Abstract: An electronic device intended for use as a tag to be attached to identify contents of the container to which it is attached. In particular, the present invention relates to an electronic tag which has a facility for storing delivery information and is equipped with a responding means for transmitting the delivery information stored therein in response to a query signal received from an interrogating apparatus. Codes, including items such as the names and addresses of the destination and the sender, and a sorting code are written into predetermined blanks of a delivery label, and into a memory. The memory responds to a query by transmitting the sorting information to allow automated sorting. The tag may be initiated only when torn, to extend battery shelf life.

Abstract: A system for identifying persons, animals or objects provided with identifying badges comprises at least one interrogator provided with a microwave transmitter producing interrogation signals modulated by a BARKER code. A plurality of transponder type identifying badges use the power of a BARKER code modulated signal received from an interrogator to transmit a respective microwave response code transposed from the received signal. At least one identification receiver is adapted to decode the microwave response codes from the badges by a correlative method. The system is incorporated into a server application, in particular a multiservice telephone installation processing the identification information that it provides.

Abstract: A detachable IC card applicable to a portable data processing device referred to as an "electronic organizer" is disclosed. The IC card is formed of microstrip lines formed on a dielectric substrate. An antenna receives an externally applied unmodulated carrier signal and guides the received signal to microstrip lines for impedance conversion. Cathode potential of a diode is varied in response to a data signal outputted from a CPU, so that the barrier capacitance of the diode varies. Accordingly, the carrier is reflected according to the data signal and radiated toward the electronic organizer main body through the antenna. An oscillator for data transmission is not required in the IC card, so that an internal battery having a large capacitance is not required, either. As a result, without increasing the size and weight of the device, radio transmission of data from the IC card can be accomplished.

Abstract: The invention relates to a transponder for a vehicle identification device in which a radio wave including vehicle information returned from transponders provided in a vehicle is received by an interrogator. The vehicle transponder receives a query radio wave and uses a detection device to generate a previously memorized coded signal train in response to a received wave. The coded signal train varies an amount of bias voltage of the detection device so that a reflection coefficient of the detection device is varied to modulate the reflection wave of the query radio wave and the modulated wave is transmitted back to the interrogator.

Abstract: An identification and telemetry system comprising: a signal responding label including a first antenna for receiving an interrogation signal and for scattering a reply signal, an impedance connected to the first antenna, means for generating the reply signal and means for varying the impedance connected to the first antenna in accordance with the reply signal; and an interrogator comprising a second antenna for transmitting an interrogation signal and for receiving the reply signal, a transmitter connected to the second antenna and including a generator of pulsed radio frequency energy, means for separating the reply signal from the transmitted signal, a receiver connected to the second antenna and means within the receiver for detecting and decoding the reply signal.

Abstract: An identification system comprising a transponder having receiver means adapted to extract powering energy from a surrounding electromagnet field, transponder transmitter means adapted to transmit at least one unique signal from the transponder, frequency generating means for generating a plurality of pre-determined frequencies, each frequency adapted to carry the signal from the transmitter means to an interrogator receiver means adapted to receive said signals to achieve identification of said transponder, said transponder transmitting signals successively or repetitively using at each successive or repetitive transmission a newly selected frequency or set of newly selected frequencies.

Abstract: A single interrogation device interrogates a plurality of transponders arranged within the range of transmission of the interrogation device and identifies them without any mutual interference.The interference free operation is obtained by the interrogation device sequentially transmitting a plurality of RF interrogation pulses, separated from each other in time and whose energy changes from one pulse to the next one, to transponders which have an energy storage element and which respond to the interrogation pulses with an answer signal in dependence upon the condition that, at the end of each interrogation pulse, the charge voltage present at the energy storage element falls within a predetermined voltage range.

Abstract: A battery-less transponder (12) for transmitting stored measurement data to an interrogation device (10) is described. The interrogation device (10) transmits an HF interrogation pulse for calling up the stored measurement data. The transponder (12) includes a resonant circuit (14) tuned to the frequency of the HF interrogation pulse, an energy storage element (C3) which is chargeable by rectification of the HF interrogation pulse and in the charged state furnishes the supply voltage for the transponder (12), and a voltage limiting means (Z, R) for limiting the voltage at the energy storage element (C3) to a predetermined voltage value. For detuning the resonance frequency thereof, a component (C4) of frequency-dependent impedance can be connected to the resonant circuit (14) via a switching element (T) which establishes the connection in dependence upon the starting of the limiting action by the voltage limiting means (Z, R).

Abstract: A transponder (14) for communicating with an interrogator (12) has a high Q-factor resonant circuit (34) of frequency f.sub.1 for receiving RF powering signals. The transponder also has a tuning circuit (56,58) which when in electrical communication with the resonant circuit (34) is operable to form a lower Q-factor resonant circuit (60) of frequency f.sub.3 for receiving RF communications from the interrogator unit. The transponder also includes a demodulator (66) which is in electrical communication with said resonant circuit (34). Additionally, the transponder (14) also included a control circuit (40) which receives a demodulated data signal from the demodulator (66). The control circuit (40) is further connected to the tuning circuit (56,58) and is operable to connect the tuning circuit (56,58) to the high Q-factor resonant circuit (34) in order to form the lower Q-factor resonant circuit (60). Control circuit (40) also converts the RF powering signals to a DC current for storing energy.

Abstract: A method and apparatus for facilitating interconnection of lead wires to an integrated circuit including the provision of an additional protective layer of insulation to the top of an integrated circuit chip or die and the provision of enlarged plated electrodes to the surface of the additional insulation to form enhanced bonding pads, such pads being electrically connected through the protective layers to the normal bonding pads of the integrated circuit device. The enhanced bonding pads are made of a soft conductive metal such that external wires to be attached thereto can be bonded to the pads using a thermal compression bonding technique.

Abstract: An interrogator-transponder system in which multiple vehicle mounted transponders which may be closely spaced in distance and moving at similar velocities, respond with a coherent identification code signal that is displaced in frequency from the interrogation signal by an amount that is identical for each transponder. The response signal spacings in time (Pulse repetition intervals) are different for each transponder but are always multiples of the pulse repetition interval of the interrogation signal. A coherent reference for the received transponder codes is obtained by combining the coherent interrogation signal with a coherent reference that is substantially identical in frequency to the displacement frequency of the transponder response signal.Means are provided in the interrogation device to determine the velocity of each transponder and its range with respect to the interrogator and to identify vehicles with inoperative transponders.

Abstract: An interrogator-transponder system in which multiple vehicle mounted transponders, which may be closely spaced in distance and moving at similar velocities, respond to an interrogation signal in a sequential or random sequential manner so as to reduce response signal interleaving to an acceptable level. The response signals include a vehicle identification code and are processed by the interrogator to yield data, for example, on specific vehicle speed, distance from the interrogator, vehicle wanted for investigation, and vehicle with an inoperative transponder.

Abstract: A retrodirective interrogation responsive system wherein a responder, illuminated by an interrogator, receives an interrogation signal, modulates information onto the interrogation signal, and retransmits the encoded interrogation signal back in the direction of arrival of the collected interrogation signal. The responder uses a Van Atta array antenna and is capable of responding to an interrogator signal incident over a wide solid angle of arrival while retrodirectively retransmitting without amplification substantially all of the collected signal within a narrow solid angle. The responder may be implemented using monolithic microwave integrated circuit technology (MMIC), thus being suitable for high volume production.

Abstract: An interrogation responder system composed of a transmitter stationarily mounted in a certain fixed place and a receiver mounted on a mobile object. The receiver on the mobile side starts the operation when a power is supplied to the entire circuit in accordance with a wake-up signal from the transmitter on the fixed side so as to modulate the electromagnetic signal emitted from the transmitter on the fixed side in accordance with a predetermined code and reflect a response. This enables continuing bilateral communication of a command, data and so forth. By starting communication between the transmitter and the receiver by a direct wave of a carrier signal in a microwave band after sensing that the receiver on the mobile side has entered a good communication zone, secure communication is enabled at a sufficient electric field strength.

Abstract: A reader transmits a pulse to a transponder. The transponder responds by transmitting a particular number (e.g. 10) of signals at a frequency dependent upon the identifying code recorded in the transponder. The reader then transmits a pulse of an opposite polarity to that previously transmitted. The transponder responds by generating 10 signals at a second frequency different from the first frequency. In this way, sequences of pulses alternatively of opposite polarity are transmitted by the reader and sequences of signals at the first and second frequencies are transmitted by the transponder. The reader decodes the sequences of signals at the first and second frequencies, in accordance with the order of the frequencies of such signals, to identify the code at the transponder. The transponder may have a programmable memory to store the code. To program the memory with such a code, the reader transmits sequences of pulses, each sequence coding for a programmable item of information (e.g.

Abstract: An improved search and rescue transponder having an improved housing assembly that permits the device to be turned on or off by rotating one segment of the housing relative to the other for ease of use even with heavy or bulky gloves. In addition, the housing assembly exterior surface includes a plurality of longitudinal ridges for ease in gripping. The housing assembly includes an upper housing and lower housing joined by a retaining ring and O-ring seal, eliminating the need for fasteners for manufacturing efficiency. The lower housing includes quick disconnect that attaches to a mounting disk affixed to a ship or life raft. The mounting disk includes a plurality of resilient fingers which act in conjunction with cam surfaces on the flange of the lower housing, which when rotated together allow for a quick disconnect.

Abstract: An emitted wave is transmitted from a central station to a passive end. A phase modulation circuit in the passive end modulates a signal resulting from the emitted wave for retransmitting it in the form of a two-phase-state modulated signal at the rhythm of a clock signal. In the central station, the modulated signal is demodulated into two quadrature signals. On the basis of the product of the two quadrature signals and the sign of the difference between the moduli of the rectified quadrature signals, the count of an up-down counter in a digital processing circuit is incremented or decremented in order for said count to be representative of the distance separating the passive end and the central station.

Abstract: A transponder location and tracking system having a phased array antenna mounted at a toll collection station includes a plurality of antenna array elements for receiving a signal from a transponder mounted on a vehicle and for providing a plurality of antenna element electrical signals. A plurality of phase detectors are provided for comparing the phase of the electrical signals to provide a plurality of phase difference signals. A plurality of angle-of-arrival calculation processors is provided for converting the phase difference signals to spatial signals to define the angles-of-arrival of the vehicle transponder signal. A position calculation processor is included for providing an output signal representative of the location of the vehicle in response to the defined angles-of-arrival. In a preferred embodiment, the transponder location and tracking system includes a plurality of receiver processing devices for amplifying and filtering the electrical signals from each antenna element.

Abstract: The disclosed system comprises a receiver that is inductively coupled to one or more passive transmitters by means of a receiving inductor. The receiver comprises a sweep signal source which is coupled equally to the receiving inductor and a reference inductor. The receiving inductor is coupled to a passive transmitter which includes an L-R-C circuit comprised of a transmitting inductor, a temperature-dependent capacitor, and a resistor that may be variable or fixed, depending upon the application. As the sweep signal source passes through the resonant frequency of the passive transmitter, the passive transmitter forms a low impedance load magnetically coupled to the receiving inductor by means of the near or induction electromagnetic field produced by the inductor. Changes in the resonant frequency are used to determine temperature variation.

Abstract: A method and apparatus for facilitating interconnection of antenna lead wires to an integrated circuit and encapsulating the assembly to form an improved miniature transponder device including the provision of an additional protective layer of insulation to the top of an integrated circuit chip or die and the provision of enlarged plated electrodes to the surface of the additional insulation to form enhanced bonding pads, such pads being electrically connected through the protective layers to the normal bonding pads of the integrated circuit device. The enhanced bonding pads are made of a soft conductive metal such that external wires to be attached thereto can be bonded to the pads using a thermal compression bonding technique, This invention also extends to a method of encapsulating a transponder in heat shrunk plastics material.

Abstract: A radio frequency automatic identification system detects targets which include solid resonators resonating at several frequencies, attributing information to the frequencies at which the target resonates. Preferred resonators are quartz crystals, which may be made by a process of heating quartz to soften it and cutting crystals to approximate size and resonant frequency. Resonators produced by such a process are measured to determine their actual resonant frequency, and preferably the crystals are sorted into predetermined frequency windows in accordance with their measured resonant frequency. A set of resonators having frequencies corresponding to predetermined data is selected from the sorted groups of resonators and incorporated into a target. The preferred target is an ink-like material having a plurality of resonators disposed in a matrix which is radio frequency transparent at the frequency of interest.

Abstract: In a system for the exchange of data by microwaves between a fixed station and a mobile station or portable badge, the information bit rate is limited, in the standby state, by the low power consumption of the badge and the high output impedance of the modem. To increase the information bit rate of the modem of a badge, the information processing circuit associated with the modem sends the modem an activation signal to reduce its output impedance. The means implemented are transistors that switch over the load of the detector transistor or of the amplifier transistor.

Abstract: A planar dipole antenna is arranged on a non-conductive substrate having an exposed, planar surface. The antenna includes a first quarter wavelength element having a first end and an opposite second end and a second quarter wavelength element having a third end and an opposite fourth end. The first, second, third and fourth ends, respectively, are arranged on a common straight line with the second and third ends adjacent to each other. A third quarter wavelength element, having a fifth end and an opposite sixth end, is arranged adjacent to the first element with its fifth end adjacent to the first end of the first element and its sixth end both adjacent to and physically connected with the third end of the second element. A signal source or sink is coupled to the first end of the first element and the fifth end of the third element, respectively, for providing electrical energy to, and/or receiving electrical energy from the antenna.

Abstract: The disclosure relates to the field of data exchange by microwaves between a fixed station, or reader, and a mobile station, or badge. To achieve economy in the energy consumption of the badge, which has a "chip card" format, its input circuit or modem connected to the antenna does not transmit the modulated signal towards the reader. It reflects, in varying degrees, the carrier transmitted by the reader. The modulation of the reflection coefficient of the antenna is obtained by variation of the gate-source junction capacitance, which it itself related to the variation of the gate-source bias voltage of the input transistor of the modem. Application to remote-control toll-gates, remote money transactions and security checks.

Abstract: A synchronous rectifier comprising: switch means responsive to a control signal for selectively providing conduction of an applied AC signal, and driver means responsive to the applied AC signal and adapted to provide said control signal in synchronism with the applied AC signal, wherein the rectifier is integratable into VLSI "chip" form.

Abstract: A system is provided for automatic identification of objects, such as rail cars and the like, utilizing two transponders, each attached to the rail car by a bracket. The bracket, which is welded along its ends to the rail car, has a lower planar surface which is placed against the side of the rail car when the bracket is welded thereto. A bottom planar surface of the transponder mates with an upper planar surface of the bracket, thus ensuring a good conduction heat flow path to the rail car and preventing over heating of the transponder when the rail car is placed in a thaw shed. The transponder is attached to the bracket by inserting a flange formed one end of the transponder under a clip projecting from the upper surface of the bracket. A threaded stud projecting upward from the bracket upper surface extends through a hole in a second flange formed at the other end of the transponder.

Abstract: An identification of friend from foe (IFF) device is described containing a radio transceiver (F) which, in addition to being designed for communication purposes, is equipped for transmitting, receiving, and evaluating IFF signals. The IFF device further includes a laser transmitter (LS) and an optical receiver (LE) which are coupled to the radio transceiver (F) via a controller (G). For identification, unmodulated direction-selective light signals and modulated nondirectional radio signals are used.

Abstract: The radio system embodying the invention comprises a central station and a passive terminal station. First and second data signals are transmitted between data processing units respectively connected to the central and terminal stations. The terminal station comprises a same low-cost circuit associated with a square two-dimensional antenna for detecting the amplitude of a first incident microwave emitted by the central station thereby recovering the first data signal and deriving, in response to the first microwaves, a microwave modulated in phase by the second data signal by means of a retroreflection of a second incident microwave. This second incident microwave is emitted by the central station to the two-dimensional antenna of the terminal station. The terminal station is of very simple design, is compact and can therefore be included as well as the corresponding data processing unit in a contact-free chip card.

Abstract: An antenna system for mounting in a roadway comprised of an electrically lossy material. The antenna system has a reflector trough shield filled with a solid dielectric. An antenna, preferably comprised of coaxial cable, is positioned in the reflector trough, which prevents electromagnetic waves radiated by the antenna from being lost into the roadway.

Abstract: A system for indenitfying objects, such as workpieces on an assembly line, includes a transponder for attaching to an object and a radio frequency (RF) transceiver. The transceiver can program the transponder with data about the specific object and interrogate the transponder to obtain previously programmed data. The transponder responds to different RF signal strengths and commands from the transceiver to select whether it will store or transmit data. Data is exchanged between the two devices using Manchester encoding. The transceiver processes the encoded data signal from the transponder by measuring and storing the intervals between level transitions in the signal. The stored intervals are then processed in non-real time to recover the data.

Abstract: An identification system to identify objects from a remote interrogation station may be used with moving objects such as railroad cars. The system remotely programs and stores information on an object and remotely retrieves information from the object. An information and identity storage device is located on the object and at least one interrogation station is located remotely from the object.

Abstract: Information is communicated by microwave radio between transponders (9,10) carried by vehicles (7,8) travelling on a road (1) and a station (22) adjacent the road. The communications from the transponders are effected by the transponders suitably modulating their reflections of beams of microwave energy transmitted by the station from aerials (B) mounted on a gantry (11) above the road, these aerials irradiating respective communication areas (28,29,30). In order to prevent communications from different transponders overlapping and hence interfering with each other the transponders are enabled for their communications by microwave energy from further aerials (A), which energy has a higher frequency to enable it to be beamed at relatively small respective activation areas (23-27) the sizes of which are such that they can each only contain one vehicle and hence one transponder at any given time.

Abstract: A circuit arrangement is described with the aid of which a control signal can be generated in dependence upon the occurrence of an extreme value of a sinusoidal oscillation. The circuit arrangement (10) includes a storage member (22) which is adapted to be charged via a diode (20) to one of the extreme values of the sinusoidal oscillation. A discharge path (26) for the storage member (22) is present, the time constant of which is so dimensioned that within the period duration of the sinusoidal oscillation an appreciable discharge of the storage member (22) takes place. A switch element (24) controllable by the charge voltage of the storage member (22) furnishes the control signal at its output (14) for the period of time during which the charge voltage at the storage member (22) is smaller than the extreme value of the sinusoidal oscillation. The circuit arrangement can be used in maintaining the oscillations of a resonance circuit stimulated to oscillate by means of a momentary HF carrier wave pulse.

Abstract: A microwave responder resonates or does not resonate with a microwave transmitted from a radio transmitter, and radiates the resonated microwave as a response signal wave. Two microstrip lines are linearly arranged to be separated from each other at a predetermined interval. A diode which is switched between ON and OFF states in response to the response signal is interposed between two end portions of the microstrip lines separated by the predetermined interval, and a distance, between distal ends of the two linearly arranged microstrip lines, which includes an impedance defined by the ON or OFF state of the diode is determined to be 1/2 a wavelength of the microwave.

Abstract: A security tag is disclosed for use with an electronic security system for a controlled area. The tag comprises circuitry for initially establishing a resonant circuit having a first resonating frequency within a first frequency range which is outside of the range of the detection frequency of the electronic security system. The tag is activated by changing the resonating frequency of the resonant circuit to a second frequency within the detection frequency range by exposing the resonant circuit to electromagnetic energy within the first frequency range at the predetermined minimum power level to short-circuit a first circuit component.

Abstract: Hyperfrequency system for remote data transmission of the type comprises at least one reader (L) associated with a plurality of responders (R) with the reader (L) comprising means to generate a hyperfrequency wave which has a certain rectilinear polarization, while each responder (R) is fitted with a rectangular flat antenna for reemission (1) which is capable of receiving said hyperfrequency wave and reemitting it with orthogonal polarization and phase modulation at two stages representing the data to be transmitted to reader (L), characterized in that the phase modulation is achieved by two transistors (Qa, Qb) which are connected respectively to two adjacent corners (a, b) of antenna (1), these two transistors being alternately blocked and saturated at the rhythm of the data to be transmitted, by additional control signals originating in an appropriate processing unit (4) in order to short circuit alternately the corresponding corner of the antenna.

Abstract: A transponder includes a receiving and evaluating section (22) andd a transmitting section (28). It further includes an energy storage means (18) which is chargeable by an HF interrogation pulse furnished by an interrogation device and supplies the supply voltage for the receiving and evaluating section (22) and for the transmitting section (28). An identification generator (30) in the transponder furnishes identification data fixedly associated therewith and a measurement data generator (32) receives from a sensor (34) measurement signals and converts said measurement signals to measurement data. The receiving and evaluating section (22) clears the transmitting section (28) for transmitting the identification data only when the supply voltage exceeds a first predetermined threshold value.

Abstract: An electromagnetic identification and location system is described. The system comprises at least one interrogator which, in operation, generates an electromagnetic interrogation field by at least one antenna coil, and at least one responder which, in response to the electromagnetic interrogation field, generates a code signal in accordance with a binary code stored in a code circuit of the responder. The code signal can be recognized by an identifier. According to the invention, the responder is provided with a generator which, in response to the interrogation field, generates and transmits a pilot signal. The system further includes a position-sensitive antenna arrangement for receiving the pilot signal.

Abstract: This is a radar transponder in which an amplifying means using a FET amplifier is inserted between a receiving antenna and a detecting means. Further, the radar transponder has a receiving on/off control circuit which stops the operation of the amplifying means in transmitting a response signal in order to enhance the receiving sensitivity thereof. Also, the radar transponder mounts the amplifying means, and the detecting means via a metal body having resilience on an antenna housing. Each circuit unit of the radar transponder and connection wirings between each circuit unit are formed by flexible printed circuit boards.

Abstract: A passive inductively and capacitively loaded antenna is shown which is retained within a closed cel styrene foam enclosure. A method for detecting buried utility components utilizing such in combination with underground radar is also shown.

Abstract: A transponder arrangement is described comprising an interrogation unit (10) which sends an RF interrogation pulse to at least one responder unit (12). The responder unit (12) then transmits back data stored therein in the form of a modulated RF carrier to the interrogation unit (10). In the responder unit (12) is an energy accumulator (136) which stores the energy contained in the RF interrogation pulse. The responder unit (12) further contains means (142, 148) which in dependence upon the termination of the reception of the RF interrogation pulse and the presence of a predetermined energy amount in the energy accumulator (126) initiate the excitation of an RF carrier wave generator (130, 132, 134) operating with the frequency contained in the RF interrogation pulse.

Abstract: A locating system and method in which a network of communication stations are spread over a surveillance area. Each moveable element is provided with a transponder having an associated identification code. A paging signal sent out over the surveillance area is picked up by the transponders and the one with the identification code provided in the page responds. The response is made at a frequency different from the page. The response is picked up by the nearest communication stations. A master station communicates with the communication stations at a frequency different from that used by the paging signal or the transponder. The master station which interrogates all the communication stations locates the paged transponder to within a sector bordered by the communication stations that received the response from the transponder. The communication stations can be subdivided into three or more interspersed arrays.

Abstract: A system for the contactless exchange of data between a transceiver and a passive data carrier is described. A prior data carrier comprises at least one digital memory and at least one digital control device for the memory. In it, the data carrier has a single-coil receiver circuit connected to a controllable switch device. In operation, the data carrier provides, in response to an electromagnetic a.c. field generated by a transceiver, via at least one rectifier, supply power for active components of the data carrier and clock signals for the control of digital components of the data carrier. According to the present invention, in order to provide for the possibility of bi-directional data exchange between a transceiver and a passsive data carrier, and in general, to provide a universally applicable data exchange system of the contactless kind, the transceiver is equipped with a modulator for amplitude modulating the a.c. field.

Abstract: An implantable transponder has a plastic holder having a hollow interior and preferably a rough outer surface, a transmit/receive unit within the hollow interior of the holder, and an electronic element electrically connected to said transmit/receive unit within the hollow interior of said holder. The transmit/receive unit includes a core and coil assembly which may be impregnated with wax, and the hollow interior of the holder is at least partially filled with a plastic filler material such as polysiloxane.

Abstract: A frequency input for receiving a frequency signal and digital storing for storing the received frequency signal. A controller has a first and second input and an output. The first input is connected to the digital storage for providing a reference signal and the output provides a frequency control signal. The second input is connected to circuitry for changing the operation mode of the controller to either an amplifier or an integratory. As an amplifier, a digitally set offset and gain is applied to the amplifier for providing an output generating approximately the frequency of a prior signal. A switch connects the frequency output to the second input when operating in the integrating mode to control the output for generating a desired frequency.

Abstract: This is a radar transponder in which an amplifying means using a FET amplifier is inserted between a receiving antenna and a detecting means. Further, the radar transponder has a receiving on/off control circuit which stops the operation of the amplifying means in transmitting a response signal in order to enhance the receiving sensitivity thereof. Also, the radar transponder mounts the amplifying means, and the detecting mounts the amplifying means, and the detecting means via a metal body having resilience on an antenna housing. Each circuit unit of the radar transponder and connection wirings between each circuit unit are formed by flexible printed circuit boards.

Abstract: A transponder that selectively provides both global and spot beam antenna coverage. The transponder comprises a channel amplifier and an antenna feed network that includes coupler means for coupling energy into a plurality of power distribution networks that feed a plurality of antenna radiating elements that form a beam that illuminates the desired coverage area. A variable power divider is coupled to the amplifier that variably couples power along two channel output paths. Each output path includes a matched bandpass filter and the second output path includes a phase delay circuit. Selective control of the ratio of the power coupled to the respective output paths, and the phase delay provided by the phase delay circuit, provides for selective coupling of the total power provided by the channel amplifier to either the full set, or a selected subset of the antenna elements which generates global and spot beams, respectively.

Abstract: A transponder for use in an interrogator/transponder system includes a piezoelectric substrate for coupling electrical energy into and/or out of a surface acoustic wave (SAW) device; a first inductive loop inductively coupled to a conductive loop on the substrate, a second inductive loop inductively coupled to the first inductive loop for transmitting and/or receiving electrical signals to and/or from the SAW device. The first inductive loop forms an intermediate inductive coupling path between the second inductive loop of the transmitter/receiver and the conductive loop on the substrate.

Abstract: The invention features a theft resistant security system for motor vehicles. The system has receptacle with a coupling coil. A SAW (surface acoustical wave) device associated with the receptacle for relative movement thereto is also provided. The SAW device has a code and its own coupling coil for interaction with the receptacle coupling coil. A testing mechanism is connected to the receptacle for determining whether the code of the SAW device is valid for operation of the motor vehicle. Problems of crosstalk and wave reflection may produce spurious code pulses in systems of this type. The invention provides techniques for eliminating or reducing these unwanted pulses.

Abstract: An identification system to identify objects from a remote interrogation station may be used with moving objects such as railroad cars. The system remotely programs and stores information on an object and remotely retrieves information from the object. An information and identity storage device is located on the object and at least one interrogation station is located remotely from the object.