摘要:
Presently disclosed is an antenna system having an array of ridged waveguide Vivaldi radiator (RWVR) antenna elements fed through a corporate network of suspended air striplines (SAS) with an electromagnetic bandgap (EBG) ground plane surrounding the ridged waveguide transition. The SAS transfers the electromagnetic energy to the radiating element via the ridged waveguide coupler. The Vivaldi radiator matches the output impedance of the ridged waveguide coupler/SAS to the intrinsic impedance of the surrounding medium. The EBG, which may be comprised of a photonic bandgap material or other metamaterial, allows for better frequency and bandwidth performance in a lower-profile array package, thereby reducing size and weight of the array for applications requiring small size and or low-inertia packaging. In alternate embodiments, radiating elements other than Vivaldi radiators may be used. This configuration also reduces the complexity of the manufacturing process, which in turn lowers cost.
摘要:
Presently disclosed is an antenna system having an array of ridged waveguide Vivaldi radiator (RWVR) antenna elements fed through a corporate network of suspended air striplines (SAS). The SAS transfers the electromagnetic energy to the radiating element via the ridged waveguide coupler. The Vivaldi radiator matches the output impedance of the ridged waveguide coupler/SAS to the impedance of the surrounding medium. Because the coupling method and the radiating elements are wideband mediums, this antenna array is capable of wideband operation. The physical dimensions of the resulting array are also not as sensitive to its electrical performance as other antenna designs since the bandwidth is quite large, reducing the occurrence of an out-of-specification antenna due to manufacturing tolerance build-up. This also reduces the complexity of the manufacturing process, which in turn lowers cost.
摘要:
Presently disclosed is an antenna system having an array of ridged waveguide Vivaldi radiator (RWVR) antenna elements fed through a corporate network of suspended air striplines (SAS) with an electromagnetic bandgap (EBG) ground plane surrounding the ridged waveguide transition. The SAS transfers the electromagnetic energy to the radiating element via the ridged waveguide coupler. The Vivaldi radiator matches the output impedance of the ridged waveguide coupler/SAS to the intrinsic impedance of the surrounding medium. The EBG, which may be comprised of a photonic bandgap material or other metamaterial, allows for better frequency and bandwidth performance in a lower-profile array package, thereby reducing size and weight of the array for applications requiring small size and or low-inertia packaging. In alternate embodiments, radiating elements other than Vivaldi radiators may be used. This configuration also reduces the complexity of the manufacturing process, which in turn lowers cost.
摘要:
Presently disclosed is an antenna system having an array of ridged waveguide Vivaldi radiator (RWVR) antenna elements fed through a corporate network of suspended air striplines (SAS). The SAS transfers the electromagnetic energy to the radiating element via the ridged waveguide coupler. The Vivaldi radiator matches the output impedance of the ridged waveguide coupler/SAS to the impedance of the surrounding medium. Because the coupling method and the radiating elements are wideband mediums, this antenna array is capable of wideband operation. The physical dimensions of the resulting array are also not as sensitive to its electrical performance as other antenna designs since the bandwidth is quite large, reducing the occurrence of an out-of-specification antenna due to manufacturing tolerance build-up. This also reduces the complexity of the manufacturing process, which in turn lowers cost.
摘要:
A rope climbing apparatus (15) comprising a frame (16), a seat (18) supported by the frame and adapted to move relative to the frame from a first position (19) to an elevated second position (20), a lower pulley assembly (21) connected to the seat, an upper pulley assembly (22) connected to the frame, a rope (23) extending between the lower pulley assembly and the upper pulley assembly and having a rope climbing portion (24) graspable by a user (25) when the user is seated on the seat, and the rope, the seat, the lower pulley assembly and the upper pulley assembly configured and arranged such that a downward force (26) on the rope climbing portion of the rope causes an upward force (28) on the seat. The downward force on the rope climbing portion may result in an upward force on the seat at a mechanical advantage provided by the lower pulley assembly and the upper pulley assembly, and the mechanical advantage may be four. The rope may comprise a first end portion (29) connected to the seat and the rope climbing portion may comprise a second end portion (30) terminating within grasp of the user when the user is seated on the seat. The first end portion of the rope may be connected to the seat via the lower pulley assembly, such that the first end portion of the rope is connected directly to the lower pulley assembly.
摘要:
A dual-polarization common aperture antenna having fully populated common aperture dual polarized arrays. The inventive antenna includes a first and second arrays of radiating slots disposed in a faceplate. The second array is generally orthogonal and therefor cross-polarized relative to the first array. The first array is waveguide fed and the second array is stripline fed. In the illustrative implementation, the first array and the second array share a common aperture. The common aperture is fully populated and each array uses the aperture in its entirety. The first and second arrays of slots are arranged for four-way symmetry. Each slot in the first array is a vertically oriented, iris-excited shunt slot fed by a rectangular waveguide and centered on a broad wall thereof. The second array is a standing wave array in which each slot is an air cavity backed slot fed by an inverted micro-stripline offset from a center thereof.
摘要:
A dual polarization multi-band antenna may include a waveguide horn, a low band feed section, a transition section, and a high band feed section coupled in series. The waveguide horn may be configured to support propagation of electromagnetic waves in a low band and a high band. The low band feed section may include horizontal and vertical feeds and may be configured to support propagation of electromagnetic waves in the low band and the high band. The high band feed section may include horizontal and vertical feeds and may be configured to support propagation of electromagnetic waves in the high band but not in the low band. The transition section may be configured to couple electromagnetic waves in the high band from the high band feed section to the low band feed section and to constructively reflect electromagnetic waves in the low band.
摘要:
A rope climbing apparatus (15) comprising a frame (16), a seat (18) supported by the frame and adapted to move relative to the frame from a first position (19) to an elevated second position (20), a lower pulley assembly (21) connected to the seat, an upper pulley assembly (22) connected to the frame, a rope (23) extending between the lower pulley assembly and the upper pulley assembly and having a rope climbing portion (24) graspable by a user (25) when the user is seated on the seat, and the rope, the seat, the lower pulley assembly and the upper pulley assembly configured and arranged such that a downward force (26) on the rope climbing portion of the rope causes an upward force (28) on the seat. The downward force on the rope climbing portion may result in an upward force on the seat at a mechanical advantage provided by the lower pulley assembly and the upper pulley assembly, and the mechanical advantage may be four. The rope may comprise a first end portion (29) connected to the seat and the rope climbing portion may comprise a second end portion (30) terminating within grasp of the user when the user is seated on the seat. The first end portion of the rope may be connected to the seat via the lower pulley assembly, such that the first end portion of the rope is connected directly to the lower pulley assembly.