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.

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 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 A Novel MIMO–SAR Solution Based on Azimuth Phase Coding Waveforms and Digital Beamforming

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3374 ◽  
Author(s):  
Fang Zhou ◽  
Jiaqiu Ai ◽  
Zhangyu Dong ◽  
Jiajia Zhang ◽  
Mengdao Xing
Keyword(s):  
Multiple Input Multiple Output ◽  
Three Dimensional ◽  
Spatial Diversity ◽  
Reconstruction Method ◽  
Digital Beamforming ◽  
Phase Coding ◽  
Imaging Result ◽  
Multiple Input ◽  
Input Multiple Output ◽  
The Time Domain

In multiple-input multiple-output synthetic aperture radar (MIMO–SAR) signal processing, a reliable separation of multiple transmitted waveforms is one of the most important and challenging issues, for the unseparated signal will degrade the performance of most MIMO–SAR applications. As a solution to this problem, a novel APC–MIMO–SAR system is proposed based on the azimuth phase coding (APC) technique to transmit multiple waveforms simultaneously. Although the echo aliasing occurs in the time domain and Doppler domain, the echoes can be separated well without performance degradation by implementing the azimuth digital beamforming (DBF) technique, comparing to the performance of the orthogonal waveforms. The proposed MIMO–SAR solution based on the APC waveforms indicates the feasibility and the spatial diversity of the MIMO–SAR system. It forms a longer baseline in elevation, which gives the potential to expand the application of MIMO–SAR in elevation, such as improving the performance of multibaseline InSAR and three-dimensional SAR imaging. Simulated results on both a point target and distributed targets validate the effectiveness of the echo separation and reconstruction method with the azimuth DBF. The feasibility and advantage of the proposed MIMO–SAR solution based on the APC waveforms are demonstrated by comparing with the imaging result of the up- and down-chirp waveforms.

scholarly journals Comparison of 10–18 GHz SAR and MIMO-based short-range imaging radars

2010 ◽  
Vol 2 (3-4) ◽  
pp. 369-377 ◽  
Author(s):  
Timofey Savelyev ◽  
Xiaodong Zhuge ◽  
Bill Yang ◽  
Pascal Aubry ◽  
Alexander Yarovoy ◽  
...  
Keyword(s):  
Short Range ◽  
Multiple Input Multiple Output ◽  
Vertical Plane ◽  
Ultra Wideband ◽  
Imaging Method ◽  
Digital Beamforming ◽  
Mimo Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Concealed Weapon Detection

This paper presents an experimental investigation of two approaches to short-range radar imaging at microwaves by means of ultra-wideband (UWB) technology. The first approach represents a classical synthetic aperture radar (SAR) that employs a transmit–receive antenna pair on mechanical scanner. The second one makes use of a multiple input multiple output (MIMO) antenna array that scans electronically in the horizontal plane and mechanically, installed on the scanner, in the vertical plane. The mechanical scanning in only one direction reduces significantly the measurement time. Two respective prototypes have been built and compared. Both systems comprise the same 10–18 GHz antennas and multi-channel video impulse electronics while the same data processing and imaging method based on Kirchhoff migration is applied to acquired data for digital beamforming. The study has been done for an application of concealed weapon detection.

scholarly journals Metamaterial-Based Highly Isolated MIMO Antenna for Portable Wireless Applications

Electronics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 267 ◽  
Author(s):  
Amjad Iqbal ◽  
Omar A Saraereh ◽  
Amal Bouazizi ◽  
Abdul Basir
Keyword(s):  
Mutual Coupling ◽  
Multiple Input Multiple Output ◽  
High Gain ◽  
Metamaterial Structure ◽  
Mimo Antenna ◽  
Wireless Applications ◽  
Capacity Loss ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Edge Separation

In this paper, a metamaterial structure is presented to lower the mutual coupling between the closely spaced microstrip patch antenna elements. Two elements Multiple Input Multiple Output (MIMO) antenna is closely placed with each other at edge to edge separation of 0.135 λ 0 (7 mm). Isolation improvement of 9 dB is achieved by keeping the metamaterial structure in between the MIMO elements. With the proposed structure, the isolation is achieved around −24.5 dB. Due to low ECC, high gain, low channel capacity loss and very low mutual coupling between elements, the proposed antenna is a good candidate for the MIMO applications. The proposed antenna is fabricated and tested. A reasonable agreement between simulated and measured results is observed.

Near Zero Parameter Metamaterial Inspired Superstrate for Isolation Improvement in MIMO Wireless Application

Frequenz ◽  
2020 ◽  
Vol 74 (1-2) ◽  
pp. 17-23
Author(s):  
Robert Mark ◽  
Soma Das
Keyword(s):  
Multiple Input Multiple Output ◽  
High Gain ◽  
Antenna System ◽  
Impedance Bandwidth ◽  
Mimo Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Wireless Application ◽  
Measured Impedance ◽  
Edge Separation

AbstractIn this paper, near zero parameter based metamaterial superstrate is presented for mutual coupling reduction in multiple-input-multiple-output (MIMO) antenna. The proposed design offers a peak isolation of 38 dB with edge-separation of 0.042λ0 at resonating frequency. To verify the simulations results, a prototype of the proposed antenna is fabricated and experimentally measured. The two elements MIMO is designed with measured impedance bandwidth of 5.6 to 5.95 GHz with a peak measured gain of 7.4 dBi and efficiency above 95 %.The measurement established an isolation enhancement of 30 dB with minimum correlation coefficient of 0.05 within operating band. The proposed method offers a good design technique for high gain and closely packed MIMO antenna system for WLAN applications.

Dual circular slot ring triple-band MIMO antenna for 5G applications

Frequenz ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Anand Kumar ◽  
Santosh Kumar Mahto ◽  
Rashmi Sinha ◽  
Arvind Choubey
Keyword(s):  
Mutual Coupling ◽  
Ground Plane ◽  
Multiple Input Multiple Output ◽  
Mobile Terminal ◽  
High Gain ◽  
Mimo Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Smart Wearable ◽  
Triple Band

AbstractA Triple-band Multiple-Input-Multiple-Output (MIMO) antenna for 5G mobile terminal applications is proposed in this paper. The design comprises four-port/two resonators, each having two concentric circular slot ring radiators etched on a ground plane of size 50 mm ${\times}$ 50 mm. The antenna is fed by perpendicularly arranged 50 Ω microstrip line feeds on the top layer. Decoupling techniques were used to suppress mutual coupling between the two resonators. The perpendicular arrangement of the feed lines and port reduces mutual coupling between the two ports and increases isolation. The antenna operates in multiple bands: 3.35–3.69 GHz, 24–28 GHz, and 37–40 GHz frequency range with central frequencies at 3.5 GHz, 26 GHz, and 38 GHz, respectively allocated for 5G. The antenna provides a gain of 2.7–7.8 dB and a radiation efficiency of 0.49–0.85 in the operating bands. Diversity performance is studied in terms of the Envelop Correlation Coefficient (ECC), Diversity Gain (DG), and Total Active Reflection Coefficient (TARC) were found to be less than 0.01, greater than 9.99 dB, and less than −10 dB respectively. The proposed antenna offers good S-parameters, voltage standing wave ratio (VSWR), TARC, radiation pattern, high gain, and low ECC. The antenna was fabricated and tested. The measured results and simulated results are in good agreement. It possesses sufficient potential for 5G mobile terminal and smart wearable applications.

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