Frequency-Selective Surface-Based MIMO Antenna Array for 5G Millimeter-Wave Applications

Abstract

In this paper, a radiating element consisting of a modified circular patch is proposed for MIMO arrays for 5G millimeter-wave applications. The radiating elements in the proposed 2 × 2 MIMO antenna array are orthogonally configured relative to each other to mitigate mutual coupling that would otherwise degrade the performance of the MIMO system. The MIMO array was fabricated on Rogers RT/Duroid high-frequency substrate with a dielectric constant of 2.2, a thickness of 0.8 mm, and a loss tangent of 0.0009. The individual antenna in the array has a measured impedance bandwidth of 1.6 GHz from 27.25 to 28.85 GHz for S11 ≤ −10 dB, and the MIMO array has a gain of 7.2 dBi at 28 GHz with inter radiator isolation greater than 26 dB. The gain of the MIMO array was increased by introducing frequency-selective surface (FSS) consisting of 7 × 7 array of unit cells comprising rectangular C-shaped resonators, with one embedded inside the other with a central crisscross slotted patch. With the FSS, the gain of the MIMO array increased to 8.6 dBi at 28 GHz. The radiation from the array is directional and perpendicular to the plain of the MIMO array. Owing to the low coupling between the radiating elements in the MIMO array, its Envelope Correlation Coefficient (ECC) is less than 0.002, and its diversity gain (DG) is better than 9.99 dB in the 5G operating band centered at 28 GHz between 26.5 GHz and 29.5 GHz.

High-Isolation Wide-Band Four-Element MIMO Antenna Covering Ka-Band for 5G Wireless Applications

“…The proposed antenna addresses the above issue with connected ground through a novel DCS structure. The proposed antenna has resulted in a stable |S-parameter| response with an isolation of > 30 dB, which is better than [16]- [18], [20], [21], [23], [44]- [46]. The designed antenna has wide bandwidth compared to [14], [15], [18]- [21], [23].…”

“…The designed antenna has wide bandwidth compared to [14], [15], [18]- [21], [23]. Most of the antenna in the literature, such as [14], [16], [18]- [21], [44]- [46], has computed the ECC using |S-parameter|, which is an approximate and inaccurate method. The correct ECC is calculated through a radiation pattern by considering all the radiation losses.…”

A Dual-Band Polarization-Insensitive Frequency Selective Surface for Electromagnetic Shielding Applications

“…On the other hand, frequency-selective surfaces (FSSs) are immune to such shortcomings and suitable, where selective shielding is required because of their small size, low cost, stable frequency responses, ease of fabrication, and employability. FSSs are the periodic arrangement of metallic resonant elements in two or three dimensions that can allow/shield/absorb electromagnetic waves and find widespread employability, including, but not limited to, radomes [ 1 ], EM absorbers [ 2 , 3 , 4 ], polarizers [ 5 ], antenna gain enhancement [ 6 ], RF energy harvesting [ 7 ], satellite communication [ 8 ], electromagnetic interference mitigation [ 9 , 10 ], and many others.…”

Superdirective Wideband Array of Circular Monopoles with Loaded Patches for Wireless Communications

“…It was reported in [ 7 ] that the normal directivity of an antenna can attain D n = (ka) 2 + 2ka, where k is the wave number and a is the radius of the smallest sphere that encloses the antenna. Superdirective antenna arrays can be designed to achieve higher levels of directivity compared to conventional antenna arrays, improving communication distance and quality [ 8 , 9 , 10 ]. Especially for devices in tight spaces, the physical size of the superdirective antenna is minimized while achieving high directivity [ 11 , 12 ].…”