High-gain on-chip antenna using a sapphire substrate for implantable wireless medical systems

Abstract

This paper presents a high-gain on-chip antenna using a sapphire substrate for implantable wireless medical systems. The antenna model is based on a dipole and the antenna elements are appropriately rolled for impedance matching. The center frequency of the fabricated on-chip antenna was measured as 360 MHz. The return loss was −3.58 dB and the input impedance was 190.5 − j74.7 Ω at 360 MHz. The maximum antenna gain of the fabricated on-chip antenna was −29.2 dBi. The on-chip antenna using a sapphire substrate achieved a 12.9 dB higher gain than that using a silicon substrate and successfully induced signal transmission at a distance of 10 cm with a transmitter chip. The implemented on-chip antenna can improve the power efficiency of implantable wireless medical systems by 95%.

Ideal Sensor Chips —A Smart Microsensor Chip with LSI and MEMS Process and Materials—

“…The on-chip antenna using a sapphire substrate achieves a 12.9 dB higher gain and can markedly reduce the power consumption of the transmitter by 95% compared with that using a silicon substrate. (22) We demonstrate signal transmission using the proposed on-chip antenna and a CMOS transmitter chip. Figure 12 shows the fabricated transmitter device connected by wire bonding and the measurement system for transmission demonstration.…”

Miniaturized Meander-Line Dipole Antenna For Short-Range Wireless Communication Networks

“…Another work on a sapphire-based antenna was reported in [5], where a stacked rectangular dielectric resonator aperture coupled antenna was designed for the C-band applications. In [6], an on-chip miniaturized antenna is proposed on a sapphire substrate for implantable wireless medical systems. The analysis has shown that an on-chip antenna with a silicon substrate has low gain, which is increased by using sapphire substrate instead of silicon for on-chip antennas.…”

Co-Design Method and Wafer-Level Packaging Technique of Thin-Film Flexible Antenna and Silicon CMOS Rectifier Chips for Wireless-Powered Neural Interface Systems

“…For realizing wireless communication and power transmission to the implanted neural interface on the brain surface, several technologies that integrate passive components (e.g., an antenna on a flexible film) with high-performance active circuits have been studied [ 18 , 19 , 20 , 21 , 22 ]. In particular, many functional circuits including amplifiers, analog-to-digital converters, signal processors, and RF circuits are needed and they should all support low-power operation [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. Very thin film flexible transistors fabricated with organic or bio-resorbable materials can be used to fabricate monolithic film devices with passive and active components.…”