Papers by Akila Murugesan
Applied Computational Electromagnetics Society Journal, May 4, 2022
This paper presents simulation-based design and analysis of a broadband dual-polarized magnetoele... more This paper presents simulation-based design and analysis of a broadband dual-polarized magnetoelectric dipole antenna element that can be used to construct VHF astronomical antenna arrays. The antenna consists of two pairs of radiating structures, each fed by a Γ-shaped feeding section. The feeding section and radiating parts are physically disconnected from each other. The antenna is evaluated by simulation, and its −10 dB impedance matching bandwidth ranges from 115 to 340 MHz. The maximum gain of the antenna is about 8 dB over the operating range. Isolation of about 20 dB is observed between the two input ports.
Frequenz
This paper reports investigations on the effect of array size on the RCS reduction bandwidth of c... more This paper reports investigations on the effect of array size on the RCS reduction bandwidth of checkerboard metasurfaces (CMS). Three CMSs, one on a Rogers substrate and the remaining on FR4, are considered. While the usual phase deviation criteria are used for the designs on both the substrates, additionally a set of modified criteria recently proposed are used for the FR4 substrate-based designs. While three different sizes – 120 mm2, 240 mm2, and 480 mm2 – are considered for the simulation-based investigations for all the structures, an additional size of 600 mm2 is also considered for one of them. The 8 and 10 dB RCS reduction bandwidths drop as array size increases. The bandwidth reduction is attributable to mutual coupling, as has been reported in an earlier study. As therefore expected, all of the three structures, for all sizes, present the same RCS reduction bandwidth when a mutual coupling mitigation technique is incorporated. For 10 dB RCS reduction bandwidth, this value...
2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/URSI)
2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/URSI)
IEEE Antennas and Wireless Propagation Letters, 2009
A novel dual-polarized magneto-electric dipole antenna excited by two 0-shaped strips is presente... more A novel dual-polarized magneto-electric dipole antenna excited by two 0-shaped strips is presented. The antenna achieves a common impedance bandwidth of 65.9% (SWR 2) at both input ports. The antenna has excellent performance in isolation, which is more than 36 dB between the two input ports, and the gain of the antenna is about 9.5 dBi. The radiation pattern and bandwidth over the operating frequency band are very stable.
2022 IEEE Microwaves, Antennas, and Propagation Conference (MAPCON)
2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI)
An existing semi-empirical expression for predicting the RCS reduction bandwidth of checkerboard ... more An existing semi-empirical expression for predicting the RCS reduction bandwidth of checkerboard metasurfaces (CMS) is examined. The bandwidth predicted by this equation, which is based on the unit cell reflection coefficient, is inconsistent with the simulated array bandwidth. By using two approaches, it is shown that the bandwidth prediction is improved considering the effect of mutual coupling. In approach (1), the mutual coupling coefficients are extracted using a discrete-port-based method and employed to update the unit cell reflection coefficient. The bandwidth predicted with the updated reflection parameters better matches the simulated array bandwidth. In approach (2), PEC baffles are introduced in the CMS to mitigate mutual coupling, resulting in a good match between unit cell reflection coefficient-based bandwidth and the array bandwidth.
2017 IEEE International Conference on Antenna Innovations & Modern Technologies for Ground, Aircraft and Satellite Applications (iAIM), 2017
Q of a patch, and its meander-line based miniaturized version, resonating at about 13.3 GHz, is e... more Q of a patch, and its meander-line based miniaturized version, resonating at about 13.3 GHz, is examined in this paper by using simulations and experiments. This examination is done with the printed structures employed in two configurations as radiators and as reflectarray elements. While impedance Q is considered for the radiators, it is reflection phase Q that is considered for reflectarray elements. In either configuration, the Q of the miniaturized antenna is observed to be larger compared to that of the patch. Both the printed structures offer similar bandwidths in either of their configurations.
2021 International Applied Computational Electromagnetics Society Symposium (ACES), 2021
In this paper, mutual coupling mitigation techniques are employed to widen the monostatic RCS red... more In this paper, mutual coupling mitigation techniques are employed to widen the monostatic RCS reduction bandwidth in Checkerboard Metasurfaces (CMS). Two methods, namely PEC baffles and vias, are applied to five previously reported CMSs. All five of them have an airgap and dielectric configuration. The baffles and vias are employed at three different positions, (A) covering the substrate and airgap, (B) only within the substrate, and (C) only within the airgap. The introduction of these baffles and vias enhances the bandwidth in the range of 5-10%.
Progress In Electromagnetics Research B, 2021
This review discusses the evolution of the various radar cross-section (RCS) reduction techniques... more This review discusses the evolution of the various radar cross-section (RCS) reduction techniques, with an emphasis on metasurfaces. The paper first introduces the terms RCS and RCS reduction and then discusses conventional and modern techniques to reduce RCS. The two main strategies used are scattering and absorption. The traditional methods of shaping and Radar Absorbing Material (RAM) are first briefly reviewed, followed by an extensive review of metasurface-based RCS reduction. RCS-reducing metasurfaces have the unique characteristics of acting as scatterers and absorbers. They are also described with regard to their passive and active configurations. The paper discusses RCS reduction techniques with respect to profile, bandwidth, angular stability, polarization sensitivity, design complexity, and cost-effectiveness. A comprehensive comparison chart based on the performance parameters such as bandwidth, size and angular stability is tabulated for the different types of metasurfaces. The review also details areas that require further investigation.
International Journal of RF and Microwave Computer-Aided Engineering, 2021
2022 IEEE Wireless Antenna and Microwave Symposium (WAMS)
IEEE Antennas and Wireless Propagation Letters, 2021
This letter presents three wideband checkerboard metasurfaces (CMSs) for monostatic radar cross-s... more This letter presents three wideband checkerboard metasurfaces (CMSs) for monostatic radar cross-section (RCS) reduction realized using low-cost FR4 material. The CMSs designed for the target RCS reduction of 10 dB using the conventional phase deviation condition of 180 ± 37°, when simulated, exhibit an overshoot in the lower frequency band and much higher reductions in the higher band. In order to maximize the bandwidth considering these variations, a constriction of 180 ± 18° in the lower frequency band and a relaxation of 180 ± 48° in the higher frequency band are made to the phase deviation condition. The three CMSs realized using these modifications offer a 10 dB RCS reduction bandwidth over the range of 94%–98%. The simulated and measured results compare favorably.
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Papers by Akila Murugesan