The growing integration of wireless communication in biomedical applications has led to increased interest in compact, efficient, and biocompatible antenna designs. This paper presents an investigation into conventional patch antenna structures tailored for use in body-centric biomedical systems operating at the 5.8 GHz ISM band. Patch antennas are well-suited for these applications due to their planar structure, ease of fabrication, and low-profile characteristics, making them ideal for both wearable and implantable devices. This study evaluates three common patch geometries rectangular, circular, and triangular fabricated on a flexible Kapton substrate with a thickness of 1.6 mm, chosen for its mechanical durability and biocompatibility. Using CST Microwave Studio and FEKO, Both are full-wave electromagnetic simulation environments, with one based on the Finite Integration Technique (FIT) and the other primarily employing the Method of Moments (MoM), each design is analyzed based on key performance indicators: return loss (S11), impedance bandwidth, gain, radiation patterns, and Specific Absorption Rate (SAR) where applicable. The results show that all geometries achieve return loss values better than −10 dB and offer sufficient bandwidth for reliable biomedical telemetry. Additionally, SAR evaluations confirm compliance with international safety standards (IEEE and ICNIRP), ensuring safe operation near or on the human body.