A bilayer metamaterial to realize the broadband transmission in a terahertz (THz) filter was proposed, whose periodic unit structure consists of two rectangular apertures. The consisting three peaks has 3dB range 0.75 THz, which is 1.6 times that monolayer structure. Different from traditional narrow band excitation mode, additional are produced by metamaterials. Sweeping frequency analysis ill...

Several previous studies in adults have investigated how one- and two-dimensional moving features are integrated into a coherent global motion percept by studying the "barber-pole illusion"; when a one-dimensional moving grating is presented within a rectangular aperture, the two-dimensional line terminators at the edges of the aperture bias the perceived direction of motion toward the longer a...

In this section we will look at the Fresnel diffraction for both circular apertures and rectangular apertures. To help our physical understanding we will begin our discussion by describing Fresnel zones. In the study of Fresnel diffraction it is convenient to divide the aperture into regions called Fresnel zones. Figure 1 shows a point source, S, illuminating an aperture a distance z 1 away. Th...

Geogrids are commonly used in transportation applications for stabilization and reinforcement due to their higher tensile strengths compared to geotextiles as well as the stiffness improvement they provide through arresting and interlocking granular particles in the geogrid apertures. Influenced by many factors, such as the aperture shape and size of geogrid, the degree of interlocking contribu...

We report the effects of system geometry on the clogging of granular material flowing out of flat-bottomed hoppers with variable aperture size D and with variable angle θ of tilt of the hopper away from horizontal. In general, larger tilt angles make the system more susceptible to clogging. To quantify this effect for a given θ, we measure the distribution of mass discharged between clogging ev...

The measurement of specular gloss using a glossmeter is normalized in the ISO 2813 Standard, which widely used for many industrial applications. In practice, principle relies on primary standard that approximates perfectly polished back glass surface and an optical design where rectangular diaphragms are source detection apertures. Any deviation refractive index or polishing level artefact, mac...

In this work, we investigate light concentration in nanoscale ridge apertures and its applications in nanomanufacturing. Optical transmission of ridge apertures in a metal film is optimized by numerical design using the finite-difference time-domain (FDTD) method. We show that ridge apertures provide an optical transmission enhancement of several orders of magnitude higher than regularly shaped...

This letter compares the 3 dB axial ratio (AR) bandwidth (BW) of transmission mode single-screen linear-to-circular polarisation convertors based on three different slot topologies. Using a conventional centre-connected cross-slot arrangement as baseline, we show that significant performance improvement can be achieved by creating more elaborate design with unit cells composed multiple unequal ...

Notch filters are integrated in plasma diagnostic systems to protect millimeter-wave receivers from intensive stray radiation. Here we present a design of a notch filter with a center frequency of 140 GHz, a rejection bandwidth of ∼900 MHz, and a typical insertion loss below 2 dB in the passband of ±9 GHz. The design is based on a fundamental rectangular waveguide with eight cylindrical cavitie...