Tissue-Emulating Phantoms for In Vitro Experimentation at Radio Frequencies: Exploring characteristics, fabrication, and testing methods

This article provides one of the first comprehensive reviews of tissue-emulating phantoms available for the in vitro experimentation of radio-frequency (RF) antennas and other electromagnetic (EM) components. Diverse recipes and formulation approaches are available in the literature for such phantoms, but a holistic overview has yet to be reported. We review RF phantoms based on their textures (i.e., liquid, semisolid, and solid) and briefly discuss the use of readily available animal tissues for in vitro experimentation. For each phantom group, we present an overview of the various recipes and fabrication methods, specify the operating frequency range and tissue(s) they emulate, discuss the associated benefits and challenges, and summarize the wireless applications for which they have been employed to date. Further, we review various methods available in the literature to measure the electrical and thermal properties of RF phantoms as required to verify their tissue-emulating capabilities. This review creates a comprehensive resource for ongoing and future studies in the field and is intended to stimulate future research in the development of tissue-emulating phantoms and wireless RF components operating in, on, or near the body.