A miniaturized UWB antenna for implantable data telemetry

A highly miniaturized antenna with wider band for biomedical applications

A highly miniaturized planar monopole antenna is presented for biomedical applications. The proposed antenna utilizes polydimethylsiloxane (PDMS) with dielectric constant 2.7 and loss tangent 0.0314 with thickness 0.3 mm as substrate and with thickness 0.2 mm as superstrate. A copper foil of 0.03 mm thickness is used for radiating elements. The proposed structure contains a unique structure, made of loop-based structure with three rectangular-shaped stubs are added to tune the operating frequency to 5.8 GHz and to improve the reflection coefficient. The incorporation of stubs achieved the intended frequency of operation, utilization of the loop-based structure for designing the antenna achieved high miniaturization. The proposed antenna is analyzed under various conditions like under skin, muscle, stomach, small intestine,, colon etc., and comparative analysis is presented with the help of reflection coefficient, radiation patterns and specific absorption rate (SAR). SAR is evaluated over a volume of 1 g tissue as per the standards of Federal Communications Commission (FCC). SAR value of the antenna is below 1.6 W/kg for input power 1.9 mW. The simulated analysis showed that the designed antenna is suitable for both implantable and endoscopic applications. Moreover the simulated and measured analysis for reflection coefficient of the proposed antenna showed good agreement.

A 300 Mbps 37 pJ/bit Pulsed Optical Biotelemetry

This article reports an implantable transcutaneous telemetry for a brain machine interface that uses a novel optical communication system to achieve a highly energy-efficient link. Based on an pulse-based coding scheme, the system uses sub-nanosecond laser pulses to achieve data rates up to 300 Mbps with relatively low power levels when compared to other methods of wireless communication. This has been implemented using a combination of discrete components (semiconductor laser and driver, fast-response Si photodiode and interface) integrated at board level together with reconfigurable logic (encoder, decoder and processing circuits implemented using Xilinx KCU105 board with Kintex UltraScale FPGA). Experimental validation has been performed using a tissue sample that achieves representative level of attenuation/scattering (porcine skin) in the optical path. Results reveal that the system can operate at data rates up to 300 Mbps with a bit error rate (BER) of less than 10 ^-10, and an energy efficiency of 37 pJ/bit. This can communicate, for example, 1,024 channels of broadband neural data sampled at 18 kHz, 16-bit with only 11 mW power consumption.