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Ill-posedness poses serious challenge to the community of inverse problems. Attention is focused on ill-posedness in electromagnetic inverse problems in this talk.
This paper will present some experiments with improving one of crucial parts of nuclear quadrupolar resonance (NQR) spectrometer, the RF decoupler. This part decouples the high power rf excitation signal from receiver port of low detected signal preamplifier. In the position of decoupler usually some LC filters and back-to-back diodes are used. We have tested rf impedance transformers of different...
Dirac cone dispensions in various periodic systems can lead to intriguing transport properties, such as Klein tunneling, Zitterbewegung, antilocalization, abnormal quantum Hall effect. From an effective medium perspective photonic crystals (PhCs) with the k = 0 Dirac-like point at the BZ center also can be regarded as the effective zero-refractive index materials with εeff = λeff = 0, which provide...
Cable is an important component of cable-stayed bridge. The force of the stay cables are important for us to know the working state of cable-stayed bridge. There are a lot of existing methods of cable force measurement, such as determination method of hydraulic pressure gauges, pressure sensor direct determination method, the magnetic flux method and frequency measurement. On the aspect of frequency...
In this paper, transmission characteristics affected by a relative position between a noise suppression sheet (NSS) placed on a periodic metal film and a transmission line are examined. A microstrip line (MSL) based on IEC standard (IEC62333-2) is fabricated, and transmission characteristics of the MSL placed on two types of NSS are measured.
We describe experimental characterization of switchable terahertz metasurfaces using broadband ellipsometry. A theoretical framework based on generalized sheet transition conditions is developed to extract surface susceptibility as a function of frequency and applied DC bias. This will allow us to make a priori predictions of the performance of these switchable devices in device applications, enabling...
The article concerns the measurement of the electric field intensity in the area. Described in the article a measuring position is fully mobile. This has been achieved through the use of, among other things laptop and a small GPS receiver with a small-sized antenna. The measurement process is carried out using specially developed for this purpose software. The position measurement application enables...
In the paper the microstrip antenna with pattern based on a unit cells composed of patches with boomerang-like shaped slots has been presented. The antenna has the base edges in the center for the higher layer and slots cut along the periphery of the cell with small perpendicular slits in the middle. The square unit cell edge is 4mm length. The antenna was simulated in CST Microwave Studio. The simulations...
In this letter, a composite metasurface for end-fire scattering is designed, fabricated and characterized. Based on the principle of scattering cancelation and method of end-fire antenna array, we proposed the lattice-like arrangement composite metasurface (LACMS). When EM waves normally illuminates on the metasurface, the scattering energy redistributes to the end-fire direction. Compared with the...
Nowadays there are too many sources of radiofrequency (RF) energy emitting at the frequency of 2.4 GHz so all the humans, using or not a wireless device, are exposed to pulsed energy during long periods of time. The principal indicator of how much energy is absorbed by the human body is the Specific Absorption Rate (SAR). There are safe values reported for human exposition to diverse sources of RF...
An up to 1100°C and 1200°C high-temperature distributed Brillouin sensing based on a GeO2-doped single mode fiber (SMF) and a pure-silica photonics crystal fiber (PCF) are demonstrated, respectively. We found that the BFS dependence on temperature of SMF and PCF agrees well with an exponential function instead of a linear function, which is mainly attributed by the change of the acoustic velocity...
The open-ended rectangular waveguide is a simple radiating structure, and a lot of effort is being spent on calculating the reflection coefficient or admittance of the structure accurately. In order to improve the accuracy of the result, more rectangular waveguide higher order modes are considered. Meanwhile, amount of computation is increased. A major thrust of the paper is to discuss approaches...
Terahertz (THz) spectroscopy is a promising way to measure the spectrum of low-frequency modes of molecules or ensembles, such as crystals and polymers, including proteins. However, the main drawback of THz spectroscopy is its extremely low sensitivity. In the present study, we report on signal enhancement in THz spectroscopy achieved by depositing a mino acid molecules or their derivatives on a gold...
The impact of the environment upon living organisms constitutes a crucial problem examined by today's science. Detailed examination of the overall influence of environmental factors upon humans is performed within, for example, a large number of medical disciplines. By extension, research institutes worldwide have analyzed diverse positive and negative factors affecting the biological system of the...
There are many factors of influencing precision of test in the RCS (Radar Cross Section) measurements. Usually applying the method of background subtraction eliminates the influence that interference signal brings. In the paper, four parts that froth support structure, the timeliness of calibrated data, the temperature of the apparatus room influencing the signal of PNA and the precision of target...
This paper proposes a novel heart-shaped band-notched UWB antenna with compact and simple structure. The antenna comprise of a microstrip feeding line, a heart-shaped patch to achieve UWB characteristic, and a defected ground with bevels to obtain good impedance match and stable gain in the operating band. The band-notched characteristic is achieved by a U-shaped slot on the patch. The measured results...
Recently, induction heating (IH) ranges, which heats using Joule heat based on eddy currents in a pan, have been increasing not only for household use but commercial use. Some of users have concerns about the possible health effects of magnetic fields from induction heating ranges. In this study, we quantitatively measured leakage magnetic fields from an IH range as a survey range. Especially, we...
In this letter, a compact wideband microstrip filter using a multiple-mode resonator (MMR) is present. The basic filter is composed of only one resonator with two symmetrical connecting lines. The resonator operates as not only a resonant element but also an open stub. By properly adjusting the lengths of the stub, the first three resonant modes of this MMR can be evenly allocated within the 4.8-to-10...
A free-space measurement system at 220 GHz ∼ 300 GHz has been built with stepped frequency continuous wave (SFCW) for Radar cross section (RCS) measurements. The system consists of vector network analyzer, Millimeter-Wave Converters and target support structure. The measurement techniques such as background subtraction, synchronous calibration and range distance compensation are verified by RCS measurement...
A novel approach to reduce the dual band microstrip antenna Radar Cross Section (RCS) based on Artificial Magnetic Conductors (AMC) is presented in this paper, and making the size of the antenna which works at 5.1 GHz and 7.4 GHz decreases by 47%. The approach taken is to devise a new dual band AMC structure which has the same frequency with this antenna and load on both sides of the radiating patch...
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