Planar MIMO Research Articles

Meander line MIMO antenna for 5.8 GHz WLAN application

A four port compact low profile planar MIMO antenna with meander line radiators and with polarization diversity effect has been proposed to cover 5.8 GHz wireless local area network application. The proposed MIMO antenna has −10 dB impedance bandwidth of 1.4 GHz (5.3–6.7 GHz) along with the compact size of 38 × 38 mm2 and an envelope correlation coefficient (ECC) of less than 4 × 10−4 in the whole band. The proposed antenna resonates at 5.8 GHz frequency, having return loss of −43.2 dB. The isolation between diagonal and opposite ports is more than 10 and 12 dB, respectively, in the presented frequency band. The total active reflection coefficient frequency response shows more than 1.0 GHz of bandwidth in the whole band. The antenna gain is more than 4.0 dBi in the operating frequency band. The radiating elements are very close to each other to make the design very compact.

Dimension-Factorized Range Migration Algorithm for Regularly Distributed Array Imaging.

The two-dimensional planar MIMO array is a popular approach for millimeter wave imaging applications. As a promising practical alternative, sparse MIMO arrays have been devised to reduce the number of antenna elements and transmitting/receiving channels with predictable and acceptable loss in image quality. In this paper, a high precision three-dimensional imaging algorithm is proposed for MIMO arrays of the regularly distributed type, especially the sparse varieties. Termed the Dimension-Factorized Range Migration Algorithm, the new imaging approach factorizes the conventional MIMO Range Migration Algorithm into multiple operations across the sparse dimensions. The thinner the sparse dimensions of the array, the more efficient the new algorithm will be. Advantages of the proposed approach are demonstrated by comparison with the conventional MIMO Range Migration Algorithm and its non-uniform fast Fourier transform based variant in terms of all the important characteristics of the approaches, especially the anti-noise capability. The computation cost is analyzed as well to evaluate the efficiency quantitatively.

A low profile planar MIMO antenna with polarization diversity for LTE 1800/1900 applications

ABSTRACTA four port MIMO antenna is proposed with polarization diversity technique to cover LTE 1800/1900 frequency standards. The antenna operates with a 2:1VSWR bandwidth of 560 MHz. The design covers −10 dB impedance band of 1.68–2.24 GHz. The minimum isolation measured among the adjacent and diagonal ports is 13 dB. The antenna offers suitable radiating characteristics for nonline of sight (NLOS) communication to solve the problem of multipath propagation. The gain of the MIMO is more than 3.0 dBi and ECC is less than 0.01 in the whole operating band. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:533–538, 2017

Design of a Planar MIMO Antenna for LTE-Advanced

This paper presents the design of a wideband microstrip patch antenna for LTE-A. The bandwidth of the conventional patch is enlarged by using etched slots at the antenna patch. The designed antenna has been fabricated by using thin film and photolithographic technique and has been measured by using the Vector Network Analyzer. The simulated and measured results were found to have good match with each other. Then, by using the designed single element antenna, a four-element MIMO antenna system has been built employing orthogonal polarization diversity. Isolation between the microstrip elements is increased by placing metal structure between antenna elements. For more isolation between antenna elements, Slotted Ground Plane SGP is utilized. It is found, by using commercial software CST Microwave Studio and measurement, that the designed planar MIMO antenna system has sufficiently high return loss and low mutual coupling at the required bandwidth of 70 MHz. It is found also that the developed antenna system meets the requirements for LTEAdvanced (2500 – 2570 MHz) band “CA-B7” as of today‟s standard based on 36.101 Table 5.5-1 (March 2012) .

Dual‐port planar MIMO antenna with ultra‐high isolation and orthogonal radiation patterns

A dual-port planar MIMO antenna designed for 2.4 GHz WLAN applications is presented. It consist of two X-shaped arms etched on a square-shaped substrate, which forms a self-decoupled structure that can generate two orthogonal modes with ultra-high isolation. In measurement, the −10 dB bandwidth covers from 2.39 to 2.51 GHz, and better than 43 dB isolation is achieved between the two ports. Meanwhile, the patterns are orthogonal, and the envelope correlation coefficient is only 0.0052. The antenna it is fabricated on FR-4 substrate, and the size is only 33 × 33 × 3.2 mm, which is very much suited to space-limited MIMO applications that require ultra-high isolation, good pattern diversity and low fabrication cost.

Planar MIMO Antenna with Slits for WBAN Applications

A planar MIMO antenna with slits for WBAN applications is proposed. The antenna consists of two PIFAs, ground pads, and two slits. By adding ground pads, the antenna size is reduced with improved impedance matching. Through two slits in a ground plane, the isolation characteristic is improved and the resonant frequency can be controlled. To analyze the antenna performance on a human body, the proposed antenna on a human equivalent flat phantom is investigated through simulations. Regardless of the existence of the phantom, the antenna operates in 2.4 GHz ISM band with the isolation higher than 18 dB.

Metamaterial-Based Design of Planar Compact MIMO Monopoles

A systematic design of planar MIMO monopole antennas with significantly reduced mutual coupling is presented, based on the concept of metamaterials. The design is performed by means of individual rectangular loop resonators, placed in the space between the antenna elements. The underlying principle is that resonators act like small metamaterial samples, thus providing an effective means of controlling electromagnetic wave propagation. The proposed design achieves considerably high levels of isolation between antenna elements, without essentially affecting the simplicity and planarity of the MIMO antenna.

Small-Size and High-Isolation MIMO Antenna for WLAN

A small-sized (15 mm×30 mm) planar monopole MIMO antenna that offers high-isolation performance is presented in this letter. The antenna is miniaturized using inductive coupling within a meander-line radiator and capacitive coupling between a radiator and an isolator. High isolation is achieved by a T-shaped stub attached to the ground plane between two radiators, which also contributes to the small size using a folded structure and the capacitive coupling with radiators. The proposed antenna operates for the WLAN band within 2.4 GHz to 2.483 GHz. The measured isolation (S21) is about –30 dB, and the envelope correlation coefficient is less than 0.1.

Compact planar MIMO antenna array with polarisation diversity on single layer

A novel compact and planar MIMO antenna array with polarisation diversity is proposed on a single layer. The proposed array is composed of two orthogonal polarised elements which act as electric and magnetic loop antennas. A high isolation of 20 dB between the two antennas is achieved at 2.3 GHz. The overall size of the array is 38 × 28 mm (i.e. 0.291 × 0.214 λ 0 ). The calculated envelope correlation coefficient is 0.00035.

A Compact Planar MIMO Antenna System of Four Elements With Similar Radiation Characteristics and Isolation Structure

A compact planar multiple-input-multiple-output (MIMO) antenna system of four elements with similar radiation characteristics is proposed for the whole 2.4-GHz WLAN band. It consists of two proximity-coupled fed microstrip square ring patch antennas and two lambda/4 microstrip slot antennas of the same linear polarization. These two types of antennas are printed on different sides of the substrate to reduce mutual coupling. With a novel isolation structure etched on the ground plane of the FR4 substrate, high port isolation (below -25 dB) and good MIMO performance are achieved. The overall lateral size of the MIMO system is only 0.64lambda times 0.48A, and good impedance matching (S11 < 10 dB) is achieved across the operating band for all the antenna elements. Full spherical radiation patterns are measured for the MIMO system, showing similar radiation characteristics, and the gains are above 2.3 dB across the operating band.