90 The 3 rd International Seminar on Science and Technology August 3 rd 2017, Postgraduate Program Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia Miniaturization of Microwave Biosensor for Non-invasive Measurements of Materials and Biological Tissues Satria Hardinata 1 , Frédérique Deshours 1 , Georges Alquié 1 , Hamid Kokabi 1 , Fabien Koskas 1 AbstractNon-invasive planar complementary split ring resonators (CSRRs) coupled to microstrip line for measuring the dielectric properties of materials and biological tissues are presented in this paper. The expectations of health professionals are increasingly turning to less invasive surgical procedures and treatments. In particular, the monitoring of vital parameters (sweat, water in the lungs, etc.) or the evolution of certain pathologies, such as cancer cells, could be observed regularly if suitable devices were developed and could especially replace traditional invasive method. Appropriate miniaturized RF or microwave devices could be an alternative for some medical diagnostic applications. These devices would make it possible to determine the dielectric characteristics of biological tissues, which represent their real pathological states. It would thus be possible, by means of dielectric contrast measurements, to follow the evolution of pathology as well as the vital parameters of a patient. The objective of this research is to produce a prototype biosensor that is suitable for measurements on biological tissues and that can be miniaturized to enhance its spatial sensitivity. This work focuses on the design, electromagnetic simulations and characterization of a new miniaturized biosensors operating between 1 and 10 GHz. The ex-vivo experimental results will be shown by measuring the S-parameters of various materials and animal biological tissues. The extraction of the dielectric parameters of these samples is obtained by the measurements of materials. KeywordsMicrowave Biosensor, Non-Invasive Measurement, Complex Permittivity, Ring Resonator, S- Parameters, Resonant Frequency. I. INTRODUCTION 1 Knowledge of the dielectric properties of biological tissues at microwave frequencies is very important for several reasons. It is linked to the development of wireless communications. Indeed, the fact that man is increasingly exposed to multiple electromagnetic sources in outdoor (LTE, GPS, ...) and indoor (WiFi, Bluetooth, ...) can be a source of physiological discomforts and even diseases. It is therefore important to know the interactions between the electromagnetic field and the human body. Another reason is the development of wireless embedded microwave sensors on the human body to perform "human 1 Satria Hardinata, Frédérique Deshours, Georges Alquié, Hamid Kokabi, and Fabien Koskas are with Sorbonne Universités, UPMC Univ Paris 06, UR2, L2E, F-75005, Paris, France. E-mail: satria.hardinata@etu.upmc.fr; frederique.deshours@upmc.fr; georges.alquié@upmc.fr; hamid.kokabi@upmc.fr; fabien.kokas@upmc.fr. monitoring", i.e. to measure vital human parameters such as post-operative follow-up or physical activity. Complex permittivity is one of the most important parameters of biological tissues in RF and microwave engineering. The response of the microwave planar circuit depends strongly on the dielectric properties of the material used as the substrate. The measurements of complex permittivity have also been explored in the field of health. Several microwave characterization techniques have been developed for the measurement of the permittivity of Materials Under Test (MUT). These methods can be classified into three categories: free space characterization technique, transmission line technique (waveguides, coaxial cable) for which the insertion of the MUT modifies the propagation and the so-called resonant methods based on a resonator coupled by transmission lines. Among these characterization techniques, the most accurate method is the resonant method The variation of the resonance frequency and the quality factor of the resonator containing the material under test gives information on the dielectric properties of the material. Recently, devices coupling a planar ring resonator to microstrip lines have been proposed to determine the dielectric constant of various materials. The planar technology makes it possible to design two types of ring resonators, either in distributed elements or in lumped elements which allow to obtain structures of reduced size. The design of microwave planar sensors provides many advantages for medical instrumentation such as portability, ability to perform non-invasive, in-depth and non-ionizing measurements. These resonators were originally used for the characterization of low-loss materials for micro- electrics. The applications for medical agro-food of these resonators are much more recent. The objective of this research is to produce a miniaturized microwave sensor prototype that is suitable for the dielectric characterization of biological tissues between 1 and 10 GHz. The principle concept of the resonators is firstly presented in chapter II, then followed by the design of the two sensors developed on a low cost substrate (substrate FR4) in chapter III. Then, the simulation and optimization process over HFSS software is shown in chapter IV. The measurements of these unloaded and loaded sensors will be presented in chapter V as well as the extraction of the dielectric parameters of the materials tested. We conclude and give a perspective for this future research in terms of applications in vascular surgery.