A new compact multiple-input multiple-output (MIMO) ultra-wideband (UWB) antenna array is presented. The antenna array initially consisted of two monopoles placed side by side at a distance of 4 mm. A strong mutual coupling was observed so the design was modified by rotating the second radiator at 90° at a distance of 1 mm. Wideband isolation is achieved by exploiting polarisation diversity of antenna elements. Simulation in HFSS and printed prototype results validate the high isolation, over 21 dB on the entire 2.5-12 GHz frequency range. A prototype was fabricated on a low loss substrate of Rogers TMM4 measuring 23 × 39.8 mm2. To evaluate the diversity performance, the envelope correlation coefficient was calculated resulting below -20 dB, thus ensuring good diversity performance. The compactness of the proposed UWB-MIMO design is finally compared against alternative solutions already present in the literature
Abstract-This work presents the analytical solution of vector wave equation in fractional space. General plane wave solution to the wave equation for fields in source-free and lossless media is obtained in fractional space. The obtained solution is a generalization of wave equation from integer dimensional space to a non-integer dimensional space. The classical results are recovered when integer-dimensional space is considered.
Presented are two different frequency reconfigurable ultra-wideband multiple-input multiple-output (MIMO) antenna array designs capable of rejecting on-demand all WLAN communications in the 4.8 to 6.2 GHz range. Both arrays consist of two monopole UWB radiators placed orthogonally with respect to each other to introduce polarisation diversity and a quarter-wave stub connected to the ground plane via pin diodes is used to introduce the on-demand band rejection feature. One array design has separate ground planes and the other has two ground planes connected with a printed conductor (i.e. shared). For both cases, an isolation better than 20 dB between the elements is achieved in the 2 to 12 GHz frequency range with simulations and a manufactured prototype.
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