Abstract: A system for the distribution of RFID signals to a remote antenna or a remote antenna network comprising: a central control module to generate signals and control the protocol operations; cable, in particular twisted pair cable, connecting the central module to one or more antenna subsystems carrying substantially baseband representations of the reader to tag modulation and tag to reader modulation.

Abstract: A system for the distribution of RFID signals to a remote antenna or a remote antenna network comprising: a central control module to generate signals and control the protocol operations; cable, in particular twisted pair cable, connecting the central module to one or more antenna subsystems carrying substantially baseband representations of the reader to tag modulation and tag to reader modulation.

Abstract: We describe an RFID tag reading system comprising a plurality of transmit/receive antennas to provide spatial transmit/receive signal diversity, and a tag signal decoder. The system combines received RF signals from the antennas, and the antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another. The system performs a tag inventory cycle comprising a plurality of tag read rounds, each having a set of time slots during which a said tag is able to transmit tag data including a tag ID. The system is configured to perform, during a tag inventory cycle, one or both of: a change in a frequency of the tag interrogation signals transmitted simultaneously from the plurality of antennas, and a change in a relative phase of a the RF tag interrogation signal transmitted from one of the antennas with respect to another.

Abstract: We describe a methods of locating an RFID tag. One method transmits tag location signals at a plurality of different frequencies from a plurality of different antennas spaced apart by more than a near field limit distance. The processing determines a phase difference at the plurality of different frequencies by determining a phase difference between either i) two or more of the transmit signals resulting in a maxima in the returned signal RSSI or ii) a first transmit signal and its corresponding return signal. The range determining uses return signals weighted by signal strength. Further data which may be used for averaging may be generated by using the above techniques along with changes in the polarisation state of the transmit and receive antennas and/or physical reconfiguration of the antennas (e.g. switch the transmit and receive elements).

Abstract: The present invention provides an apparatus comprising a plurality of planar waveguides and method of making the same. The apparatus includes first, second, and third layers formed above a substrate and adjacent each other. The second layer is formed between the first and third layers of a material and comprises a plurality of organofunctional siloxane-based resin or polymer waveguides. Each waveguide has an input on one edge of the second layer and an output on one edge of the second layer so that the input and output are on different line-of-sight paths. The plurality of waveguides is formed such that intersections of the waveguides occur at approximately right angles and the outputs and inputs located on edges that are opposite one another are offset from each other in a direction that is perpendicular to the direction of the corresponding input or output signal.

Abstract: The present invention provides an apparatus comprising a plurality of planar waveguides and method of making the same. The apparatus includes first, second, and third layers formed above a substrate and adjacent each other. The second layer is formed between the first and third layers of a material and comprises a plurality of organofunctional siloxane-based resin or polymer waveguides. Each waveguide has an input on one edge of the second layer and an output on one edge of the second layer so that the input and output are on different line-of-sight paths. The plurality of waveguides is formed such that intersections of the waveguides occur at approximately right angles and the outputs and inputs located on edges that are opposite one another are offset from each other in a direction that is perpendicular to the direction of the corresponding input or output signal.

Abstract: The present invention provides a planar waveguide. In one embodiment, the planar waveguide includes first and third layers formed above a substrate and adjacent each other. The first and third layers are formed of a first material having a first index of refraction. The planar waveguide also includes a second layer formed between the first and third layers of a second material having a second index of refraction that is larger than the first index of refraction. The planar waveguide further includes a plurality of organo-functional siloxane based resin or polymer waveguides formed in the second layer. Each organo-functional siloxane based resin or polymer waveguide has an input on one edge of the second layer and an output on one edge of the second layer so that the input and output are on different line-of-sight paths.

Abstract: We describe an RFID tag reading system comprising a plurality of transmit/receive antennas to provide spatial transmit/receive signal diversity, and a tag signal decoder. The system combines received RF signals from the antennas, and the antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another. The system performs a tag inventory cycle comprising a plurality of tag read rounds, each having a set of time slots during which a said tag is able to transmit tag data including a tag ID. The system is configured to perform, during a tag inventory cycle, one or both of: a change in a frequency of the tag interrogation signals transmitted simultaneously from the plurality of antennas, and a change in a relative phase of a the RF tag interrogation signal transmitted from one of the antennas with respect to another.

Abstract: We describe a methods of locating an RFID tag. One method transmits tag location signals at a plurality of different frequencies from a plurality of different antennas spaced apart by more than a near field limit distance. The processing determines a phase difference at the plurality of different frequencies by determining a phase difference between either i) two or more of the transmit signals resulting in a maxima in the returned signal RSSI or ii) a first transmit signal and its corresponding return signal. The range determining uses return signals weighted by signal strength. Further data which may be used for averaging may be generated by using the above techniques along with changes in the polarisation state of the transmit and receive antennas and/or physical reconfiguration of the antennas (e.g. switch the transmit and receive elements).

Abstract: The present invention provides a planar waveguide. In one embodiment, the planar waveguide includes first and third layers formed above a substrate and adjacent each other. The first and third layers are formed of a first material having a first index of refraction. The planar waveguide also includes a second layer formed between the first and third layers of a second material having a second index of refraction that is larger than the first index of refraction. The planar waveguide further includes a plurality of organo-functional siloxane based resin or polymer waveguides formed in the second layer. Each organo-functional siloxane based resin or polymer waveguide has an input on one edge of the second layer and an output on one edge of the second layer so that the input and output are on different line-of-sight paths.

Abstract: A wavelength control system comprising a wavelength tunable laser, a temperature sensing mechanism and a bias controller responsive to the sensed temperature whereby emission wavelength or the wavelength tunable laser is maintained substantially constant by adjusting the bias applied to the wavelength tunable laser accordingly with temperature.

Abstract: A method of transmission of radio signals over all types of graded-index multimode fibre is provided. The method comprises launching optical radiation into the core of the multimode fibre away from the centre of the core so as to strongly excite a subset of the available modes of the multimode fibre. The subset of modes excited are within a small number of mode groups and thus have similar propagation constants leading to a reduction in modal dispersion and modal interference and smoothing of the frequency response passband region beyond the fibres specified 3 dB base band bandwidth assisting RF transmission and recovery from this region.

Abstract: A method is provided for the transmission of digital and radio frequency signals, for example for multiservice applications, over all types of multimode optical fibre link using laser diodes. The method comprises launching optical radiation into the core of the multimode optical fibre, in a manner that restricts the number of excited modes within it. The subset of modes that are excited suppress additional noise due to the presence of a multiplicity of signals, and ensure high quality transmission.

Abstract: A WDM optical wavelength converter for converting modulated radiation at a first WDM wavelength channel (?1) to corresponding modulated radiation at another WDM wavelength channel (?2) comprises: a semiconductor laser (e.g., a sampled grating distributed Bragg reflector SGDBR device) integrated with a semiconductor optical amplifier (SOA). The converter is characterized in that the laser is wavelength tuneable over at least a plurality of wavelength channels and preferably all wavelength channels.

Abstract: Embodiments of the present invention provide an integrated wavelength converter and optical router which is based on an optical device which includes upper and lower waveguide structures. The upper wave guide structure includes first and second portions, and includes a reflecting surface for reflecting optical signals between the first and second portions. Each of the portions is able to be optically coupled with a respective part of the lower wave-guide structure, such that optical signals can be coupled between respective parts of the lower waveguide structure.