In this paper, a simple and compact tri-band multiple-input-multiple-output (MIMO) antenna for wireless applications is proposed. The antenna is composed of two symmetric monopoles placed a distance of 0.106λ0 and occupies 0.26λ0 × 0.25λ0 board area. The tri-arm monopole offers operation over 2.1–2.7 GHz, 3.3–3.7 GHz and 4.9–5.35 GHz with percentage impedance bandwidth of 25%, 11.4% and 8.7%, respectively. An isolation greater than 20 dB is achieved by integrating a stub in the ground plane and adding a stub in the feed line. The structure exhibits stable gain and radiation patterns. Various performance metrics including envelope correlation coefficient (ECC), diversity gain (DG) and mean effective gain (MEG) are measured.

https://www.jpier.org/pierc/pierc86/15.18061803.pdf

A Simple Tri-Band MIMO Antenna Using a Single Ground Stub

A printed multiband multiple input multiple output (MIMO) antenna system is proposed in this paper. The MIMO antenna system is composed of two identical antenna elements which are perpendicular to each other. The defected ground plane with two microstrip lines is introduced to suppress the coupling between the antenna elements. The proposed MIMO system operates at two separated impedance bandwidths of 770 MHz (2.09–2.86 GHz) and 890 MHz (5.05–5.94 GHz) with an overall size of 50 × 50 × 1.59 mm3. The achieved isolation at the lower and higher frequency bands is higher than 20.9 dB and 17.8 dB, respectively. The proposed MIMO antenna system is feasible to be used for time-division long-term-evolution (TD-LTE, 2300–2655 MHz) and wireless local area network 802.11 a/b/g (WLAN, 2.4–2.4835 GHz, 5.15–5.875 GHz) applications.

https://www.jpier.org/pierl/pierl74/19.18021302.pdf

A Novel Multiband MIMO Antenna for TD-LTE and WLAN Applications

Design of dual band MIMO antenna with improved isolation

In this paper, a novel microstrip line-fed meander-line-based four-elements quad band Multiple Input and Multiple Output (MIMO) antenna is proposed with a gain enhancement technique. The proposed structure resonates at four bands simultaneously, that is, 1.23, 2.45, 3.5 and 4.9 GHz, which resemble GPS L2, Wi-Fi, Wi-MAX and WLAN wireless application bands, respectively. The unit element is extended to four elements MIMO antenna structure exhibiting isolation of more than 22 dB between the adjacent elements without disturbing the resonant frequencies. In order to enhance the gain, two orthogonal microstrip lines are incorporated between the antenna elements which result in significant gain improvement over all the four resonances. Furthermore, the diversity performance of the MIMO structure is analyzed. The Envelope Co-Relation Coefficient (ECC), Diversity Gain (DG), Channel Capacity Loss (CCL), Mean Effective Gain (MEG) and Multiplexing Efficiency are obtained as 0.003, 10 dB, 0.0025 bps/Hz, −3 dB (almost) and 0.64 (min.), respectively, which are competent and compatible with practical wireless applications. The Total Active Reflection Coefficient (TARC) resembles the characteristic of the individual antenna elements. The layout area of the overall MIMO antenna is 0.33 λ × 0.29 λ, where λ is the free-space wavelength corresponding to the lowest resonance. The advantage of the proposed structure has been assessed by comparing it with previously reported MIMO structures based on number of antenna elements, isolation, gain, CCL and compactness. A prototype of the proposed MIMO structure is fabricated, and the measured results are found to be aligned with the simulated results.

https://www.mdpi.com/1424-8220/22/19/7143/pdf?version=1663752355

Compact Quad Band MIMO Antenna Design with Enhanced Gain for Wireless Communications

Compact C‐shaped MIMO diversity antenna for quad band applications with hexagonal stub for isolation improvement

Abstract—Nowadays everyone needs electronic gadgets in compact size, and single device should accomplish all the tasks. A compact MIMO antenna resonating at multi-band of frequencies is proposed in the current research work. The proposed MIMO antenna consists of two elements. The edge to edge separation between the two antennas is λ0/31 and still maintains low mutual coupling levels between the two antennas. The proposed MIMO antenna resonates at 4.75 GHz, 5.89 GHz, 6.74 GHz, 8.25 GHz and 9.82 GHz. The mutual coupling is reduced by −23.78 dB at 4.75 GHz, −25.71 dB at 5.89 GHz, −29 dB at 6.74 GHz, −32.79 dB at 8.25 GHz and −21.5 dB at 9.82 GHz, respectively. The performance of the proposed MIMO system was evaluated in terms of S-parameters, Envelope Correlation Coefficient (ECC), Voltage Standing Wave Ratio (VSWR), and Radiation Pattern. The measured and simulated results are presented.

/pdf/compact-multi-band-mimo-antenna-with-improved-isolation-bglbjyco48.pdf

and Avala Mallikarjuna Prasad

Papers

Compact Multi-Band MIMO Antenna with Improved Isolation