presented patch antenna has a compact volume of 50 mm3 i.e., 10 × 10 × 0.5 mm3. All the Simulations have been carried out within homogeneous skin phantom and head scalp phantom. Miniaturization of antenna and enhancement of bandwidth is achieved by using various techniques described in this work. The designed patch antenna has wide axial ratio bandwidth of 20.08 and 15.44% inside scalp phantom and homogeneous skin phantom, respectively. Obtained impedance bandwidths are 56.79 and 49.75% inside scalp phantom and homogeneous skin phantom, respectively. At 2.45 GHz, obtained peak gains are −25.18 and −28.12 dB, respectively. The proposed antenna is enclosed in a biocompatible material to avoid direct contact with the human tissue. For patient safety concerns, simulated maximum specific absorption ratio values are also investigated and are under the limits of the IEEE standard. The allowable input power is also calculated in this work. Link budget analysis is used in this work to determine the far-field communication range of the designed antenna.