Low-RCS Low-Profile Four-Element MIMO Antenna Using Polarization Conversion Metasurface

Compact antenna, appropriate gain, high efficiency, wide bandwidth, minimum envelope correlation coefficient (ECC), large total active reflection coefficient (TARC) bandwidth, and low specific absorption rate (SAR) are certain conditions set on the present/future generations of wireless communication antennas with the lowest cost of implementation. A compact low profile folded MIMO antenna has been designed using CST tool to cover application at 5.2 GHz. The reported folded MIMO antenna has bandwidth of 600 MHz (5.0-5.6 GHz) and has fractional bandwidth of 11.32 % along with the compact size of 37.5 × 17.0 mm2 . The reported MIMO antenna has ECC of < 10-2. The proposed folded MIMO antenna resonates at 5.2 GHz and has return loss of -44.0 dB. The inter-port isolation in antenna ports is > 11.50 dB in the defined frequency band. The response of TARC shows > 580 MHz of bandwidth with pair of excitation angles at antenna ports. The gain of antenna is > 3.0 dBi in the operating band. The reported radiating geometry makes the design very compact. To check the radiation effect on human body in different positions, the SAR is evaluated for indoor environment.

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A Novel 2.4-GHz Low-Profile Smart MIMO Antenna with Reconfigurable Frequency-Selective Reflectors

Advanced Electromagnetics ◽

10.7716/aem.v9i2.1369 ◽

2020 ◽

Vol 9 (2) ◽

pp. 42-51

Author(s):

C.-H. Tsai ◽

J.-S. Sun ◽

S.-J. Chung ◽

J.-H. Tarng

Keyword(s):

Multiple Input Multiple Output ◽

Antenna System ◽

Switching Network ◽

Ieee 802.11A ◽

Mimo Antenna ◽

Low Profile ◽

Specific Direction ◽

Input Multiple Output ◽

Frequency Selective ◽

Beam Switching

In this paper, a new low-profile smart multiple-input multiple-output (MIMO) antenna system is presented for WiFi IEEE 802.11a/b/g/n/ac/ax applications. The proposed compact 2.4-GHz antenna system employs two beam-switching antenna cells for MIMO operation. Each antenna cell is composed of four reconfigurable frequency-selective reflectors (RFSRs) and a one-to-four switching feeding network. The RFSRs are constructed using a one-wavelength metal loop resonator, which functions as a radiating antenna or a wave reflector to reflect beams along a specific direction, as controlled by the switching network. The feeding switching network utilizes PIN diodes to adjust the phase and impedance required for changing the operational status of each RFSR. The overall dimensions of the antenna system, including the metallic ground, are 120 mm ´ 120 mm ´ 9.5 mm. Moreover, the measured operational bandwidth of the 2.4-GHz antenna is approximately 100 MHz, and the radiation efficiency of each directed beam is 40%–70%.

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Wearable Metamaterial Dual-Polarized High Isolation UWB MIMO Vivaldi Antenna for 5G and Satellite Communications

Micromachines ◽

10.3390/mi12121559 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1559

Author(s):

Adam R. H. Alhawari ◽

Tale Saeidi ◽

Abdulkarem Hussein Mohammed Almawgani ◽

Ayman Taher Hindi ◽

Hisham Alghamdi ◽

...

Keyword(s):

Mutual Coupling ◽

Multiple Input Multiple Output ◽

Satellite Communications ◽

Ultra Wideband ◽

Diversity Gain ◽

Mimo Antenna ◽

Antenna Performance ◽

Low Profile ◽

Input Multiple Output ◽

Conductive Textile

A low-profile Multiple Input Multiple Output (MIMO) antenna showing dual polarization, low mutual coupling, and acceptable diversity gain is presented by this paper. The antenna introduces the requirements of fifth generation (5G) and the satellite communications. A horizontally (4.8–31 GHz) and vertically polarized (7.6–37 GHz) modified antipodal Vivaldi antennas are simulated, fabricated, and integrated, and then their characteristics are examined. An ultra-wideband (UWB) at working bandwidths of 3.7–3.85 GHz and 5–40 GHz are achieved. Low mutual coupling of less than −22 dB is achieved after loading the antenna with cross-curves, staircase meander line, and integration of the metamaterial elements. The antennas are designed on a denim textile substrate with = 1.4 and h= 0.5 mm. A conductive textile called ShieldIt is utilized as conductor with conductivity of 1.8 × 104. After optimizing the proposed UWB-MIMO antenna’s characteristics, it is increased to four elements positioned at the four corners of a denim textile substrate to be employed as a UWB-MIMO antenna for handset communications, 5G, Ka and Ku band, and satellite communications (X-band). The proposed eight port UWB-MIMO antenna has a maximum gain of 10.7 dBi, 98% radiation efficiency, less than 0.01 ECC, and acceptable diversity gain. Afterwards, the eight-ports antenna performance is examined on a simulated real voxel hand and chest. Then, it is evaluated and compared on physical hand and chest of body. Evidently, the simulated and measured results show good agreement between them. The proposed UWB-MIMO antenna offers a compact and flexible design, which is suitably wearable for 5G and satellite communications applications.

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Design and Performance Analysis of a Compact Planar MIMO Antenna for IoT Applications

Sensors ◽

10.3390/s21237909 ◽

2021 ◽

Vol 21 (23) ◽

pp. 7909

Author(s):

Saminathan Thiruvenkadam ◽

Eswaran Parthasarathy ◽

Sandeep Kumar Palaniswamy ◽

Sachin Kumar ◽

Lulu Wang

Keyword(s):

Multiple Input Multiple Output ◽

Back Side ◽

Mimo Antenna ◽

Iot Applications ◽

Quarter Wavelength ◽

Low Profile ◽

Compact Size ◽

Communication Devices ◽

Input Multiple Output ◽

And Performance

This article presents a quad-band multiple-input-multiple-output (MIMO) antenna for the Internet of Things (IoT) applications. The proposed antenna consists of four quarter-wavelength asymmetrical meandered radiators, microstrip feed lines, and modified ground planes. The antenna elements are arranged in a chiral pattern to improve isolation between them, with two radiators and two ground planes placed on the front side of the substrate and the other two on the back side. The MIMO antenna has an operating bandwidth (S11 ≤ −10 dB) of 1.76–1.84 GHz, 2.37–2.56 GHz, 3.23–3.68 GHz, and 5.34–5.84 GHz, covering GSM, WLAN, WiMAX, and 5G frequency bands. The isolation between the radiating elements is greater than 18 dB in the operating bands. The peak gain of the antenna is 3.6 dBi, and the envelope correlation coefficient (ECC) is less than 0.04. Furthermore, the proposed antenna is validated for IoT-based smart home (SH) applications. The prototype MIMO antenna is integrated with a commercially available ZigBee device, and the measured values are found to be consistent with the expected results. The proposed MIMO antenna could be a good candidate for IoT systems/modules due to its low profile, compact size, lightweight, and easy integration with wireless communication devices.

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