Figure - available via license: Creative Commons Attribution 3.0 Unported
Content may be subject to copyright.
(a) Top and (b) side view of patch antenna on a heterogeneous substrate (the inclusions are not drawn to scale to aid visualization of the structure).
Source publication
This communication examines the performance of a rectangular patch antenna on heterogeneous substrates composed of metallic cuboid inclusions compared with homogenous substrates via simulations and measurements. The communication examines how the orientation of the inclusions affects the performance of the patch antenna. Anisotropy and diamagnetism...
Similar publications
A meta-atom platform providing decoupled tuning for the constitutive wave parameters remains as a challenging problem, since the proposition of Pendry. Here we propose an electromagnetic meta-atom design of internal anisotropy (εr ≠ εθ), as a pathway for decoupling of the effective- permittivity εeff and permeability μeff. Deriving effective parame...
Citations
... Precisely, during the design of telecommunication systems such as antenna reflectors as shown in figurer 1 a), b) ,c) [8], printed substrate antennas as shown in Figure 1) d), [2], the electrical properties of the materials used in the manufacture of these systems or even perform numerical simulations, especially electrical permittivity, magnetic permeability and electrical conductivity must be considered by knowing their effect on the absorption, transmissions and reflections characteristics such as S-parameters [1][2][3][4][5][6][7][8][9][10]. In several years, Fibers Reinforced Polymer (FRP) became more interesting and indispensable in the field of manufacturing of radio frequencies telecommunication systems and radio absorption material (RAM) due of its ability to withstand external conditions , besides his special electrical properties, although the electrical properties of FRP are Bi-anisotropic ,which they could be represented as tensors to describe the heterogeneous nature and the fibers orientation effect on the their electromagnetic behavior when exposed under microwaves [9][10][11][12][13][14][15][16][17][18]. These last one are related to several parameters such as volume fraction and fibers orientations inside the FRP, fibers orientation could be very effective when it comes to the S-parameters because its decide the behavior of the FRP under microwaves. ...
The main goal of this paper is studying the composite material behavior under microwave which they used in antennas reflectors. For that, a transmission line method based on X-band WR90 rectangular waveguide is used. The Bi-anisotropic electrical properties are defined as tensors in finite element model. The fibers of the single layer composite are oriented in different directions. The S-parameters (S11 and S12) are calculated using COMSOL Multiyphysics, the S-parameters and currents density behavior show that they very affected by the orientations of the fibers which mean must be considered in any design of RF equipments, more the fibers are parallel with the electrical field more the reflection coefficient get higher.
... 3D printing not only allows the external shape to be controlled, but by changing the way the internal structure is printed the local relative permittivity can be varied. Various papers have explored the concept via theory, simulations, and traditional manufacturing of using air or metallic inclusions to alter the dielectric properties [20]- [24]. As long as the inclusions are smaller than ~ λ/5, then an artificial dielectric is formed. ...
This paper discusses the research related to 3D printed radiofrequency (RF) devices, using fused filament fabrication, carried out at Loughborough University. Different multidisciplinary aspects include the ability to 3D print unique shapes, the ability to tailor the infill to make functionally graded and heterogeneous substrates, characterizing the dielectric properties and how these materials can be used for antennas and other RF designs.
... Antennas using paper substrates have been designed for a variety of applications including wearable applications, sensing, and handheld devices [4], [5], [6], [7]. The literature on antennas developed on nonwoven Latex material with high wetness absorbing strength [8], semiflexible RT Duroid substrate for wearable BAN applications [9], Kapton substrate [10], [11], liquid crystal polymer substrate [12], Synthetic Dielectric and Heterogeneous substrates [13], [14] have been widely studied. However, the fabricating techniques and methodologies utilized for designing the antennas on various substrates involve added complexity. ...
This paper demonstrates a compact flexible antenna for body-worn applications at the ISM band. The antenna is designed on a non-conducting jeans textile substrate with permittivity (ԑ r ) = 1.6, loss tangent (tan ) = 0.085. Adhesive copper tape of thickness 0.03mm is utilized as conducting patch and ground. The overall size of the antenna is 0.533λ × 0.533λ × 0.006λ Analysis where λ corresponds to the lowest operating frequency. and simulations are performed using FEM based ANSYS HFSS simulator. Dual-band operation is obtained at frequencies ranging from 1.96-3.22 GHz and 4.76-5.54 GHz. The design is utilized for a wearable application is also analyzed in the closed proximity of the human phantom model to determine the Specific Absorption Rate (SAR). The antenna exhibits SAR 1.33 W/Kg making it suitable for wearable applications.
... These capabilities can address the requirements of 3-D electromagnetic designs incorporating nonplanar composite structures and nonhomogeneous materials. Single material additive manufacturing has found application in the realization of many microwave and millimeter-wave devices, including metamaterials [2]- [4], horn and patch antennas [5]- [7], graded index and Luneburg lenses [8]- [10], frequency selective surfaces [11], [12], and and microwave filters [13], [14]. ...
The additive manufacturing process of multimaterial extrusion offers performance advantages using functional materials including conductors while making accessible the third dimension in the design of electronics. In this work, we show that the additional geometrical freedom offered by this technique can be exploited for the design and realization of filters made of 3-D resonators that exhibit enhanced characteristics. The coupling properties of 3-D grounded square split ring resonators (SRRs) are initially explored. We demonstrate by simulations and experiments that SRRs with finite height display significantly stronger coupling compared to equivalent thin printed circuit structures. The observed trend can be exploited for designing filters with wider operational bandwidths for a given footprint, or miniaturized layouts and enhanced compatibility with fabrication limits for minimum feature size and spacing without performance degradation. This concept is demonstrated by presenting results of full-wave simulations for sample bandpass filters with identical footprint but formed by coupled 3-D square SRRs of different heights, showing that filters with taller resonators exhibit increasingly wider bandwidths. Two filter prototypes with center frequencies at 1.6 and 2.45 GHz are manufactured by multimaterial 3-D printing. The measured characteristics of these prototypes are found to be in good agreement with numerical simulations taking into account the effect of the lossier metallic and dielectric materials used in 3-D printing and confirm the predicted larger bandwidth of the filters made of 3-D SRRs with marginally higher insertion losses.
... Note that due to the layer-by-layer fabrication of fused deposition modeling (FDM) based 3DP process, the printed dielectrics are inherently uniaxially anisotropic having different permittivity in two orthogonal directions, for example in planar and thickness directions, depending upon the toolpath. [9][10][11] The material can be printed using different infill densities (or solid volume fraction) and the printed material becomes a three-layer sandwich construction having top and bottom layers and core ( Figure 1). The layer thicknesses can be controlled through user defined inputs. ...
... The choice of in-fill density of 3D printed materials influences the heterogeneity on dielectric properties of core because the voids and the solid dielectric are arranged in series and parallel in the in-plane and thickness directions, respectively, and are expected to affect antenna response. 10,12,13 This article focuses on developing simulation models based on permittivity anisotropy in the substrate material. As a guiding principle, experimental X-ray images are used to construct equivalent models for series and parallel equivalent permittivity values based on the printed specimens fill densities. ...
Microstrip patch antennas with a tunable radiofrequency (RF) response are a great candidate for additive manufacturing (AM) process. First, three separate sets of ABS samples were created at three different machine preset fill densities using an extrusion based 3D printer. Once fabricated, actual solid volume fraction of each set of samples was measured using a 3D X-ray computed tomography microscope. It is observed that the factory preset fill-density values are only applied to the core region and actual solid volume fractions for each sample set are different from printer-preset values. Also, the printed materials appeared to exhibit anisotropy such that the thickness direction dielectric properties are different from the in-plane properties (planar isotropy). Microstrip patch antennas created on the AM fabricated ABS were tested for resonant frequencies using a vector network analyzer (VNA). The measured resonant frequencies combined with ANSYS-HFSS simulation were used to estimate bulk dielectric constant of ABS and equivalent dielectric properties in planar and thickness directions. It is observed that the antenna resonant frequency decreases with an increase in core solid volume fraction. Also, in-plane permittivity appeared to have minimal effect on antenna resonant frequency, while the thickness direction properties have substantial effects.
... Furthermore, the shapes of the metallic inclusions may result in anisotropy. The anisotropic and diamagnetic effects due to cuboid metallic inclusions have been analyzed using EM simulations in [15] [16], but fabrication of such heterogeneous material have not been widely reported in the literature. The artificial anisotropic dielectrics will give extra design freedom for future innovative antenna applications. ...
This study presents the analysis and fabrication of artificial materials with metallic cuboid inclusions (termed here as meta-atoms) in a dielectric host material. These synthetic materials or metamaterials have been additively manufactured with a fused deposition modelling three-dimensional (3D) printer. The effective permittivity and permeability have been numerically analysed using the Maxwell-Garnett and Lewin's approximation. Simulations and measurements have shown good agreement with analytical calculations. The anisotropy of the heterogeneous mixture due to the orientation of the meta-atoms has been demonstrated. The effective permittivity has been increased by the presence of the meta-atoms, which has the potential of producing 3D-printing metamaterials with tailored electromagnetic properties.
... The focus of the RF characterization effort was on understanding Transactions of the ASME the effect of material porosity change on the resonant frequency of a well-known antenna. A microstrip patch antenna configuration was considered [23,24]. The 3D-printed dielectric specimens were used to construct several patch antennas as shown in Fig. 2 (LulzBot samples) and Fig. 3 (dimension samples). ...
The resonant frequencies of microstrip patch antennas on Low, Medium, and High Density materials were 5.64, 4.92, and 4.58 GHz, respectively representing increase in the dielectric constant value with increasing material density. Similarly the resonant frequencies of the antennas on 25%, 50%, and 75% fill densities were found to be 5.68 GHz, 5.47 GHz, and 5.05 GHz, respectively. These results clearly demonstrate the ability to control the dielectric constant of the 3D printed material based on prescribed fill density. To understand the effect of pore distribution, a 3D X-ray computed tomography microscope was also used. The great advantage of this 3D microscopy is that it is fully non-destructive and requires no specimen preparation. Hence the manufacturing defects and microstructural variations can be quantified from image data. This provides insight to further understand pore distribution-property relationships in these dielectric materials. In summary, there exists defined relationships between dielectric properties and fill density for 3D printed ABS substrates created using two separate 3D printers. Results obtained from this research are important to design and characterize dielectric substrates with desired anisotropy.
This paper presents a new way to estimate delay spread in machine workspaces by using fractal geometry. In this way, inventories can be created quickly and used within a ray tracing software to estimate the radio environment of machine workspaces as part of the planning process. Delay spread is an important metric in assessing the performance of wireless technologies. Predicted 5G cyber–physical systems in workplaces will require high-density use of wirelessly connected machine-to-machine RF modules. In workshops, the surfaces and edges of machines, shelves, and furniture influence the multipath/power delay profile of the space. However, with the fast construction pace and high occupancy of buildings, it is impractical to characterize the location as building work progresses. Consequently, it becomes more probable that the radio communication system deployed will perform suboptimally. In this work, the Wi-Fi band was investigated. In addition, representative simulations were also carried out at millimetre wave frequencies of 28 GHz and 60 GHz.
