Abstract: A broadband bicone antenna supports frequency selective control of electrical length. Frequency selective control of the electrical length of an antenna can provide an antenna exhibiting two or more different electrical lengths where use of each length depends upon the operating frequencies of the signals. The electrical length of the bicone antenna may be reduced in response to higher operating frequencies. Such reduction in electrical length at higher frequencies can provide improved antenna radiation patterns for the antenna. Further, the electrical length of the bicone antenna may be increased in response to low frequency operation. Such increase in electrical length may improve VSWR performance at lower frequencies. Simultaneous operation of the bicone antenna at varied electrical lengths for varied frequency bands can provide improved broadband performance of the antenna.

Abstract: The present invention improves the geometry of ferrite circulators in order to increase the average power handling by decreasing the temperature rise in the ferrite and associated adhesive bonds. Embodiments of the present invention utilize dielectric attachments on the sides of the ferrite element, which maximizes the area of contact and minimizes the path length from the ferrite element out to the thermally conductive attachments.

Abstract: The present invention provides an antenna system for reading RFID tags and/or transmitting and receiving wireless network signals, including for example wireless local area network (WLAN) signals, in a material handling environment. A ruggedized antenna can be mounted on the load backrest of a lift truck and configured to accomplish the reading of RFID tags that indicate particular pallet storage locations and the reading of RFID tags that indicate warehouse locations, such as specific loading docks. The antenna system can also be configured to accomplish transmitting and receiving WLAN signals for communication with a warehouse.

Abstract: In one exemplary embodiment in accordance with the invention, an order-picking system includes a picking cart having a radio frequency (RF) antenna arranged above an object-stacking surface of the picking cart. The order-picking system further includes a radio frequency identification (RFID) tag reader coupled to the RF antenna. The RFID tag reader is configured to identify a first RFID tag attached to a first tagged object placed on the picking cart and further configured to eliminate identification of a second RFID tag attached to a second tagged object located outside a perimeter of the object-stacking surface of the picking cart.

Abstract: A removable mount for mounting an electronic system component on a forklift includes, in one embodiment, a mounting plate having a major surface for mounting the electronic system component and an inverted J-shaped part located at a top portion of the mounting plate. The inverted J-shaped part is adapted for mounting the mounting plate on an unmodified original equipment manufacture (OEM) carriage of the forklift or an unmodified OEM sideshifter of the forklift. The mounting plate also has a slot to accommodate a fastener for anchoring the mounting plate to the unmodified OEM carriage or to the unmodified OEM sideshifter.

Abstract: A cable assembly for a lift truck includes, in one exemplary embodiment, a transportation cable loosely housed in a self-retracting hose preformed to default to a coiled shape when no pressure is applied to elongate the self-retracting hose. The self-retracting hose has a slick external surface that is selected to prevent adherence of the surface to any portion of the lift truck. The transportation cable is used for transporting a communication signal and/or a power supply voltage.

Abstract: A ferrite load driver system in accordance with the invention includes a clock generator configured to generate a digital clock signal. The system further includes a digital pulse generator configured to generate an enable pulse having a pulse width equal to a certain number of clock cycles of the digital clock signal. The enable pulse is received by a driver element of the system. The driver element responds by driving a current in a first direction through the ferrite load for setting a first magnetic flux.

Abstract: An improved multi-junction waveguide circulator overlaps two quarter-wave dielectric transformer sections so that the transitional sections occur concurrently in the same length of waveguide. Consequently, the two quarter-wavelength sections require a total length of between one-quarter wavelength and one-half wavelength, with no air gap between the two sections along the length of the internal cavity. The improved waveguide circulator can be implemented in variations from a minimum of two ferrite circulator elements held in close proximity to one another to any number of ferrite elements as required to achieve the desired isolation performance or to create a switch matrix with any combination of input and output ports. The improved waveguide circulator minimizes the length of the transitions between adjacent ferrite elements and thus reduces losses, component size, and mass.

Abstract: The present invention provides an antenna for reading RFID tags in a material handling environment. At least one ruggedized, upward-looking antenna is mounted on the fork (or other base-level platform) of a pallet jack or pallet truck. The antenna can be configured to read RFID tags on pallets that are loaded on the pallet jack and communicate the tag information to a warehouse management system.

Abstract: The present invention provides a tine-mounted antenna for reading RFID tags in a warehouse environment using RFID technology operating at ultra-high frequencies (UHF) or microwave frequencies and backscatter coupling techniques. At least one ruggedized antenna is mounted on the tine (or other base-level platform) of a lift truck (e.g., a forklift). The antenna can be configured to read RFID tags on pallets that are loaded on the lift truck and communicate the tag information to a warehouse management system.

Abstract: A high impedance bicone antenna system supporting ultra wideband operation. The antenna may comprise a reduced aperture size and reduced half-angles of the conductive cones forming the antenna. Reduction in cone angles may increase the impedance of the cones. An impedance matching mechanism for interfacing to the high impedance bicone may be positioned within one of the cones by a dielectric material. The impedance matching mechanism may be a flat conductive taper functioning as an impedance matching transmission line between an external feed line and the antenna. The conductive taper may function as a center conductor of a coaxial feed mechanism where the inside of the cone around the taper serves as the outside conductor, or return, of the tapered feed. The geometry of the cones may be modified to provide one or more end segments that are substantially cylindrical.

Abstract: An improved multi-junction waveguide circulator overlaps two quarter-wave dielectric transformer sections so that the transitional sections occur concurrently in the same length of waveguide. Consequently, the two quarter-wavelength sections require a total length of between one-quarter wavelength and one-half wavelength, with no air gap between the two sections along the length of the internal cavity. The improved waveguide circulator can be implemented in variations from a minimum of two ferrite circulator elements held in close proximity to one another to any number of ferrite elements as required to achieve the desired isolation performance or to create a switch matrix with any combination of input and output ports. The improved waveguide circulator minimizes the length of the transitions between adjacent ferrite elements and thus reduces losses, component size, and mass.

Abstract: A broadband omni-directional bicone antenna. The antenna can comprise conductive surfaces of conical voids provided within a solid dielectric structure. The outside surface of the solid structure can support a radio frequency (RF) lens geometry operable for beam forming. The beam forming can modify the elevation pattern of the electromagnetic radiation from the bicone antenna. The solid dielectric structure may be machined or molded from a single piece of material. The conical voids provided within the solid structure can be metallized to provide conductive bicone radiators. The outer surface beam shaping lenses can be zoned or continuous and can provide elevation patterns with increased gain, cosecant squared falloff, or various other patterns. The beam shaping lens may be formed from any low-loss dielectric. Alternatively, the lens may be formed from a less dense material such as dielectric foam that can support radial conductive beam forming vanes.

Abstract: A connecting system can couple two waveguides to one another, wherein each of the waveguides comprises a flange or a protruding rim. When the waveguides are connected together, the flanges can face one another in an adjoining arrangement. The connecting system can comprise two members, each having a groove, recess, or slot that receives a circumferential area of the adjoining flanges. The two members can be disposed on opposite lateral sides of the waveguides with each groove embracing a peripheral area of the adjoining flanges. A fastener or another apparatus can bring the two members towards one another, thereby causing the flanges to move deeper into the grooves. That is, the two members can clamp around opposing sides of the flanges. In response to the flanges moving deeper into the grooves, the sidewalls of the grooves can compress the flanges together to attach the waveguides to one another.

Abstract: A mixed-signal circuit board can provide a flexible arrangement of multiple RF transmission mediums in a single lightweight and compact structure as well as support embedding electronic devices within RF transmission paths. The transmission mediums may include a voided waveguide, a dielectric waveguide, a microstrip, a suspended microstrip, a traditional stripline, and a suspended stripline. The center conductors in each transmission medium may be constructed on the same plane or the same PCB layer in order to simplify coplanar design. A distribution board can be provided to deliver the power supply and control signals to the active electronic devices placed in the signal path of the RF board for signal processing and within covered cavities provided within the RF board.

Abstract: A compact system can use modular components to enhance the isolation or quality of signals that an antenna array produces. The system can comprise an array of input coupler modules and an array of output coupler modules respectively on the input and output sides of a signal routing device. Each input coupler module can receive a signal from a specific element in the antenna array and can divide or split that received signal into a multiple signal components, such as seven. The signal routing device can route each of those signal components to a different output coupler module in the array of output coupler modules. Thus, each output coupler module can receive and combine multiple signal components, such as seven, from different input coupler modules. The signal routing device can include a readily manufacturable phase trimming section to compensate for phase mismatches.

Abstract: In one of several embodiments, an RFID system for a forklift incorporates a metal plate to which is attached an electronic circuit assembly. Also attached to the metal plate, is an antenna assembly housing an RFID interrogator antenna and/or a wireless local area network (WLAN) antenna. The metal plate operates as a ground plane to the antenna assembly and also serves as a mounting plate for mounting the RFID system on a sideshifter or a carriage of the forklift.

Abstract: A balun is a device for coupling together balanced and unbalanced electrical signals. An ultra-wide bandwidth balun can operate in a frequency band of more than 1.5 GHz to 26.5 GHz. The balun can be based upon a resistively loaded choke structure. The loading can be in the form of resistive cards or vanes. The vanes may be aligned with the electric field between the choke and an outer ground to prevent effective short circuits at points where the choke is half wavelength multiples in length. The resistive loading may also suppress higher order modes within the choke structure. The wideband balun can be very small to satisfy the tight space constraints of many modern communication applications. The balun may be fabricated using standard printed circuit board manufacturing techniques which may dramatically reduce production costs.

Abstract: A compact circular waveguide system can connect circular waveguides through a bend while avoiding excessive interaction between the orthogonal modes of the circular waveguides. A compact bend system with circular waveguide input and output can be achieved by providing short quarter wave transformers. The quarter wave transformers can be positioned at the transitions between the circular waveguides and a single-mode quasi-rectangular waveguide segment. Within the single-mode quasi-rectangular waveguide segment, a bend can be formed without concern for mixing of the orthogonal modes of the circular guided wave. The undesired mode of propagation can be substantially reduced or eliminated within the quarter wave transformers with a resistive mode suppressor. The compact system can be machined out of a single block of material from the outside flange faces.

Abstract: A ferrite load driver system in accordance with the invention includes a clock generator configured to generate a digital clock signal. The system further includes a digital pulse generator configured to generate an enable pulse having a pulse width equal to a certain number of clock cycles of the digital clock signal. The enable pulse is received by a driver element of the system. The driver element responds by driving a current in a first direction through the ferrite load for setting a first magnetic flux.