Design of dual-polarized MIMO linear antenna arrays with increased port-to-port isolation

Design Optimization of Feeding Networks with a Special Size for Self-Interference Cancellation

“…In [21], self-interference suppression was achieved by using differential feedings in an 8 × 8 antenna array, but Tx ports and Rx ports with different polarizations are necessary. In [22,23], the FNs utilizing the pairwise antiphased feeding technique were used to improve the isolation between subarrays. Yet this technique can only be used to cancel the interference between different polarizations of the same array.…”

On the Design of Dual-Polarised Linear Antenna Arrays with Enhanced Port-to-Port Isolation

“…Even if complex feeding methods such as a differential-driven antenna [8,9], hybrid-fed techniques [10] or aperture-coupled with specific slot shapes are taken in consideration, the maximum level of isolation will attain 40 dB [11,12]. For this reason, increasing the port-to-port isolation of microstrip antenna arrays could be achieved by applying dedicated feeding networks that utilise compensation of the crosstalk between the array ports by means of the pairwise anti-phased feeding technique where couples of radiators which are the image mirror one of another are fed by currents shifted by 180 • in the phase [13][14][15][16][17][18]. The application of this technique contributes to an increase in isolation to over 50 dB [16][17][18] and polarisation purity to more than 36 dB [19].…”

“…This is observed especially when the radiators and FN are located on the same layer of printed circuit board (PCB). In such a case, even after the optimisation process, it is difficult to obtain isolation better than 50 dB [13,14,24]. The achievement of higher isolation requires the use of multilayer PCBs in which radiators and FN are separated by means of ground planes [9,[25][26][27].…”

“…This paper describes the design process of the dual-polarisation linear antenna arrays using a four-element antenna array for U-NII 5.15-5.925 GHz frequency band as an example. In comparison to earlier works by the same authors [13,14], this paper contains a detailed description of the array design: a presentation of the theoretical model for port-to-port isolation, a discussion of the influence of mechanical symmetry and couplings between the radiators and/or FN on port-to-port isolation and a description of the method of selection of the feeding network elements performed by circuit and full-wave simulations. In practical realisations of the antenna arrays described in this paper, electromagnetically coupled microstrip antennas (ECMSA) are utilised as a single radiator [34].…”