Showing papers on "Relative permittivity published in 2016"
TL;DR: A feasible approach to modify the tribo-material of TENG by filling it with high permittivity nanoparticles and forming pores is designed, which gives a better understanding of the triboelectricity produced by the TENG from the view of materials and provides a new and effective way to enhance the performance of T ENG from the material itself, not just its surface modification.
Abstract: Understanding of the triboelectric charge accumulation from the view of materials plays a critical role in enhancing the output performance of triboelectric nanogenerator (TENG). In this paper, we have designed a feasible approach to modify the tribo-material of TENG by filling it with high permittivity nanoparticles and forming pores. The influence of dielectricity and porosity on the output performance is discussed experimentally and theoretically, which indicates that both the surface charge density and the charge transfer quantity have a close relationship with the relative permittivity and porosity of the tribo-material. A high output performance TENG based on a composite sponge PDMS film (CS-TENG) is fabricated by optimizing both the dielectric properties and the porosity of the tribo-material. With the combination of the enhancement of permittivity and production of pores in the PDMS film, the charge density of ∼19 nC cm(-2), open-circuit voltage of 338 V, and power density of 6.47 W m(-2) are obtained at working frequency of 2.5 Hz with the optimized film consisting of 10% SrTiO3 nanoparticles (∼100 nm in size) and 15% pores in volume, which gives over 5-fold power enhancement compared with the nanogenerator based on the pure PDMS film. This work gives a better understanding of the triboelectricity produced by the TENG from the view of materials and provides a new and effective way to enhance the performance of TENG from the material itself, not just its surface modification.
412 citations
Patent•
AT&T1
TL;DR: In this paper, the subject disclosure may include a solid dielectric antenna having a non-uniform spatial distribution of relative permittivity, which may be considered as a potential source of eavesdropping.
Abstract: Aspects of the subject disclosure may include, for example, a solid dielectric antenna having a non-uniform spatial distribution of relative permittivity.
245 citations
TL;DR: In this article, the data for all reported low-loss microwave dielectric ceramic materials with ultra-low sintering temperatures are collected and tabulated, and the table of these materials gives the relative permittivity, quality factor (tan ǫ ), temperature variation of the resonant frequency, crystal structure, sinting temperature, measurement frequency and references.
Abstract: The recent rapid advances in wireless telecommunication, Internet of Things, the Tactile Internet (5th generation wireless systems), the Industrial Internet, electronic warfare, satellite broadcasting, and intelligent transport systems demand low loss dielectric materials with ultra-low sintering temperatures with modern component fabrication techniques. Properties of microwave ceramics depend on several parameters including their composition, the purity of starting materials, processing conditions, and their ultimate densification/porosity. The preparation, characterization and properties of important materials families such as glass ceramics and molybdates, tellurates, tungstates and vanadates, in combination with Bi, K, Na, Ag, Li, Ba, Ca, etc. with ultra-low sintering temperatures are discussed. In this review the data for all reported low-loss microwave dielectric ceramic materials with ultra-low sintering temperatures are collected and tabulated. The table of these materials gives the relative permittivity, quality factor (tan δ ), temperature variation of the resonant frequency, crystal structure, sintering temperature, measurement frequency and references. The data arranged in the order of increasing relative permittivity will be very useful for scientists, industrialists, engineers and students working on current and emerging applications of microelectronics.
216 citations
TL;DR: Self-standing films of native cellulose nanofibrils (CNFs) were synthesized and characterized to suggest that CNF is a suitable precursor material for disposable piezoelectric sensors, actuators, or energy generators with potential applications in the fields of electronics, sensors, and biomedical diagnostics.
Abstract: Self-standing films (45 μm thick) of native cellulose nanofibrils (CNFs) were synthesized and characterized for their piezoelectric response. The surface and the microstructure of the films were evaluated with image-based analysis and scanning electron microscopy (SEM). The measured dielectric properties of the films at 1 kHz and 9.97 GHz indicated a relative permittivity of 3.47 and 3.38 and loss tangent tan δ of 0.011 and 0.071, respectively. The films were used as functional sensing layers in piezoelectric sensors with corresponding sensitivities of 4.7–6.4 pC/N in ambient conditions. This piezoelectric response is expected to increase remarkably upon film polarization resulting from the alignment of the cellulose crystalline regions in the film. The CNF sensor characteristics were compared with those of polyvinylidene fluoride (PVDF) as reference piezoelectric polymer. Overall, the results suggest that CNF is a suitable precursor material for disposable piezoelectric sensors, actuators, or energy gene...
192 citations
TL;DR: In this article, a piezoelectric-composite slurry with BaTiO3 nanoparticles (100nm) was 3D printed using Mask-Image-Projection-based Stereolithography (MIP-SL) technology.
183 citations
TL;DR: In this article, a single-compound triple complementary split-ring resonator (SC-TCSRR) was used to determine the complex permittivity and thickness of a material under test (MUT).
Abstract: This paper presents a novel noncontact measurement technique that entails using a single-compound triple complementary split-ring resonator (SC-TCSRR) to determine the complex permittivity and thickness of a material under test (MUT). The proposed technique overcomes the problem engendered by the existence of air gaps between the sensor ground plane and the MUT. In the proposed approach, a derived governing equation of the resonance frequencies is used to estimate the thickness and complex permittivity of the MUT by calculating the resonant frequency $(f_{{ r}})$ and magnitude response in a single-step noncontact measurement process. This study theoretically analyzed and experimentally verified a simple and low-cost SC-TCSRR measurement method for assessing materials in a noncontact method. For a 0.2-mm air gap, the experiments yielded average measurement errors of 4.32% and 5.05% for the thickness and permittivity, respectively. The proposed SC-TCSRR technique provides excellent solutions for reducing the effect of air-gap conditions on permittivity, thickness, and loss tangent in noncontact measurements.
174 citations
15 May 2016
TL;DR: In this paper, a split-ring resonator (SRR)-based sensor for the detection of solid thickness and relative permittivity characterization of solid and liquid materials is proposed, which is composed of two SRRs hosted in a microstrip transmission line.
Abstract: A split-ring resonator (SRR)-based sensor for the detection of solid thickness and relative permittivity characterization of solid and liquid materials is proposed. The structure is composed of two SRRs hosted in a microstrip transmission line. The sensing principle is based on the detection of the notch introduced by the resonators in the transmission coefficient. Hence, a frequency shift of the notch is related to a change in the effective permittivity of the structure when the sensor is covered with any solid or liquid material. A complete characterization of the sensor, for the three proposed applications, is performed through simulations. Finally, all simulated results are corroborated with measurements. The proposed sensor is implemented in single-layer printed technology, resulting in a low-cost and low-complexity solution. It presents real-time response and high sensitivity. Moreover, it is fully submersible and reusable.
152 citations
TL;DR: In this article, the projection-based stereolithography (SLA) method was used to print high dielectric polymer/ceramic composite materials into 3D capacitors.
135 citations
TL;DR: In this article, Niobium and aluminum co-doped TiO2 ceramics were synthesized via a solid-state reaction route, and a colossal permittivity over 105 with relatively low dielectric loss could be noted in the NAT10 ceramic.
Abstract: Niobium and aluminum co-doped TiO2 ceramics, i.e., (Nb0.5Al0.5)xTi1−xO2 (x = 0, 0.01, 0.05, 0.1, 0.15, abbreviated as NAT100x) were synthesized via a solid-state reaction route. As could be seen from X-ray diffraction (XRD) patterns, all samples were in pure rutile phases. A colossal permittivity (CP) over 105 with relatively low dielectric loss could be noted in the NAT10 ceramic. Additionally, the high dielectric permittivity (>105) could be maintained over a wide temperature range of −100–250 °C and frequency range of 102 to 106 Hz, respectively. This indicated that the dielectric property of NAT10 possessed superior temperature-dependent and frequency-dependent stability. Analysis of impedance spectroscopy and current density vs. electric field plots revealed that the CP was attributed to an internal barrier layer capacitance effect.
120 citations
TL;DR: In this paper, the effects of the mass fraction on the microstructure and dielectric properties of BST/PVDF composites were investigated, and the results showed that the surface of BST particles was covered by silane coupling agent.
104 citations
TL;DR: Thedielectric behavior and impedance spectrum of the polycrystalline ceramic sample indicated that the internal barrier layer capacitor (IBLC) mode made a major contribution to the high ceramic dielectric permittivity, instead of the electron-pinned defect-dipoles.
Abstract: In this paper, we investigated the dielectric properties of (In + Nb) co-doped rutile TiO2 single crystal and polycrystalline ceramics. Both of them showed colossal, up to 10(4), dielectric permittivity at room temperature. The single crystal sample showed one dielectric relaxation process with a large dielectric loss. The voltage-dependence of dielectric permittivity and the impedance spectrum suggest that the high dielectric permittivity of single crystal originated from the surface barrier layer capacitor (SBLC). The impedance spectroscopy at different temperature confirmed that the (In + Nb) co-doped rutile TiO2 polycrystalline ceramic had semiconductor grains and insulating grain boundaries, and that the activation energies were calculated to be 0.052 eV and 0.35 eV for grain and grain boundary, respectively. The dielectric behavior and impedance spectrum of the polycrystalline ceramic sample indicated that the internal barrier layer capacitor (IBLC) mode made a major contribution to the high ceramic dielectric permittivity, instead of the electron-pinned defect-dipoles.
TL;DR: In this paper, the current state of understanding of the mechanisms underlying the high and stable values of both relative permittivity and resistivity that are characteristic of BaTiO3-Bi(M)O3 dielectrics as well as the processing challenges and opportunities associated with these materials are reviewed.
Abstract: As part of a continued push for high permittivity dielectrics suitable for use at elevated operating temperatures and/or large electric fields, modifications of BaTiO3 with Bi(M)O3, where M represents a net-trivalent B-site occupied by one or more species, have received a great deal of recent attention. Materials in this composition family exhibit weakly coupled relaxor behavior that is not only remarkably stable at high temperatures and under large electric fields, but is also quite similar across various identities of M. Moderate levels of Bi content (as much as 50 mol%) appear to be crucial to the stability of the dielectric response. In addition, the presence of significant Bi reduces the processing temperatures required for densification and increases the required oxygen content in processing atmospheres relative to traditional X7R-type BaTiO3-based dielectrics. Although detailed understanding of the structure–processing–property relationships in this class of materials is still in its infancy, this article reviews the current state of understanding of the mechanisms underlying the high and stable values of both relative permittivity and resistivity that are characteristic of BaTiO3-Bi(M)O3 dielectrics as well as the processing challenges and opportunities associated with these materials.
TL;DR: Experimental results agree with percolation theory, which indicates that the enhanced dielectric properties of the BT–Fe3O4/PVDF composites originate from the interfacial polarization induced by the external magnetic field.
Abstract: We report enhancement of the dielectric permittivity of poly(vinylidene fluoride) (PVDF) generated by depositing magnetic iron oxide (Fe3O4) nanoparticles on the surface of barium titanate (BT) to fabricate BT–Fe3O4/PVDF composites. This process introduced an external magnetic field and the influences of external magnetic field on dielectric properties of composites were investigated systematically. The composites subjected to magnetic field treatment for 30 min at 60 °C exhibited the largest dielectric permittivity (385 at 100 Hz) when the BT–Fe3O4 concentration is approximately 33 vol.%. The BT–Fe3O4 suppressed the formation of a conducting path in the composite and induced low dielectric loss (0.3) and low conductivity (4.12 × 10−9 S/cm) in the composite. Series-parallel model suggested that the enhanced dielectric permittivity of BT–Fe3O4/PVDF composites should arise from the ultrahigh permittivity of BT–Fe3O4 hybrid particles. However, the experimental results of the BT–Fe3O4/PVDF composites treated by magnetic field agree with percolation theory, which indicates that the enhanced dielectric properties of the BT–Fe3O4/PVDF composites originate from the interfacial polarization induced by the external magnetic field. This work provides a simple and effective way for preparing nanocomposites with enhanced dielectric properties for use in the electronics industry.
TL;DR: This work first investigates the CP behavior of rutile TiO2 ceramics co-doped with niobium and erbium, and may provide comprehensive guidance to develop high-performance CP materials for fully solid-state capacitor and energy storage applications.
Abstract: The search for colossal permittivity (CP) materials is imperative because of their potential for promising applications in the areas of device miniaturization and energy storage. High-performance CP materials require high dielectric permittivity, low dielectric loss and relatively weak dependence of frequency- and temperature. In this work, we first investigate the CP behavior of rutile TiO2 ceramics co-doped with niobium and erbium, i.e., (Er0.5Nb0.5)xTi1−xO2. Excellent dielectric properties were observed in the materials, including a CP of up to 104–105 and a low dielectric loss (tanδ) down to 0.03, which are lower than that of the previously reported co-doped TiO2 CP materials when measured at 1 kHz. Stabilities of frequency and temperature were also accomplished via doping Er and Nb. Valence states of the elements in the material were analyzed using X-ray photoelectron spectroscopy. The Er induced secondary phases were observed using elemental mapping and energy-dispersive spectrometry. Consequently, this work may provide comprehensive guidance to develop high-performance CP materials for fully solid-state capacitor and energy storage applications.
TL;DR: In this paper, a glass-free low temperature sinterable CuMoO4 ceramic was prepared by a solid state ceramic route, and the structural, microstructural, electron dispersive spectrum, and X-ray photoelectron spectroscopy analysis revealed the quality of the material synthesized.
Abstract: A new glass-free low temperature sinterable CuMoO4 ceramic was prepared by a solid state ceramic route. The structural, microstructural, electron dispersive spectrum, and X-ray photoelectron spectroscopy analysis revealed the quality of the material synthesized. The CuMoO4 ceramic sintered at 650 °C exhibits densification of 96% and low coefficient of thermal expansion (CTE) of 4.6 ppm/°C in the temperature range of 25–500 °C. It has relative permittivity (er) of 7.9, quality factor (Qf) of 53 000 GHz, and temperature coefficient of resonant frequency (τf) of −36 ppm/°C (25–85 °C) at 12.7 GHz. The sintered ceramic also shows er of 11 and low dielectric loss (tan δ) of 2.7 × 10–4 at the frequency of 1 MHz. The full width half-maximum (fwhm) of A1g Raman mode of CuMoO4 ceramic at different sintering temperatures correlate well with the Qf values. The low sintering temperature, low relative permittivity, high-quality factor, and matching coefficient of thermal expansion to that of Si make CuMoO4 a suitable c...
TL;DR: In this paper, the role of the barrier thickness (2.0, 2.4 and 2.8 mm) and of the kind of dielectric material (alumina, mullite, pyrex, quartz) on the filamentary behavior in the plasma and on the CO2 conversion in a tubular flowing DBD, by means of mass spectrometry measurements correlated with electrical characterization and IR imaging.
Abstract: Dielectric barrier discharges (DBDs) are commonly used to generate cold plasmas at atmospheric pressure. Whatever their configuration (tubular or planar), the presence of a dielectric barrier is mandatory to prevent too much charge build up in the plasma and the formation of a thermal arc. In this article, the role of the barrier thickness (2.0, 2.4 and 2.8 mm) and of the kind of dielectric material (alumina, mullite, pyrex, quartz) is investigated on the filamentary behavior in the plasma and on the CO2 conversion in a tubular flowing DBD, by means of mass spectrometry measurements correlated with electrical characterization and IR imaging. Increasing the barrier thickness decreases the capacitance, while preserving the electrical charge. As a result, the voltage over the dielectric increases and a larger number of microdischarges is generated, which enhances the CO2 conversion. Furthermore, changing the dielectric material of the barrier, while keeping the same geometry and dimensions, also affects the CO2 conversion. The highest CO2 conversion and energy efficiency are obtained for quartz and alumina, thus not following the trend of the relative permittivity. From the electrical characterization, we clearly demonstrate that the most important parameters are the somewhat higher effective plasma voltage (yielding a somewhat higher electric field and electron energy in the plasma) for quartz, as well as the higher plasma current (and thus larger electron density) and the larger number of microdischarge filaments (mainly for alumina, but also for quartz). The latter could be correlated to the higher surface roughness for alumina and to the higher voltage over the dielectric for quartz.
TL;DR: A novel time domain measurement technique is proposed to facilitate the simultaneous measurement of electrical properties (complex relative permittivity) and geometrical parameters (thickness) of the material under test (MUT).
Abstract: A novel time domain measurement technique is proposed to facilitate the simultaneous measurement of electrical properties (complex relative permittivity) and geometrical parameters (thickness) of the material under test (MUT). The overall process is noninvasive and noncontacting, which uses the measured scattering data of the MUT in the equivalent time domain or spatial domain. The effective time domain scattering data are employed to detect the primary and secondary peaks of the overall reflection and transmission coefficients. To this end, a novel algorithm is proposed to obtain the complex permittivity and thickness of the MUT in terms of extracted reflection and transmission power peaks. From the practical point of view, the main advantage of the proposed scheme is that one avoids the complicated calibration procedure normally required to define the reference plane. For increasing the accuracy of the overall reconstruction process, an automated optimization procedure based on parameter sensitivity analysis is proposed, which uses standard time gating procedure to implement the corresponding direct problem. The proposed technique is validated by extracting the relative permittivity, the dielectric loss (effective conductivity), and the thickness of various standard materials, such as polyethylene, Plexiglas, PVC, mortar, nylon, and so on, and comparing the extracted data with their values available in the literature.
TL;DR: In this paper, a two-dimensional modeling of planar heterojunction perovskite solar cells was performed combining the optical and electrical responses to reveal the impact of the carrier diffusion length, the relative permittivity of absorber layer and the valence band offset of the absorber/hole transport material (HTM).
TL;DR: In this paper, the authors investigated the fabrication and simulation techniques of FGM with various spatial distributions of dielectric permittivity using centrifugal force and verified the validity of the simulation technique.
Abstract: An innovation for the higher performance and reliability of electric power apparatus can be brought about by a novel technique on electrical insulating materials. The application of functionally graded materials (FGM) with spatial distribution of dielectric permittivity in solid insulator is an effective technique to contribute to the above innovation, because FGM can control the electric field distribution with a simple shape. In this paper, we investigated the fabrication and simulation techniques of FGM with various spatial distributions of dielectric permittivity using centrifugal force. Firstly, we developed a simulation technique to estimate the dielectric permittivity distribution of FGM by considering the particle movement in a viscous fluid under centrifugal force. Secondly, based on the simulation technique, we fabricated FGM samples with various relative permittivity distribution and confirmed the validity of the simulation technique. Consequently, the fabrication results provided a good agreement with the simulation results.
TL;DR: In this article, a microfluidic-integrated microwave sensor with potential application in microliter-volume biological/biomedical liquid sample characterization and quantification is presented, which is designed based on the resonance method, providing the best sensing accuracy, and implemented by using a substrate integrated-waveguide structure combining with a rectangular slot antenna operating at 10 GHz.
Abstract: A novel microfluidic-integrated microwave sensor with potential application in microliter-volume biological/biomedical liquid sample characterization and quantification is presented in this paper. The sensor is designed based on the resonance method, providing the best sensing accuracy, and implemented by using a substrate-integrated-waveguide (SIW) structure combining with a rectangular slot antenna operating at 10 GHz. The device can perform accurate characterization of various liquid materials from very low to high loss, demonstrated by the measurement of deionized water and methanol liquid mixtures. The measured relative permittivity, which is the real part of complex permittivity, ranges from 8.58 to 66.12, which is simply limited by the choice of test materials available in our laboratory, not any other technical considerations of the sensor. The fabricated sensor prototype requires a very small liquid volume of less than 7 $\mu \text{L}$ , while still offering an overall accuracy of better than 3%, as compared with the commercial and other published works. The key advantages of the proposed sensor are that it combines: 1) a very low-profile planar and miniaturized structure sensing microliter liquid volume; 2) ease of design and fabrication, which makes it cost-effective to manufacture; and 3) noninvasive and contactless measurements. Moreover, since the microfluidic subsystem can potentially be detached from the SIW microwave sensor and, afterward, replaced by a new microfluidic component, the sensor can be reused with no life-cycle limitation and without degrading any figure of merit.
TL;DR: In this article, the effects of the filler particle alignment and the filler fraction on the dielectric permittivity as well as the Dielectric loss of the composites were studied.
TL;DR: In this paper, a polymer composite with high dielectric permittivity and low electrical loss was successfully fabricated by embedding a core-shell structure whisker in polymer matrix.
01 Sep 2016
TL;DR: In this article, a microstrip line with stubs and a superstrate was used to determine the complex permittivity of polylactide acid (PLA) at microwave frequencies.
Abstract: The use of 3D-printing based on extrusion depositing technologies for electromagnetic applications (such as dielectric antenna design or human mimicking tissues) is increasing as a low cost alternative to other small-scale fabrication technologies. As a result, it is of utmost scientific interest to know the exact dielectric properties of commercially available printable materials, such as polylactide acid (PLA). The extrusion depositing process may originate an anisotropic behavior of the material permittivity especially at mm-waves. We investigate this plastic's complex permittivity across the microwave spectrum from 0.5 GHz to 20 GHz and at 40 GHz and 60 GHz. We propose a new indirect method for the complex permittivity determination at microwave frequencies based on a microstrip line with stubs and a superstrate. At 40 GHz and 60 GHz, the printed PLA samples are characterized using waveguide and open resonator methods. Results show that throughout the tested frequency range the dielectric constant along the normal direction to the printing surface is around 2.75±0.05 and tan δ = (1.1±0.2)×10−2. However, at least for the tested mm-wave bands, the dielectric constant along the parallel direction to the printing surface is around 2.96, corresponding to nearly 7% anisotropy.
TL;DR: In this article, a designed nano-KTN/Ag core/shell structure endows nano-KNN@Ag/PVDF composite films with excellent properties of remarkably enhanced dielectric permittivity, low loss tangent and flexibility.
Abstract: A designed nano-KTN/Ag core/shell structure endows nano-KTN@Ag/PVDF composite films with excellent properties of remarkably enhanced dielectric permittivity, low loss tangent and flexibility. It has been found that the incorporation of KTN@Ag nanoparticles can increase the average crystallite size of the β phase in a polymer matrix, which elevates the polarization level of the polymer matrix and increases the dielectric permittivity of the nanocomposites. 25 vol% composites own a remarkably enhanced dielectric permittivity (er = 230) at 100 Hz, which is due to MWS polarization at the internal interface between nano-KTN@Ag and the PVDF matrix, the increased induced polarization of the nanoparticles and the “boundary layer capacitor effect”. The low loss tangent is achieved because of an enhanced polarization reverse speed by the Ag shells and a blockage of charge transfer by PVDF chains. The percolation threshold of the composite films (fc = 0.317) was predicted by the percolation theory, and the theoretical results were in good agreement with the experimental data.
TL;DR: Li4WO5 was found to be chemically compatible with silver powders when sintered at 890 °C as discussed by the authors, which is a promising candidate as a base material in low temperature co-fired ceramic technology.
Abstract: A Li4WO5 ceramic with rock salt structure was prepared by the solid-state reaction method and its microwave dielectric properties was demonstrated for the first time. It could be well densified at relatively low sintering temperature (∼890 °C). XRD and DTA analysis revealed a phase transformation from cubic to orthorhombic occured at 700 °C. Excellent microwave dielectric properties with a near-zero temperature coefficient of resonant frequency ∼−2.6 ppm/°C, a relative permittivity ∼8.6 and a quality factor ∼23,100 GHz (at 11.0 GHz) was obtained. Li4WO5 was found to be chemically compatible with silver powders when sintered at 890 °C. All the results indicate that the Li4WO5 ceramic is a promising candidate as a base material in low temperature cofired ceramic technology.
TL;DR: It is shown that both smaller thickness and larger relative permittivity of c-PMMA contributes to reduced operating voltage, and negligible hysteresis brings evidence to small trap states in the semiconductor near gate dielectric of the n-type OFETs with c- PMMA.
Abstract: Recent improvement in the performance of the n-type organic semiconductors as well as thin gate dielectrics based on cross-linked polymers offers new opportunities to develop high-performance low-voltage n-type OFETs suitable for organic complementary circuits. Using TIPS-tetracyanotriphenodioxazine (TIPS-TPDO-tetraCN) and cross-linked poly(methyl methacrylate) (c-PMMA), respectively as n-type organic semiconductor and gate dielectric, linear regime field-effect mobility (1.8 ± 0.2) × 10–2 cm2 V–1s–1, small spatial standard deviation of threshold voltage (∼0.1 V), and operating voltage less than 3 V are attainable with the same device structure and contact materials used commonly for p-type OFETs. Through comparative static and dynamic characterizations of c-PMMA and PMMA gate dielectrics, it is shown that both smaller thickness and larger relative permittivity of c-PMMA contributes to reduced operating voltage. Furthermore, negligible hysteresis brings evidence to small trap states in the semiconductor n...
19 May 2016
TL;DR: Measurement of dielectric constants of three types of polylactic acid (PLA) plastic materials that can be used for 3D printing of antennas and other radio frequency (RF) devices are considered.
Abstract: 3D printing technology provides an affordable method of prototyping antennas. To design antennas with this technology it is necessary to characterize the materials used for printing precisely in terms of their permittivity and conductivity. Two major groups of materials for antenna design are dielectric and conductive materials. In this paper, we consider measurement of dielectric constants of three types of polylactic acid (PLA) plastic materials that can be used for 3D printing of antennas and other radio frequency (RF) devices.
TL;DR: In this paper, the complex permittivity of polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene and cross-linked polystyrene (Rexolite), has been measured at frequency range from 5 GHz to 50 GHz.
Abstract: Complex permittivity of Polytetrafluoroethylene (PTFE), Polypropylene (PP), Polyethylene (PE) and cross-linked Polystyrene (Rexolite), has been measured at frequency range from 5 GHz to 50 GHz. Measurements have been performed in two cylindrical cavities employing several quasi $\text{TE}_{0 \mathrm{mn}}$ modes excited in samples under test. Measurement uncertainties for the real part of permittivity were $\pm$ 0.5% while for the imaginary part of permittivity in the range from $\pm$ 8% for the lowest loss materials to $\pm$ 3% for Rexolite. It has been confirmed that the real part of permittivity of all measured polymers is constant in the microwave frequency spectrum to within measurement uncertainties, while the dielectric loss tangent values vary with frequency
TL;DR: In this article, the authors introduced a method of using patch antennas to generate millimeter-wave Hermite-Gaussian (HG) beams at E-band using four inset-fed microstrip patch elements arranged with a microstrip corporate feeding network.
Abstract: This letter introduces a method of using patch antennas to generate millimeter-wave Hermite–Gaussian (HG) beams at E-band. An HG11 beam is formed using four inset-fed microstrip patch elements arranged with a microstrip corporate feeding network. The designed antennas are fabricated on a high-performance FR4 circuit board with a relative permittivity of 3.75 and a loss tangent of 0.018. The overall size of the antenna array is 8 × 8 × 0.125 mm3. A full-wave electromagnetic simulator, HFSS, is used to design the array. Radiation pattern measurements were taken on an NSI 700S-360 spherical near-field system at 73 GHz together with an Agilent vector network analyzer. The simulations and measurements are in good agreement.
TL;DR: In this paper, a Rectangular Dielectric Resonator Antenna (RDRA) with a modified feeding line is designed and investigated at 28 GHz, where the modified feed line was designed to excite the DR with relative permittivity of 10 which contributes to a wide bandwidth operation.
Abstract: In this paper, a Rectangular Dielectric Resonator Antenna (RDRA) with a modified feeding line is designed and investigated at 28 GHz. The modified feed line is designed to excite the DR with relative permittivity of 10 which contributes to a wide bandwidth operation. The proposed single RDRA has been fabricated and mounted on a RT/Duroid 5880 (er = 2.2 and tanδ = 0.0009) substrate. The optimized single element has been applied to array structure to improve the gain and achieve the required gain performance. The radiation pattern, impedance bandwidth and gain are simulated and measured accordingly. The number of elements and element spacing are studied for an optimum performance. The proposed antenna obtains a reflection coefficient response from 27.0 GHz to 29.1 GHz which cover the desired frequency band. This makes the proposed antenna achieve 2.1 GHz impedance bandwidth and gain of 12.1 dB. Thus, it has potential for millimeter wave and 5G applications