Embedded Bare and Insulated Antennas

A quantitative study is made of the receiving qualities of antennas embedded a short distance below the surface of a dissipative material in terms of the complex transfer function and the properties of the antenna. Types of antennas investigated include bare and insulated dipoles as single elements and in two-element broadside arrays. The eccentrically insulated dipole is also studied. Actual voltages across practical load impedances are determined when the antennas are embedded specifically at depths of 0.1, 0.5, and 1.0 cm in hide or skin. Comparable results apply also to muscle. A similar but more involved analysis is required if quantitative account is to be taken of a subcutaneous layer of fat between the skin and muscle. It is shown that the frequency for maximum voltage across the load with skin as the material is 700 MHz and that resonant bare dipoles have a practical length. However, the higher directivity of insulated dipoles provides comparable voltages with the same antennas and loads at 3 GHz.