Browsing by Author "Gunavathi, Nagarajan"

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    Dual-band complementary split-ring resonator engraved rectangular monopole for GSM and WLAN/WIMAX/5G sub-6 GHz band (New Radio Band)
    (Electromagnetics Academy, 2021-07-07) Christydass, Samuel Prasad Jones; Gunavathi, Nagarajan
    In this paper, a rectangular monopole antenna engraved with a complementary split-ring resonator is proposed for dual-band operation. The proposed antenna is fabricated on an FR4 substrate with a dimension of 20 x 34 x 1.6 mm3. The entire simulation is done using CST EM studio software. The proposed antenna exhibits dual-band operation from 1.78 GHz to 1.90 GHz and from 3.45 GHz to 6.58 GHz. The band from 1.78 GHz to 1.90 GHz is due to the inclusion of CSRR, and its corresponding bandwidth is 120 MHz. It is validated with the quasi-static analysis. The permittivity characteristics of the proposed CSRR are retrieved using the NRW method and presented. The resonant frequency of the band created by the CSRR is 1.83 GHz with -37.68 dB as its return loss values. The second wider band is due to the combination of the mode created by the CSRR along with the radiating patch from 3.45 GHz to 6.58 GHz with 3132 MHz which has a dual resonance at 3.65 GHz and 5.59 GHz with a return loss of -30.23 dB and -29.80 dB. The optimal values are chosen with the help of parametric analysis. The designed antenna is fabricated and measured. The measured results of return loss, gain, E-plane, and H-plane are compared with simulated results, and they are complying with each other. The dual-band operation, compact size, stable radiation pattern along with gain above 2.3 dBi in the whole resonating band make it suitable for the GSM and WLAN/WiMAX/5G Sub-6 GHz band (new radio band).
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    Metamaterial Perfect Absorber Using Vanadium Oxide Hexagonal Ring Structure
    (Electromagnetics Academy, 2022-08-17) Reddy, Mekala Ananda; Praveena, Namanathan; Gunavathi, Nagarajan; Pandeeswari, Ramasamy
    A Metamaterial Terahertz perfect absorber is proposed in this letter. The structure comprises Vanadium oxide (VO2) resonator hexagonal rings placed on top of a silicon dioxide (SiO2) substrate in a concentric pattern on a metal ground layer, with 1 THz and 6 THz operating frequency. Numerical studies are done by an electromagnetic solver. The results show almost perfect absorption, with 112% average absorption at different incident polarization angles, in the range of 1.64 to 6.1 THz. The optimization is carried out on physical dimensions for maximum absorption results. The proposed design can be used as a highly efficient absorber in applications like solar energy harvesting, cloaking, sensing, imaging technology, and EMC projects.
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    Octa-band metamaterial inspired multiband monopole antenna for wireless application
    (Electromagnetics Academy, 2021-06-11) Christydass, Samuel Prasad Jones; Gunavathi, Nagarajan
    In this paper, a Rectangular Monopole Antenna (RMPA) with offset microstrip feed is presented. The structure is fabricated on an FR4 substrate with a dimension of 28 x 32 x 1.6 mm3. The proposed structure achieves multiband operation by engraving 2 Complementary Split Ring Resonators (CSRRs) and a C-Shaped slot. Also, 2 Split Ring Resonators (SRRs) are printed on the adjacent sides of the radiating element. The parametric analysis is used to determine the optimum position of the feed and other critical parameters. The proposed structure operates at 2.25 GHz, 3.86 GHz, 4.60 GHz, 5.64 GHz, 5.86 GHz, 6.94 GHz,7.48 GHz, and 9.47 GHz. The permeability of the SRR and permittivity of the CSRR are extracted and presented. The proposed antenna is fabricated and measured. The measured results of S11, radiation pattern, and gain are on par with the simulated results. The proposed antenna's simulated surface current and efficiency are also presented to validate the performance. Simple structure, stable radiation patten, multiband operation, reasonable gain, and efficiency are the significant features of the proposed RMPA.