This paper presents an in-depth review of the performance improvement of antennas using metasurface. Metasurface is a periodic arrangement of perfect electric conductors (PECs) on a metalbacked dielectric substrate that do not exist in nature and are able to manipulate the behavior of electromagnetic (EM) waves incident on it. The manipulations of EM waves improve the performances in terms of impedance bandwidth, gain, size, specific absorption rate (SAR), radar-cross-section (RCS), and polarization conversions. Consequently, numerous recent works on metasurface-inspired antenna design and their theoretical perspectives on performance enhancements are discussed. By adopting the discussed theories, novel metasurfaces are developed and proposed that analyze impedance-bandwidth enhancement, gain enhancement, and SAR reduction. For designing the metasurfaces, initially a conventional rectangular unit cell (CRUC) is theoretically developed using transmission line model at 2.45 GHz. Following that, the CRUC-based metasurface is incorporated with a monopole antenna, which enhanced the impedance-bandwidth from 140 MHz to 320 MHz and the gain from 2.5 dB to 7.4 dB. On the body, the presence of the metasurface retains all the performances as free space, with a reduced 1 g SAR of 0.034 and 10 g SAR of 0.024 W/kg.
The electrical signals are invariably accompanied by components that are unrelated to the phenomenon being studied. Spurious or unwanted signal components which may occur at any frequency within band pass of the system are known as noise. The instruments are designed in such a way that the noise is minimized to facilitate accurate and sensitive measurement. Noise in Electrocardiograph (ECG) recording occurs due to high frequency Electromagnetic (EM) noise, motion artifacts and power line (50Hz or 60Hz) interference. For extraction of information from noisy signals, it is essential to increase or improve Signal to Noise ratio (SNR) which ultimately improves the performance. To process the signal waveform without distortion, the band pass of the system must be introduced such that all the frequency components of the signal contribute to signal strength. Most signal conditioners include low-pass filters designed specifically to provide maximum rejection of 50Hz noise. Such filters are called “notch filters”. Notch filters having only zeros in the transfer function has very wide notch bandwidth and offers more attenuation at adjacent frequencies. In this paper, we use Notch filter with poles added at multiple points of a unit circle (0).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.