MicrowaveMicrowave is a form of electromagnetic radiation with wavelengths ranging from about 30 centimeters to one millimeter corresponding to frequencies between 1000 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes UHF, SHF and EHF (millimeter wave) bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 0.3 m and 3 mm). In all cases, microwaves include the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum.
Crystal detectorA crystal detector is an obsolete electronic component used in some early 20th century radio receivers that consists of a piece of crystalline mineral which rectifies the alternating current radio signal. It was employed as a detector (demodulator) to extract the audio modulation signal from the modulated carrier, to produce the sound in the earphones. It was the first type of semiconductor diode, and one of the first semiconductor electronic devices.
Metabiaugmented hexagonal prismIn geometry, the metabiaugmented hexagonal prism is one of the Johnson solids (J_56). As the name suggests, it can be constructed by doubly augmenting a hexagonal prism by attaching square pyramids (J_1) to two of its nonadjacent, nonparallel equatorial faces. Attaching the pyramids to opposite equatorial faces yields a parabiaugmented hexagonal prism. (The solid obtained by attaching pyramids to adjacent equatorial faces is not convex, and thus not a Johnson solid.
Parabiaugmented hexagonal prismIn geometry, the parabiaugmented hexagonal prism is one of the Johnson solids (J_55). As the name suggests, it can be constructed by doubly augmenting a hexagonal prism by attaching square pyramids (J_1) to two of its nonadjacent, parallel (opposite) equatorial faces. Attaching the pyramids to nonadjacent, nonparallel equatorial faces yields a metabiaugmented hexagonal prism (J_56). (The solid obtained by attaching pyramids to adjacent equatorial faces is not convex, and thus not a Johnson solid.
