Isolation Improvement in UWB-MIMO Antenna System Using Slotted Stub

Abstract

Multiple-input multiple-output (MIMO) scheme refers to the technology where more than one antenna is used for transmitting and receiving the information packets. It enhances the channel capacity without more power. The available space in the modern compact devices is limited and MIMO antenna elements need to be placed closely. The closely spaced antennas undergo an undesirable coupling, which deteriorates the antenna parameters. In this paper, an ultra wide-band (UWB) MIMO antenna system with an improved isolation is presented. The system has a wide bandwidth range from 2–13.7 GHz. The antenna elements are closely placed with an edge to edge distance of 3 mm. In addition to the UWB attribute of the system, the mutual coupling between the antennas is reduced by using slotted stub. The isolation is improved and is below −20 dB within the whole operating range. By introducing the decoupling network, the key performance parameters of the antenna are not affected. The system is designed on an inexpensive and easily available FR-4 substrate. To better understand the working of the proposed system, the equivalent circuit model is also presented. To model the proposed system accurately, different radiating modes and inter-mode coupling is considered and modeled. The EM model, circuit model, and the measured results are in good agreement. Different key performance parameters of the system and the antenna element such as envelope correlation coefficient (ECC), diversity gain, channel capcity loss (CCL) gain, radiation patterns, surface currents, and scattering parameters are presented. State-of-the-art comparison with the recent literature shows that the proposed antenna has minimal dimensions, a large bandwidth, an adequate gain value and a high isolation. It is worth noticeable that the proposed antenna has high isolation even the patches has low edge-to-edge gap (3 mm). Based on its good performance and compact dimensions, the proposed antenna is a suitable choice for high throughput compact UWB transceivers.

Design and Fabrication of a Printed Tri-Band Antenna for 5G Applications Operating across Ka-, and V-Band Spectrums

“…In order to obtain the targeted bands, a rectangular shaped stub is loaded at the bottom of semi-circular shaped radiator. The stub loading technique is well known due to its numerous advantages, not limited to improvement of the impedance bandwidth and improved matching at the desired frequency, as explained briefly in [23][24][25]. The stub loaded semi-circular radiator offers tri band operational modes with pass bands of 29.7−33 GHz, 38−40.5 GHz and 52−58 GHz with respective resonances at 30 GHz, 39 GHz, and 54 GHz.…”

Half-Elliptical Resonator Lowpass Filter with a Wide Stopband for Low Band 5G Communication Systems

“…Microstrip technology was used for implementation of the proposed filter. This technology has several advantages, such as low fabrication cost, planar configuration and ease of integration with other Radio Frequency (RF) components; hence, it has been widely used in microwave component designs, including filters [30,31], metasurfaces [32][33][34], power dividers [35][36][37], phase shifters [38] and antennas [39][40][41][42]. The LCE circuit is used to locate the transmission zeros (TZs) of the resonator.…”

Design and Performance Analysis of a Compact Quad-Element UWB MIMO Antenna for Automotive Communications

“…However, high mutual coupling between the antenna elements can be a problem in MIMO systems. Many techniques, such as the orthogonal arrangement of the antenna elements [7], decoupling structures [8][9][10][11], quasi-self-complementary designs [12][13][14], and fractal structures [15], have been proposed for improving inter-element isolation. In [16], the radiating elements were wrapped around a cuboid polystyrene block to improve the correlation between them.…”

“…The proposed MIMO antenna performs better in terms of the DG, the TARC, and the MEG, whereas in [11,15,16,22,24,32] the DG of the reported antenna designs was not investigated.…”