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In this paper, the authors introduce a novel fractal-frequency selective surface (F-FSS) geometry for dual-bandpass applications. The centriole-symmetric geometry and dual-band characteristics have been achieved by introducing a golden ratio-based fractal geometry. The characteristic mode and equivalent circuit model analysis of the proposed geometry have been performed. The design offers significant autonomy in controlling the two resonant frequencies separately. Additionally, it demonstrates robust stability against variations in bending angle and polarization. To verify the concept, 7 × 7 array with a dimension of 0. 51 λ 0 × 0. 51 λ 0 × 0. 02 λ 0 (where the free-space wavelength (λ 0) is 39. 20 mm) is simulated, fabricated, and tested in an anechoic chamber. In measurement, the proposed F-FSS geometry achieves notches at 7.74 and 11.80 GHz, with fractional bandwidth of 6.10% and 3.90%, respectively. The design showcases a thickness-bandwidth ratio (T-BR) of 0.62 and 1.54 within their respective frequency bands. The measured results match closely with the simulation results and yield a low RCS value. [ABSTRACT FROM AUTHOR]

In this paper, a wideband high gain Vivaldi antenna based on spoof surface plasmon polaritons metamaterial for radio astronomy application is proposed. The height of the spoof surface plasmon polaritons structures fits the exponential function, thus the structure is named exponential spoof surface plasmon polaritons (ESSPP) metamaterial. With the exponential heights, the ESSPP metamaterial could correct the phase difference in a wide band, the gain is improved in the wide frequency range from 3 GHz to 9 GHz, and the proposed antenna exhibits stable radiation patterns with an average gain of 10.6 dBi. [ABSTRACT FROM AUTHOR]

In this paper, performance of a Swastika slot-ultra-wideband (SS-UWB) patch antenna for an on-body application is investigated. This antenna is intended for the use in UWB wireless body area network (WBAN) applications, between 3.1 and 10.6 GHz. The proposed antenna is a SS-UWB patch antenna of dimension 27 mm × 27 mm × 1.6 mm. It is fabricated and tested in free space scenario instead in anechoic chamber to obtain more realistic on-body measurement results. This SS-UWB patch antenna covers the ultra-wide frequency spectrum in the range 4.25–12.5 GHz [8.25 GHz] with a quasi-omni directional gain from 1.77 to 5.6 dB. This antenna's efficiency is from 81.3% to 90.67% (−1.8 to −0.85 dB) over free space. The antenna is characterized in free space as well as on body model with and without antenna body gap. Measured results obtained from the antenna like S 11 , radiation pattern, antenna efficiency, and gain are matched with the simulated results. [ABSTRACT FROM AUTHOR]

This paper presents the design of a frequency-reconfigurable SIW microstrip antenna based on the resonant cavity model. Aiming to create a guideline for the design of this class of radiator, a collection of rectangular and triangular cavities laterally bounded by perfect electric and magnetic walls, as well as their resonant frequencies and internal electric field distributions are described. In addition, a list of selected possibilities of such cavities combined with other geometries, enabling frequency reconfigurability is presented together with the graphical evaluation of operating frequency range. The theoretical analysis is confirmed by the design of an L1/E1-L5/E5a global navigation satellite systems (GNSS) antenna. Measurements in an anechoic chamber and tests with a software defined radio (SDR) GNSS receiver validate the manufactured prototype. [ABSTRACT FROM AUTHOR]