Design guidelines for the SPICE parameters of waveform-selective metasurfaces varying with the incident pulse width at a constant oscillation frequency

In this study, we numerically demonstrate how the response of recently reported circuit-based metasurfaces is characterized by their circuit parameters. These metasurfaces, which include a set of four diodes as a full wave rectifier, are capable of sensing different waves even at the same frequency in response to the incident waveform, or more specifically the pulse width. This study reveals the relationship between the electromagnetic response of such waveform-selective metasurfaces and the SPICE parameters of the diodes used. First, we show that reducing a parasitic capacitive component of the diodes is important for realization of waveform-selective metasurfaces in a higher frequency regime. Second, we report that the operating power level is closely related to the saturation current and the breakdown voltage of the diodes. Moreover, the operating power range is found to be broadened by introducing an additional resistor into the inside of the diode bridge. Our study is expected to provide design guidelines for circuit-based waveform-selective metasurfaces to select/fabricate optimal diodes and enhance the waveform-selective performance at the target frequency and power level.Comment: 9 pages, 9 figure

A Needle-type Complementary Metal Oxide Semiconductor-compatible Glucose Fuel Cell Fabricated by Carbon Nanohorns for Biomedical Applications

This study details the development of a solid-state complementary metal-oxide semi-conductor (CMOS)-compatible glucose fuel cell, consisting of various amounts (% wt.) carbon nanohorns (CNHs). It was fabricated on an anode area using one-dimensional (1D) structural CNHs, which express an open-circuit voltage (OCV) of 375 mV, the power density of 8.64 µW/cm2 and current density 23.05 µA/cm2 in 30 mM glucose solution. The cell can be manufactured via a CMOS fabrication process, using materials biocompatible with the human body. The CNHs enhanced the fuel cell due to their high electrocatalytic ability. Here, CNHs were used to fabricate a 17.5 mm × 0.7 mm solid-state CMOS-compatible glucose fuel cell with 375 mV of OCV - the highest reported value for such a cell with an anode area of 16.2 mm × 0.3 mm. The highest power is 0.42 µW. Power generation is the main challenge for developing glucose fuel cells to make the implantable devices that can be used for biomedical applications