Reducing Waves on the Body Surface in Near-Field Medical Diagnostics by a Dielectric Rod Antenna

The multipath interference caused by the waves traveling on the body surface is a factor that limits the detection accuracy of microwave-based biomedical diagnostic systems. The waves traveling along these paths do not carry information about the area of interest, which is inside the body and are more sensitive to the changes in the space close to the antennas. In this article for the first time, by placing a dielectric rod between the radiating element of the antenna and the body, the waves on the body surface are largely reduced while the antenna remains matched to the body. We design a dielectric rod antenna (DRA) by deriving a 2-D analytical solution of the wave propagation in a two-layer cylindrical structure. The design is extended to 3-D and further optimized using numerical simulations. It was shown that the addition of the dielectric rod enhances the field confinement by a factor of 2. The performance of the antenna, as verified by phantom measurements, shows that using the DRA increases the ratio of the transmission coefficient to power on the body surface to up to 24 dB and the antenna bandwidth is increased by 71% compared with the antenna without the dielectric rod.

Automated summary

This study introduces the use of a dielectric rod to reduce multipath interference on the body surface, improving the performance of microwave-based biomedical diagnostic systems. Through analytical and numerical methods, a dielectric rod antenna (DRA) is designed and optimized. Experimental results show that the addition of the dielectric rod significantly enhances the transmission coefficient and increases the antenna bandwidth.