Compact S-Shaped EBG Structures for Reduction of Mutual Coupling
21 Feb 2015-pp 21-25
TL;DR: Two new shapes of EBG structures are presented for reducing mutual coupling between patch antenna MIMO arrays, the first of which is contained an S-shape patch with a via at center of it and the second one is a multilayer structure that is based on the S- shape formation.
Abstract: In this article, two new shapes of EBG structures are presented for reducing mutual coupling between patch antenna MIMO arrays. The first structure is contained an S-shape patch with a via at center of it and the second one is a multilayer structure that is based on the S-shape formation. The patch antennas are operating at 5.35 GHz, which is defined for wireless application. Here an array of 2×5 EBG structures is implemented to reduce mutual coupling to more than 13.5dB and 20.5 dB respectively for first and second structures. The total size of antenna is 36mm×68mm×1.6mm. All the simulations have been carried out with HFSS for full wave simulation. The surface current density is reduced dramatically more than 84% and 92% for first and second structures respectively. In addition the effect of the change in unit cells distance on mutual coupling are studied for the second structure. The results are compared with some previous researches.
Citations
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TL;DR: In this paper, a planar compact electromagnetic bandgap (EBG) structure with the potential to reduce the mutual coupling between the elements of a microstrip antenna array was proposed.
Abstract: This research work presents a planar compact electromagnetic bandgap (EBG) structure with the potential to reduce the mutual coupling between the elements of a microstrip antenna array The proposed structure is investigated at 559 GHz, which is the centre frequency of the wireless local area network band To achieve the highest radiation performance for microstrip antenna arrays, with minimal inter-element spacing and mutual coupling, different unit cell arrangements were considered along with two adjacent patch elements The simulations and measurement results for the proposed arrangements indicate that the mutual coupling tends to diminish significantly For instance, when adjacent patches are spaced by 04
λ
, the mutual coupling improves by ~25 dB For the particular spacing of 04
λ
, it is favourably observed that the proposed EBG cells can also improve the antenna gain by ~25 dB Such improvements can be attributed to the compactness of the cells (~
λ
/8 × λ
/10) and their remarkable ability to suppress the surface waves
50 citations
TL;DR: In this article, a modified version of Minkowski fractal geometry is applied on the patch elements, and at the same time 1D electromagnetic bandgap (EBG) structures, composed of 4 EBG elements, are placed between the array elements in a very close distance.
Abstract: This paper presents the simultaneous application of Minkowski fractal geometry and EBG structures for mutual coupling reduction in microstrip array antennas for the first time. In this approach, a modified version of Minkowski fractal geometry is applied on the patch elements, and at the same time 1D electromagnetic bandgap (EBG) structures, composed of 4 EBG elements, are placed between the array elements in a very close distance. Unlike many other coupling reduction methods, which have at least one of the issues of gain reduction or complex fabrication, the proposed method does need any via or double-sided etching and slightly increases the gain of the antenna, while an excellent reduction level of 22.7 dB has been achieved. To verify the concept, 2 array antennas with the spacing of λ0 and λ0/3 were fabricated and tested, showing very good agreement between predicted and measured results.
31 citations
TL;DR: In this paper, a cavity-based microwave sensor for permittivity determination of industrial liquids is presented, which is developed on a Substrate Integrated Waveguide (SIW) and is equipped with a photonic band gap method and variable capacitors.
Abstract: In this paper, we present a novel tunable microwave sensor for permittivity determination of industrial liquids. The proposed sensor is cavity based which is developed on a Substrate Integrated Waveguide (SIW). To enhance the characterization accuracy, the reconfigurable sensor is equipped with a Photonic Band Gap method and variable capacitors. Moreover, we employ the cavity perturbation technique in order to calculate the permittivity. In the characterization process, we obtain the permittivity of an unknown material by considering a resonant frequency shift. In fact, a capacitance is the main parameter for controlling the sensor resonance. We herein change this capacitance via reconfigurable SIW cavity and applying different materials. The proposed tunable architecture lets us study the material characteristic in the wider frequency range. The structure is designed in 5–6 GHz in order to determine the electromagnetic behavior of a brand new and used transformer oil samples. The results present a highly accurate permittivity of these oil samples. Hence, the proposed method and setup is not only suitable for oil ageing programs, but also applicable for other industrial liquid applications.
26 citations
TL;DR: In this article, a wideband circularly polarized (CP) conformal array is decoupled by a single-negative (SNG) metamaterial (MTM) isolator.
Abstract: Decoupling of a wideband circularly polarized (CP) conformal array is studied by a single-negative (SNG) metamaterial (MTM) isolator. The conformal array consists of two wideband CP antennas, which are assembled on an arched carrier, and a wideband SNG structure is placed between the antenna elements for coupling reduction. The SNG structure consists of four wheel-shaped units concentrically. The SNG structure is bianisotropic, and its constitutive parameters are tailored to form a wide isolation band. By using the proposed wideband SNG structure, the mutual coupling between the conformal antenna elements is reduced up to 25 dB at 4.5 GHz, and the mutual coupling is improved in the 3.9–5.05 GHz band. In addition, the loading of the SNG structure has little effect on the axial-ratio bandwidth. Besides, the gain and radiation patterns are improved. This research provides some basis in the decoupling of the conformal array.
24 citations
Cites background from "Compact S-Shaped EBG Structures for..."
...Good decoupling is obtained by complicated structures with conformal split-ring resonators between the monopoles and EBG structures on the back....
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...In order to reduce the mutual coupling of the surface waves, a bandgap can be achieved by means of an electromagnetic bandgap (EBG) [5] and a defected ground structure (DGS) [6]....
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...[5] A. Veeramani, A. S. Arezomand, J. Vijayakrishnan, and F. B. Zarrabi, “Compact S-shaped EBG structures for reduction of mutual coupling,” in Proc....
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TL;DR: In this article, a hexagonal-shaped multiple-input multiple-output (MIMO) patch antenna is presented, which covers the S band (2-4 GHz), WLAN (2400-2480 MHz & 5150-5350/5725-5875 MHz), UWB (3.1-10.6 GHz), and X band (8-12 GHz) applications.
Abstract: In this paper, a hexagonal-shaped multiple-input multiple-output (MIMO) patch antenna is presented. It covers the S band (2–4 GHz), WLAN (2400–2480 MHz & 5150–5350/5725–5875 MHz), UWB (3.1–10.6 GHz), and X band (8–12 GHz) applications. The proposed structure is simulated and fabricated on an FR4 substrate with overall dimensions of 0.186λ0 × 0.373λ0 and separation of two patches with a distance of 0.053λ0 (where λ0 is the wavelength at 2GHz). The single UWB patch is antenna derived from the triangular-shaped edge cuttings in the bottom of the rectangular patch antenna with a partial and defected ground. The proposed MIMO structure produces simulated results from 2GHz to 13.3 GHz and measured results from 2.1 GHz to 12.9 GHz, with good agreement. The proposed structure resonates at 3.4 GHz, 5.8 GHz, 10.2 GHz, and 11.8 GHz. The isolation is improved to above 20 dB by placing an E-shaped tree structure and parasitic element in most of the band. The radiation efficiency and peak gain values are 78–94% and 1.4–6.6 dB, respectively. Diversity performance of the proposed structure is verified with low envelope correlation coefficient (ECC < 0.04), high diversity gain (DG > 9.985), and acceptable total active reflection coefficient (TARC < −10 dB) values.
12 citations
Cites methods from "Compact S-Shaped EBG Structures for..."
...S-shaped EBG structures are placed between two elements of a MIMO antenna for coupling reduction [12]....
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References
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01 Jan 1992
TL;DR: In this article, a brief overview of the basic characteristics of microstrip antennas is given, and the most significant developments in microstrip antenna technology have been made in the last several years.
Abstract: Microstrip antennas have been one of the most innovative topics in antenna theory and design in recent years, and are increasingly finding application in a wide range of modern microwave systems. This paper begins with a brief overview of the basic characteristics of microstrip antennas, and then concentrates on the most significant developments in microstrip antenna technology that have been made in the last several years. Emphasis is on new antenna configurations for improved electrical performance and manufacturability and on advances in the analytical modeling of microstrip antennas and arrays. >
1,604 citations
"Compact S-Shaped EBG Structures for..." refers background in this paper
...EBG structures are defined as a kind of artificial magnetic conductor (AMC) that prevent/assist the propagation of electromagnetic waves in a specified band of frequency for all incident angles and all polarization states [8]-[9]....
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TL;DR: In this paper, a mushroom-like E-plane coupled E-strip antenna array on a thick and high permittivity substrate has been analyzed using the finite-difference time-domain (FDTD) method.
Abstract: Utilization of electromagnetic band-gap (EBG) structures is becoming attractive in the electromagnetic and antenna community. In this paper, a mushroom-like EBG structure is analyzed using the finite-difference time-domain (FDTD) method. Its band-gap feature of surface-wave suppression is demonstrated by exhibiting the near field distributions of the electromagnetic waves. The mutual coupling of microstrip antennas is parametrically investigated, including both the E and H coupling directions, different substrate thickness, and various dielectric constants. It is observed that the E-plane coupled microstrip antenna array on a thick and high permittivity substrate has a strong mutual coupling due to the pronounced surface waves. Therefore, an EBG structure is inserted between array elements to reduce the mutual coupling. This idea has been verified by both the FDTD simulations and experimental results. As a result, a significant 8 dB mutual coupling reduction is noticed from the measurements.
1,394 citations
"Compact S-Shaped EBG Structures for..." refers background in this paper
...However, for the particular case of patch antennas, the reduction of mutual coupling by means of a periodic structure becomes particularly challenging when grating lobes must be avoided....
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TL;DR: In this article, the authors focus on the reflection phase feature of EBG surfaces, which can be used to identify the input-match frequency band inside of which a low profile wire antenna exhibits a good return loss.
Abstract: 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.
945 citations
"Compact S-Shaped EBG Structures for..." refers background in this paper
...EBG structures are defined as a kind of artificial magnetic conductor (AMC) that prevent/assist the propagation of electromagnetic waves in a specified band of frequency for all incident angles and all polarization states [8]-[9]....
[...]
TL;DR: In this paper, a configuration of uniplanar compact electromagnetic band-gap (UC-EBG) structures is proposed to reduce mutual coupling between the radiating elements of an antenna array.
Abstract: Reducing mutual coupling between elements of an antenna array is one of the main topics in array designs. The use of electromagnetic band-gap (EBG) structures built by microstrip technology is an attractive way to mitigate the mutual coupling problem. This letter describes a novel configuration of uniplanar compact electromagnetic band-gap (UC-EBG) structures to reduce mutual coupling between the radiating elements. The idea is to use the UC-EBG structures placed on top of the antenna layer. The main objective is to reduce both the element separation and the mutual coupling between the patch antennas, which in turn increases antenna directivity. The proposed configuration eliminates drawbacks of similar structures presented in previous works.
312 citations
TL;DR: In this paper, a general technique was proposed to compensate these currents and suppress radiation in horizontal directions, where dielectric polarization currents were identified as the physical sources of this radiation.
Abstract: Microstrip (patch) antennas usually strongly radiate in directions along the ground plane. This effect causes unwanted radiation patterns and increased coupling among array elements. Dielectric polarization currents are identified as physical sources of this radiation. A general technique is proposed to compensate these currents and suppress radiation in horizontal directions.
173 citations
"Compact S-Shaped EBG Structures for..." refers background in this paper
...The near-field coupling is strong in situations where the antennas are printed on dielectric substrates with very low permittivity [11]....
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