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

Cost-effective 60 GHz modules were developed for home-link systems which needed the bit rate of several Gbps. The modules are composed of a packaged MMIC mounted on the printed circuit board and a post-wall planar antenna formed on the backside of the board. The antenna gain is 20 dBi. The board with the size of 75/spl times/32/spl times/1.2 mm/sup 3/ is inserted into the card-edge connector to feed the IF signal and the DC power. The module can be characterized to have no mm-wave terminals. When the output power of the transmitter module (Tx) was 8 dBm at 61.0 GHz, the IF output power of the receiver module (Rx) P/sub IFout/ was -37 dBm at the distance D=10 m between Tx and Rx. This experiment suggests the capability of the transmission with the bandwidth of 2.5 GHz and the C/N of 25 dB in the home-link systems.

Cost-effective 60-GHz modules with a post-wall planar antenna for gigabit home-link systems

Localization of Radiation Integrals Using the Fresnel Zone Numbers

A radial line slot antenna (RLSA) is a high gain and high efficiency planar antenna proposed for DBS subscribers in the 12 GHz band. In recent years, several radio systems have been developed in the millimeter wave band. In conventional RLS, a radial waveguide has been fed by a coaxial feeder. In the millimeter wave band, fabrication of the feeder is considerably difficult, since the physical size is small. High accuracy in manufacturing is needed to give high antenna efficiency. We have proposed a planar feed circuit with a ring slot and a microstrip line (see Kigure, Y. et al., IEICE Natl. Conv. Rec., B-1-102, 1999). The feed circuit may be easily integrated with an RF planar circuit. In this structure, however, undesired radiation to the back of the antenna is significant and the antenna efficiency is degraded. In terms of efficiency in the millimeter wave band, a rectangular waveguide is more attractive for feeding a radial waveguide. A rectangular-to-radial waveguide transformer through a ring slot is proposed. This transformer is slightly bulky, however there is no leakage. It is suitable for integrating with existing RF modules that have an interface to the rectangular waveguide. The rectangular-to-radial waveguide transformer through a ring slot is designed and fabricated at the 12 GHz band and we integrate a RLSA with this feed circuit at the 38 GHz band.

A millimeter-wave radial line slot antenna fed by a rectangular waveguide through a ring slot

[1] The authors propose to use planar antennas of waveguide slots with the simple structure of postwall waveguide for base station antennas in Local Multipoint Distribution Systems (LMDS). The array has a cosecant radiation pattern with null filling in the vertical plane for uniform illumination in a sector area. The slots are paired as an element to achieve traveling wave excitation because the phase, as well as the amplitude, has to be controlled for null filling in a cosecant pattern. It is the first time to design an array of reflection-canceling slot pairs to get a tapered distribution both in amplitude and phase. This paper extends the designability of the reflection-canceling slot arrays. A 16-element array is designed at 25–26 GHz band. The model array has a cosecant pattern with 3-dB deviations and a peak gain of 17.1 dBi in measurements.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2001RS002580

Postwall waveguide slot array with cosecant radiation pattern and null filling for base station antennas in local multidistributed systems

A proto-cluster core is the most massive dark matter halo (DMH) in a given proto-cluster. To reveal the galaxy formation in core regions, we search for proto-cluster cores at $z\sim 2$ in $\sim 1.5\, \mathrm{deg}^{2}$ of the COSMOS field. Using pairs of massive galaxies ($\log(M_{*}/M_{\odot})\geq11$) as tracers of cores, we find 75 candidate cores, among which 54\% are estimated to be real. A clustering analysis finds that these cores have an average DMH mass of $2.6_{-0.8}^{+0.9}\times 10^{13}\, M_{\odot}$, or $4.0_{-1.5}^{+1.8}\, \times 10^{13} M_{\odot}$ after contamination correction. The extended Press-Schechter model shows that their descendant mass at $z=0$ is consistent with Fornax-like or Virgo-like clusters. Moreover, using the IllustrisTNG simulation, we confirm that pairs of massive galaxies are good tracers of DMHs massive enough to be regarded as proto-cluster cores. We then derive the stellar mass function (SMF) and the quiescent fraction for member galaxies of the 75 candidate cores. We find that the core galaxies have a more top-heavy SMF than field galaxies at the same redshift, showing an excess at $\log(M_{*}/M_{\odot})\gtrsim 10.5$. The quiescent fraction, $0.17_{-0.04}^{+0.04}$ in the mass range $9.0\leq \log(M_{*}/M_{\odot})\leq 11.0$, is about three times higher than that of field counterparts, giving an environmental quenching efficiency of $0.13_{-0.04}^{+0.04}$. These results suggest that stellar mass assembly and quenching are accelerated as early as at $z\sim 2$ in proto-cluster cores.

Makoto Ando

Papers

Cost-effective 60-GHz modules with a post-wall planar antenna for gigabit home-link systems

Localization of Radiation Integrals Using the Fresnel Zone Numbers

A millimeter-wave radial line slot antenna fed by a rectangular waveguide through a ring slot

Postwall waveguide slot array with cosecant radiation pattern and null filling for base station antennas in local multidistributed systems

A systematic search for galaxy proto-cluster cores at z ∼ 2