Slotted Electromagnetic Band Gap Research Articles

Reduction of Mutual Coupling between Radiating Elements of an Array Antenna Using EBG Electromagnetic Band Structures

In this paper, a new array antenna configuration based on Electromagnetic Band Gap (EBG) structures has been proposed for 3.5GHz wireless communication systems. The proposed slotted EBG structure, high impedance surface (SHI), consists of three squares and a square ring deposited on a substrate (Rogers RO4350) which has a relative permittivity of 10.2 and a thickness of 1.27mm. Initially a matrix of 3×7 unit cells of EBG structures is introduced between two patches of an array and then a matrix of 3×14 unit cell of EBG structures is integrated between eight patches, which resonate around 3.5GHz (Wi MAX). The insertion of these structures between the radiating elements of an array antenna reduces the mutual coupling and antenna dimensions by approximately (8dB, 11%) and (12 dB, 5%) respectively for two, eight elements array antenna. In addition, the directivity has been slightly improved in the presence of EBG structures, from 4.52dB to 6.09dB for a two-element array antenna, and from 8.18dB to 8.4dB for an eight-element antenna.

Compact stack EBG structure for enhanced isolation between stack patch antenna array elements for MIMO application

AbstractIn this research article, a compact wideband stack patch antenna array integrated with compact stack electromagnetic band gap (EBG) structure for multiple input multiple output (MIMO) application is proposed. The wide resonance bandwidth is achieved at 2.45 GHz band by stack arrangement of compact meander line slot driven and parasitic patch elements. The isolation bandwidth is matched with resonance bandwidth with the design of a compact stack L slot EBG structure. The polarization diversity and three-layer EBG structure ensure an enhancement in isolation level. To validate the performance of the proposed stack antenna array, a prototype was fabricated and tested for different MIMO parameters. The measured result confirms the effectiveness of the proposed antenna array in a diverse MIMO environment.

Reduction of Mutual Coupling in Compact Antenna Array Using Meander Line Slot EBG Structure

This paper presents the design and the fabrication of a compact Multiple-Input Multiple-Output (MIMO) antenna array with very low mutual coupling, operating in the 2.4 GHz band. The compact design is achieved by the introduction of a meander line structure in the conventional patch antenna. The reduced mutual coupling of about 52 dB is realized by inserting a periodic array of Electromagnetic Band Gap (EBG) elements in the radiating antenna elements. A prototype of the proposed antenna array has been manufactured on an FR4 substrate with a dielectric constant of 4.4 and a height of 1.6 mm. The excellent agreement between simulated and measured data confirms the performance of the proposed antenna array in a MIMO environment. This MIMO antenna array has a compact size of 0.40λ0×0.2λ0. For the validation of the results, the overall dimensions and the isolation level of the proposed design have been compared with designs previously reported in the literature and it has been found out that the proposed design is superior in both isolation level and compactness than its counterparts.

Novel design of triple-bands EBG

This paper presents a novel design for a triple band electromagnetic band gap (EBG) structures that provides three band gaps, with operating frequency of below 10 GHz, while the ordinary mushroom like EBG structure gives only one band gap. Complexity reduction (reduce the number of unit cells and Vias) was achieved by replacing each four cells of the Mushroom like EBG by the one of double slotted type EBG (DSTEBG) or triple side slotted EBG (TSSEBG). The Mushroom like EBG was further modified by increasing its size and inserting the slots to gain more capacitance and inductance which resulted into triple band stop.The new designs wer compared with bandwidths expressed by other EBGs and -20 dB cut-off frequencies. The size of EBG element and the gap between EBG elements, and slot width were investigated to analyse their effect on the transmission response. The structures were designed from 2.54 mm Rogers RT/Duroid 6010 substrate with relative permittivity of 10.2 and loss tangent of 0.0023. Among the investigated EBGs, the single band mushroom like EBG and the triple band of the TSSEBG demonstrated better bandwidth and lower resonance frequency performance, whereas the DSTEBG showed larger bandwidth for the first and third band. The proposed EBGs could be useful in the antenna design and other microwave circuits.

Novel double-side EBG based mutual coupling reduction for compact quad port UWB MIMO antenna

In this article, novel compact quad-port double-side Multiple-input-multiple- output (MIMO) antenna designed with Electromagnetic Band Gap (EBG) structure to improve isolation for Ultra Wide Band (UWB) applications. The presented MIMO configuration comprises four polygon shape radiating elements and partial slotted EBG stub ground structure. Both sides of the FR4 substrate are symmetrical, each side consisting of two radiators, and one partial ground plane is related with the other two components attached on the opposite side. The EBG decoupling structures are used on both the front and the back side of the board to diminish the correlation coupling among the radiators. The proposed MIMO antenna performance has also been studied regarding impedance bandwidth, current distribution, radiation model, envelope correlation coefficient (ECC), peak gain and TARC. The proposed MIMO antenna system has an impedance bandwidth of 3.1–11 GHz, peak gain of 2.5–6.8 dBi and less than 0.004 ECC. Furthermore, the proposed MIMO antenna shows UWB bandwidth, an almost omnidirectional radiation pattern, high isolation, uniform gain, and multi-polarization. The proposed double-sided MIMO antenna was tested in an indoor environment using NI USRP to verify performance in real time.

Design and analysis of triple notch ultrawideband antenna using single slotted electromagnetic bandgap inspired structure

ABSTRACTA microstrip line fed pentagonal printed ultra wideband (UWB) monopole antenna with partial ground plane having triple notches is proposed. The realized antenna has an operating bandwidth (VSWR ≤ 2) ranging from 3.1 GHz and continuing beyond 12 GHz. A novel mushroom-shaped slotted electromagnetic bandgap (EBG) inspired structure is used near the feedline to introduce triple notches at CBRS (3.5–3.7) GHz, WLAN (5.15–5.725) GHz and X-band downlink satellite communication (7.25–7.75) GHz frequencies. The band notch characteristics are demonstrated with current distribution and impedance analysis. Further, the proposed structure has stable radiation patterns, gain and group delay in the UWB range except the notch frequencies. Finally, a prototype of the proposed antenna is fabricated and measured results are in good agreement with the simulated results.

Design of defective electromagnetic band-gap structures for use in dual-band patch antennas

Generally, the surface wave of an antenna can be suppressed by integrating the electromagnetic band-gap (EBG) structures. However, to achieve this effect, the EBG cells must be reasonably designed, otherwise it may lead to performance degradation instead. In this article, a dual-band pinwheel-shaped slot EBG structure is proposed. When applied to a patch antenna, defects are introduced into 3 rows of the EBG unit cells. The proposed antenna, incorporating EBGs designed with structural defects, to radiate at 4.9 and 5.4 GHz is simulated and tested. The measured results show that the −10-dB bandwidth of the proposed EBG antenna is extended by 41% and 25.4% at low frequency and high frequency, respectively. In addition, the peak gain of the proposed EBG antenna is increased by 2.44 dB at 4.9 GHz and 2.86 dB at 5.4 GHz with >40% efficiency. When compared with the periodic EBG antenna, this antenna is more effective. Thus, these experimental results show that the performance of the EBG antenna can be improved by interrupting the periodicity of the EBGs structures.

Gain Enhancement and RCS Reduction for Patch Antenna by Using Polarization-Dependent EBG Surface

A novel antenna design is proposed to enhance the gain and reduce the radar cross section (RCS) of a patch antenna by using metamaterial surface. A polarization-dependent metamaterial surface composed of blocks of slotted electromagnetic bandgap (EBG) structures are adopted in this letter. The layout pattern of the slotted EBG elements is designed to enhance the gain of the antenna. Chessboard configuration is further equipped for scattering cancellation. The induced currents on the EBG are studied, resulting in the mechanism of the gain enhancement by the EBGs clearly explained for the first time. This enables the strategy of designing a high-gain and low-RCS antenna by using EBGs. Full-wave simulations validate that high gain in the operating frequency band and low-RCS in a broad frequency band for normal incidence are achieved by the proposed antenna.

DESIGN AND ANALYSIS OF META-MATERIAL BASED WLAN ANTENNA

In this paper, a 2.42 GHz micro-strip patch antenna is designed and analyzed using a conventional and a metamaterial (artificial) based Electromagnetic Bandgap (EBG) ground planes. The directivity, return loss and VSWR of the conventional 2.42 GHz patch antenna were found to be 5.23dB, -13.2dB, and 1.5 respectively. The proposed antenna then being mounted on a Mushroom-type EBG structures (artificial ground plane) produced better far-field performance as compared to conventional counterpart i.e. the return loss, directivity and VSWR were improved by 80.3%, 58.5% and 24.6%. The WLAN antenna was designed and tested on a miniaturized slotted EBG structure. The slotted EBG was 11.4 % compact as compared to the mushroom structure. The directivity, return loss and VSWR of the antenna using the slotted EBG are improved by be 51%, 31.8%, 15.4% respectively as compared to the patch conventional WLAN patch antenna. The antenna can be used for WLAN applications.

Study of different shape Electromagnetic Band Gap (EBG) structures for single and dual band applications

In this paper, single and dual band EBG structures for wider bandwidth are proposed. In each of the discussed EBGs, a metallic patch of regular geometry is chosen for the unit element. The patch is further modified by cutting slots to get extra inductance and capacitance which results into lower cut-off frequency and larger bandwidth. The proposed EBG structures are compared with the standard mushroom type EBG with respect to surface wave attenuation. The -20 dB cut-off frequencies and bandwidths of the various EBGs are compared. The effect of unit element size, gap between unit elements and via diameter on the transmission response is presented. Among the discussed EBGs, the swastika type structure is compact, single band and has wider bandwidth. The square patch with a single disconnected loop type slot EBG and the Fractal EBG are dual band. While square patch is more compact, the fractal EBG has wider bandwidth. All the EBGs can be useful in the design of antenna and other microwave circuits.

A NOVEL COMPACT SPLIT RING SLOTTED ELECTROMAGNETIC BANDGAP STRUCTURE FOR MICROSTRIP PATCH ANTENNA PERFORMANCE ENHANCEMENT

A novel design of an electromagnetic bandgap (EBG) structure based on the uniplanar compact EBG (UCEBG) concept is proposed in this paper. The structure is realized by inserting split- ring slots inside two reversely connected rectangular patches, which is known as a split-ring slotted electromagnetic bandgap (SRS-EBG) structure. The bandgap properties of the EBG structure are examined by the suspended microstrip line and flnite element methods (FEM). The achieved bandgaps have widths of 4.3 (59.31%) and 5.16GHz (38.88%), which are centered at 7 and 13GHz, respectively. The SRS-EBG is applied to enhance the performance of a single-element microstrip patch antenna (at 7GHz) and a two-element array (at 13GHz) conflguration. A wider bandwidth is obtained with a better re∞ection coe-cient level for the single element antenna; a reduction in mutual coupling of more than 20.57dB is obtained for the array design. In both cases, the gain and radiation characteristics are improved. The results are verifled by measuring the fabricated lab prototype, and a comparison with the computed results showed good agreement.

Locally Resonant Cavity Cell Model for Meandering Slotted Electromagnetic Band Gap Structure

This letter utilizes a simple locally resonant cavity cell (LRCC) model to provide an insight into the physical mechanism and the relationship between locally resonant modes and surface-wave suppression band-gaps of the proposed meandering slotted electromagnetic band-gap (MSEBG) structure. The MSEBG structures have two surface-wave suppression band-gaps that are separately yielded by cross slots and meandering slots. It was proved that the cross slots and the meandering slots produced two different groups of monopolarized (MP) degenerate modes whose corresponding frequencies located within the two surface-wave suppression band-gaps. The dual-band MSEBG structure was fabricated, and an experimental verification was conducted by surface-wave band-gap measurement using a pair of shield loops. By adjusting the dimension of meandering slot, we can design a dual-band-gap EBG structure effectively.

Reflection phase characterizations of the EBG ground plane for low profile wire antenna applications

Mushroom-like electromagnetic band-gap (EBG) structures exhibit unique electromagnetic properties that have led to a wide range of electromagnetic device applications. This paper focuses on the reflection phase feature of EBG surfaces: when plane waves normally illuminate an EBG structure, the phase of the reflected field changes continuously from 180/spl deg/ to -180/spl deg/ versus frequency. One important application of this feature is that one can replace a conventional perfect electric conductor (PEC) ground plane with an EBG ground plane for a low profile wire antenna design. For this design, the operational frequency band of an EBG structure is defined as the frequency region within which a low profile wire antenna radiates efficiently, namely, having a good return loss and radiation patterns. The operational frequency band is the overlap of the input-match frequency band and the surface-wave frequency bandgap. It is revealed that the reflection phase curve can be used to identify the input-match frequency band inside of which a low profile wire antenna exhibits a good return loss. The surface-wave frequency bandgap of the EBG surface that helps improve radiation patterns is very close to its input-match frequency band, resulting in an effective operational frequency band. In contrast, a thin grounded slab cannot work efficiently as a ground plane for low profile wire antennas because its surface-wave frequency bandgap and input-match frequency band do not overlap. Parametric studies have been performed to obtain design guidelines for EBG ground planes. Two novel EBG ground planes with interesting electromagnetic features are also presented. The rectangular patch EBG ground plane has a polarization dependent reflection phase and the slotted patch EBG ground plane shows a compact size.