Abstract: An antenna feed network including a 180° hybrid coupler having a feed port, a 0° port; and a 180° port having an approximately 180° phase difference with the 0° port. A first antenna port is coupled to the 0° port; and a second antenna port is coupled to the 0° port via a respective phased line, the second antenna port having an approximately 90° phase difference with the first antenna port. A third antenna port is coupled to the 180° port; and a fourth antenna port is coupled to the 180° port via a respective phased line, the fourth antenna port having an approximately 90° phase difference with the third antenna port. The feed network can be used to drive antenna elements in phase quadrature. In a preferred embodiment the feed network drives a quadriflar helix antenna.

Abstract: A multi-band antenna comprising two or more low frequency radiators dimensioned to operate in a low frequency band, and two or more high frequency radiators dimensioned to operate in a high frequency band. Each high frequency radiator is substantially coplanar with the low frequency radiators, and is formed in a spiral with the high and low frequency radiators interleaved. A hybrid feed network has two or more antenna ports, each antenna port being coupled with a low frequency radiator and a high frequency radiator. The antenna can be used for receiving GPS L1/L2 signals. The antenna is configured to send and/or receive circularly polarized radiation.

Abstract: A multi-band antenna comprising two or more low frequency radiators dimensioned to operate in a low frequency band, and two or more high frequency radiators dimensioned to operate in a high frequency band. Each high frequency radiator is substantially coplanar with the low frequency radiators, and is formed in a spiral with the high and low frequency radiators interleaved. A hybrid feed network has two or more antenna ports, each antenna port being coupled with a low frequency radiator and a high frequency radiator. The antenna can be used for receiving GPS L1/L2 signals. The antenna is configured to send and/or receive circularly polarized radiation.

Abstract: An antenna feed network including a 180° hybrid coupler having a feed port, a 0° port; and a 180° port having an approximately 180° phase difference with the 0° port. A first antenna port is coupled to the 0° port; and a second antenna port is coupled to the 0° port via a respective phased line, the second antenna port having an approximately 90° phase difference with the first antenna port. A third antenna port is coupled to the 180° port; and a fourth antenna port is coupled to the 180° port via a respective phased line, the fourth antenna port having an approximately 90° phase difference with the third antenna port. The feed network can be used to drive antenna elements in phase quadrature. In a preferred embodiment the feed network drives a quadriflar helix antenna.

Abstract: A fiducial beam monitor includes a patterned diode layer on a semiconducting substrate. An electrical field between the diode (or diodes) on the diode layer and the semiconducting substrate modulates the size of the depletion layer formed by the diode or diode. A high energy beam incident upon a diode on the diode layer produces a greater current than a high energy beam incident upon a non-diodic region of the same layer. In use, the beam monitor is typically fixed to the backside of a workpiece such as a semitransparent membrane being patterned by a focused high energy beam that is translated with respect to workpiece and attached monitor. The changes in current during translation are then correlated with the position of the beam with respect to the pattern on the diode layer.

Abstract: An improved process for the alkylation of benzene in the presence of an alkylation catalyst. The catalyst bed may be caused to move in a direction countercurrent to the movement of the benzene and olefin, or a portion of the catalyst bed is periodically removed and replaced. A regeneration step, whereby the catalyst is heated in a controlled oxygen atmosphere in order to reactivate the catalyst, is also described.

Abstract: An improved process for the alkylation of benzene in the presence of an alkylation catalyst. The catalyst bed may be caused to move in a direction countercurrent to the movement of the benzene and olefin, or a portion of the catalyst bed is periodically removed and replaced. A regeneration step, whereby the catalyst is heated in a controlled oxygen atmosphere in order to reactivate the catalyst, is also described.

Abstract: A dissolving tank for dissolving a large amount of gas in a liquid and including a generally horizontally disposed tray (28) (29) mounted within the tank (2) (21) to divide the tank (2) (21) into an upper reaction zone (36) and a lower discharge zone (38). The tray (28) (29) has formed therein both a central opening (34) (35) for fluid communication between the discharge zone (38) and the reaction zone (36) and peripheral openings (32) (33) which allow any liquid which collects on the tray (28) (29) to flow from reaction zone (36) to discharge zone (38). The dissolving tank further includes liquid feed means (10) positioned within the tank (2) (21) below the tray (28) (29) to discharge liquid upwardly through the central opening (34) (35) of the tray (28) (29) and into the reaction zone (36). The dissolving tank further includes liquid distribution means (14) mounted within the tank (2) (21) above the tray (28) (29) and having flared sidewalls (15) and a vertically-oriented distribution orifice (16).