Abstract: A group of SAW RFID tags or sensors each has a transducer with interdigitated fingers, a different set of fingers in each tag or sensor being reversed in phase to cause the tag or sensor to provide a unique identifier in a returned impulse response produced by the tag or sensor when interrogated by an interrogation signal.

Abstract: SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, internal dimensions of IDTs are inversely proportional to operating frequency, such that high frequency IDTs present significant manufacturing difficulties. Fabrication of IDTs for high frequency applications is simplified by exploiting a harmonic frequency SAW generated by IDTs. An IDT may therefore be designed according to fundamental frequency internal dimension criteria but can operate at a multiple of the fundamental frequency, thereby providing much higher frequency operation than conventional SAW systems.

Abstract: A SAW communication device has a main IDT mounted on an SAW substrate to receive an RF signal received by an antenna and convert the RF signal to an acoustic wave which travels along the SAW substrate in opposite directions from the main IDT. At least two secondary IDTs are mounted on the SAW substrate on opposite sides of and spaced from the main IDT to receive and reflect the acoustic wave in a modulated form such that the modulated acoustic wave from one secondary IDT is delayed relatively to the modulated acoustic wave from a secondary IDT on the opposite side of the main IDT to the one secondary IDT. The main IDT is also operable to receive and convert the reflected modulated acoustic waves to a further RF signal with a concatenated waveform corresponding to the two modulated acoustic waves and transmit the further RF signal from the antenna.

Abstract: A communication signal receiver and associated method are disclosed. A plurality of communication signals are received at an atenna array and time multiplexed into a single multiplexed signal. Each of the communication signals comprises an unknown mixture of a plurality of source signals from a plurality of communication signal sources. A signal separation network is configured to separate the K source signals from the multiplexed signal.

Abstract: A group of SAW RFID tags or sensors each has a transducer with interdigitated fingers, a different set of fingers in each tag or sensor being reversed in phase to cause the tag or sensor to provide a unique identifier in a returned impulse response produced by the tag or sensor when interrogated by an interrogation signal.

Abstract: A SAW RFID tag or sensor has an antenna for receiving and propagating an RF signal, an input/output IDT electrically connected to the antenna, and a dual track reflective IDT having a first track and a second track located adjacent and acoustically coupled to the input/output IDT. An RF signal received from the antenna by the input/output IDT is transformed by the input/output IDT into an acoustic way which is propagated to the dual track IDT. One track of the dual track IDT is in-phase with the phase reference of the input/output IDT and the other track is in quadrature phase with said phase reference. The input/output IDT receives two orthogonal complex modulated acoustic waves reflected from the first and second tracks and transforms them to a modulated orthogonal complex RF signal which is propagated from the antenna.

Abstract: An adaptive tuning method for a wireless communication device determines the impedance of a matching circuit relative to an impedance to be matched and adjusts the impedance of the matching circuit accordingly. A passive surface acoustic wave (SAW) device includes multiple terminated interdigital transducers (IDTs) which generate reflected SAWs when excited by incident SAWs, each reflected SAW having magnitude and phase characteristics dependent upon the particular IDT termination. According to the invention, the IDT terminations include the impedance matching circuit and the impedance to be matched. Input IDTs in the SAW device are excited with electrical signals, which are converted to generate the incident SAWs. The resultant reflected SAWs are converted by output IDTs into output electrical signal signals which can then be analyzed to determine magnitude and phase differences between the output electrical signal signals and generate an impedance matching circuit control signal based thereon.

Abstract: A leaky surface acoustic wave resonator includes reflectors each having metal fingers on the piezoelectric substrate. The metal fingers have a ration of finger width to finger width plus the width of the space therebetween of from 0.75 to 1.0.

Abstract: A communication system for two-way exchange of information using a binary coded waveform has a base unit operable to transmit and receive electromagnetic radiation waveforms modulated by binary coded voice or data message signals, and a hybrid unit remote from the base unit and operable to receive and transmit binary coded electromagnetic radiation waveforms from and to the base unit.

Abstract: SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, conventional SAW expanders and compressors typically have insertion losses greater than 20 dB, which can have a profound effect on an RF link budget in a communication system. Insertion losses are drastically reduced by using a single phase unidirectional transducer (SPUDT-type) instead of a conventional IDT as a SAW expander/compressor. A SPUDT-type reflects SAW components which are lost in conventional IDT designs so that a stronger SAW is directed toward a transmission element. In a receiver, a SPUDT-type directs a stronger SAW toward a compressor IDT.

Abstract: An adaptive tuning method for a wireless communication device determines the impedance of a matching circuit relative to an impedance to be matched and adjusts the impedance of the matching circuit accordingly. A passive surface acoustic wave (SAW) device includes multiple terminated interdigital transducers (IDTs) which generate reflected SAWs when excited by incident SAWs, each reflected SAW having magnitude and phase characteristics dependent upon the particular IDT termination. According to the invention, the IDT terminations include the impedance matching circuit and the impedance to be matched. Input IDTs in the SAW device are excited with electrical signals, which are converted to generate the incident SAWs. The resultant reflected SAWs are converted by output IDTs into output electrical signal signals which can then be analyzed to determine magnitude and phase differences between the output electrical signal signals and generate an impedance matching circuit control signal based thereon.

Abstract: A system and method for redirecting data to a mobile device having a long-range RF transceiver and a short-range RF transceiver is provided. The system determines whether the mobile device is in physical proximity to the short-range RF network, and if so, redirects data to the mobile device via the short-range RF network, and if not, redirects data to the mobile device via the long-range RF network. Multiple methods for determining the physical location of the mobile device are provided. Also provided is a short-range RF network including a plurality of RF-enabled interface cradles for generating a network of pico-cells within one or more office locations. As a mobile device comes within the vicinity of one of these pico-cells, contact information is provided to the system indicating the phyiscal location of the mobile device.

Abstract: SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, conventional SAW expanders and compressors typically have insertion losses greater than 20 dB, which can have a profound effect on an RF link budget in a communication system. Insertion losses are drastically reduced by using a single phase unidirectional transducer (SPUDT-type) instead of a conventional IDT as a SAW expander/compressor. A SPUDT-type reflects SAW components which are lost in conventional IDT designs so that a stronger SAW is directed toward a transmission element. In a receiver, a SPUDT-type directs a stronger SAW toward a compressor IDT.

Abstract: SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, internal dimensions of IDTs are inversely proportional to operating frequency, such that high frequency IDTs present significant manufacturing difficulties. Fabrication of IDTs for high frequency applications is simplified by exploiting a harmonic frequency SAW generated by IDTs. An IDT may therefore be designed according to fundamental frequency internal dimension criteria but can operate at a multiple of the fundamental frequency, thereby providing much higher frequency operation than conventional SAW systems.

Abstract: A differential SAW filter having a cascaded structure includes including an input SAW stage and an output SAW stage. The two SAW stages are configured so that the distance of travel of the surface acoustic waves from a single unbalanced input of the input stage to the dual balanced outputs of the output stage is electrically equidistant, thus resulting in a balanced differential output. The input stage includes a single unbalanced input coupled to a pair of outer IDTs, which both launch a surface acoustic wave to a single input stage inner IDT. The input stage inner IDT connects to the input IDT of the output SAW stage, which launches a surface acoustic wave to a pair of identical, but inverted output IDTs that form the differential, balanced output signals.

Abstract: An RF antenna system is disclosed having at least one meandering antenna line with an aggregate structure formed to substantially extend in two dimensions, to effectively form a top-loaded monopole antenna. The meandering antenna line includes at least one localized bend for providing a compressed effective antenna length in a compact package. The present antenna can be made as an antenna system having discrete transmit and receive antenna lines, so as to form a dual antenna system. The localized bends on each line electromagnetically couple with the respective bends on the other line, thus increasing electromagnetic coupling efficiency, thereby increasing antenna bandwidth and gain.

Abstract: An RF data communications device antenna system is shown that includes a dipole and an electromagnetic coupler that provides coupling between each dipole arm to establish a desired resonant bandwidth. An LC matching circuit is provided for matching the dipole to the impedance of the RF data communications device and for transforming the RF signal between the dipole arms of the antenna system.

Abstract: A radio telecommunications antenna includes a telescoping antenna portion for substantially receiving an electromagnetic signal. The telescoping portion is attached by an antenna mast for conducting the electromagnetic signal. A dielectric spacer and an inductor are in electrical contact with the antenna mast. An RF connector is in electrical contact with the dielectric spacer, opposite the antenna mast, so as to form a capacitor. The RF connector is also in electrical contact with the inductor so that the capacitor and the inductor form an LC circuit with values selected to provide a predetermined impedance match with the remainder of the antenna.