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Antennae (sg.: antenna) (sometimes referred to as "feelers") are paired appendages used for sensing in arthropods. Antennae are connected to the first one or two segments of the arthropod head. They vary widely in form but are always made of one or more jointed segments.
In botany, "seta" refers to the stalk supporting the capsule of a moss or liverwort (both closely related in a clade called "Setaphyta"), and supplying it with nutrients. The seta is part of the sporophyte and has a short foot embedded in the gametophyte on which it is parasitic.
Antenna designs incorporating metamaterials can step-up the antenna's radiated power. Conventional antennas that are very small compared to the wavelength reflect most of the signal back to the source. A metamaterial antenna behaves as if it were much larger than its actual size, because its novel structure stores and re-radiates energy.
A patch antenna is a narrowband, wide-beam antenna fabricated by etching the antenna element pattern in metal trace bonded to an insulating dielectric substrate, such as a printed circuit board, with a continuous metal layer bonded to the opposite side of the substrate which forms a ground plane. Common microstrip antenna shapes are square ...
Inevitably some antennas won't conveniently fit into any one basic type, so the last section on real antennas is an "everything else" category for a few peculiar antennas that don't fit cleanly into any of the categories or subcategories used in this article; for example, random wire antennas and antennas that are laid down on the ground ...
Feed horn with concentric rings (left) and LNB (right) on a Hughes DirecWay home satellite dish. An LNBF (LNB with integrated feed horn) that has been cut into two.Visible is the scalar horn antenna (the funnel with concentric rings), which couples the microwave beam into a short waveguide (the tube connecting the feed horn to the LNB electronics part of the LNBF).
E-plane plate lens antenna of the target tracking radar for the US Air Force Nike Ajax anti-aircraft missile, 1954 Dielectric lens/horn antenna in the Atacama Millimeter Array radio telescope A lens antenna is a directional antenna that uses a shaped piece of microwave -transparent material to bend and focus microwaves by refraction , as an ...
An antenna like effect is achieved by periodic swing of electrons from its capacitive element to the ground plane which behaves like an inductor. The authors further argued that the operation of a dielectric antenna resembles the antenna conceived by Marconi, the only difference is that inductive element is replaced by the dielectric material. [5]