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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]

Current physics is considered to be based on Newtonian mechanics. The existence of electromagnetic waves was demonstrated by the Maxwell equations. It is also possible to assume that the constitution of electromagnetic waves forms the fundamental principles of physics, including the composition of materials. To demonstrate this assumption, we introduced electromagnetic waves in coaxial cables and determined the propagation constant of these waves, as reported in this Session. The result showed that the real part of the propagation constant, known as the attenuation constant, can be set to zero. In this case, by expressing the variable of the electromagnetic waves as angular frequency («), it is possible to treat the variable of the function as an angle (in radians). As a consequence, we are able to introduce a mathematical representation of phase (neighborhood and metric) for electromagnetic waves. Thus, we demonstrate that the mathematical representation of electromagnetic waves is possible. [ABSTRACT FROM AUTHOR]

The empirical frequency variations of the complex dielectric permittivity of Rimamid 200, Ultem PEI 1000 and Rexolite 1422 polymer materials in the range from 0.1 to 32 GHz are presented. The feasibility of employing Rimamid 200 as a microwave material is confirmed by examining S-parameters of the in-series PK2-18-01R-01R and PK2-50-05R-05R-05R coaxial adapters having identical beads fabricated from Ultem PEI 1000 and Rimamid 200. A reflection coefficient of smaller than –24 dB and a loss factor of lower than –0.16 dB in the frequency range of 0.01–50 GHz are achieved using the adapters with Rimamid 200 beads. It is noted that Rimamide 200 is a promising material for manufacturing dielectric beads and other elements of microwave equipment. [ABSTRACT FROM AUTHOR]

In this study, we measured the shielding effectiveness (SE) of single-walled carbon nanotubes (SWCNTs), which have attracted interest as potential conductive materials. We studied the preparation of SWCNTs in the form of a film for measurement and the design of coaxial jigs. In addition, coaxial jigs with a maximum operating frequency of 8 GHz were designed and verified to overcome the maximum operating frequency limit of 1.5 GHz in the ASTM D4935 standard. A 3D electromagnetic simulation was used to design the coaxial jigs and a comparative test with the ASTM D4935 standard was performed to verify the proposed measurement jigs. Measurement samples were prepared for each SWCNT powder type, and the SE of the SWCNTs was measured using the proposed measurement jigs. [ABSTRACT FROM AUTHOR]

Heaviside reformulated the Maxwell equations because he considered that electromagnetic fields and waves have duality. As a result of the reformulation, the Poynting vector was obtained. When the variations of an electromagnetic field propagate in space as waves, this wave is referred to as an electromagnetic wave. The Poynting vector represents the traveling direction of the electromagnetic wave. In this Session, we reexamine electromagnetic fields and waves by focusing on the relationship between the Poynting vector and the duality. According to Wikipedia, no current flows in a vacuum because there are no electrons or electric charges. However, this seems to be incorrect, and the current I(x) given by rotH = I(x) flows in a vacuum. Moreover, a voltage V(x) given by rotE = -V(x) is generated because the magnetic field is the dual of the electric field and the current is the dual of the voltage. As a result, the presence of a coil in a vacuum is expressed by rotE = -V (x) = -∂B I ∂t = - pLI (x). Namely, the Maxwell equations indicate that "self-induction can occur everywhere in the atmosphere", as described by Heaviside in the book written by Nahin. Moreover, a capacitor in the atmosphere, including a vacuum, is also given by an equation because it is the dual of the coil. Thus, electromagnetic waves have physical properties of circuit elements including coils and capacitors, which are different from those of lines of forces, such as lines of electric and magnetic forces. The physics of electromagnetic waves is included in classical physics but is different from Newtonian mechanics and uses complex numbers. [ABSTRACT FROM AUTHOR]

• New apparatus: a large coaxial cell with a flow through system for high frequency broadband dielectric spectroscopy. • Calibration based on a single measurement made on reference liquid (deionized water) • Computation of complex permittivity performed based on iterative solver or optimization method using a frequency dependent model of the complex permittivity. • High performance obtained for the determination of the real part of the complex permittivity and good performance for the determination of the imaginary part of the complex permittivity. This paper presents a new apparatus: a large flow through coaxial cell designed for broadband dielectric characterization of material under controlled hydraulic and chemical boundaries. The cell is calibrated with a single measurement made on a perfectly known dielectric liquid (deionized water) together with an optimization procedure. Then, two methods are proposed to compute the dielectric characteristics: an iterative solver and an optimization method. These two methods are systematically investigated for two reference liquids: a low loss dielectric material (ethylene glycol) and high loss dielectric liquid (saline solutions with different concentration). Tabulated data were used to perform a quantitative error analysis in terms of estimated complex permittivity. The results have shown high performance in terms of real part and good performance in terms of real part. The measurements on saline solution also highlight the impact of electrode polarization with dramatic effect in the lower part of the frequency range. [ABSTRACT FROM AUTHOR]

In this session, we explain that Heaviside reformulated the Maxwell equations and showed by the vector analysis method that the direction of a flow of power of electromagnetic waves is given by the Poynting vector. Therefore, it was shown that the direction of the flow is perpendicular to the electric and magnetic flux lines. Namely, the direction of the interaction of electromagnetic waves is different from and perpendicular to the directions of the flux lines. Therefore, we examine the arrangement of the electric and magnetic fields of electromagnetic waves. As a result, it is shown that the arrangement of the electric and magnetic fields that form in coaxial transmission lines is highly effective for the transfer and work of electromagnetic waves. [ABSTRACT FROM AUTHOR]

• Scattering matrix measurements on coaxial transmission line, filled with test material. • Algorithm to estimate reflection loss for test material from scattering matrix measurements. • Test material: Ash by-products from Steel Plants – presently dumped in land fills, research on utilizing these ashes as conductive filler for microwave absorber applications. • Targeted Domain: Cement based Microwave Absorber for Low-cost large area absorber deployment. Cement based EM smart structures. • Large area absorber: Required for EMI shielding at structural level for critical infrastructure including data servers from intentional EMI and non-intentional EMI. Coaxial transmission line technique to determine Plane Wave Reflection Loss of dielectric powders is proposed. The technique provides rapid determination of suitability of powders as conductive filler for Microwave Absorbers, specifically cement based Absorber. Ash by-product from steel industry including Argon Oxygen Decarburization (AOD), Acid Recovery Station (ARS) and Electric Arc Furnace (EAF) are considered over frequency range 1–12 GHz. Scattering parameters (S-matrix) of ash filled coaxial lines are measured. Short-Open technique is adopted. Formulation to compute reflection loss from measured S 11 is presented. Teflon, with known reflection loss, is considered for validation. A 10 % error in computed results is observed in range 1–4 GHz, and 10–15 % in range 4–12 GHz. Broadband MAM characterization employing Free Space Methods involve enormous material requirement, frequency dependent prototype dimensions and anechoic chambers. The error percentage notwithstanding, the technique provides rapid estimates, enabling smart selection of conductive fillers, providing cost and time reduction. [ABSTRACT FROM AUTHOR]