A helical folded dipole antenna for medical implant communication applications

Currently, most of implanted medical devices are using inductive coupling for communication, which leads to difficulty in transmitting medical data records for several meters range. In order for the implanted device is able to be used in longer range transmission, the device is wirelessly transmitted in the form of electromagnetic signals. This initiates us to study on a patient home monitoring system, in which the external devices such as portable equipments will provide a benefit for healthcare provider in accessing the important patient medical information via a networked connection. Because of this reason, an electrically small antenna for implantable devices is very essential components in monitoring systems to provide wirelessly communication between a patient and an access point. In this paper, a helical folded dipole antenna for an implantable device is proposed for wireless patient monitoring system. The implanted device is assumed to be applied by a syringe injection allowing to the device is simply injected into the human body. The proposed antenna is operated in UHF band 924 MHz, as a band of Indonesian RFID applications. The antenna is quite small in comparison to the band operation (ka≈0.08). Sufficient electrical performances are obtained such as reflection coefficient, impedance bandwidth, radiation pattern and gain. According to the link budget analysis, the proposed antenna has adequate gain within 10m transmission range by 225 MHz bandwidth (VSWR ≤ 2).