Design and analysis of a conformal patch antenna for a wearable breast hyperthermia treatment system

Abstract

To overcome the limitations of currently available clinical hyperthermia systems which are based on rigid waveguide antennas, a wearable microwave hyperthermia system is presented. A light wearable system can improve patient comfort and be located in close proximity to the breast, thereby enhancing energy deposition and reducing power requirements. The objective of this work was to design and assess the feasibility of a conformal patch antenna element of an array system to be integrated into a wearable hyperthermia bra. The feasibility of implementing antennas with silver printed ink technology on flexible substrates was evaluated. A coupled electromagnetic-bioheat transfer solver and a hemispheric heterogeneous numerical breast phantom were used to design and optimize a 915 MHz patch antenna. The optimization goals were device miniaturization, operating bandwidth, enhanced energy deposition pattern in targets, and reduced Efield back radiation. The antenna performance was evaluated for devices incorporating a hemispheric conformal groundplane and a rectangular groundplane configuration. Simulated results indicated a stable -10 dB return loss bandwidth of 88 MHz for both the conformal and rectangular groundplane configurations. Considering applied power levels restricted to 15 W, treatment volumes (T>41° C) and depth from the skin surface were 11.32 cm 3 and 27.94 mm, respectively, for the conformal groundplane configuration, and 2.79 cm 3 and 19.72 mm, respectively, for the rectangular groundplane configuration. E-field back-radiation reduced by 85.06% for the conformal groundplane compared to the rectangular groundplane configuration. A prototype antenna with rectangular groundplane was fabricatd and experimentally evaluated. The groundplane was created by printing silver ink (Metalon JS-B25P) on polyethylene terephthalate (PET) film surface. Experiments revealed stable antenna performance for power levels up to 15.3 W. In conclusion, the proposed patch antenna with conformal groundplane and prined ink technology shows promising performance to be integrated in a clinical array system.

Design of a compact antenna with flared groundplane for a wearable breast hyperthermia system

“…Future studies will incorporate detailed anatomical features as informed by patient-specific images to illustrate potential clinical applications of the proposed design. Ongoing studies are investigating potential for implementing conformal patch antenna designs with conductive-ink printers on thin, flexible substrates to facilitate integration within hyperthermia garments [51]. While this study focused on the performance of the antenna with a single radiating element, future work investigating how multiple antennas can be integrated within the system (i.e.…”