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

A 16×16-element plate-laminated-waveguide slot array antenna is fabricated by diffusion bonding of thin copper plates with inclusion of equivalent over-etching amount. The measured reflection characteristic has good agreement with the design one by considering the equivalent over-etching amount. At the design frequency, 32.6-dBi gain, 76.5% antenna efficiency and 19.2% bandwidth for gain more than 31.5 dBi have been achieved.

A 16×16-element plate-laminated-waveguide slot array with 19.2% bandwidth in the 60-GHz Band

The reflection characteristics of large alternating-phase fed single-layer waveguide arrays with center-feeds are investigated to identify the mechanism for bandwidth narrowing effects. Firstly, the overall reflection for the whole array is analyzed by FEM and fine agreement with measurements is demonstrated. It is deviating from the conventional prediction based upon a simple sum of reflections from components in the array, such as the multiple-way power divider, the slot waveguides and the aperture at the antenna input. Careful diagnosis reveals that the mutual coupling between the alternating phase waveguides via external half-space is the key factor in reflection accumulation. Amongst all, the slot with strong excitation whose position depends upon the aperture illumination design produces the dominant contribution in the mutual coupling.

Reflection Characteristics of Center-Feed Single-Layer Waveguide Arrays

A matching crossed-slot, which is accommodated at the shorted end of a waveguide crossed-slot array and radiates all the residual power with circular polarisation in an array beam direction, is analysed and designed by the method of moments (MoM). The eigenmode functions for a crossed-slot derived numerically by the edge-based finite element method (FEM) are utilised as the basis functions in the MoM. The mechanism of circular polarisation is interpreted in terms of two modes each radiating linear polarisation. A matching crossed-slot is designed and tested at 3.6 GHz. The measured reflection is suppressed below -15 dB over a 5.6% bandwidth from 3.5 GHz to 3.7 GHz. The calculated and measured axial ratios in a direction of 50 degrees are 0.32 dB and 1.5 dB, respectively.

Waveguide matching crossed-slot

This paper presents a measurement method for determining effective conductivity of copper-clad dielectric laminate substrates in the millimeter-wave region. The conductivity is indirectly evaluated from measured resonant frequencies and unloaded Q values of a number of Whispering Gallery modes excited in a circular disk sample, which consists of a copper-clad dielectric substrate with a large diameter of 20-30 wavelengths. We can, therefore, obtain easily the frequency dependence of the effective conductivity of the sample under test in a wide range of frequency at once. Almost identical conductivity is predicted for two kinds of WG resonators (the copper-clad type and the sandwich type) with different field distribution; it is self-consistent and provides the important foundation for the method if not for the alternative method at this moment. We measure three kinds of copper foils in 55-65GHz band, where the conductivity of electrodeposited copper foil is smaller than that of rolled copper foil and shiny-both-sides copper foil. The measured conductivity for the electrodeposited copper foil decreases with an increase in the frequency. The transmission losses measured for microstrip lines which are fabricated from these substrates are accurately predicted with the conductivity evaluated by this method.

Evaluation of Effective Conductivity of Copper-Clad Dielectric Laminate Substrates in Millimeter-Wave Bands Using Whispering Gallery Mode Resonators

In the millimeter-wave band, the series-fed array antenna is facing a problem of large transmission loss and narrow bandwidth by using a high-permittivity and large-loss-tangent material In this paper, an air region is inserted in the half of the height in the LTCC waveguide of er =66 and tanδ =0013 to reduce the transmission loss The reduction of the equivalent dielectric constant by the air insertion structure enhances both the gain and the bandwidth of the series-fed slot array The transmission loss of the single-mode rectangular waveguide has been reduced to about 1/6 by using the partially-filled structure in the 60-GHz band In a onedimensional slot array, the total loss has also been reduced to about 1/7 And the 3 dB-down gain bandwidth has also been increased from 13 GHz to 23 GHz key words: waveguide, LTCC, loss, slot array, long-line effect millimeterwave

Makoto Ando

Papers

A 16×16-element plate-laminated-waveguide slot array with 19.2% bandwidth in the 60-GHz Band

Reflection Characteristics of Center-Feed Single-Layer Waveguide Arrays

Waveguide matching crossed-slot

Evaluation of Effective Conductivity of Copper-Clad Dielectric Laminate Substrates in Millimeter-Wave Bands Using Whispering Gallery Mode Resonators

LTCC Partially-Filled Post-Wall Rectangular-Waveguide Slot Array Antenna in the Millimeter-Wave Band