Articles written in Sadhana

    • Analysis and design of broadband U-slot cut rectangular microstrip antennas


      More Details Abstract Fulltext PDF

      Broadband microstrip antenna using variations of U-slot has been widely reported. However, in most of the reported work, an in-depth explanation about the mode introduced by U-slot and procedure to design U-slot cut antennas at any given frequency is not explained. In this paper, first an extensive analysis to study thebroadband response in symmetrical and a new configuration of asymmetrical U-slot cut rectangular microstrip antennas is presented. The U-slot tunes higher-order orthogonal mode resonance frequency of the patch with respect to fundamental mode to realise wider bandwidth. Further formulation in resonant length at modified patch modes in symmetrical U-slot cut antenna is proposed. Frequencies calculated using these formulations show closer agreement with simulated and measured results. Using proposed formulations, a procedure to design U-slot cut antenna at different frequencies over 800–4000 MHz range which shows broadband response is explained. Thus, the proposed work gives an insight into the functioning of widely used U-slot cut antennas and the formulations will be helpful for designing at any given frequency

    • Modified designs of broadband E-shape microstrip antennas


      More Details Abstract Fulltext PDF

      Wideband designs of rectangular microstrip antennas embedded with three rectangular slots are proposed. These slots modify resonance frequencies of patch’s TM₁₀, TM₀₂ and TM₁₁ mode, to give bandwidth of more than 500 MHz (>50%). Further, pair of slots cut variations of rectangular patch with three slots is proposed. Additional pair of slots tune the next higher order TM₁₂ mode frequency with respect to modified lower order resonant modes, resulting in further increase in bandwidth of more than 600 MHz ([55%). Increased bandwidth obtained in the proposed designs is more than that obtained from equivalent E-shape and U-slot cut patches. As compared with Ψ-shape patch antenna, the proposed configurations yield wider bandwidth with 38% reduction in patch size.

    • Rectangular microstrip antenna loaded with offset U-slot and rectangular slot for wideband and circular polarized response in GSM 900 and GPS L5 band applications


      More Details Abstract Fulltext PDF

      Wideband and circular polarized designs of rectangular microstrip antennas employing offset positions of the U-slot and rectangular slot are presented. Query ID=‘‘Q1’’ Text=‘‘’EXTC’ expand’’ An interspacing between the patch TM10, TM11 and TM02 resonant modes is optimized due to the presence of two offsetslots that yields a wideband response with the presence of circular polarized bandwidth towards the higher frequencies, thus providing separate regions for the two responses. In 900 MHz spectrum, the proposed design yields maximum impedance bandwidth of 298 MHz (32.07%) with an axial ratio bandwidth of 13 MHz (1.26%). The proposed designs exhibit pattern maximum in the broadside direction with a gain of larger than 6 dBi. Simulated results have been verified using the experimentation, which shows close agreement.

  • Sadhana | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2022-2023 Indian Academy of Sciences, Bengaluru.