Measuring Health: A Guide to Rating Scales and Questionnaires

The substrate integrated waveguide (SIW) technique makes it possible that a complete circuit including planar circuitry, transitions, and rectangular waveguides are fabricated in planar form using a standard printed circuit board or other planar processing techniques. In this paper, guided wave and modes characteristics of such an SIW periodic structure are studied in detail for the first time. A numerical multimode calibration procedure is proposed and developed with a commercial software package on the basis of a full-wave finite-element method for the accurate extraction of complex propagation constants of the SIW structure. Two different lengths of the SIW are numerically simulated under multimode excitation. By means of our proposed technique, the complex propagation constant of each SIW mode can accurately be extracted and the electromagnetic bandstop phenomena of periodic structures are also investigated. Experiments are made to validate our proposed technique. Simple design rules are provided and discussed.

Guided-wave and leakage characteristics of substrate integrated waveguide

Astronomical data analysis software and systems

There is increased recognition by the world’s scientific, industrial, and political communities that the concentrations of greenhouse gases in the earth’s
atmosphere, particularly CO_2, are increasing. For
example, recent studies of Antarctic ice cores to
depths of over 3600 m, spanning over 420 000 years,
indicate an 80 ppm increase in atmospheric CO_2 in
the past 200 years (with most of this increase
occurring in the past 50 years) compared to the
previous 80 ppm increase that required 10 000 years.2
The 160 nation Framework Convention for Climate
Change (FCCC) in Kyoto focused world attention on
possible links between CO2 and future climate change
and active discussion of these issues continues.3 In
the United States, the PCAST report4 “Federal
Energy Research and Development for the Challenges
of the Twenty First Century” focused attention
on the growing worldwide demand for energy and the
need to move away from current fossil fuel utilization.
According to the U.S. DOE Energy Information
Administration,5 carbon emission from the transportation
(air, ground, sea), industrial (heavy manufacturing,
agriculture, construction, mining, chemicals,
petroleum), buildings (internal heating, cooling, lighting),
and electrical (power generation) sectors of the
World economy amounted to ca. 1823 million metric
tons (MMT) in 1990, with an estimated increase to
2466 MMT in 2008-2012 (Table 1).

Catalysis Research of Relevance to Carbon Management: Progress, Challenges, and Opportunities

Substrate-integrated waveguide (SIW) technology represents an emerging and very promising candidate for the development of circuits and components operating in the microwave and millimetre-wave region. SIW structures are generally fabricated by using two rows of conducting cylinders or slots embedded in a dielectric substrate that connects two parallel metal plates, and permit the implementation of classical rectangular waveguide components in planar form, along with printed circuitry, active devices and antennas. This study aims to provide an overview of the recent advances in the modelling, design and technological implementation of SIW structures and components.

Review of substrate-integrated waveguide circuits and antennas

The authors propose a switched beam slot array antenna with the 4-way Butler matrix All are integrated in one substrate Experiments in the 26 GHz hand confirm the key operation of this structure of the antenna; four almost-identical beams are switched to cover the total horizontal 90-degree sector with equal angular spacing A gain of 213 dB was observed though two beams have a lower gain by about 18 dB due to the grating lobes A narrower waveguide could eliminate the defects

A beam switching slot array with a 4-way Butler matrix installed in a single layer post-wall waveguide

A large-diameter uniform plasma is obtained by microwave discharge without the use of magnetic fields at pressures in the mTorr range. Microwave fields at 2.45 GHz are radiated from a multislotted planar antenna located a short distance above the glass window of a discharge chamber. Overdense plasmas are produced with ± 3–4% uniformity of ion saturation current over 30 cm diameter for wide ranges of microwave power and gas pressure. The discharge can be started up at pressures as low as 0.5 mTorr. The efficient production of overdense plasmas is investigated by measuring microwave field propagation in the system.

https://iopscience.iop.org/article/10.1143/JJAP.38.4309/pdf

Production of Large-Diameter Uniform Plasma in mTorr Range Using Microwave Discharge

Interfaces between a coaxial structure and a post-wall waveguide are proposed as the essential components for cost-effective millimeter-wave modules. PTFE substrate is selected in terms of loss and manufacturability. The reflection and the transmission characteristics are investigated. The short-stepped and the short-taper-stepped feeding structures provide 14.7% and 13.2% bandwidths for the reflection smaller than -15 dB, respectively. The 46 x 40 mm 2 size antenna fed by the short-stepped structure in PTFE substrate gives 27.3 dBi with 58.2% efficiency at 60.0 GHz. Feeding structures in PTFE substrate fulfill electrical and manufacturing demands in millimeter-wave bands.

/pdf/a-coaxial-line-to-post-wall-waveguide-transition-for-a-cost-4zl7lwpbmw.pdf

A Coaxial Line to Post-Wall Waveguide Transition for a Cost-Effective Transformer between a RF-Device and a Planar Slot-Array Antenna in 60-GHz Band

A method is proposed for accurately calculating the radiation pattern of reflector antennas in the entire angular range from the main beam direction to the off axis region. The principle of the method is similar to the physical optics diffraction theory, and consists of the result obtained by conventional physical optics corrected with the contribution from the edge current calculated by the geometrical theory of diffraction. However, the edge current is expressed in a simple form by means of a local coordinate system defined by the peripheral line and the mirror normal at each edge point and of the incident electromagnetic vector components in reference to this coordinate system. Therefore, it is possible to treat an arbitrarily shaped mirror surface and an antenna with a primary radiator using an arbitrary pattern. It is confirmed that the results obtained by the present method approach those obtained by the physical optics method near the main beam and those obtained by the geometrical theory of diffraction at the off axis. Accuracy is tested by applying the present method to the problem of diffraction from a circular disk for which a rigorous solution exists. The present method makes unnecessary the distinction of the use of physical optics (main beam) and the geometrical theory of diffraction (off axis) performed so far, in an empirical manner. It is possible systematically to obtain the pattern near the first-third side lobes where two methods may be connected.

Makoto Ando

Papers

A beam switching slot array with a 4-way Butler matrix installed in a single layer post-wall waveguide

Production of Large-Diameter Uniform Plasma in mTorr Range Using Microwave Discharge

A Coaxial Line to Post-Wall Waveguide Transition for a Cost-Effective Transformer between a RF-Device and a Planar Slot-Array Antenna in 60-GHz Band

Radiation pattern analysis of reflector antennas

Simple Analysis of a Slot and a Reflection-Canceling Post in a Rectangular Waveguide Using only the Axial Uniform Currents on the Post Surface