Abstract: RF communications circuitry, which includes a first tunable RF filter and a first RF low noise amplifier (LNA) is disclosed. The first tunable RF filter includes a pair of weakly coupled resonators, and receives and filters a first upstream RF signal to provide a first filtered RF signal. The first RF LNA is coupled to the first tunable RF filter, and receives and amplifies an RF input signal to provide an RF output signal.

Abstract: A radio device includes a rectangular substrate including first and second opposite sides and third and fourth opposite sides; a ground plane formed in the substrate, cut out along the third side from a corner at one end of the second side; a first monopole antenna extending away from the ground plane along the third side from a first feeding unit provided on the third side; a second monopole antenna extending away from the ground plane along the fourth side from a second feeding unit provided on the fourth side; and a ground element formed in the ground plane, extending toward the second side along the third side, from one end of the ground element connected to the ground plane. A length from the first feeding unit through the one end to another end of the ground element corresponds to one fourth of a wavelength of radio waves.

Abstract: A method for inductively coupled communications is described. The method includes generating a retransmitted modulated signal that is stronger than a received signal from a first device. The method also includes generating a suppressed carrier signal from the retransmitted modulated signal for retransmission to the first device. The method further includes filtering a superimposed signal of the suppressed carrier signal on the received signal to attenuate modulation sidebands. The method additionally includes synchronizing to the first device based on the filtered signal.

Abstract: A system and method is provided for crosstalk reduction in a coupled transmission line on a multilayer structure. The coupled transmission line provides a high frequency signal such as from a local oscillator to an electronic component such as a mixer. The signal carried by the coupled transmission line may be buffered and asymmetrically tapped. The coupled transmission line may have individual parallel lines extending in the direction of current flow. The lines may carry current in opposite directions. Each line contains strips and/or is disposed on a different metallization layer. Strips on each metallization layer (before being routed to another metallization layer) may carry current in opposite directions and overlying strips on different metallization layers may carry current in opposite directions. Multiple strips of an individual line present on a single metallization layer may be disposed symmetrically around a centerline of the coupled transmission line.

Abstract: An SPDT switch in a RF communication transceiver provides for choosing the transmit/receive path for the RF signal. It consists of the series and shunt branches each consisting of stack of FETs. Performance metrics of the RF switch are insertion loss and isolation. At high frequency, the device/FET capacitance and the parasitic capacitances provide a leakage path for the signal, resulting in higher insertion loss and lower isolation. A parallel resonant LC network across each of the series and/or shunt branch FETs in a SPDT switch provides lower insertion loss, higher switch isolation, and lower out of band harmonics when compared to that of the state of the art SPDT switch. A method to reduce the form factor of such switch configuration is disclosed which is useful in wireless front end modules.

Abstract: RF communications circuitry, which includes a first group of RF power amplifier circuits and a first weakly coupled RF network, is disclosed. The first group of RF power amplifier circuits includes a first RF power amplifier circuit, which receives and amplifies a first RF amplifier input signal to provide a first RF amplifier output signal, and a second RF power amplifier circuit, which receives and amplifies a second RF amplifier input signal to provide a second RF amplifier output signal. The first weakly coupled RF network includes a first pair of weakly coupled RF resonators coupled to the first RF power amplifier circuit and a second pair of weakly coupled RF resonators coupled to the second RF power amplifier circuit.

Abstract: A multi-band antenna includes a radiating portion, a feed portion, a ground portion, a first switch module, and a second switch module. The radiating portion includes a plurality of connecting ends. The ground portion includes two ground sections with different impedances. The first switch module connects the feed portion to a first connecting end or a second connecting end, and the second switch module connects one of the ground sections to a third connecting end or a fourth connecting end. A wireless communication device employing the multi-band antenna is also disclosed.

Abstract: Embodiments of the subject technology provides a novel approach to address desense and provide electrostatic discharge (ESD) protection among components for a collocated antenna and speaker configuration in a mobile computing device. The available metal around the periphery of speaker components are used as part of implementing an antenna(s) and also for tuning the antenna, which results in an efficient antenna design that can be implemented within an available (relatively small) area of a PCB and also without adding components, which could further increase the overall cost of the mobile computing device. An inductor is used to isolate the antenna away from a ground to mitigate desense for the antenna. The inductor is connected to a diode and capacitor in series. The diode provides ESD protection for the speaker. The capacitor is connected to the diode in parallel to shunt nonlinearities generated by the diode to ground.

Abstract: In an impedance matching device, a storage unit stores a control value representing a load value and a value equivalent to input impedance in advance. The control value identifies inductance and capacitance values matching a predetermined impedance value by use of either a first or second matching circuit. An impedance estimation unit estimates input impedance of the power transmission antenna. The load value estimation unit estimates load value of a circuit connected to a power reception antenna and consuming transmitted electric power. A circuit selection unit electrically connects the first matching circuit, the second matching circuit, or a through circuit per the load value and the input impedance equivalent value. A control value output unit reads out the control value stored in the storage unit based on the load value and the input impedance equivalent value, and outputs the control value to the circuit selected by the circuit selection unit.

Abstract: Embodiments of the present invention provide a wireless terminal including a PCB, an antenna, and a data connector. The PCB has a groove, which divides the PCB into a first part and a second part. The second part is connected to the antenna, the first part is connected to the data connector through a rotating shaft, and connecting wires of the data connector are connected to the second part. The first part and the second part each have a ground. The ground of the first part is connected to a metal casing of the data connector and a ground wire of the data connector is connected to the ground of the second part and the ground wire of the data connector is electrically connected to the metal casing of the data connector.

Abstract: In one embodiment, a balanced to unbalanced transformer utilizes a crossover configuration such that some portion of the secondary coil (inductor) is shared between two resonators (capacitors). Adding a first capacitor in parallel with a portion of the secondary inductor creates a first harmonic trap (filter), and also efficiently uses the secondary coil (inductor) as a resonating element. Adding a second capacitor which shares (crossover configuration) a portion of the secondary inductor with the first capacitor creates a second harmonic trap (filter), which may be tuned to the same harmonic as the first harmonic trap, or may be tuned to a different harmonic.

Abstract: In a case in which a capacitor is not provided in parallel with a second inductance element, the impedance ratio between a first inductance element and the second inductance element is constant regardless of the frequency, but when a capacitor is provided, the parallel impedance of the capacitor and the second inductance element gradually increases at frequencies equal to and below the resonant frequency. Consequently, at frequencies equal to or below the resonant frequency, the higher the frequency becomes, the larger the value of the real portion of the impedance observed on a high-frequency-circuit side becomes. Therefore, by appropriately setting the values of the first inductance element, the second inductance element, and the capacitor, the frequency characteristics of the real portion of the impedance observed on the high-frequency-circuit side can be set to be similar to the frequency characteristics of the radiation resistance of the antenna.

Abstract: In an impedance matching device, a storage unit stores a control value representing a load value and a value equivalent to input impedance in advance. The control value identifies inductance and capacitance values matching a predetermined impedance value by use of either a first or second matching circuit. An impedance estimation unit estimates input impedance of the power transmission antenna. The load value estimation unit estimates load value of a circuit connected to a power reception antenna and consuming transmitted electric power. A circuit selection unit electrically connects the first matching circuit, the second matching circuit, or a through circuit per the load value and the input impedance equivalent value. A control value output unit reads out the control value stored in the storage unit based on the load value and the input impedance equivalent value, and outputs the control value to the circuit selected by the circuit selection unit.

Abstract: A power distributing duplexer system is provided. In some aspects, the system includes a duplexer configured to couple an antenna to a transmitter and a receiver. The system also includes a balancing network coupled to the duplexer. The balancing network includes a network impedance. The balancing network is configured to adjust the network impedance to match an antenna impedance of the antenna. The balancing network includes a plurality of balancing network modules coupled to the duplexer. Each of the plurality of balancing network modules is configured to receive a portion of an output voltage from the duplexer.

Abstract: An antenna structure (111) commences at a feed point (202) that is coupled to an inverted F antenna section (204). The inverted F antenna section is coupled to a monopole section (210) that is further coupled to a helical section (216). The inverted F section, monopole section, and helical section are coupled in series together.

Abstract: An impedance matching network includes a first terminal, a second terminal, and a reference potential terminal. The impedance matching network further includes a first shunt branch between the first terminal and the reference potential terminal, the first shunt branch including a capacitive element. The impedance matching network also includes a second shunt branch between the second terminal and the reference potential terminal, the second shunt branch including an inductive element. Furthermore, the impedance matching network includes a transmission line transformer with a first inductor path and a second inductor path, wherein the first inductor path connects the first terminal and the second terminal. An alternative impedance matching network includes a transformer and an adaptive matching network. The transformer is configured to transform an impedance connected to a first port so that a corresponding transformed impedance lies within a confined impedance region in a complex impedance plane.

Abstract: An electromagnetic-coupling module including a radio IC chip and a feeder circuit board on which the radio IC chip is mounted and a feeder circuit including a resonant circuit having a predetermined resonant frequency is attached to an article. The article has a radiation element that radiates a transmission signal supplied from the feeder circuit of the electromagnetic-coupling module via electromagnetic coupling and that supplies a received reception signal to the feeder circuit via the electromagnetic coupling.

Abstract: In a filter module capable of handling multiple bands, cross wiring with an RF-IC is to be solved. The filter module includes: an antenna terminal; first and second transmission filters; first and second reception filters; a first switch circuit connected to the antenna terminal, and selectively connected to the first and second transmission filters; a second switch circuit connected to the antenna terminal, and selectively connected to the first and second reception filters; a first matching circuit connected between the first switch circuit and the first transmission filter or between the second switch circuit and the first reception filter; and a second matching circuit connected between the first switch circuit and the second transmission filter or between the second switch circuit and the second reception filter.

Abstract: A wireless electronic device may contain at least one adjustable antenna tuning element for use in tuning the operating frequency range of the device. The antenna tuning element may include radio-frequency switches, continuously/semi-continuously adjustable components such as tunable resistors, inductors, and capacitors, and other load circuits that provide desired impedance characteristics. A test system that is used for performing passive radio-frequency (RF) testing on antenna tuning elements in partially assembled devices is provided. The test system may include an RF tester and a test host. The tester may be used to gather scattering parameter measurements from the antenna tuning element. The test host may be used to ensure that power and appropriate control signals are being supplied to the antenna tuning element so that the antenna tuning element is placed in desired tuning states during testing.

Abstract: A portable communication apparatus includes a first antenna radiator, a second antenna radiator, a first feeding point, a second feeding point, and a matching circuit. The first antenna radiator is used for radiating a high-frequency band signal. The second antenna radiator is used for radiating a low-frequency band signal. The first feeding point is coupled to the first antenna radiator and is utilized for processing feed-in or feed-out of the signal of first antenna radiator. The second feeding point is coupled to the second antenna radiator and is utilized for processing feed-in or feed-out of the signal of second antenna radiator. The first feeding point is separate from the second feeding point. The matching circuit is coupled to the first and second feeding points, and used for impedance matching with the first antenna radiator and the second antenna radiator.

Abstract: An electromagnetic-coupling module including a radio IC chip and a feeder circuit board on which the radio IC chip is mounted and a feeder circuit including a resonant circuit having a predetermined resonant frequency is attached to an article. The article has a radiation element that radiates a transmission signal supplied from the feeder circuit of the electromagnetic-coupling module via electromagnetic coupling and that supplies a received reception signal to the feeder circuit via the electromagnetic coupling.

Abstract: A frequency stabilization circuit includes a primary side circuit connected to a feeder circuit, and a secondary side circuit electromagnetically coupled to the primary side circuit. The primary side circuit is a series circuit including a first coiled conductor and a second coiled conductor, and the secondary side circuit is a series circuit including a third coiled conductor and a fourth coiled conductor. An antenna element is connected through a high pass filter to a first antenna connection portion set as a connection point of the first coiled conductor and the second coiled conductor. Additionally, the antenna element is connected through a low pass filter to a second antenna connection portion set as a connection point between the second coiled conductor and the fourth coiled conductor.

Abstract: A capacitive loop antenna is disclosed. The capacitive loop antenna comprises a shorting-to-ground terminal, for providing grounding, a feeding terminal, for receiving a first radio frequency feeding signal, and a first capacitive loop. The first capacitive loop comprises a first connection element, a first radiator, comprising an end electrically connected to the feeding terminal via the first connection element, to feed the first radio frequency feeding signal to the first radiator, a second connection element, and a second radiator, comprising an end electrically connected to the shorting-to-ground terminal via the second connection element. A first section of another end of the first radiator is capacitively coupled with the second radiator.

Abstract: A method for the impedance matching of front end circuits to antennas in mutually different transmission and reception frequency ranges is specified. A suitable matching circuit is furthermore specified. The impedance matching in a transmission frequency range is determined such that an excessively poor impedance matching in a reception frequency range is prevented in this case.

Abstract: An automatic antenna impedance matching method for a radiofrequency transmission circuit. An impedance matching network is inserted between an amplifier and an antenna. The output current and voltage of the amplifier and their phase difference are measured by a variable measurement impedance, and the complex load impedance of the amplifier is deduced from this; the impedance of the antenna is calculated as a function of this complex impedance and as a function of the known current values of the impedances of the matching network. Starting from the value found for the impedance of the antenna, new values of the matching network are calculated that allow the load to be matched to the nominal impedance of the amplifier. The measurement impedance has a value controllable by the calculation processor according to the application and notably as a function of the operating frequency and of the nominal impedance of the amplifier.

Abstract: According to various aspects, exemplary embodiments are disclosed of antenna assemblies and methods of manufacturing the same. In an exemplary embodiment, a method generally includes forming (e.g., molding, etc.) a sleeve over and/or between a first portion of a first component (e.g., a bushing, etc.) and a second portion of a second component (e.g., adaptor, etc.). The sleeve is coupled to the first and second portions of the respective first and second components. The method may also include removably attaching an antenna connector subassembly to the first component such that a printed circuit board assembly of the antenna connector subassembly is covered by the sleeve. The method may additionally include overmolding a sheath over the sleeve and one or more radiating elements of a multiband antenna assembly that includes the antenna connector subassembly, whereby the sleeve covers and protects the printed circuit board assembly during the overmolding.

Abstract: Various embodiments of an antenna device for a wireless terminal are disclosed. The antenna device includes a radiator configured to be extracted from/retracted into the wireless terminal, a L-C lumped circuit, and a noise removing coil coupled between the radiator and the L-C lumped circuit, to attenuate noise introduced through the radiator. The radiator may be configured as a helical coil or at least one meandering printed pattern so as to reduce its overall length while maintaining a desired electrical length. In embodiments, the antenna device is useful for UHF/VHF frequency bands. Multi-band configurations are disclosed. In one embodiment, a stainless steel tube member substantially surrounds a helical coil, and the tube member operates at a lower frequency band than the helical coil.

Abstract: An antenna apparatus for a wireless device includes a continuous metallic component electrically connected to a circuit card assembly through an interconnection, an antenna matching circuit electrically connected to the continuous metallic component, a first electrical connection between the continuous metallic component and the interconnection, and at least one additional electrical connection between the interconnection and the circuit card assembly, the antenna matching circuit and the interconnection causing the continuous metallic component to resonate at an at least one desired frequency.

Abstract: An antenna device includes an antenna element and an impedance converting circuit connected to the antenna element. The impedance converting circuit is connected to a power-supply end of the antenna element. The impedance converting circuit is interposed between the antenna element and a power-supply circuit. The impedance converting circuit includes a first inductance element connected to the power-supply circuit and a second inductance element coupled to the first inductance element. A first end and a second end of the first inductance element are connected to the power-supply circuit and the antenna, respectively. A first end and a second end of the second inductance element are connected to the antenna element and ground, respectively.

Abstract: An electronic device includes an antenna, an RF circuit, and a matching circuit. The matching circuit is configured to provide variable impedance between the antenna and the RF circuit, wherein the matching circuit includes a first element having a first terminal and a second terminal, and wherein the first terminal is coupled to the antenna; a second element having a third terminal connected to the second terminal of the first element and a fourth terminal coupled to the RF circuit; a first tuning cell connected to the second terminal of the first element and the third terminal of the second element, and comprising a first tuning element, a second tuning element and a first control element, wherein the first control element determines whether to make a first node connected between the first and second tuning elements couple to a voltage level.

Abstract: Mobile devices with conductive liquid antennas and related methods are provided. In this regard, a representative mobile device includes a first antenna having a first channel and a first liquid, the first channel defining a first interior volume, the first liquid being electrically conductive and located within the first channel, the first liquid further exhibiting a first volume smaller than the first interior volume; and a first antenna feed mounted such that, responsive to the device being in a first orientation, the first liquid electrically communicates with the first antenna feed.

Abstract: A self-configurable resonance antenna includes a main antenna for transmitting and receiving radio waves of a plurality of mutually different frequency bands, a coupling element having at least two radiating patches with different effective electrical lengths for configuring the impedance of the self-configurable resonance antenna, and a matching circuit disposed between the main antenna and the coupling element. The matching circuit has a filter, a RF detector, a switching logic and a RF switch, the RF switch switching between at least the two radiating patches with different effective electrical lengths for adjusting the main antenna operating in different frequency bands.

Abstract: An antenna (100) with an embedded wideband matching substrate (102) is provided. The substrate (102) comprises impedance matching circuitry (300) providing a low frequency (LF) matching circuit (330) and a high frequency (HF) matching circuit (340) for tri-band operation. A stripline (314) having a stripline ground (324) is disposed on the substrate. The stripline (314) provides a matching element and the stripline ground (324) provides a common ground (324) for both the HF and LF matching circuits. The substrate (102) is shaped with a tabular portion (106) which facilitates encasing the substrate (102) within a casing (118). The tabular portion (106) further provides an alignment feature for wrapping of a flexible radiating element about the casing and flexible antenna rod (126) to complete the antenna structure (100).

Abstract: An antenna is provided with improved ruggedness and flexibility through the use of an embedded substrate with impedance matching circuitry disposed thereon, and a flexible electrical interconnect. The flexible electrical interconnect is coupled between the substrate and an antenna connector. The antenna comprises a first top flexible section having the flexible radiator element, a second stiff section comprising the impedance matching circuit for multi-band operation, and a third lower flexible section comprising the flexible electrical interconnect. Portable radio products incorporating the antenna can now provide multiband capability along with protection against drop.

Abstract: A transceiving circuit (1, 1?) for contactless communication comprises transmitter means (3) being adapted to generate an electromagnetic carrier signal and to modulate the carrier signal according to transmitting data, and an antenna (5) being connected to and driven by the transmitter means (3) with the modulated carrier signal. At least one impedance-matching capacitor (C1a) is arranged serially to the antenna (5).

Abstract: A frequency stabilization device includes a first radiating element, a second radiating element, a feeding circuit connected to the first and second radiating elements, and a frequency stabilization circuit disposed between the feeding circuit and the first radiating element. The frequency stabilization circuit includes a primary-side series circuit connected to the feeding circuit and a secondary-side series circuit coupled to the primary-side series circuit via an electric field or a magnetic field. A first inductance element and a second inductance element are connected in series to each other, and a third inductance element and a fourth inductance element are connected in series to each other. The first and third inductance elements are coupled to each other, and the second and fourth inductance elements are coupled to each other.

Abstract: Provided is a method for implementing a terminal antenna, including: welding a metal shell for fixing a side key on a ground of a printed circuit board; dividing the ground of the printed circuit board into a first ground and a second ground, connecting the first ground with the second ground by at least one first isolating unit, the first ground being welded with the metal shell, and a length of the first ground being ¼ of a wavelength of a radio operating frequency band, and connecting the first ground with an antenna receiving/transmitting unit, thereby implementing a terminal antenna by taking the first ground as a radiator. The present invention also provides a corresponding terminal antenna and a terminal thereof.

Abstract: A communication device includes a ground element and an antenna element. The antenna element is adjacent to an edge of the ground element, and includes a first metal element and a second metal element. A first end of the first metal element is coupled through a first shorting element to the ground element. A second end of the first metal element is open and adjacent to the first end. The second metal element is between the first metal element and the edge of the ground element. A shorting point on the second metal element is coupled through a second shorting element to the ground element. A feeding point on the second metal element is coupled through a capacitive element to a signal source. A third end of the second metal element is adjacent to the first shorting element. A fourth end of the second metal element is open.

Abstract: A power feeding apparatus, power receiving apparatus, wireless power feeding system, and method for wireless transfer of power are provided. The power feeding apparatus includes an impedance detector, a controller, a power transmitter, a variable matching circuit, and a signal transmitter. The controller is configured to provide first control information and second control information based on an impedance detected by the impedance detector. The power feeding apparatus' variable matching circuit is configured to change a variable diameter of a power feeding coil according to the first control information. The power receiving apparatus includes a power receiver, a signal receiver, and a variable matching circuit. The power receiving apparatus'variable matching circuit is configured to change a variable diameter of a power feeding coil according to the second control information provided by the power feeding apparatus.

Abstract: An antenna switch is presented. The antenna switch can connect an antenna to either transmit circuitry or receive circuitry, depending on control signals applied to the antenna switch while presenting different impedances to a connected circuitry.

Abstract: An antenna device including: a conductive ground sheet of a substantially planar form; and a series of spaced apart conductive patches arranged substantially in a plane parallel to the conductive ground plane; a series of conductive feed interconnections electromagnetically coupled to the spaced apart array of conductive patches.

Abstract: A spiral, helical antenna is configured to produce a generally circular polarized radiation pattern covering a range of frequencies, over a ground plane. The antenna is comprised of a spring-like spiral conductor that may be held in compression by a size and shape regulating outer nonconductive membrane. The assembly may be compressed and or extended to adjust the antenna for best performance in a particular situation. The assembly may be compressed into a generally flattened state for storage and or transportation, and extended at a later time for use. Accurate antenna dimensions and good performance are afforded by the use of high quality spring materials in conjunction with precise membrane dimensions.

Abstract: A measurement bridge, in particular for a network analyzer, including a reference port, a central output port and a balun having a first balun input connector and a first and a second balun output connector. The first balun output connector is connected to a first signal path and the second balun output connector is connected to a second signal path. The central output port is connected to the first signal path, and the reference port is connected to the second signal path. The electrical parameters of the first signal path and the second signal path are approximately the same.

Abstract: There is provided a radio device including an antenna, a first impedance converting circuit, a second impedance converting circuit and a differential output unit. The antenna has a first terminal and a second terminal to receive a signal. The first impedance converting circuit and the second impedance converting circuit have a first impedance and a second impedance, respectively. The first impedance and the second impedance each are controllable. One end of the first impedance converting circuit and one end of the second impedance converting circuit are connected to the first terminal and the second terminal of the antenna, respectively. The differential output unit is connected to the other end of the first impedance converting circuit and the other end of the second impedance converting circuit through which the signal received by the antenna is input to the differential output unit, and transform the signal into a differential signal.

Abstract: Microstrip patch antenna (46), feed structure (48), and matching circuit (50) designs for an RFID tag (10). A balanced feed design using balanced feeds coupled by a shorting stub (56) to create a virtual short between the two feeds so as to eliminate the need for physically connecting the substrate to the ground plane. A dual feed structure design using a four-terminal IC can be connected to two antennas (46a,46b) resonating at different frequencies so as to provide directional and polarization diversity. A combined near-field/far-field design using a microstrip antenna providing electromagnetic coupling for far-field operation, and a looping matching circuit providing inductive coupling for near-field operation. A dual-antenna design using first and second microstrip antennas providing directional diversity when affixed to a cylindrical or conical object, and a protective superstrate (66). An annular antenna (46c) design for application to the top of a metal cylinder around a stem.

Abstract: An electronic device including a processor and an antenna device is provided. The antenna device includes a power feeding unit, a first radiation section connected to the power feeding unit, and a switching element including a first terminal electrically connected to first portion of the first radiation section, and a second terminal electrically connected to a second portion of the first radiation section. The processor uses a first resonance frequency band when the switching element is opened and uses a second resonance frequency which is different from the first when the switching element is closed.

Abstract: Disclosed in an example embodiment herein is a dual mode patch antenna designed to operate in the TM02 mode. The antenna comprising a circular patch antenna configured to operate at a first frequency, and a cylindrical matching element coupled to the circular patch antenna configured to operate at a second frequency. A feed surface is coupled to the cylindrical matching element.

Abstract: An apparatus for collecting wireless is provided. The apparatus includes an antenna and a collection circuit. The antenna generates an alternating current (AC) voltage from a radio wave. The collection circuit generates a direct current (DC) voltage corresponding to the AC voltage, determines whether the DC voltage is lower than a preset value, and changes an internal impedance of the collection circuit if it is determined that the DC voltage is lower than the preset voltage.

Abstract: A reflective impedance element is connected to a port of a composite right/left-handed transmission line, and operates at a predetermined operating frequency so that an impedance when the reflective impedance element is seen from the port becomes a pure imaginary number jB. A reflective impedance component is connected to a port of the composite right/left-handed transmission line, and operates at the predetermined operating frequency so that an impedance when the reflective impedance element is seen from the port becomes ?jB.

Abstract: An RFID device for sensing the properties of a material in proximity to a UHF tag. The RFID device includes a microchip, an antenna operatively coupled to the microchip, and an impedance transforming section operatively coupled to the microchip and to the antenna. Changing an electrical characteristic of at least one component of the RFID device results in a complex reflected signal at a reader device representing a sensed state of a material in proximity to the RFID device.