10 research outputs found

    A miniaturized 3 dimensional bandpass frequency selective surface

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    A planar bandpass frequency selective surface (FSS) is proposed along with an alternative 3D element design with the intent of miniaturizing the unit cell. The two structures are simulated in CST and compared. Such techniques show the potential of using 3D elements in FSS design to miniaturize the structure for space constrained applications

    Artificially engineered capacitors for discrete high-frequency electronic circuitry

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    The concept of the artificially engineered capacitor (AEC) is presented as a 3D printable 3D capacitive component for the use in discrete RF/microwave electronic circuitry. The intention of the AEC concept is a highly customizable 3D printable component whose capacitance value is stable over a wider frequency band when compared to commercial alternatives. AECs can be viewed as impedance structures with predominantly capacitive characteristics. Both series and shunt AEC configurations are considered with simulation and measurement data along with equivalent circuit models. The tolerance of the equivalent capacitance over frequency is focused upon in this paper. Within the 40 % tolerance band from the nominal value an improvement of 26 % and 197 % frequency band was achieved for the series and shunt variants respectively when compared to a commercial alternative. Further simulations show that with finer 3D printing resolutions, this frequency stable bandwidth can be further increased. Finally, an example design application of a halfwavelength microstrip resonator is presented in which the AECs’ Q factor is measured, and the its equivalent circuits are implemented and validated via simulations and measurements.</div

    Meta-atom loaded patch antenna

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    © 2018 Institution of Engineering and Technology. All rights reserved. The design of a meta-atom/metamaterial assisted patch antenna is presented. By utilizing strategically placed meta-atom in the patch antenna design miniaturization benefits can be gained with minimal impact to the total efficiency and the fractional bandwidth

    Equivalent circuit analysis for 3D metamaterials with fringing field correction factor

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    © 2017 Institution of Engineering and Technology. All rights reserved. This paper presents a fringing field correction factor for circuit modelling techniques of metasurfaces and metamaterials. The theory is then applied to periodic three dimensional metamaterial meta-atoms. Equivalent circuits have been validated using CST Microwave Studio

    Evaluation of microwave characterization methods for additively manufactured materials

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    Additive manufacturing (AM) has become more important and common in recent years. Advantages of AM include the ability to rapidly design and fabricate samples much faster than traditional manufacturing processes and to create complex internal geometries. Materials are crucial components of microwave systems and proper and accurate measurement of their dielectric properties is important to aid a high level of accuracy in design. There are numerous measurement techniques and finding the most appropriate method is important and requires consideration of all different factors and limitations. One limitation of sample preparation is that the sample size needs to fit in the measurement method. By utilizing the advantage of additive manufacturing, the material can be characterized using different measurement methods. In this paper, the additive manufacturing process and dielectric measurement methods have been critically reviewed. The test specimens for measuring dielectric properties were fabricated using fused filament fabrication (FFF)-based additive manufacturing and were measured using four different commercial dielectric properties measurement instruments including split post dielectric resonator (SPDR), rectangular waveguide, TE01δ cavity resonator, and open resonator. The measured results from the four techniques have been compared and have shown reasonable agreement with measurements within a 10 percent range

    Multi-material additive manufacturing of low sintering temperature Bi2Mo2O9 ceramics with Ag floating electrodes by selective laser burnout

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    Additive manufacturing (AM) of co-fired low temperature ceramics offers a unique route for fabrication of novel 3D radio frequency (RF) and microwave communication components, embedded electronics and sensors. This paper describes the first-ever direct 3D printing of low temperature co-fired ceramics/floating electrode 3D structures. Slurry-based AM and selective laser burnout (SLB) were used to fabricate bulk dielectric, Bi2Mo2O9 (BMO, sintering temperature = 620–650°C, εr = 38) with silver (Ag) internal floating electrodes. A printable BMO slurry was developed and the SLB optimised to improve edge definition and burn out the binder without damaging the ceramic. The SLB increased the green strength needed for shape retention, produced crack-free parts and prevented Ag leaching into the ceramic during co-firing. The green parts were sintered after SLB in a conventional furnace at 645°C for 4 h and achieved 94.5% density, compressive strength of 4097 MPa, a relative permittivity (εr) of 33.8 and a loss tangent (tan δ) of 0.0004 (8 GHz) for BMO. The feasibility of using SLB followed by a post-printing sintering step to create BMO/Ag 3D structures was thus demonstrated

    Parasitic inductance control of multi-layer ceramic capacitors using metamaterials

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    This paper presents methods of influencing the resonant frequency of a multi-layer ceramic capacitor by controlling the localized characteristic impedance of the transmission line. The methods give circuit designers more flexibility when using chip capacitors by allowing them influence over where the resonant frequency occur

    Equivalent circuit modelling of meta-atoms

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    This paper presents a technique for designing an equivalent circuit for periodic meta-atom structures that utilize solutions for infinite arrays of inductive/capacitive conductive posts in a plane wave [1]. The model has been validated against simulation results

    Artificially Engineered Capacitors for Discrete High Frequency Electronic Circuitry - Data set

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    Measurement and simulation data presented in the paper titled 'Artificially Engineered Capacitors for Discrete High Frequency Electronic Circuitry'

    Supplementary Information Files for ' Multi-material additive manufacturing of low sintering temperature Bi2Mo2O9 ceramics with Ag floating electrodes by selective laser burnout'

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    Supplementary Information Files for ' Multi-material additive manufacturing of low sintering temperature Bi2Mo2O9 ceramics with Ag floating electrodes by selective laser burnout'Abstract:Additive manufacturing (AM) of co-fired low temperature ceramics offers a unique route for fabrication of novel 3D radio frequency (RF) and microwave communication components, embedded electronics and sensors. This paper describes the first-ever direct 3D printing of low temperature co-fired ceramics/floating electrode 3D structures. Slurry-based AM and selective laser burnout (SLB) were used to fabricate bulk dielectric, Bi2Mo2O9 (BMO, sintering temperature = 620–650°C, εr = 38) with silver (Ag) internal floating electrodes. A printable BMO slurry was developed and the SLB optimised to improve edge definition and burn out the binder without damaging the ceramic. The SLB increased the green strength needed for shape retention, produced crack-free parts and prevented Ag leaching into the ceramic during co-firing. The green parts were sintered after SLB in a conventional furnace at 645°C for 4 h and achieved 94.5% density, compressive strength of 4097 MPa, a relative permittivity (εr) of 33.8 and a loss tangent (tan δ) of 0.0004 (8 GHz) for BMO. The feasibility of using SLB followed by a post-printing sintering step to create BMO/Ag 3D structures was thus demonstrated.</div
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