Multiple-input multiple-output (MIMO) technique is expected to be extensively used in future wireless systems to increase capacity of wireless channels. Nevertheless, the capacity gain comes with a cost. In particular...
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ISBN:
(纸本)9789082797039
Multiple-input multiple-output (MIMO) technique is expected to be extensively used in future wireless systems to increase capacity of wireless channels. Nevertheless, the capacity gain comes with a cost. In particular, multiple analog radio frequency (RF) chains are required at both the transmitter and the receiver, thereby leading to a higher implementation cost, more power consumption, and lower energy efficiency. This paper presents a receiver with only one RF chain for 2x2 MIMO transmission system. Proposeddesign is based on a time modulated antenna array (TMAA) with beam-steering functionality and a wideband software defined radio (SdR). Spatial streams were created by demultiplexing spectral components (sidebands) generated by periodical ON/OFF switching Number of RF chains was reduced from 2 to 1 while maintaining sufficiently low correlation of spatial streams, which is required to perform MIMO transmission. Feasibility of proposed technique is evaluated by means of experimental verification.
This article presents a design of a time modulated antenna array with UWB Vivaldi elements. The array is composed by 7 elements worked in the range of frequency from 2.65 GHz to 17.26Ghz. The design consists in the op...
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ISBN:
(纸本)9781538671023
This article presents a design of a time modulated antenna array with UWB Vivaldi elements. The array is composed by 7 elements worked in the range of frequency from 2.65 GHz to 17.26Ghz. The design consists in the optimization of the switching times of the Vivaldi elements for side lobe and side band levels reduction. The optimization is carried out by the particle swarm optimization. Simulation results show a good performance of the proposedarray.
This research presents the design of time-modulated antenna arrays with UWB performance. The antenna arrays consider a linear topology with eight UWB disk-notch patch antennas. The technological problem is to find out...
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This research presents the design of time-modulated antenna arrays with UWB performance. The antenna arrays consider a linear topology with eight UWB disk-notch patch antennas. The technological problem is to find out the optimum antenna positions and/or time sequences to reduce the side lobes and the sidebands in all of the UWB frequency ranges. The design process is formulated as a bacterial foraging optimization. The results show that the uniform array generates a better SLL performance whereas the non-uniform array obtains a wider bandwidth. The uniform array obtains an SLL < -20 dB from 3.37 GHz to 4.8 GHz and the non-uniform array generates an SLL < -7 dB from 2.97 GHz to 5.26 GHz. The sideband levels are very similar for both cases with a value of around -17 dB.
A modified approach of tapered amplitude weighting for subarrayed4d antenna arrays is proposed in this paper. Based on the combination of time weighted subarray outputs and constant element static weightings in subar...
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ISBN:
(纸本)9781509028863
A modified approach of tapered amplitude weighting for subarrayed4d antenna arrays is proposed in this paper. Based on the combination of time weighted subarray outputs and constant element static weightings in subarrays, this approach can significantly suppress the quantitative sidelobe level of subarrayed4d arrays. Numerical examples with three different approaches of amplitude tapers in 4d linear arrays are presented and compared to demonstrate the effectiveness of the proposed modified approach. Simulation results validate that this approach is a good trade-off of low sidelobe level and simplicity of design.
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