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Capacitive Loaded Dipole as an Implanted Antenna

Ali Ahmed Younis Ibraheem

Abstract


Implanted antenna plays a vital role in biomedical applications so it has a growing interesting in the recently. The implanted antenna must be extremely minimized while keeping the Specific Absorption Rate (SAR) inside the human body as small as possible. Most of the proposed designs for implanted antenna have a small efficiency and high SAR for small antenna size. In this paper, a capacitive loaded dipole antenna is proposed for implanted applications such as gastrointestinal capsules. The proposed antenna is a dipole antenna loaded with a circular disc, the disc acts as capacitor so; the physical length of the antenna can be reduced while keeping the electrical length equal to the length of half wavelength dipole antenna. The proposed antenna has been simulated inside a model equivalent to the human body muscle tissue at the medical implanted communication service (MICS) band (401-405 MHz). The antenna has a total size of 79 mm3, radiation efficiency of 5.5 % and the 1g averaged SAR is 0.9 W/kg for 1 W input power at the MICS frequency band. Also the detuning effect due to change of the electrical properties of the human body tissues is still within the antenna bandwidth. The proposed antenna can be designed at the other frequency bands for biomedical applications such as: Wireless Medical Telecommunication Services (WMTS) (1395-1405 MHz) and Industrial, Scientific, and Medical (ISM) (2400-2480 MHz). The radius of the circular disc can be used to reduce the physical length of the antenna.


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References


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