LEE- Biyomedikal Mühendisliği Lisansüstü Programı

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http://hdl.handle.net/11527/19218

Gözat

Yazar "Kaya, İlke" ile LEE- Biyomedikal Mühendisliği Lisansüstü Programı'a göz atma
  • Öge
    Sagittal posture analysis using wearable vivaldi antenna
    (Graduate School, 2024-06-11) Kaya, İlke ; Abdolsaheb Yılmaz, Tuba ; 504211405 ; Biomedical Engineering
    A healthy posture is one that allows the body to spend minimum energy. Poor posture can cause back pain, balance disorders, and breathing difficulties. In addition, unhealthy posture brings mental disorders. For this reason, correct evaluation of posture becomes important. There are many methods to evaluate posture. However, traditional methods produce qualitative results because they depend on observation. Although radiography is considered one of the most efficient posture assessment methods, it has negative health effects. This study aimed to evaluate sagittal posture using two identical Vivaldi antennas. The studies were carried out in a simulation environment and an experimental environment and compared. In simulation studies, one of the antennas was kept fixed in free-space while the other was positioned at certain angles. S parameters taken from different angles were compared. Additionally, muscle phantom has been added at certain frequencies. The muscle phantom was bent at certain angles along with the antennas and the S parameters were compared. In experimental studies, two antennas were positioned opposite each other, similar to simulation studies. While one antenna was kept fixed, the other was rotated at certain angles with the help of a goniometer to obtain S parameters. The studies were repeated with a female volunteer. The volunteer's T4 and T12 vertebreas were found manually and marked. Antenna directives are attached to the marked points, facing each other. With the help of an inclinometer application on the phone, the volunteer's posture angles were adjusted and S parameters were obtained. The measurements were repeated by adding foam between the antenna and the body. All experimental studies carried out in the laboratory were repeated with the antipodal Vivaldi antenna and the results were compared. Looking at the simulation results, there are differences between the S21 parameters taken from different degrees of the antennas. However, when the antennas are directly attached to the body, it is seen that the S21 responses decrease and the noise increases. In addition, due to the rigid structure of Vivaldi antennas, roundings are seen on the body in different postures, creating unwanted gaps between the antenna and the body. These gaps affect the individual performance of the antennas. When looking at the S21 parameters of the Vivaldi antenna after the Gaussian filter applied to the S parameters, it can be seen that 4 out of 5 angles can be separated. This does not apply to the antipodal Vivaldi antenna. It was observed that when foam was added between the body and the antenna, there was still noise, but the individual antenna performances were more stable, and the gaps between the body and the antenna could be kept more stable. In the study conducted with Vivaldi antennas, it was seen that all 5 angles could be easily separated when the Gaussian filter was applied. Although it is seen that 5 angles can be separated with antipodal Vivaldi antennas, the differences in the Vivaldi antenna are more obvious.