Com Dev Limited

Mark Iv Industries Corporation

The Chinese University of Hong Kong

Safavi-naeini, Safieddin

Rafi, Gholamreza Zeinolabedin

Chaudhuri, Sujeet K.

Tang, Wai-cheung

Wai-Cheung Tang

Thua Van Ho

David Siu

Daniel L Terrier

Van Dokas

Richard J Cameron

Roger Tong

Joseph Sferrazza

Bruce C Beggs

Ming Yu

Ke-Li Wu

Safieddin Safavi-Naeini

Japjeev Kohli

Weimin He

Yong Huang

Gholamreza Zeinolabedin Rafi

Sujeet K Chaudhuri

Jeffrey Zhu

Martin Capper

Paul Anthony Laing Manuel

Henry Sun Yee Woo

James B Dorey

Joseph Frenna

David M Bryant

An electronic toll collection system wherein the reader includes a switching network and a plurality of transceivers operating under the control of a controller. The reader further includes failure detection circuitry for determining whether any of the transceivers have failed based upon the RF outputs of the transceivers. If the controller determines that a transceiver has failed, then it alters the switching pattern such that the switching network excludes the failed transceiver from being connected to the antennas. The reader thereby provides for adaptive RF channel assignment, as the particular transceiver used to excite a particular antenna may be dynamically altered, and the provision of at least two transceivers in the reader ensures transceiver redundancy.

Transceiver redundancy in an electronic toll collection system

A multi-band antenna for multi-band radio frequency telecommunications. The multi-band antenna includes a conductive patch separated from a ground plane by a dielectric material. A slot pattern formed in the conductive patch defines a perimeter substantially surrounding two feed pins and arranged symmetrically about a center line. The slot pattern includes one or more inwardly extending arms projected along axes that pass between the two feed pins. The axes may be parallel to the center line. The slot pattern may be arranged using folded slots. In one embodiment, circular polarization is realized at GPS frequency by using one feed pin and linear or circular polarization is realized by using one or two feed pins for other bands. The feed pins may be controlled independently without a fixed phase and amplitude arrangement necessary to achieve a fixed polarization (linear, circular, or elliptical), which allows for adaptive pattern and polarization agility.

Multi-band antenna

A dual mode transponder for engaging in RF communications with a roadside reader from a vehicle. The transponder includes an antenna, an electronic toll collection (ETC) component, and an external interface. The ETC component implements a pre-defined ETC communications protocol to detect and interpret received signals and generate response signals when operating in an ETC mode. The ETC component also includes a bypass port. The external interface is coupled to the bypass port and has an external port for receiving input signals. The ETC component includes a bypass module for receiving a bypass instruction and entering a bypass mode. In the bypass mode the ETC component refrains from implementing the ETC communications protocol. Instead, the ETC component transmits the input signals relayed from the external interface to the ETC component to the reader.

Dual mode electronic toll collection transponder

A method and system for communicating state information from a transponder to a reader. The transponder outputs linearly polarized RF signals having either a first polarization, such as horizontal, or a second polarization, such as vertical. The polarization is selected so as to indicate a first state or a second state. The reader detects whether received RF signals have the first polarization or the second polarization, and thereby determines the state of the transponder. In some embodiments, the reader may include two linearly polarized antennas, one with the first polarization and one with the second polarization, for receiving the RF signals from the transponder and determining the polarization of the received RF signals. The system may be implemented within an electronic toll collection system, wherein the transponders are affixed to the interior of vehicle windshields using a rotatable mounting mechanism having two selectable positions.

Method of enabling two-state operation of electronic toll collection system

A transponder formed on a circuit substrate having a longitudinal axis and a transverse axis. An antenna is disposed on one side of a transverse axis, extending in a longitudinal direction, and the remaining circuit components are disposed on the other side of the transverse axis. The remaining circuit components may include a controller, an RF transceiver, and a battery. A ground plane defines an antenna space within which the antenna is disposed.

Compact microstrip transponder antenna

An external indicator for use in proximity to an on-board unit or transponder for an electronic toll collection (ETC) system. The external indicator senses RF transmissions from the on-board unit and/or roadside readers of the ETC system and produces sensory outputs when transmissions are detected. The external indicator receives RF signals, demodulates them, and analyses the demodulated RF signals to determine if it has received a roadside reader trigger signal and/or a transponder response signal. A sensory indicator, such as a visual, auditory, or kinetic device, alerts an occupant of a vehicle to the detected RF transmissions and, accordingly, to the likely occurrence of an ETC transaction.

External indicator for electronic toll communications

An improved electronic toll collection system having two lane-based antennas per laneway. The antennas include an overhead antenna and a side mount antenna. The side mount antenna is disposed so as to communicate especially with license plate transponders. The two antennas are coupled to a transaction processing system for conducting toll transaction communications with a vehicle-mounted transponder through one of the two antennas.

Electronic toll collection system

A compact inverted-F antenna having a radiator arm formed from portions disposed in two parallel spaced apart planes and connected together electrically to form a folded meander-line topology. The planes may be defined by the surfaces of a dielectric substrate and the radiator arm may be formed from upper and lower conductive traces printed on either side of the dielectric substrate and interconnected serially through filled via holes. The antenna includes a ground plane parallel to and spaced apart from the radiator arm. The ground plane may be a grid conductive wall formed from filled via holes through the dielectric substrate.

Compact inverted-F antenna

The invention provides a method and apparatus for a adaptively predistorted filter which has a transfer function that satisfies performance criteria specified for at (east one property of the filter. The transfer function is obtained by adaptively predistorting the transfer function poles to meet the performance criteria such that at least one of the poles is shifted by a unique amount.

Microwave filter with adaptive predistortion

The invention relates to a single mode multi-cavity microwave filter that includes a housing formed with a plurality of walls which define at least two rows of side-by-side dielectric loaded cavities, wherein sequential cavities are coupled to one another via slots formed in the walls therebetween and at least one pair of non-sequential adjacent cavities are coupled via a probe. The coupling via the slots is defined mathematically as positive coupling. The probe is selectively configurable to provide positive or negative coupling relative to the sign of the slot coupling. Further, at least one non-adjacent, non-sequential pair of cavities is coupled via a second probe that may be configured to provide either positive or negative coupling relative to the sign of the slot coupling. The filter housing supports a plurality of adjustable fins which extend into the slots, one fin to each slot, to selectively adjust the size of the slot.

Folded single mode dielectric resonator filter with cross couplings

Multi-mode waveguide filters are temperature compensated using dielectric material contained within at least one cavity of a filter. The variation in operating frequency of the filter that would otherwise result from changes in temperature is substantially balanced by a change in operating frequency with temperature caused by a change in a dielectric constant of the dielectric material so that the operating frequency of the filter remains substantially constant with temperature. The filter can have one or more dual-mode or triple-mode cavities. In a method of constructing and compensating a filter, the amount of dielectric material is selected so that the dielectric material does not resonate at the operating frequency of the cavity, the amount of dielectric material in the cavity being adjustable after each cavity is constructed. The cavity is operated with a fixed amount of dielectric material contained in the cavity for each mode and the change in operating frequency of the filter with temperature is determined. If the change in operating frequency of the filter is not at an acceptable level, the amount of dielectric material contained in the cavity for each mode is varied and the filter is operated through a range of temperatures to determine whether the change in operating frequency is then at an acceptable level. These steps are repeated until the change in operating frequency of the filter is at an acceptable level.

Multi-mode temperature compensated filters and a method of constructing

A two, three or four channel multiplexer can be operated in the TE.sub.01.delta. or HE.sub.11.delta. modes, each channel of the multiplexer has one bandpass filter, with each filter usually having a plurality of cavities. One cavity of each filter is a common cavity with all of the other filters of the multiplexer. The common cavity contains one independent dielectric quarter-cut or half-cut image resonator for each filter representing a channel of the multiplexer. Each resonator is mounted on a suitable support the common cavity provides a common junction and contains a loop coupling to couple electromagnetic energy between the various channels. The multiplexer has at least one input and at least one output. Previous microwave multiplexers have a plurality of bandpass filters arranged on a coaxial manifold. With the multiplexer of the present invention, the manifold can be eliminated. Further, at the S-band or L-band, substantial weight and volume savings can be achieved using the multiplexer of the present invention without sacrificing performance. This can be very important for space applications.

Dielectric image-resonator multiplexer

A triple mode dielectric loaded bandpass filter has at least one cavity resonating in three independent orthogonal modes. A triple mode cavity can be mounted adjacent to either single, dual or triple mode cavities. Inter-cavity coupling is achieved through the iris having two separate apertures that together form a T-shape. The cavities can be planar mounted. The filter is designed for use in the satellite communication industry and results in substantial savings in weight and size when compared to previous filters.

Triple mode dielectric loaded bandpass filter

A bandpass filter has a plurality of cascade cavities that operate in a dual-mode and are mounted in a planar relationship to one another. Each cavity contains a dielectric resonator and resonates at its resonant frequency in two HE.sub.11.delta. modes. An iris is located between adjacent cavities and contains an aperture that can independently control inter-cavity coupling. The dielectric resonator is cylindrical in shape and an adjustable metallic plunger is located in a wall of each cavity so that the cavity can be tuned over a relatively broad range. The filter has good mechanical and thermal stability as well as being extremely flexible in the arrangement of cavities.

Planar dual-mode cavity filters including dielectric resonators

An odd order bandpass filter has at least one cavity resonating at its resonant frequency in three independent orthogonal modes. The filter has at least one feedback coupling that is made to resonate and change sign at a center frequency. When the filter has two cavities, one being a triple cavity and the other being a dual mode cavity, the filter can be operated to achieve an elliptic function response. Also, the filter of the present invention can achieve a weight and volume reduction when compared to six-pole dual mode filters.

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Mannheim, Canada

Wai-Cheung Tang