High‐gain, high‐isolation, and wideband millimetre‐wave closely spaced multiple‐input multiple‐output antenna with metamaterial wall and metamaterial superstrate for 5G applications

This paper presents a close-spaced dual-band 2 × 2 multiple-input multiple-output (MIMO) antenna with high isolation based on half-mode substrate integrated waveguide (HMSIW). The dual-band operation of the antenna element is achieved by loading a rectangular patch outside the radiating aperture of an HMSIW cavity. The HMSIW cavity is excited by a coaxial probe, whereas the rectangular patch is energized through proximity coupling by the radiating aperture of HMSIW. The antenna elements can be closely placed using the rotation and orthogonal arrangement for a 2 × 2 array. Small neutralization lines at the center of the MIMO antenna can increase the isolation among its elements by around 10 dB in the lower band and 5 dB in the higher band. A prototype of the MIMO antenna is fabricated and its performance is measured. The measured results show that the resonant frequencies are centered at 4.43 and 5.39 GHz with bandwidths of 110 and 80 MHz and peak gains of 6 and 6.4 dBi, respectively. The minimum isolation in both bands is greater than 35 dB. The envelope correlation coefficient is lower than 0.005 within two operating bands.

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A High Isolation MIMO Antenna without Decoupling Structure for LTE 700 MHz

International Journal of Antennas and Propagation ◽

10.1155/2015/436259 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Yanjie Wu ◽

Yunliang Long

Keyword(s):

Impedance Matching ◽

Multiple Input Multiple Output ◽

Monopole Antenna ◽

Antenna Element ◽

Mimo Antenna ◽

High Isolation ◽

Antenna Performance ◽

Measurement Results ◽

Multiple Input ◽

Input Multiple Output

This paper presents a long-term evolution (LTE) 700 MHz band multiple-input-multiple-output (MIMO) antenna, and high isolation between the two symmetrical antenna elements is obtained without introducing extra decoupling structure. Each antenna element is a combination antenna of PIFA and a meander monopole antenna. The end of the PIFA and the meander monopole antenna are, respectively, overlapped with the 50 Ω microstrip feed line, the two overlapping areas produce additional capacitance which can be considered decoupling structures to enhance the isolation for the MIMO antenna, as well as the impedance matching of the antenna elements. The MIMO antenna is etched on FR4 PCB board with dimensions of 71 × 40 × 1.6 mm3; the edge-to-edge separation of the two antenna elements is only nearly 0.037 λat 700 MHz. Both simulation and measurement results are used to confirm the MIMO antenna performance; the operating bandwidth is 698–750 MHz withS11≤−6 dB andS21≤−23 dB.

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Frequency reconfigurable multiple-input multiple-output antenna with high isolation

IET Microwaves Antennas & Propagation ◽

10.1049/iet-map.2011.0325 ◽

2012 ◽

Vol 6 (10) ◽

pp. 1095 ◽

Cited By ~ 31

Author(s):

Z.-J. Jin ◽

J.-H. Lim ◽

T.-Y. Yun

Keyword(s):

Multiple Input Multiple Output ◽

High Isolation ◽

Multiple Input ◽

Input Multiple Output

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High Isolation Millimeter-Wave Wideband MIMO Antenna for 5G Communication

International Journal of Antennas and Propagation ◽

10.1155/2019/4283010 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 6

Author(s):

Fei Wang ◽

Zhaoyun Duan ◽

Xin Wang ◽

Qing Zhou ◽

Yubin Gong

Keyword(s):

Wireless Communications ◽

Transmission Coefficient ◽

Millimeter Wave ◽

Multiple Input Multiple Output ◽

Mimo Antenna ◽

High Isolation ◽

Multiple Input ◽

Input Multiple Output ◽

The Stability ◽

24 Ghz

A millimeter-wave wideband antenna is presented for the 5th generation applications. The operation band ranges from 24 GHz to 39 GHz which covers most of the Ka band. Furthermore, a 9×9 multiple-input-multiple-output (MIMO) antenna is developed. The high isolation is achieved without introducing external decoupling structures. The transmission coefficient is under −20 dB within only 0.4 mm space between antenna elements. The radiation pattern also shows the stability within the wide operation band. Both simulated and measured results show that this proposed MIMO antenna is suitable for the future wireless communications.

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

Remote Sensing ◽

10.3390/rs12193161 ◽

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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