DESIGN AND MEASUREMENTS OF A MULTIPLE-OUTPUT TRANSMITTER FOR MIMO APPLICATIONS

2011 ◽  
Vol 20 (03) ◽  
pp. 515-529 ◽  
Author(s):  
CONSTANTINOS I. VOTIS ◽  
PANOS KOSTARAKIS ◽  
LEONIDAS P. IVRISSIMTZIS
Keyword(s):  
Antenna Array ◽  
Beam Steering ◽  
Multiple Input Multiple Output ◽  
Direct Digital Synthesis ◽  
Digital Beamforming ◽  
Channel Sounder ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Digital Synthesis ◽  
Array Performance

The design of a multiple-output transmitter for digital beamforming (DBF), Multiple-Input Multiple-Output (MIMO) and channel sounder applications, based on Direct Digital Synthesis (DDS) system is presented and investigated in terms of antenna array performance. DDS generates independently modulated signals on specific carrier frequencies and is employed as the first stage in the proposed implementation, furnishing output signal of configurable amplitude, phase and frequency. The resulting phase progression, amplitude and beamforming accuracy of a beam steering array are further investigated, showing that the proposed architecture can provide a steering beam with high accuracy. Experimental results of system performance indicate that this architecture can drive efficiently and accurately an antenna array with independent modulated RF signals, with programmable frequency, initial phase, and magnitude.

scholarly journals MIMO Antenna Array Design with Polynomial Factorization

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Wen-Qin Wang ◽  
Huaizong Shao ◽  
Jingye Cai
Keyword(s):  
Antenna Array ◽  
Degrees Of Freedom ◽  
Multiple Input Multiple Output ◽  
Factorization Method ◽  
Polynomial Factorization ◽  
Mimo Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Simulation Results ◽  
Array Performance

One of the main advantages of multiple-input multiple-output (MIMO) antenna is that the degrees-of-freedom can be significantly increased by the concept of virtual antenna array, and thus the MIMO antenna array should be carefully designed to fully utilize the virtual antenna array. In this paper, we design the MIMO antenna array with the polynomial factorization method. For a desired virtual antenna array, the polynomial factorization method can optimally design the specified MIMO transmitter and receiver. The array performance is examined by analyzing the degrees-of-freedom and statistical output signal-to-interference-plus-noise ratio (SINR) performance. Design examples and simulation results are provided.

Experimental investigation of beam-steering applied to 2 × 2 MIMO system with single receiving RF chain and time-modulated antenna array

2020 ◽  
Vol 12 (6) ◽  
pp. 504-512
Author(s):  
Grzegorz Bogdan ◽  
Konrad Godziszewski ◽  
Yevhen Yashchyshyn
Keyword(s):  
Experimental Investigation ◽  
Antenna Array ◽  
Software Defined Radio ◽  
Mimo System ◽  
Beam Steering ◽  
Multiple Input Multiple Output ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Considerable Impact ◽  
Rf Chain

AbstractMultiple antennas and multiple radio frequency (RF) chains in both the transmitter and receiver are required in conventional radio systems employing the multiple-input multiple-output (MIMO) method. This paper presents an experimental investigation of a beam-steering time-modulated MIMO receiver with a single RF chain. Implementation of the receiver is based on a time-modulated antenna array (TMAA) and a software-defined radio. The sidebands generated inherently by the TMAA are utilized as virtual spatial channels with the beam-steering functionality. Performance of the system is investigated experimentally. The bit error rate and condition number of the channel matrix are examined for different radiation patterns in order to determine favorable configurations in a given multipath environment. Obtained results show a considerable impact of the beam-steering on the performance of MIMO transmission.

Compact four-port vertically polarized UWB monopole antenna for MIMO communications

Circuit World ◽  
2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Premalatha J. ◽  
Sheela D.
Keyword(s):  
Antenna Array ◽  
Performance Metrics ◽  
Multiple Input Multiple Output ◽  
Unit Cell ◽  
Ultra Wideband ◽  
Mimo Communications ◽  
Content Type ◽  
Directional Radiation ◽  
Multiple Input ◽  
Input Multiple Output

Purpose This paper aims to present the design of a compact vertically polarized four-element UWB antenna suitable for MIMO communications. Design/methodology/approach The unit cell antenna is constructed using a square ring radiator excited through a stepped impedance feed. The proposed antenna covers the Ultra-wideband (UWB) spectrum ranging from 2.2 to 12.3 GHz. The isolation between the unit cell antennas in the array is enhanced using a simple microstrip line resonator. The decoupling element is connected to the ground through a via. Findings The proposed scheme offers at least 16 dB improvement in the port-to-port coupling. Furthermore, the four-element antenna array is constructed using a specific interlocking scheme. The proposed antenna array’s Multiple Input Multiple Output (MIMO) performance metrics are analyzed. Originality/value By suitably selecting the excitation port, directional radiation patterns can be realized. The combined radiation pattern covers 360 degrees. A prototype antenna array is fabricated, and the simulation results are verified using real-time experiments. The proposed antenna is a suitable candidate for shark fin housing in automotive communications.

scholarly journals Downlink Multiuser Hybrid Beamforming for MmWave Massive MIMO-NOMA System with Imperfect CSI

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Jing Jiang ◽  
Ming Lei ◽  
Huanhuan Hou
Keyword(s):  
Multiple Access ◽  
Multiple Input Multiple Output ◽  
Digital Beamforming ◽  
Cluster Set ◽  
Power Difference ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Hybrid Beamforming ◽  
Rate Requirement ◽  
Effective Channel

This paper aims to provide a comprehensive scheme with limited feedback for downlink millimeter wave (mmWave) multiuser multiple-input multiple-output (MIMO) nonorthogonal multiple access (NOMA) system. Based on the feedback of the best beam and the channel quality information (CQI) on this beam, the users are grouped into a cluster having the same or coherent best beam and the maximal CQI-difference. To further reduce the intercluster interference, only the candidate cluster can join the cluster set whose intercluster correlation with the existing clusters is lower than threshold. Based on the results of clustering, mmWave hybrid beamforming is designed. To improve the user experience, each cluster selects the best beam of the user with the higher guaranteed rate requirement as the analog beamforming vector. For digital beamforming, the weak user applies the block diagonalization algorithm based on the strong user’s effective channel to reduce its intracluster interference. Finally, an intracluster power allocation algorithm is developed to maximize the power difference in each cluster which is beneficial to improve the successive interference cancelation (SIC) performance of the strong user. Finally, simulation results show that the proposed MIMO-NOMA scheme offers a higher sum rate than the traditional orthogonal multiple access (OMA) scheme under practical conditions.

scholarly journals DBF Processing in Range-Doppler Domain for MWE SAR Waveform Separation Based on Digital Array-Fed Reflector Antenna

2020 ◽  
Vol 12 (19) ◽  
pp. 3161
Author(s):  
Shenjing Wang ◽  
Yifan Sun ◽  
Feng He ◽  
Zaoyu Sun ◽  
Pengcheng Li ◽  
...  
Keyword(s):  
Rapid Development ◽  
Multiple Input Multiple Output ◽  
High Gain ◽  
Reflector Antenna ◽  
Time Shift ◽  
Planar Antenna ◽  
Digital Beamforming ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Short Time

With the rapid development of the multiple-input multiple-output synthetic aperture radar (MIMO SAR) system, the demands for miniaturization and high gain of antenna are increasing. The digital array-fed reflector antenna has such virtues so that it can play an important role in such system. However, the geometric models and signal models based on a reflector antenna are considerably different from the directly radiating planar antenna. The signal processing for the reflector antenna is more complex and difficult. As a result, the applications of the reflector antenna in SAR system are not as mature as those of the planar antenna. A combination of multidimensional waveform encoding (MWE) technique and digital beamforming (DBF) technology at the receiving end can greatly improve the MIMO SAR system performance, especially ambiguity suppression and waveform separation. This configuration can realize different radar functions and meet multidimensional observation requirements, such as the polarized SAR. Thus, this study combines digital array-fed reflector antenna and the DBF technique in the elevation direction for MWE SAR waveform separation. The echo models for the array-fed reflector antenna and the planar antenna are established based on short-time shift-orthogonal waveforms. In the models, a mismatch in steering vectors is inevitable if DBF processing is continuously performed traditionally in the azimuth-elevation two-dimensional time domain. This mismatch will worsen the waveform separation effect and the image quality. Therefore, we propose a DBF method which is processed in range-Doppler domain. The method enables waveform separation without ambiguity at the receiver. Then, the conventional SAR imaging methods are enabled, and we acquire an ideal SAR image. The simulation results for both point targets and distributed targets prove the effect and feasibility of the proposed DBF method.

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