To overcome the narrow axial ratio (AR) bandwidth inherent in conventional linearly to circularly polarised converters, this research proposes a metasurface (MS) with a diamond‐shaped configuration that can mitigate the effect of surface wave (SW) along the MS edge and achieve a wider 3 dB AR bandwidth. The diamond‐shaped MS structure is realised by slanting a square MS by 45°, and it consists of constituent unit cells of rectangular and arbitrary shapes. The rectangular unit cells are positioned 45° to the square dielectric substrate, and the unit cells along the MS edge are partially cut into arbitrary shape to be perfectly aligned along the edge. The 3 dB AR bandwidths and degradation of the MS are characterised by SW and magnetic current distribution. Simulations are carried out and an MS prototype is fabricated to verify the results. The effects of partially cut unit cells (PCUCs) along the MS edge on the SW are characterised. The simulation and measured 3 dB AR bandwidths of the diamond‐shaped MS are 37.6 and 28.8%, respectively. The novelty of the proposed diamond‐shaped MS polarisation converter lies in the implementation of arbitrary‐shaped PCUCs and the use of the diamond‐shaped configuration in place of conventional square geometry to realise wider AR bandwidth.

In this paper, a dual band textile antenna operable at 2.4/5.2 GHz for WLAN application has been presented. The wearable 1 mm thick felt fabric having relative permittivity of 1.90 and loss tangent of 0.016 has been used as substrate material. The return loss, radiation pattern and realized gain measurements are used to characterize a prototype using vector network analyzer and anechoic chamber. The |S 11 | is lower than -10 dB covered the frequency band from 2.16 GHz to 2.63 GHz and from 4.45 GHz to 5.90 GHz. The gains at two bands are 1.8 dBi and 3.2 dBi, respectively. This antenna yields omnidirectional pattern. The simulation and measurement results are in good agreement. Additional, the effects on the return loss for the antenna under the bent conditions are further discussed.

No abstract

No abstract

Comparative study of some novel wideband Tulip Flower Monopole Antennas (TFMAs) is presented in this paper. To Improve the bandwidth and increase the gain, modification of the shape of the curves and slots in the patch and ground plane was carried out on the seven TFMAs. TFMA-A, TFMA-B, TFMA-C, and TFMA-D have dimensions of 50 × 50 mm 2 , while TFMA-E, TFMA-F, and TFMA-G have dimensions of 30 × 70 mm 2 . From the simulation result, TFMA-A operated from 2 GHz to more than 30 GHz with a return loss of 15 dB occupies most of its operating frequency. In the whole frequency work, the peak directivity performance in the order of superiority is obtained for TFMA-G, TFMA-F, TFMA-D, TFMA-E, TFMA-C, TFMA-B, and TFMA-A. The improvement of directivity is reached for TFMA-D of 5.03 if it is compared to TFMA-A at 24 GHz. TFMA-G obtains the peak of directivity of 10.148 dBi at 23 GHz. The impedance bandwidth and directivity of the antenna element change by varying the curvature, the shape, and the position of slot in the radiator and ground plane also the height of the microstrip feeding line and ground plane. The return losses of the TFMA-A and TFMA-E show good agreement between simulation and measurement results.