Characterization of power amplifier for wideband hyperthermia treatment system

This paper presents a multichannel wideband hyperthermia treatment (HT) system, with focus on investigating the behavior of the wideband power amplifier (PA) module. Analysis is conducted using small signal, large signal, as well as two-tone characterization of the PA. The impact of nonlinearity of the PA is investigated. In particular, the study includes the effect of inter-modulation products (IMPs) in altering system efficiency to localize energy in the malignant tissues. Quantitative analysis is performed of the specific absorption rate (SAR) associated with IMPs. Initial results reveal the spilling out of energy associated with IMPs, which can lead to hot spots associated with excessive heating of healthy tissue. Solutions are discussed to minimize such spots and to optimize the performance of the proposed system.