# Monitoring of Surgically Treated Upper Arm Fracture by Implanted Antenna at 402 MHz
###### Abstract
With the advances in wireless communication in bioengineering, antenna technology has become progressively more important in applications of healthcare and remote patient monitoring systems. Healthcare monitoring is based on body-centric wireless communications (BSWCs) and includes wearable and implantable monitoring systems [3]. When designing an antenna for the implanted device, the electrical properties of the surrounding biological tissues must be considered. The quality of the implanted antenna is characterized by the amount of power transmitted outside the body [4; 5; 6; 7]. Implanted medical devices have become essential in a wide range of medical applications, such as intracranial pressure monitoring, continuous blood pressure measurements, glucose monitoring, and heartbeat monitoring and control [8; 9; 10]. The medical implanted device includes electronics, sensors, battery, and antenna. All these components must be fit into housing that has an ergonomic shape, which requires dense packaging and good integration of the components. Miniaturization techniques have to be considered in the design and manufacturing procedures of the antenna as it occupies most of the implanted device's volume. Early studies in antenna miniaturization show that the efficiency and impedance of bandwidth are reduced as a result of reducing the whole size of the antenna. Many recent investigations have been carried out to reduce the overall size of different types of antennas while keeping satisfactory matching properties and acceptable bandwidth. These techniques mainly depend on changing the physical and electrical properties of the antenna. Planar antennas can be miniaturized by using high permittivity substrate, reactive components, and shorting pins. Topology-based techniques design a larger radiating structure by the efficient use of the available volume or space, such as meander and fractal antennas [11]. More recently, metamaterials are composite media that can be engineered to exhibit unique electromagnetic properties. It is worth mentioning that these metamaterials are artificial structures composed of arrangements of periodic or non-periodic homogeneous metal structures of a size much smaller than the guided wavelength on the surface of dielectric material. The permittivity and permeability of the metamaterial depends on this created structure. Due to the unique electromagnetic properties that are not available in natural materials, antennas with novel characteristics, enhanced performance, and a compact size can be designed [12; 13]. This study proposes a solution by implanted antenna for the monitoring of humerus fracture healing, which should be healed within 6 weeks. The traditional monitoring is usually processed by repeated X-ray images and visits to clinical laboratories or hospitals, which is difficult, especially for elderly patients. We aim to avoid this difficulty and comfort the patient during the treatment period. This fracture is treated surgically, and the proposed monitoring technique is used by implanting a half-wave dipole antenna between the fractured shaft and the muscle tissue within the human body during the surgical operation. The change in the transmission of APD in cases of recovered and fractured bone is used for monitoring the healing status. The operating frequency was selected at 402 MHz to save a number of electromagnetic (EM) losses within the human tissues as the losses reduce at low frequencies. Two different topologies of the half-wave dipole antenna were tested. A proposed model for the post-surgical treated human humerus was presented. This model includes a metal fixation plate to hold the fractured bone in its place and a medical splint layer to hold and save the upper arm during the healing period. Towards this end, different positions of the fracture were considered. The monitoring technique was simulated by CST Microwave studio for the common types of fractures and showed good results by planar and wire half-wave dipole antennas.