L-shaped Slots Research Articles

2‐D low‐profile beam‐switching multibeam antenna based on dimension gradient metasurface

A 2-D multibeam antenna based on the dimension gradient metasurface is proposed in this paper. The metasurface is composed of four subunits formed by square patches with the dimension gradient in a 5 × 5 pattern. When the dimension gradient of subunits is adjusted, the beam direction in the azimuth plane can be switched in a larger range. Furthermore, by introducing L-shaped slots in the ground plane and two stubs on the feeding lines, the peak gain, sidelobe level and isolation of the antenna can be improved. Meanwhile, the antenna maintains a low profile of 0.06 λ0. The measured results show that the impedance bandwidth of the antenna is 16.5% (5.5–6.49 GHz). Four beams are generated and pointed at (φ0, θ0) = (70°, 23°), (160°, 24°), (250°, 21°), and (340°, 24°). The peak gains of the beams reach 8.54 dBi.

Broadband Compact MIMO Antenna Employing CRLH Transmission Lines with High Isolation

A broadband and planar multiple-input multiple-output (MIMO) antenna with pattern diversity is presented in this letter. The four-port MIMO antenna is designed by using a novel metamaterial structure with small dimensions of 60 × 60 × 1.6 mm3. Each radiating element of the MIMO antenna is comprised of composite right/left-hand (CRLH) transmission lines (TLs). Between its four elements, there are four open L-shaped slot loading on the ground plane of the patch antenna system. The antenna obtains the wide frequency range of 2.31–4.99 GHz. In addition, The proposed antenna has an isolation greater than 20 dB between its four elements. The MIMO antenna has excellent bandwidth performance and good diversity properties between elements.

2.4 GHz and 5 GHz Dual Band Wi-Fi Antenna Design for IoT Based Smart Media Application

Internet of Things (IoT) based application requires integration with the wireless communication technology to make the application data readily available. In this article, a dual band microstrip patch antenna operating at 2.4 GHz and 5 GHz frequencies is designed for use in Wi-Fi applications. The main purpose is to design a compact, easy to manufacture, cheap and high-performance microstrip patch antenna. The antenna is printed on the substrate of FR4 with two C-shaped strips and a microstrip feed line on the front side. There is L-shaped slot in the ground plane on the bottom side. The overall geometric size of the antenna is 29x26x1.6mm3. The antenna bandwidth is 140MHz and 552MHz at 2.45GHz and 5GHz respectively.

Tri-band MIMO antenna design based on characteristic modes manipulation

Several MIMO antennas based on the theory of characteristic modes have been proposed, but few of them introduce systematic design methods for microstrip MIMO antenna to obtain three frequency bands and as well as to reduce mutual coupling between the MIMO units. In this paper, a tri-band MIMO antenna is designed under the guidance of characteristic mode analysis. Firstly, the characteristic modes of the basic rectangular microstrip antenna are adjusted by loading rectangular spiral shaped stub and L-shaped slot at its proper positions to form a tri-band antenna unit. Next, based on the analysis of Modal significance and modal current distributions, the mode causing mutual coupling of the initial two-port MIMO antenna is determined, and then the meandering neutralization line connecting two adjacent edges and the rectangular gap in the middle of the common ground plane are designed as decoupling structures, which improve the isolation to more than 18 dB between two units with a distance of only 7.4 mm. Finally, the measured results prove the correctness and feasibility of the proposed systematic design process for the MIMO antenna, in terms of its compact size 32 mm ×26 mm, envelope correlation coefficient (ECC) less than 0.35, peak gain greater than 1.26 dBi and radiation efficiency greater than 76% in the three desired frequency bands (2.35–2.5 GHz, 3.25–3.85 GHz, and 4.4–6.2 GHz).

A compact broadband microstrip slot circularly polarized antenna using parasitic elements

ABSTRACT A new broadband circularly polarized (CP) microstrip slot antenna (MSA) is proposed in this study. The proposed CP MSA is comprised of a square-loop feed configuration, four rectangular patches as parasitic patches, and a square ground plane etched with four L-shaped slots as parasitic slots. The square-loop feed configuration, which can stimulate a 270° phase difference, comprises an arc-shaped strip and a square-loop. Rectangular patches and L-shaped slots as parasitic elements are together arranged and etched at the side of the square-loop feed configuration to excite multiple CP resonant modes using a capacitively coupled feeding technology. A prototype of the proposed antenna was simulated, manufactured, and measured in this study. The measured results depict that the CP MSA features a wide impedance bandwidth of 4.36–5.36 GHz (20.6%) for|S11| < −10 dB and broad axial ratio bandwidth (ARBW) of 4.53–5.30 GHz (15.7%) for AR < 3 dB. Thus, the proposed CP MSA would be an outstanding candidate in wireless communication systems.

High gain wideband and multi-band on-demand reconfigurable antenna for modern wireless application

AbstractThis paper proposes a wide band and multiband frequency reconfigurable antenna that can operate in the UWB, GSM, GPS, 4G LTE, WLAN, and WiMAX bands. The antenna is made up of a trapezoidal-shaped monopole radiator, which was inspired by a rectangular monopole antenna. The ground plane is modified by embedding T and L-shaped slots to notch the desired operating frequency. The proposed antenna can switch to six different frequencies using RF PIN diodes, making it suitable for modern wireless applications. A multilayer frequency selective surface (FSS) reflector is presented to improve the gain of the proposed reconfigurable antenna. The low-profile design achieved a significant increase in gain while retaining the UWB antenna's excellent impedance bandwidth. Because of the use of the FSS reflector, the antenna's average peak gain has increased from 6 to 10.4 dBi. The proposed antenna has a wide switching capability, which validates its unique feasibility for high-speed multiple Internet of Things applications via a common embedded platform under various applications.

Cross-polar reflective linear polarization rotator using anisotropic ultrathin metamaterial

A reflection type linear polarization rotator using L-shaped slot resonator is presented. The proposed metamaterial structure realizes wideband performance (relative bandwidth of 10.35%) due to the overlapping of two nearby resonance modes at 7.54 GHz and 8.03 GHz. The polarization rotation is achieved owing to the structural anisotropy along the two diagonals of the proposed resonator. The polarization conversion ratio (PCR) of the proposed structure is more than 90% in the frequency band of 7.42–8.23 GHz. The proposed structure is competitive in terms of its ultrathin substrate thickness, very low form factor, and wide-angle performance.

Thin Circularly Polarized Slot Array Antenna for High-Band UWB Applications

This paper presents a thin 2 × 2 circularly polarized slot array antenna that operates in the high-band ultra-wideband (UWB) system. The proposed antenna is composed of three parts: a top metal part that consists of an L-shaped slot structure, a dielectric substrate, and a bottom floating metal layer. The design model and characteristics of the antenna element and array antenna are investigated through simulation and measurement. Experimental results show that the maximum gain of the prototype array antenna is 6.94 dBi at 9.02 GHz. The antenna size is 29.2 mm × 31.7 mm, and its thickness is 1.636 mm. By using a slot antenna structure, a thin circularly polarized antenna (thickness: 1.636 mm) with high gain was demonstrated. The antenna characteristics qualify the antenna to be used in high-band UWB applications.

Dual-Band Folded Monopole MIMO Antennas with Enhanced Isolation

In this paper, a compact dual-band multiple-input multiple-output (MIMO) diversity antenna is proposed. Each of the two MIMO antennas consists of two folded strips working as radiating elements that are fed by a microstrip line. The antennas operate in three WLAN bands: ISM 2.45 GHz, 5.25 GHz, and ISM 5.775 GHz. To improve the isolation at WLAN (2.4–2.48 GHz), two L-shaped slots are etched in the ground plane while a U-shaped slot is cut in the ground plane to enhance isolation at WLAN (5.15–5.35 GHz and 5.725–5.825 GHz). Three slots on the substrate between radiating patches are also employed for an extra reduction in the mutual coupling at 2.45 GHz. The antenna performance was examined by simulation employing CST Microwave Studio Software. The proposed antenna offers minimum isolation of more than 19.5 dB, a low envelope correlation coefficient (ECC) of less than 0.0016, and good radiation efficiency (∼∼80%) through the operating frequency bands. The antenna is compact, thin, and suitable for portable devices.

A circularly polarized antenna array with sequential-phase feed network

In this paper, a simple broadband circularly polarized (CP) patch antenna design is proposed. The antenna uses a 2 × 2 array fed by a sequential-phase feed network to improve the axial ratio (AR) bandwidth and gain, and an L-shaped slot is used to remove the coupling between the feed network and the radiation patches. Similarly, to reduce coupling, the height between two substrates is discussed as an important parameter. The proposed antenna is fabricated to verify the simulated results. Measured results show that the impedance bandwidth is 65.2% (1.68–3.31 GHz), the AR bandwidth obtained at the same time is 61.6% (1.86–3.39 GHz), and the effective relative bandwidth is 58% (1.86–3.31 GHz), and the peak gain is about 7.13 dBi at 2.7 GHz.

Quadruple Band-Notched Compact Monopole UWB Antenna for Wireless Applications

A printed quadruple band-notched ultra-wideband (UWB) antenna characteristic is presented. The designed UWB antenna has a size of 32 mm × 30 mm × 1.6 mm and covers an impedance bandwidth off 2.9–14.5 GHz for the entire frequency band. The entire frequency band maintains voltage standing wave ratio (VSWR) &lt;2, except at WiMAX (3.1–3.6 GHz), WLAN (4.92–6.12 GHz), downlink of X-band for satellite communication systems (7.5–8.4 GHz), and X-band (10.2–11 GHz). By inserting a pair of L-shaped slots into the radiating element, a H-shaped resonator and rectangular split-ring resonators are closely arranged to the microstrip feed-line, alongside the measured impedance bandwidth of 129%. The fabricated antenna radiation pattern and return loss is presented.

Compact Dual-Band Antenna with Paired L-Shape Slots for On- and Off-Body Wireless Communication.

A simple dual-band patch antenna with paired L-shap slots for on- and off-body communications has been presented in this article. The proposed antenna resonates in the industrial, scientific, and medical (ISM) band at two different frequencies, at 2.45 GHz and 5.8 GHz. At the lower frequency band, the antenna’s radiation pattern is broadsided directional, whereas it is omni-directional at the higher frequency band. The efficiency and performance of the proposed antenna under the influence of the physical body are improved, and the specific absorption rate (SAR) value is significantly reduced by creating a full ground plane behind the substrate. The substrate’s material is FR-4, the thickness of which is 1.6 mm and it has a loss tangent of = 0.02. The overall size of the proposed design is 40 mm × 30 mm × 1.6 mm. Physical phantoms, such as skin, fat and muscle, are used to evaluate the impact of physical layers at 2.45 GHz and 5.8 GHz. The SAR values are assessed and found to be 0.19 W/kg and 1.18 W/kg at 2.45 GHz and 5.8 GHz, respectively, over 1 gram of mass tissue. The acquired results indicate that this antenna can be used for future on- and off-body communications and wireless services.

Novel Broadband Circularly Polarized Monopole Antenna for Multi-communication Systems

This paper proposes a novel coplanar waveguide (CPW) fed broadband circularly polarized (CP) monopole antenna, which applies to C-band and various wireless communication systems. The antenna consists of the double circular-shaped patch (DCSP) with square and L-shaped slots, and an improved asymmetric ground plane. The prototype of the designed antenna has been fabricated. The results of the measurement show that the 10-dB impedance bandwidth (ZBW) is 117.8% (2.2–8.5 GHz), the 3-dB axial ratio bandwidth (ARBW) is 62% (4.45–8.45 GHz).

DESIGN OF RECONFIGURABLE SLOT ANTENNA USING VARACTOR DIODE AT FREQUENCY 4.5GHZ

In this Research Paper, reconfigurable slot antenna for LTE (2.6GHz), AMT-fixed service (4.5GHz), and WLAN (5.4GHz) applications is displayed. There are two L-shaped slots and a U-shaped slot placed in the ground plane. The size of the antenna is short down as a result of these slots. There are three varactor diodes placed in these slots. This is done for the intention of frequency, directivity, and polarization reconfiguration. The directivities and polarization conditions of the antenna are changed at various frequencies i.e. at 2.6GHz, 5.4GHz, and at 4.5 GHz. These three various types of frequencies correspond to different states of the antenna. The states of the antenna are swapped by redirecting the varactor diodes on and off. The varactor diodes are used in this paper as they have the characteristic of fast frequency tuning.

Designing of Single Band Four Antenna Array for 5G Mobile Applications using MISO Technique

In 5G applications, this paper proposes a single-band four-antenna array for faster velocity and single output (MISO) mechanisms. There were also separate based on step-impedance resonators, L-shaped slot antennas in the established MISO antenna array stepped impedance resonator (SIRs). By calculating the SIR's impedance ratio, the proper single-resonance can be obtained, and for each component in the antenna. By tuning the alignment of the antenna's micro strip antenna app, good impedance matching can be assumed. A decided return loss of more than 10 dB and a measured inter-element isolation of greater than 10.2 dB are illustrated by the experimental results were obtained over the long-term evolution (LTE) band 52 (3358-3640 MHz) and LTE band 20 20 with a simulated cost efficiency of well over 61 percent for each antenna line (5250-5985 MHz). Besides that, between arbitrary two antenna pieces, the decided envelope correlation the coefficient (ECC) is higher than 0.2, and the proposed MISO antenna array achieves a simulated channel capacity of more than 42.5 bps/Hz within both transmission bands. Absolute anthropomorphic mannequins (SAM) in the head and human brain in the presence of, in particular, the MISO antenna array can ensure adequate radiation and MISO accuracy.

A side-edge frame dual-band eight-element MIMO antenna array for 5G handset

Abstract In this paper, a dual-band 8 × 8 multi-input multi-output (MIMO) array antenna operating in 3.5 GHz band (3400–3600 MHz) and 5.5 GHz band (5150–5925 MHz) for 5G mobile handset is presented. The proposed hybrid antenna includes a comb-shaped monopole and an L-shaped open slot antenna which are symmetrically located on the inner surface of the side-edge frame of smartphone. Pattern diversity is achieved that can mitigate envelope correlation coefficients (ECCs) and improve the MIMO system performances. The prototype of proposed dual-band eight-element MIMO antenna is fabricated and experimentally measured. The results show that isolation &lt;−10 and &lt;−15 dB, respectively in the lower band and high band without any additional decoupling element are achieved and the desired bands are satisfied under the condition of −6 dB impedance matching. Moreover, the essential parameters for evaluation of the MIMO system performance such as the ECC, mean effective gain (MEG), and ergodic channel capacity are calculated. Furthermore, the influence of user's hand on the radiation characteristics of proposed MIMO antenna are also investigated and discussed. Based on the result, the proposed MIMO antenna is a good candidate for use in future 5G applications.

Dual-band-notched UWB MIMO antennas with miniaturization using half-cutting technology

Abstract A compact four-element ultra-wideband (UWB) multiple-input–multiple-output (MIMO) antenna with dual polarization and dual-notched capabilities was developed and fabricated. The MIMO antenna is composed of four orthogonally placed half-cutting UWB antenna elements. This orthogonal placement improves the isolation. Furthermore, an L-shaped slot and a continuous bending slot are etched to realize the band-rejection function in the WiMAX and WLAN bands. The result shows that the antenna achieved operating bands of 2.9–16.5 GHz (140.2%, S11 &lt; −10 dB), fully covering the UWB (3.1–10.6 GHz). The port isolation is greater than 23 dB in the frequency band of interest, excluding two rejected bands. Moreover, the MIMO antenna has excellent diversity performance, such as a low envelope correlation coefficient (&lt;0.004), high diversity gain (approximately 10 dB), and good omnidirectional radiation characteristics.

A ring monopole quad band antenna loaded with metamaterial and slots for wireless applications

The present wireless applications demand a compact, multi-operated, and stable radiation pattern antenna with good gain and impedance matching performance. To accomplish this requirement. In this paper, we propose a compact metamaterial structure loaded quad band antenna. The structural specifications/layout of the antenna consists of a circular ring monopole fed by a microstrip line. The ground part of the antenna is loaded with a metamaterial rectangular split-ring resonator (RSRR), an L-shaped slot, and two horizontally placed rectangular slots parallel to each other. No external matching circuit is utilized and impedance matching is solely controlled by the placement of slots. The antenna shows operation at 2.1 GHz (2.01-2.24 GHz, a bandwidth of 230 MHz (WLAN)), 4.5 GHz (4.35-4.66 GHz, a bandwidth of 310 MHz (C-band)), 5.5 GHz (5.37-5.77 GHz bandwidth of 400 MHz (WiMAX)), and 7.2 GHz (7.08-7.33 GHz, a bandwidth of 250 MHz (satellite band)). The antenna exhibits good gain and stable radiation pattern in both the plane and thus can be utilized for aforementioned applications.

A Compact Wideband Circularly Polarized Microstrip Slot Antenna with Parasitic Elements

A compact wideband circularly polarized (CP) microstrip slot antenna (MSA) with parasitic elements is designed in this letter. The CP MSA comprises a square-loop sequential-phase (SP) feeding configuration, four rotated rectangular patches, and four L-shaped slots embedded in the ground plane. The square-loop SP feeding structure comprises a square loop and an arc-shaped strip, which could provide a 270° phase difference. Four rotated rectangular patches are placed at the edge of the square-loop feeding configuration using a capacitively tightly coupled feeding method to stimulate the CP resonant mode. After selecting these elements and tuning proper dimensions, the broad operating bandwidths of 4.38–5.25 GHz (18%) for |S11| &lt;–10 dB and 4.65–5.31 GHz (13.2%) for AR &lt;3 dB could be realized. Hence, the designed CP MSA has a potential application value in wireless communication.

Five-port MIMO antenna for n79-5G band with improved isolation by diversity and decoupling techniques

A compact five-port multi-input multi-output (MIMO) antenna for n79 (4.4–5 GHz) 5G band exhibiting pattern and polarization diversity with good isolation is proposed in this paper. This MIMO antenna system comprises of four linearly polarized (LP) endfire monopole antenna elements and one broadside L-shaped slot circularly polarized (CP) antenna element, which provides both pattern and polarization diversity. A T-shaped slot as a decoupling structure is further used to improve the interport isolation by 4 dB. The return loss bandwidth for all antenna elements is in the desired frequency range, and antenna elements provide isolation better than 23 dB. The pattern and polarization diversity provide a low envelope correlation coefficient and good isolation between any two-port of the MIMO antenna. For experimental verification, the proposed 5-port MIMO antenna system is fabricated and measured, which provides decent agreement with the simulated performance.