3-D Printed UWB Microwave Bodyscope for Biomedical Measurements

Abstract

In this letter a 3D printed compact UWB extended gap ridge horn (EGRH) antenna designed to be used for biological measurements of the human body is described. The operational frequency covers the microwave band of interest from 0.5 to 3.0 GHz (for a S11 under -7dB). The 3D printed EGRH antenna is dielectrically matched to the permittivity of the human body and because of its compactness it can be visualized as a general purpose microwave probe among the RF biomedical community. The probe has proven its capability as a pass-through propagation sensor for different parts of the human body and as a sensor detecting a 1 cm diameter object placed inside an artificial head phantom.

A 3-D-Printed High-Dielectric Materials-Filled Pyramidal Double-Ridged Horn Antenna for Abdominal Fat Measurement System

“…The antenna was further filled with the TiO2 mixture, and it was placed upside down and was well shaken in order to remove any remaining bubble gaps produced during the mixing and filling procedures, i.e., shown in Fig. 9 (c) [38]. With regard to the minor air gap, the vacuum chamber can be used during the mixing and filling procedures; however, the tiny air gaps can be ignored by the antenna system at the low-frequency range [18].…”

Resonance-Based Microwave Technique for Body Implant Sensing

“…The generic scenario, shown in Figure 1, consists of a bistatic geometry with the transmitting (Tx) and receiving (Rx) probe antennas represented by two dielectrically filled ridge horn antennas [6], and the ID is represented as a cylindrical object of length lID, located at a distance truer→TD and truer→RD from Tx and Rx probes respectively, all of it immersed into a dielectric medium of permittivity εr(r), supposed to be low frequency dispersive in the range of the ID resonance. Let PT=|aT|2 and PR=|bR|2 be the transmitted and received power into the Tx and Rx respectively, ZinID the impedance of the ID when fed into a virtual port, and ZLDID a virtual impedance loading the device’s port, that will model the operational state of the ID.…”

“…The technique described in the previous section for difference resonance sensing of IDs in a biological material is tested first through simulations conducted in CST Studio, and then through experimental measurements conducted with two ridged horn antennas [6], integrated in the measurement set up in Figure 3 and filled with a phantom mimicking the permittivity of biological tissue which values have been extracted from [16].…”

“…At simulation stage, the ridged horn antennas in [6] integrated on the hexagonal set up in Figure 3, have been modeled using CST Studio. The phantom material filling the horns and the set up has been defined according to [16] (εr′=57 and prefixtanδ=0.6 at 0.8 GHz).…”

“…UHF signals with a convenient dynamic range and appropriate antenna probes [6] are able to penetrate some tens of cm into the body and interact with those devices giving a scattering response that may be strongly influenced by the electrical resonance of the ID, therefore, allowing to monitor the state of the device. In order to obtain a proper diagnostic, it is necessary to have a clear signature of the scattered signal, as the one produced by a change of the resonant frequency.…”