EN - TMI - Curso Engenheiros Navais – ramo Armas e Electrónica
Permanent URI for this collection
Browse
Browsing EN - TMI - Curso Engenheiros Navais – ramo Armas e Electrónica by Subject "Antena wearable"
Now showing 1 - 1 of 1
Results Per Page
Sort Options
- Design and Study of a Wearable Antenna for Aquatic CommunicationPublication . Candeias, Catarina Calvão; Felício, João Monteiro; Damas, Bruno ; Fernandes, Carlos A.Efficient communication in aquatic environments remains a significant engineering challenge, due to the high permittivity and conductivity of water, which cause severe attenuation of electromagnetic waves. This dissertation explores a practical solution: the design and simulation of a wearable antenna integrated into a swimmer’s suit, aiming to enable reliable short-range, of a few centimeters, communication between the user and an external receiver. Such a system is particularly relevant in scenarios where mobility, comfort and operational efficiency are essential, including aquatic sports, search-and-rescue missions and military operations. The antenna was designed to operate at 2.45 GHz, a frequency within the Industrial, Scientific and Medical (ISM) band, due to its compatibility with low-power wireless protocols such as Bluetooth. A theoretical analysis of electromagnetic wave propagation in water was conducted, including the impact of human tissue and water attenuation and material influence. Link budget calculations and analytical models were used to compare multiple operating frequencies and to define antenna positioning scenarios. Two antenna topologies were initially analyzed through numerical simulations using CST Studio Suite, the Inverted-F Antenna (IFA) and a Slotted Patch antenna. The latter antenna was selected and further optimized for integration into a flexible neoprene layer, simulating realistic wearable conditions near the human body. Further studies concluded that this antenna was sensitive to water layers changing its resonant frequency significantly. A search for an alternative antenna was needed. The study introduced a third antenna, the Wearable Parallel Patch Antenna (WPPA), simulations and experimental work were conducted and prevailed and the trials demonstrated good enough results for its fabrication. A homogeneous phantom was fabricated to replicate the dielectric properties of muscle tissue at 2.45 GHz, enabling realistic physical testing of the antenna in aquatic and non-aquatic environments. Experimental measurements were conducted using the fabricated antenna, and the final results showed a good agreement with the simulations. The WPPA exhibits a linear polarized antenna with a bandwidth of |S11| < 10dB, achieving a gain of -5.11 dBi in the water environment and 6.36 dBi in the air environment. To enable data collection from the WPPA, an ESP32- CAM microcontroller with integrated Bluetooth was connected to it, while a second ESP32-CAM was linked to the receiving antenna positioned outside the aquatic environment. This setup allowed the external antenna to capture both the distance between the two antennas and the Received Signal Strength Indicator (RSSI). Future research would be valuable to further investigate the practical application of this approach, particularly in using ESP32-CAM units with external antennas for wireless real world implementations.