IEEE Access (Jan 2024)
Bandwidth, Gain Improvement, and Notched-Band Frequency of SWB Wave Coplanar Vivaldi Antenna Using CSRR
Abstract
Antennas with high gain that can operate in Super Wide Band (SWB) frequencies can be employed for a variety of wireless applications that serve different telecommunications infrastructure and radar applications. However, wide-bandwidth antennas suffer from interference from other wireless technology networks, necessitating the deployment of strategies to block some undesired signal frequencies. A new method for increasing bandwidth by shortening the taper slot length of the Vivaldi antenna and increasing the antenna radiation pattern by using a wavy structure and adding a Square-Complimentary Split Ring Resonator (S-CSRR) structure that can notched-band several frequencies has been investigated on the Coplanar Vivaldi Antenna (CVA). In this study, we investigated seven different types of antennas: Conventional CVA (C-CVA), CVA-Short Slot and Long-Slot (CVA-SS and CVA-LS) with antenna lengths of 10 and 15 cm, wave CVA (WCVA), and WCVA with CSRR. In all frequency bands ranging from 2.3 to more than 30 GHz, the $S_{11}$ of the CVA-SS antenna is less than −15 dB with minimum $S_{11}$ of −62.21 dB. When compared to the CVA-LS without a corrugated construction, the WCVA-SS antenna has 5.77 dBi improvement of directivity at 15 GHz. By incorporating the S-CSRR structure into WCVA, four notched frequency bands are formed: 3.335–3.72 GHz (WiMAX spectrum), 4.72 - 5.354 GHz (WLAN), 6.07–6.743 GHz (Wifi 6E usage), and 7.408–8.293 GHz (X-satellite bands). S-CSRR also potentially result in circular polarization at 4.6–5.3 GHz with the minimum AR of 0.438 (at 5 GHz), at $7.8-8.2$ GHz with the minimum AR of 0.732 (at 8GHz) and at 27 GHz with AR of 2.1 by constructing a U shape with four SCRRs. There was also good agreement between simulation and measurement results. As a result, the WCVA-SS antenna with a Square-CSRR structure may be recommended for the usage of SWB antennas, where a single antenna can serve numerous telecommunications and radar system applications.
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