Which frequency range?

Maybe its just called an tenna but in reality its a microwave/RF based surface sensor?Do check beforehand what already exists there via IEEE explore

Hi

Placing antenna close to the body increase some loses because of the water inside tissue. Also It changes the antenna radiation pattern because it is placed near an object. Here is my papar about body match antenna. I wrote it in a very simple way just about 2 pages paper:

https://drive.google.com/file/d/14Hp7m_iJ1I7r88D4QXiVhsD0lZ9tsQPI/view?usp=sharing

An antenna that is matched to radiate in air will be mismatched to radiate into the body. A body matched antenna has been matched so that it gives a good match when placed against or in the body. That means that all the power should come out of the antenna and you won't lose sensitivity because of wasted power reflected back from the antenna. There will be lots of loss of sensitivity anyway because of the high loss for propagation in the body.

The permittivity of the substrate does not affect the far-field pattern. If the antenna is matched to radiate into the dielectric it is placed in, all the power will be radiated and the far-field pattern depends only on that dielectric and on the size and shape of the antenna aperture.

Body matched antenna means at a particular or band of frequency, field patterns (modes) of the antenna match to that of body.

Yes, the permittivity of the substrate is related to the far field pattern of the antenna. It is because the dominant or types of mode of radiation is a function of the coupling effect of the field of both the substrate and the radiator. The surface wave depends upon both the thickness and permittivity of the dielectric. Further, resonating length of the antenna is a function of frequency and dielectric constant of the substrate due to the presence of fringing field components.

For your first question, I think that a “body-matched antenna” is an antenna that is designed to have the required performance while located on or inside the human body.

For your second question, I think that the substrate of the antenna material will affect both near and far fields when the electrical parameters of the substrate are differing from required by design. If you were talking about the human body as a substrate, it is a different case because this “substrate” is a multilayer structure. There will be multiple reflections from each border between layers and it must be accounted for. Actually, it is something like having several radiating RF energy sources, each with its own power and phase. All these powers and phases should be calculated or simulated and then accounted for to get the final results.