Journal of Nano- and Electronic Physics. Scientific journal. ISSN: 2077-6772. Journal abbreviation: J. Nano- Electron. Phys. No page charges. All articles are freely available on-line. Issued 4 times per year. Publisher: Sumy State University. (Sumy, Ukraine)

A graphene-based 1 × 2 array antenna with circular polarization for terahertz applications is prescribed in this article. Initially, a novel concept of a folded quarter wave impedance transformer is utilized in the design process of a single element for minimizing the overall antenna size. The opposite corners of the patches have been truncated and structural modifications are performed with the insertion of four flower-shaped slots along with an additional circular slot for achieving a much-improved reflection coefficient and better impedance bandwidth. It also shows a much wider 3 dB axial ratio bandwidth, confirming circular polarization due to the suggested modifications in its geometry. Then, an array antenna has been formed to provide better gain. The configured patches are fed by a magic-T power divider to attain the required impedance matching. The results of the CP antenna array have been analyzed using the HFSS and CST simulators. The propounded 1 × 2 array antenna shows circular polarization with a 3 dB AR bandwidth of 205 GHz (2.345–2.55 THz) and wide spectral coverage of 210 GHz (2.345 $-$ 2.555 THz) along with a maximum gain of 8.65 dB and 99.8 % radiation efficiency with a total size of 53.5 × 102 × 1.56 μm³. It could be utilized for high-speed data transmission, material characterization, terahertz spectroscopy, terahertz imaging, etc. applications.

In this paper, a printed 1×8 array antenna operating at 2.4 GHz is proposed for radio frequency identification (RFID) Reader. The proposed array antenna is composed of eight identical modified patch elements. The radiating elements are fed in parallel via a simple 50 Ohm microstrip line matched with a quarter-wave impedance transformer using a T magic power divider to divide the input power into two equal quantities with the same phase. The suggested array configuration is designed using Rogers RT/duroid 5880 substrate having dielectric constant ε_r= 2.2, dielectric loss tangent = 0.0009, and substrate’s height of 1.56mm. The overall dimension of the 1×8 array antenna is 117×475mm². The proposed array antenna shows good impedance matching, high gain and directional radiation patterns. The proposed array antenna has a high gain about of 14.61dBi, high radiation efficiency of 98.3%, and a good reflection coefficient S11 of -13.14dB and voltage standing wave ratio (VSWR) of 1.56 at 2.4 GHz.