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In this work, a design study of octagonal shape FSS (Frequency Selective Surface) based type A-sandwich radome wall is proposed for broadband airborne application. The type A-sandwich structure comprises composite materials of low density core layer sandwiched between two high density dielectric skin layers. Further to enhance the EM performance analysis over complete frequency band of 6.3 GHz – 11.9 GHz, the FSS structure is embedded in the core layer of type A-sandwich dielectric wall. The analysis of radome wall EM performance parameters are computed depend on TLM (equivalent transmission line method). A comparative analysis of EM performance is carried at normal as well as higher incident angles of 10°, 20° and 30° for both TE and TM polarization. The analysis shows the characteristics of FSS based type A-sandwich radome wall are superior as compared to conventional A-sandwich radome wall configuration. The designing and simulation approach involves a high frequency electromagnetic simulation tool.

In this research paper, a circularly polarized IRNSS (Indian Regional Navigation Satellite System) receiver antenna is presented using the characteristic mode analysis (CMA) technique. The proposed antenna has been designed for S-band application (2483.50- 2500.00 MHz) with 16.5 MHz bandwidth for IRNSS receiver application. CMA technique has been used to determine the optimum feed location on antenna to obtain circular polarization (CP) for excitation of two orthogonal modes (TM10 and TM01) with equal in amplitude and 90o out of phase. The proposed antenna uses probe feed configuration and design using dielectric laminates FR4 (dielectric constant is 4.3 and loss tangent is 0.025). The axial ratio bandwidth (< 3 dB) of the proposed antenna is obtained from (2431.4 to 2562 MHz). The aim of this antenna to improve the technology of designing of antenna so as small in size miniaturization, less complex, better-improved parameters, rejection and easy to designing and integration with circuits.

In the proposed research work, antennas with circular polarization has been designed with the help of IE3D electromagnetic simulator. Four different geometry has been chosen for this. In that, 2 similar slots have been etched diagonally on the square microstrip patch. Four slots like square, circular, ring and cross-shaped was selected in order to create and prove circular polarization behavior. Axial ratio (A.R.) performance plot reflects the required circular polarization characteristics. Antennas performance was characterized with respect to reflection coefficient, impedance plot and three dimensional patterns. One of the antennas was fabricated in the laboratory and experimentally measured in order to validate the procedure.

This research paper presents the design of microstrip patch antenna through the simulation done by MATLAB source codes, which were developed using method of moment. In order to design, a simplest geometry of the patch antenna is chosen. Antennas of different length, width and feed locations are simulated. Antennas have been analyzed with various performance parameters such as impedance, radiation pattern, reflection coefficient, directivity and VSWR obtained. In order to validate the design approach, MATLAB simulation results for four antennas have been compared with the results obtained from electromagnetic CST simulator. Also one of the antennas has been fabricated in the laboratory and experimentally measured.