An ultraminiaturized implantable antenna with low SAR for biotelemetry

Bio implants are popularized in health care industry for patient monitoring. This article presents an ultraminiaturized flexible slotted patch antenna with superstrate for bio implantable applications. The radiator is designed on Roger 6010 with dimension 5 x 6.2 x 0.508 mm3 which is 0.130 x 0.161 x 0.012 lambda g at 2.45 GHz. The superstrate ensures protection of body tissues and reduces SAR. Achieved gain and bandwidth of the antenna in free space are -27.07dBi and 30 MHz, respectively. Antenna bandwidth on body tissues like stomach, heart and liver are 124 MHz, 138 MHz and 175 MHz, respectively. SAR analysis is carried out using both homogeneous and heterogeneous human body models for 1 g and 10 g tissues during simulation. Head, heart, liver and stomach phantom shows simulated SAR value of 33.53 W/Kg, 52.49 W/Kg, 32.49 W/Kg and 31.37 W/Kg, respectively for 1 g tissue with 1 W input power and is within IEEE standard limit of 1.6 W/Kg with maximum allowable power of 47 mW, 30 mW, 48 mW and 50 mW. Performance validation of antenna is done with liver, heart and minced meat of pork for body tissues. Brain tissue is mimicked with saline solution. The link budget analysis is performed using NI-USRP 2920 module and LabVIEW with data transfer at a transmission rate of 1/2/5 Mbps and shows a wireless transmission link of 15 m for bio telemetry.