This article proposes a novel measurement method based on parallel-plate dielectric resonator (PPDR) for determining complex permittivity of low-loss materials over wide frequency range. Two 1.0-mm coaxial probes are placed symmetrically as coupling structure in the center top and bottom PPDR, only TM0np resonant modes will be selectively excited. For each value <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math...

In most measurement models of the cylindrical cavity, concentricity between rod-like sample and cavity is a basic premise an accurate calculation model. Once randomly placed in off-axis position hole real will not conform to established model should be taken into account error. this article, method calculate permittivity at presented. The actual location first obtained application vision measurement. Field distribution calculated by using mode-matching method. measured divided finite small...

We report on an experimental demonstration of two-way communication between sky and underwater for the first time. Signal transmission from to is realized by thermoacoustic effect (TE), while sky, this based microwave vibration measurement (MVM). With a homemade setup, “UESTC” realized. This study suggests that TE combined with MVM has potential be used wireless underwater.

The dielectric property of microwave semiconductor materials is investigated under a strong electromagnetic field environment through compressed rectangular cavity around the frequency 2.45G. It demonstrated that indium phosphate (InP), kind material, changes when larger power injected into designed cavity. strength electric in Measurement results show InP has an obvious nonlinear acts on material. According to effective experimental method and theoretical analysis, we conclude behavior not...

In this letter, an improved cylindrical cavity for high-sensitivity detection is proposed. The characterized by symmetric double ridges inside. double-ridged realizes the electric field compression of TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathbf {01}{n}}$ </tex-math></inline-formula> modes loading two metal and further greatly improves sensitivity. parameters ridge are optimized determined...

The influence of strong microwave electric field (SMEF) on the dielectric properties materials is result joint action thermal effect and non-thermal effect. Generally, SMEF stronger than effect, which makes difficult to detect. Moreover, it distinguish these two factors from each other. Therefore, formation mechanism characteristics have not been elucidated so far. In this paper, a separation extraction model property material proposed based time modulation method cavity perturbation method....

To determine the complex permittivity of material mounted on metal surface, free-space reflection method is a good candidate due to its advantages being nondestructive and contactless. When using method, extraction coefficient (CRC) metal-backed key realize accurate measurement. Traditionally, assumes that interrogating wave single plane wave, plane-wave model used. However, focused beam usually used in practice for reducing edge effect leads difference between actual test scene traditional...

With the development of 5G technology, accurate measurement complex permittivity a printed circuit board (PCB) in wide frequency range is crucial for design high-frequency circuits. In this paper, microwave device and method based on double-sided parallel-strip line (DSPSL) resonator have been developed to measure typical PCBs vertical direction. The includes DSPSL resonator, coupling probe, pressure monitor, Farran C4209 vector network analyzer (100 K 9 GHz), FEV-10-PR-0006 multiplier...

Aluminum alloys are ideal lightweight structural materials for spacecraft, but they susceptible to local corrosion during service. Herein, a systematic investigation is carried out determine the fatigue behavior of 5B70 aluminum alloy under salt spray precorrosion. The mechanism corrosion, life, crack propagation, and failure fracture studied. Under mainly undergoes pitting via galvanic mechanism. After precorrosion, formation macroscopic cracks accelerated, which significantly reduces its...

Due to the inherent material characteristics of fireworks and negligent safety management, accidents have occurred in recent years, resulting significant personal property losses. Therefore, status inspection other energy-containing materials is a hot issue field production, storage, transportation, application. The dielectric constant parameter used characterize interaction between electromagnetic waves. methods obtaining this microwave band are not only numerous but also fast easy. Thus,...

Abstract In this paper, a directivity‐enhanced planar slot antenna (PSA) backed by substrate integrated waveguide (SIW) cavity is proposed to solve the problem of maximum gain direction bias. According radiation principle antenna, reason for bias explained and solution has been given. Ulteriorly, frequency caused changing directivity also resonance modes solved introducing metal via. An example with 5.8 GHz which 5.28 dBi total thickness less than λ/4 After structural optimization...

The resonant cavity method is a commonly used for high-temperature testing of the complex permittivity dielectric materials. When testing, microwave surface resistance metal material will deteriorate due to factors such as oxidation reaction and thermal fatigue, resulting in decrease accuracy repeatability. Therefore, when designing cavity, temperature response characteristics should be obtained advance. In this paper, measurement materials based on separate cylindrical resonator proposed,...

Abstract We propose the equivalent source of reflector in finite‐different time‐domain (ESR‐FDTD) for rapid analysis corner scattering terahertz computed tomography (THz‐CT) imaging. The ESR‐FDTD is used instead THz‐CT imaging system, which can significantly reduce computational domain system and effectively time memory usage. electric field distribution beam reflected by that radiated from ESR are compared, results show distributions its almost same. phenomenon does not fully satisfy...

The discrepancy issue of the complex permittivity during fiber production adversely affect overall electrical properties fiber-reinforced composites. As known from reported works literature, no test fixture is currently available to directly measure monofilament with micron-sized diameter in low frequency range. In this paper, ridged semi-cylindrical cavity working at multiple microwave frequencies proposed for measurement monofilament. This consists semi-cylinder Y-shaped slot and metallic...

Although the theory of characteristic modes (TCM) has been widely used for solving external resonant (ER) problems metallic objects, there are still some issues not fully discussed in literature, which prevent application internal (IR) problems. In this letter, a new method based on surface integral equation (SIE) formulation is proposed to analyze IR characteristics arbitrarily shaped cavities with holes. The generalized eigenvalue small range derived, and discontinuous eigenvalues...

Abstract Measuring silicon carbide (SIC) fibers is a widely used technique in searching for SIC materials with high absorbing properties. Nevertheless, obtaining reasonable electromagnetic properties most of the existing experimental setups fiber remains difficult. Additionally, being critical load‐carrying component composite materials, changing during oxidation conditions would directly impact practical application fibers. Aiming at solving such problems, this paper investigates and...

This study examined the effects of Accentuated Eccentric Loading Countermovement Jump (AEL CMJ) training on jump performance, lower body strength, sprint and change direction ability, compared to drop (DJ) training. used a randomized controlled trial (RCT) with parallel design. Forty men physical education students (Mean ± SD: age 22.60 3.24 years, mass 75.21 8.12 kg, height 1.79 0.07 m) were randomly assigned AEL (n = 14), DJ 13), or control group (CON, n 13). The groups trained three times...