This work presents the thorough hybrid (numerical and experimental) development of a miniaturized microwave antenna, to be better matched to the permittivity of the human skin. This would allow the abdominal fat to be measured more accurately, based on the employed reflection methods with minimal mismatches. This objective was achieved by designing the pyramidal horn antenna that was modeled based on the proposed and manufactured ceramic composite material. Moreover, by using the developed composite of barium titanate and titanium oxide, the ratio of the two could be precisely adjusted, so that the permittivity was a reasonable match to that of the skin. This step was validated by the open-ended probe method. This framework can be instrumental in a range of microwave biomedical applications, which aim to realize the body-centric systems.