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A design for manufacturing (DFM) of a well‐performing wideband coaxial filter line using direct metal laser sintering (DMLS) additive manufacturing is proposed. The demonstrated transmission line is an air‐filled coaxial line chosen for low loss and consistent group delay over the bandwidth. Transmission line theory is used first to account for the impact of the shorted stub needed to support the central conductor. Deviations due to parasitics are described to transition the design from an ideal model to a physical prototype. The constraints inherent in DMLS are discussed and accounted for throughout the DFM. This process is demonstrated with a prototype having return and insertion losses of greater than 10 dB and less than 1.64 dB, respectively, over a 5.3:1 bandwidth from 6.4 to 33.9 GHz with a flat group delay of 129 ps ± 7%. [ABSTRACT FROM AUTHOR]

The following study investigates the use of a coaxial transmission line for determining the properties of powdery dielectric materials (1–10 GHz). Four powdery materials with dielectric constants ranging from 3.5 to 70 (SiO2, Al2O3, CeO2, and TiO2) were experimentally investigated at varying volume loading fractions. Powder particles were mixed with a paraffin matrix and properties of the powder were analysed using ten mixing equations to verify their accuracy. These powder‐paraffin composites were also modelled at varying volume loadings for comparison with experimental data to gain a better understanding of the interactions between the different phases. The optimal volume loading fraction was determined to be 10% for all powders tested. A metric for selecting the most well‐suited mixing equation was proposed that involved taking the ratio of the particle dielectric to that of the matrix. This study ultimately provides guidance for experimentally measuring the dielectric properties of unknown powdery materials that have applications for new devices that utilised powder‐based dielectric materials. [ABSTRACT FROM AUTHOR]

This article is a study of an empirical design of an open-ended coaxial cavity resonator. The coaxial cavity resonator can be designed using the coaxial transmission-line theory. It can be done by using the radius of the inner conductor, the inner radius, and the length of the resonator. However, the basic coaxial transmission-line theory can be seen that the characteristics of the resonant frequency and the Q value are varied by the change of length, regardless of the value of radius of the inner conductor and inner radius of the resonator. We find out the impact of radius of the inner conductor, inner radius of the resonator, and the length of the resonator parameter and propose the optimized empirical resonator design method by reducing the error between the theoretical value and the design value. High frequency structure simulator was used for simulation and the material of the resonator was designed with a copper. Based on the simulation, several resonators are fabricated by the size of 14 mm for the radius of inner conductor, 2, 5, and 10 mm, respectively, for the inner radius of resonator, and 8.5 mm for the length of the resonator. The resonant frequencies of the produced resonators were measured at 6.1, 5.7, and 6.5 GHz, respectively. According to the result of simulation and measurement, we know that we can design the relatively exact open-ended coaxial cavity resonator by applying the basic coaxial transmission-line theory directly when the length of the resonator is less than 10 mm, and adding the correction factor of 0.5 GHz to the calculated resonant frequency in case of more than 10 mm of the length of the resonator. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:606-610, 2014 [ABSTRACT FROM AUTHOR]

In this article, we present a study dealing with the design, optimization, and manufacturing of different versions of a broadband monopole antenna with a convex conical reflector. These antennas are created by a wire monopole that is placed into the axis of a convex conical reflector. The principle of antennas is based on the transformation of the impedance of a coaxial transmission line to the open space impedance via a circular waveguide. The results of simulations performed in CST Microwave Studio are mutually compared. Then, the simulated versions of broadband monopole antennas were optimized with respect to specified objectives. According the available materials, we built selected versions of the antenna and experimentally verified their properties. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1243-1247, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27598 [ABSTRACT FROM AUTHOR]

In this article, we present a very simple toolkit for permittivity and permeability measurement in the microwave region in real time. This kit contains a coaxial cell and a dedicated software compatible with any Vector Network Analyzer (VNA) for the reconstruction of permittivity and permeability data. The customizing design of the coaxial cell depends on the applications and material forms. The dedicated software for overall cells reconstructs directly in real time the permittivity and the permeability from the S-parameters measured. The Nicolson & Ross-Weir algorithm is using after a de-embedding process done by modeling our cell with an identity card (IC). The novelty of our method is that, after calibration process of the VNA to remove the cable effect, the measurement of the permittivity and permeability were done directly after only one measurement in real time. To validate the accuracy of this new measurement process for new applications, we reconstruct the permittivity of two material forms (dielectric or/and magnetic solids, semisolid). This new toolkit is called EpsiMu (www.epsimu.fr). © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2643-2648, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25570 [ABSTRACT FROM AUTHOR]

In this article, we propose a new method to measure the complex relative permittivity (ℇr = ℇr′ - jℇr″) and permeability (μr = μr′ - jμr″) of liquid- or powder-type materials using a two-port probe which is constructed from coaxial transmission lines. The two-port probe is a simple structure that can be easily fabricated with low cost in comparison with conventional probes which are the type of the cavity and waveguide. And we have adopted the Cole–Cole equation and air-filled coaxial cable for calibrating the proposed probe. To verify the performance of the proposed probe, we measured the properties of materials in the form of liquids and powders and compared the results with those measured by the air-filled coaxial cable, which shows good agreement. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2977–2979, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24793 [ABSTRACT FROM AUTHOR]