8-Port Semi-Circular Arc MIMO Antenna with an Inverted L-Strip Loaded Connected Ground for UWB Applications

Abstract

Multiple-input multiple-output (MIMO) antennas with four and eight elements having connected grounds are designed for ultra-wideband applications. Careful optimization of the lines connecting the grounds leads to reduced mutual coupling amongst the radiating patches. The proposed antenna has a modified substrate geometry and comprises a circular arc-shaped conductive element on the top with the modified ground plane geometry. Polarization diversity and isolation are achieved by replicating the elements orthogonally forming a plus shape antenna structure. The modified ground plane consists of an inverted L strip and semi ellipse slot over the partial ground that helps the antenna in achieving effective wide bandwidth spanning from (117.91%) 2.84–11 GHz. Both 4/8-port antenna achieves a size of 0.61 λ × 0.61 λ mm2 (lowest frequency) where 4-port antenna is printed on FR4 substrate. The 4-port UWB MIMO antenna attains wide impedance bandwidth, Omni-directional pattern, isolation >15 dB, ECC < 0.015, and average gain >4.5 dB making the MIMO antenna suitable for portable UWB applications. Four element antenna structure is further extended to 8-element configuration with the connected ground where the decent value of IBW, isolation, and ECC is achieved.

Planar MIMO antenna for mmWave applications: Evolution, present status & future scope

“…In [ 55 , [87] , [88] , [89] , [90] , [91] , [92] , [93] , [94] ], and [ 95 ], the designs share the common ground between all ports of MIMO, in which the first four are 2-port, and others are 4-port MIMO where elements are arranged in orthogonal orientation for better isolation. In Ref.…”

A double‐leaf‐shaped four‐port MIMO antenna for ultra‐wideband applications

“…The time‐domain analysis of the UWB antenna is necessary for system applications. Two similar antennas are placed at a distance enough to ensure the far‐field scenario (15 cm in this case) in the time‐domain analysis 44 . One antenna works as a transmitter and the other as a receiver.…”

“…Two similar antennas are placed at a distance enough to ensure the far-field scenario (15 cm in this case) in the time-domain analysis. 44 One antenna works as a transmitter and the other as a receiver. A short Gaussian pulse excites the transmitter antenna, received at the other end, and the obtained results are analyzed.…”

“…The coplanar waveguide (CPW) feed arrangement is one of the most suitable methods for achieving UWB performance 7,8 . In the large variety of UWB MIMO antenna designs available in the literature, 9–45 the intra‐element isolation is improved using many different techniques, including stubs between antenna elements, EBG (electromagnetic bandgap) structures, FSS (frequency selective surfaces), neutralization lines, DGS (defected ground structure), slotted edge substrate, and different decoupling structures. In the above‐discussed geometries, either the design dimensions are large compared to those of wireless devices, or their bandwidth is unable to cover the future wireless communication services beyond 14 GHz, or the MIMO parameter values are barely acceptable.…”

A butterfly-like slot UWB antenna with WLAN band-notch characteristics for MIMO applications

“…In [10,11], neutralization line structure is added between antenna elements to reduce mutual coupling. In [12,13,14,15], the antenna elements are placed in an orthogonal way, and polarization diversity technology is adopted to achieve natural isolation between antenna units. In addition, the isolation degree of antenna can be enhanced by introducing parasitic element [16,17,18,19], EBG structure [20] and decoupling network [21].…”