A four-port MIMO antenna array with wideband and high isolation characteristics for imminent wireless systems functioning in 5G New Radio (NR) sub-6 GHz n77/n78/n79 and 5 GHz WLAN bands is proposed. Each array antenna element is a microstrip-line fed monopole type. The novelty of the antenna lies in loading an “EL” slot into the radiating element along with two identical stubs coupled to the partial ground in order to improve the impedance matching and radiation characteristics across the bands of interest. To further attain high port isolation without affecting the compactness and radiation performance of each antenna element, the technique of introducing an innovative un-protruded multi-slot (UPMS) isolating element (of low-profile 2 × 19 mm2) between two closely spaced antenna elements (with an edge-to-edge distance of approx. 0.03λ at 4.6 GHz) is also presented. Besides demonstrating a small footprint of 30 × 40 × 1.6 mm3, the proposed four-port MIMO antenna array has also shown wide 10-dB impedance bandwidth of 58.56% (3.20–5.85 GHz), high isolation of more than 17.5 dB, and good gain and efficiency of around 3.5 dBi and 85%, respectively, across the bands of interest. Finally, the MIMO performance metrics of the proposed antenna are also analyzed.

Wideband Four-Port MIMO antenna array with high isolation for future wireless systems

This paper introduces new compact microstrip line fed dual-band printed MIMO antennas resonating at 28 GHz and 38 GHz which are appropriate for 5G mobile communications. The first design in this work is a two-element conventional rectangular microstrip patch antenna with inset feed intended for 28 GHz and 38 GHz bands. The second design is symmetric dual-band two-element MIMO slottedrectangular patches via microstrip inset fed lines. The dual-band response is attained from inverted I-shaped slots inserted in main patches. The third design is symmetric dual-band four-element MIMO antenna with inverted I-shaped slotted rectangular patches. A slot formed DGS is inserted in the partial rectangular ground plane. The substrate size is 55× 110 mm2, while the introduced antennas have very modest planar configurations and inhabit an insignificant area which make them fit easier within handset devices for the forthcoming 5G mobile communications. Better return losses and larger bandwidths are realized. The MIMO antennas have low mutual coupling without using any added constructions. The antenna systems offer appropriate values of directivity, gain, and radiation efficiency with anticipated reflection and correlation coefficient characteristics which are seemly for 5G mobile applications. The antenna systems are fabricated by a photolithography process that uses optic-radiation to copy the mask on a silicon slab by the aid of photoresist layers and measured using Vector Network Analyzer ZVA 67 (measures up to 67 GHz frequency) with a port impedance of 50 Ω.

https://www.jpier.org/pierc/pierc93/09.19032303.pdf

Novel Dual-Band 28/38 GHz MIMO Antennas for 5G Mobile Applications

In this paper, two compact and small size 2 × 2 and 4 × 4 multiple-input-multiple-output (MIMO) antennas are designed and fabricated for ultra-wideband applications. Using the neutralization line technique, the mutual coupling between the radiating patches is highly reduced. The overall dimension of the proposed 2 × 2 and 4 × 4 UWB MIMO antennas are 21 × 34 × 1.6 mm3 and 48 × 34 × 1.6 mm3, respectively. The measured bandwidth of 95.22% (3.51–9.89 GHz) and 96.47% (3.52–10.08 GHz) with better isolation of ≤–22 dB and ≤–23 dB for 2 port and 4 port antennas are, respectively, achieved. The measured (4 × 4 antenna) realized gain and radiation efficiency vary from 0.95 to 2.91 dB and from 70.01% to 79.87% respectively, throughout the entire frequency band. Moreover, the performance of 4 × 4 MIMO antenna, in terms of isolation, realized gain, radiation efficiency, envelope correlation coefficient (ECC), diversity gain (DG), mean effective gain (MEG), total active reflection coefficient (TARC), channel capacity loss (CCL) and radiation patterns are studied and corresponding results are validated with the measured results.

Neutralization technique based two and four port high isolation MIMO antennas for UWB communication

In this paper, an ultra-compact two-port MIMO antenna working in the frequency range of 3.1–10.6 GHz with dual band-notched characteristics is presented. The MIMO antenna consists of two identical octagonal-shaped radiating elements placed adjacent to each other with a connected ground plane. The overall size of the proposed two-port UWB-MIMO antenna is 19 × 30 × 0.8 mm3. In the ground plane of antenna elements, a T-shaped stub is introduced to create band-notch at 5.5 GHz. Also, an open-ended half-guided-wavelength resonator slot is introduced along the upper edge of the octagonal radiator to obtain a broader notched-band (4.37–5.95 GHz). The second band-notch is created around 7 GHz (6.52–7.45 GHz) by etching another open-ended slot from the radiating patch. The two-notch bands reject interference due to HiperLAN, WiMAX, INSAT/Super-extended C-band, downlink of X-band satellite communication and RFID service bands. A pair of L-shaped slits are introduced in the feed line to improve impedance matching, for the frequency band available between the two notches. The proposed design is fabricated on an FR-4 substrate and minimum isolation greater than 18 dB (a major portion >22 dB) and envelope correlation coefficient (ECC) less than 0.13 are obtained. The antenna gain varies in the range of 1.2–2.91 dBi with a variation of 1.71 dBi only. A radiation efficiency, greater than 70% is achieved throughout the operating frequency band.

An ultra-compact two-port UWB-MIMO antenna with dual band-notched characteristics

Written communications recorded through channels such as mailing lists or issue trackers, but also code co-changes, have been used to identify emerging collaborations in software projects. Also, such data has been used to identify the relation between developers' roles in communication networks and source code changes, or to identify mentors aiding newcomers to evolve the software project. However, results of such analyses may be different depending on the communication channel being mined. This paper investigates how collaboration links vary and complement each other when they are identified through data from three different kinds of communication channels, i.e., mailing lists, issue trackers, and IRC chat logs. Also, the study investigates how such links overlap with links mined from code changes, and how the use of different sources would influence (i) the identification of project mentors, and (ii) the presence of a correlation between the social role of a developer and her changes. Results of a study conducted on seven open source projects indicate that the overlap of communication links between the various sources is relatively low, and that the application of networks obtained from different sources may lead to different results.

How Developers' Collaborations Identified from Different Sources Tell Us about Code Changes

In this paper, a novel structure of CPW-Fed MIMO antenna is presented for dual-band applications covering 2.4/5.8 GHz ISM band, 2300 MHz LTE-4G band, HiperLAN (5–6 GHz) and IEEE C-bands. A Rectangle-Split-Ring-Resonator (RSRR) slot has been embedded in the patch antenna to create a band-notch centered around 3.74 GHz in order to isolate the high traffic of 3.5 GHz WiMAX band and convert a wideband antenna into a dual-band antenna which is mainly focused on the WLAN bands. A modified ground structure is implemented to control and achieve a higher impedance bandwidth (IBW) up to 64% in the upper band, ranging from 3.90 to 7.55 GHz while the lower band, ranges from 2.24 to 2.90 GHz with an IBW of 26%. A novel ITI-shaped isolation structure is designed and placed between the patch antennas, which are separated by a center-to-center distance of 0.35λ0, helping in achieving a minimum measured isolation of 24 dB across the dual-band. The design has been fabricated on an FR-4 substrate of dimension 72 × 56 × 0.8 mm3 with a minimum measured gain of 2.5 dBi across the operating bands.

A novel ITI-shaped isolation structure placed between two-port CPW-fed dual-band MIMO antenna for high isolation

In this paper, a compact modified Sierpinski carpet fractal ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with a square-shaped funnel-like ground stub is presented and experimentally investigated. Miniaturization and wideband performance are achieved by using the proposed fractal structure. Iterated function system (IFS) method is used to design the proposed fractal structure. The self-similarity dimension of the proposed fractal structure is 1.72. The dimension of the proposed MIMO antenna is 24 × 30 mm2 and consists of two novels modified Sierpinski carpet fractal monopole-antenna elements. The impedance bandwidth of the presented antenna is 9.6 GHz (S11

A compact modified sierpinski carpet fractal UWB MIMO antenna with square-shaped funnel-like ground stub

Abstract In this paper, a compact 4×4 multiple-input-multiple-output (MIMO) patch antenna has been presented for triple band operation. Out of the 4 antennas, two are tuned to cover DCS (Digital Cellular System) downlink and two are tuned to cover DCS uplink frequency separately along with two common operating frequency centered around 2.45 GHz and 875 MHz. Four complementary split-ring resonators (CSRRs) have been etched in the ground plane exactly below the four patch antennas for attaining compactness from 0.36λ02 to 0.13λ02. In addition to this, by optimizing CSRRs outer radius, one lower common band operation of around 875 MHz (0.031λ02) has been obtained. Two, square split-ring resonators (SRRs) are placed between patch antennas to increase isolation by almost 7 dB around DCS band. The proposed MIMO antenna has been fabricated on an FR4 substrate (60×60×0.8) mm3 with dielectric constant, εr=4.3 having an antenna area of 0.13λ02. The Proposed MIMO antenna has two common operating bands, 850–900 MHz, 2410–2466 MHz and one individual band from 1725–1770 MHz for one group of two antennas of dimensions 17×22 mm2 and another individual band from 1800–1845 MHz for another group of two antennas of dimensions 17×23 mm2, where reflection coefficient is less than −10 dB with a minimum isolation of 17 dB. Diversity performance of the proposed MIMO antenna has been verified experimentally on all three bands. However, there is a slight deviation in the DCS operating band due to two different groups of antennas.

High Isolation Compact Four-Port MIMO Antenna Loaded with CSRR for Multiband Applications

A microstrip-fed two-port multiple-input-multiple-output (MIMO) antenna has been designed for triple-band applications covering the entire ultra-wideband (UWB) with one band-notched characteristic. A defected ground structure (DGS) has been used to obtain a wideband resonance. A crescent ring has been etched on each of the two circular patch antennas to produce a band-notch characteristic centered at 5 GHz, ranging from 3.96 to 6.2 GHz. These introduce notches at 5.2/5.8 WLAN, 5.5 WiMAX, LMI C-Band and also reject the large capacity microwave relay trunk network, ranging from 4.40 to 4.99 GHz, such as in the Indian national satellite (INSAT) system operating between 4.5 and 4.8 GHz, thus making our MIMO antenna immune to many unlicensed bands. The proposed MIMO antenna elements have been isolated by more than 16 dB throughout the operating band using a modified inter-digital capacitor (MIDC) placed between the circular patch antennas. The MIDC also helps in achieving a center-band, ranging from 6.2 to 8.93 GHz and is useful in IEEE INSAT/Super Extended C-band. The lower-band ranges from 3.08 to 3.96 GHz and covers 3.5 GHz WiMAX while the upper-band, ranging from 10 to 16 GHz, is useful for X-band and Ku-band applications. Finally, the MIMO antenna has been fabricated on an FR-4 substrate of dimensions 50×30×1.6 mm3 with a compact antenna area of 0.158λ0. All results along with the diversity performance have been experimentally verified.

/pdf/design-of-triple-band-mimo-antenna-with-one-band-notched-2punxqhv85.pdf

Amit Kumar

Papers

An ultra-compact two-port UWB-MIMO antenna with dual band-notched characteristics

A novel ITI-shaped isolation structure placed between two-port CPW-fed dual-band MIMO antenna for high isolation

A compact modified sierpinski carpet fractal UWB MIMO antenna with square-shaped funnel-like ground stub

High Isolation Compact Four-Port MIMO Antenna Loaded with CSRR for Multiband Applications

Design of Triple-Band MIMO Antenna with One Band-Notched Characteristic