Research Article Computational Modeling of the Bent Antenna in an On-Body Mode Using the Cylindrical TLM Approach Jugoslav J. Jokovi´ c , Tijana Z. Dimitrijevi´ c , Aleksandar S. Atanaskovi´ c , and Nebojˇ sa S. Donˇ cov Faculty of Electronic Engineering, University of Niˇ s, Aleksandra Medvedeva 14, 18 000 Niˇ s, Serbia Correspondence should be addressed to Jugoslav J. Jokovi´ c; jugoslav.jokovic@elfak.ni.ac.rs Received 2 March 2022; Accepted 26 July 2022; Published 6 September 2022 Academic Editor: Mohammad Yaghoub Abdollahzadeh Jamalabadi Copyright © 2022 Jugoslav J. Jokovi´ c et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. is paper presents the suitability and computational features of the cylindrical TLM approach, when it is used as an accurate and efficient alternative for the analysis of the bending effect on performances of the antenna operating in an on-body mode. A design goal was to create the model of the rectangular patch antenna wrapped around the part of a cylinder, which can be used to represent a human body (torso, leg, or arm) and simultaneously to model dielectric properties of muscle tissue. Moreover, the paper illustrates problems in terms of accuracy and limitations when the antenna deformation is modelled by using numerical methods based on the cubic mesh. e advantages of the cylindrical TLM method over the rectangular TLM approach have been emphasized through an analysis of how the bending affects the resonant frequency of the antenna. 1. Introduction Biomedical engineering (BME) has been a hot research topic in the past few decades. A number of problem-solving techniques of engineering have already found useful ap- plications in biology and medicine, leading to many ad- vanced BME devices [1, 2]. ese devices can contribute to better quality of human health and care when used in di- agnostics, treatment, or studies of treatment and recovery. Currently, there is a wide range of BME products of various complexities and applications, and they can be in general classified as either diagnostic or treatment devices. One of the key components in many BME devices is an antenna, which can be placed near to, inside, or on a human body [3]. For devices employed for diagnosis or treatment, one or more antennas are usually placed near to and around the human body, e.g., for microwave resonant imaging (MRI) and microwave imaging (MI) diagnosis [2, 4] or for hyperthermia treatment [5]. e antenna can also be implanted into the human body either directly or through a capsule travelling through the body [6] or it can be posi- tioned on the human body, e.g., placed on a garment or mounted directly over the torso [3] in order to form a bio- wireless sensing and communication system for on-body or off-body transmission links [7]. e design of majority of these antennas faces with physical constraints such as size, power, and safety limitations, which can overall affect the efficiency of the BME device itself. Focusing on antennas deployed on the different parts on the human body (so-called on-body and wearable antennas), either embedded into human skin or clothing (e.g., textile antennas), other challenges in their design exist, such as the close proximity of the human body leading to antenna detuning, disturbing the antenna impedance and reducing the antenna gain and efficiency [8, 9]. Also, variations of human body posture and motions in everyday activities are causing a number of deformations such as stretching, twisting, bending, and crumpling or more often a combi- nation of two or more of these deformations. As a result of deformed antenna geometry, many antenna parameters change like shifting resonant frequency, changing gain, radiation pattern, and polarization [9]. In literature, the impact of cylindrical bending on mostly printed textile antenna performances has been dominantly Hindawi Mathematical Problems in Engineering Volume 2022, Article ID 8486740, 7 pages https://doi.org/10.1155/2022/8486740