A dual-band slotted square ring patch antenna for local hyperthermia applications

Abstract

In this paper, a simple dual-band compact slotted square ring patch antenna has been used as hyperthermia applicators in the treatment of cancerous human cells at superficial depths inside the body. The proposed antenna has the advantages of dual-band (f1 = 434 MHz and f2 = 915 MHz) operation and more compact size (124 × 124 mm2) than the current state-of-the-art designs without significant frequency detuning or impedance mismatch which makes it a more suitable choice for local hyperthermia. The proposed antenna provides a suitable specific absorption rate (SAR) penetration profile and shows a good resonance at two designed frequencies. We have optimized the structure so that the SAR level performed by the structure is sufficiently enough so as to meet the IEEE standard requirements for medical applications including hyperthermia. We have simulated and measured the structure with a low-profile substrate (i.e., FR4 substrate with εr = 4.4 and thickness of 1.6 mm). During the design process, the simplified planar tri-layered tissue model interfaced with a water bolus was used to incorporate the main electrical effects on the antenna. The results validate the proposed antenna design.