Abstract: An apparatus for matching impedance for use in a wireless communication is provided. The apparatus includes a forward path carrying a transmission signal to an antenna. The apparatus further comprises a quadrature feedback path configured to extract and feed back in-phase and quadrature phase components from each of a forward signal being transmitted toward the antenna and a reverse signal reflected from the antenna. A tunable matching network (TMN) is coupled to the forward path, having a plurality of tunable elements for matching an internal impedance to an impedance of the antenna. A controller is configured to calculate TMN input impedance's amplitude and phase based on the in-phase and quadrature phase components from each of the forward signal and the reverse signal.

Abstract: An apparatus for controlling impedance in an adaptive tuning antenna circuit is disclosed, wherein a matching unit is connected to an output terminal where a coupler outputs a coupled power of a transmission signal, a controller adjusts an impedance of the matching unit to cause the reflected power outputted by the coupler to be minimized, and the controller adjusts an impedance of a tuner to allow a combined impedance of the tuner and an antenna to be equal to the impedance of the matching unit but with opposite phases, thereby adjusting the impedance of the antenna in the optimal state.

Abstract: An active antenna and associated circuit topology is adapted to provide active impedance matching and band switching of the antenna using a shared tunable component. Using a shared tunable component, such as a tunable capacitor or other tunable component, the antenna provides a low cost and effective active antenna solution. In certain embodiments, one or more passive components can be further utilized to design band switching of the antenna from a first frequency to a second desired frequency.

Abstract: An electronic device may include radio-frequency transceiver circuitry and antenna structures. The radio-frequency transceiver circuitry may transmit signals for the antenna structures that pass through electrical components such as switches. Harmonics of the transmitted signals may be generated as the signals pass through the electrical components. To reduce interference that might otherwise adversely affect sensitive receiver circuitry in the electronic device, adjustable filter circuitry may be interposed between the electrical components and the antenna structures. Control signals may adjust the adjustable circuitry in real time during operation of an electronic device to ensure that transmitted signals can pass through the adjustable filter circuitry while blocking the harmonic signals.

Abstract: An antenna tuner control system includes an RF path, a lookup table and a state table analysis component. The RF path is configured to generate an RF signal. The lookup table has a state table that correlates antenna states with impedance values. The state table analysis component is configured to generate a tuner control signal from the RF signal using the lookup table.

Abstract: In a method for operating a transponder (1, 41), the transponder (1, 4) receives a signal from a transmitter (2, 42). The signal comprises an information about a reference sensitivity and the transponder (1, 41) has an input sensitivity such that the transponder (1, 41) detects only signals above a certain power corresponding to the input sensitivity. In response to the received signal, the input sensitivity of the transponder (1, 41) is adjusted to the reference sensitivity.

Abstract: A mobile wireless communications device may include a portable housing, and an antenna carried by the portable housing. The mobile wireless communications device may further include wireless communications circuitry carried by the portable housing and an adjustable impedance matching network coupled between the wireless communications circuitry and the antenna. An audio input transducer and an audio output transducer may be carried by the portable housing. The mobile wireless communications device may further include a controller carried by the portable housing and configured to determine an acoustic coupling between the audio input transducer and the audio output transducer. The controller may further be configured to adjust the adjustable impedance matching network based upon the determined acoustic coupling.

Abstract: An antenna device of an embodiment includes: an antenna having a feeding point and an end portion apart from the feeding point, the end portion being an open end; a variable impedance matching circuit connected to the antenna at the feeding point; a probe placed in such a position that the distance from the end portion to a tip of the probe is equal to or shorter than one eighth of the wavelength corresponding to the maximum radio frequency used in the antenna device; and a controller that is connected to the probe, and controls the variable impedance matching circuit, based on an electrical signal measured with the probe.

Abstract: A modified PIFA antenna is designed for wireless local area network (WLAN) applications. The modified PIFA antenna is configured to resist detuning effects caused by use of various cable lengths and is adapted for use in the 2.4 GHz operation band. A slot extends between the ground and feed portions of the antenna for slightly increasing frequency bandwidth of the antenna.

Abstract: Real-time calibration of a tunable matching network that matches the dynamic impedance of an antenna in a radio frequency receiver system. The radio frequency receiver system includes two non-linear equations that may be solved to determine the reflection coefficient of the antenna. The tunable matching network is repeatedly perturbed and the power received by the antenna is measured after each perturbation at the same node in the matching network. The measured power values are used by an optimizer in converging to a solution that provides the reflection coefficient of the antenna. The reflection coefficient of the antenna may be used to determine the input impedance of the antenna. The elements of the matching circuit are then adjusted to match the input impedance of the antenna.

Abstract: An electronic device including a first body and a second body is disclosed. The first body includes a first system circuit board, a first grounding element, and a primary antenna. The first grounding element is disposed on the first system circuit board. The primary antenna is disposed on the first system circuit board and electrically connected to the first grounding element. The primary antenna transmits/receives at least one radio frequency (RF) signal. The second body includes a second system circuit board and a clearance area. The clearance area is on the second system circuit board, and no circuit exists in the clearance area. When the first body and the second body are stacked by parallelizing the first system circuit board and the second system circuit board, the clearance area is corresponding to the primary antenna.

Abstract: An impedance matching circuit for matching planar antennas includes a signal path with a signal path input and a signal path output. A first capacitive element with variable capacitance is connected between the signal path input and signal path output. A second capacitive element with variable capacitance is connected between the signal path and ground. A first inductive element is connected between the signal path input and ground. A second inductive element is connected between the signal path output and ground. An antenna line with an impedance between 30 and 60 ohm is connected to the signal path output.

Abstract: A tunable impedance network and a method for tuning the tunable impedance network are disclosed. In one aspect, the tunable impedance network comprises a plurality of transformers connected in series. Each transformer has a primary winding and a secondary winding. The transformers have a voltage transformation ratio of N:1 with N>1. An impedance structure, acting as a resonant circuit together with the inductance of the secondary winding, is connected at the secondary winding of each transformer. A control circuit or processor is configured to tune the imaginary part of at least one of the impedance structures so as to change its resonance frequency to mimic a reference impedance. The control circuit is further configured to tune the real part of at least one of the impedance structures so as to change its Q-factor to mimic the reference impedance.

Abstract: A printed antenna module applied to an RF detection procedure is provided. The module comprises a substrate, a ground terminal part, a feeding part, an antenna body, and a second connecting end. The substrate comprises a first surface and a second surface. The ground terminal part and the feeding part are disposed on the first surface. A first end of the feeding part corresponds to the ground terminal part. The antenna body, disposed on the first surface relative to the ground terminal part, comprises a first extending part. One end of the first extending part forms a first connecting end. The second connecting end is disposed on the first surface. The shapes of the first and the second connecting ends correspond to each other. A second end of the feeding part is connected to the second connecting end. An RF detection point is formed on the second surface.

Abstract: A method includes, during transmission and/or reception of a radio frequency signal, detecting an impedance associated with an antenna connected with a matching network; algorithmically determining a reactance value of at least one reactive element that forms a part of the matching network in accordance with the detected impedance and at least one parameter including at least one of a currently used radio frequency, at least one user/device factor, at least one radio frequency offset value, and at least one predetermined constant; and setting the value of the at least one reactive element to match the determined value.

Abstract: An antenna device that includes an antenna having a single feed and a shunt circuit. The shunt circuit includes a first shunt matching circuit causing impedance, viewed from a main path connecting the antenna and a radio frequency circuit, to be substantially infinite with respect to all frequency ranges handled by the antenna, and a second shunt matching circuit providing a predetermined impedance characteristic with respect to a first subset of the frequency ranges handled by the antenna. Each of the first and second shunt matching circuits are selectively connected to the main path, and a selection controller of the antenna device controls selection of which of the first and second shunt matching circuits are connected to the main path.

Abstract: The invention relates to a device for transmitting and/or receiving radio frequency signals comprising at least one antenna and/or at least one filter realised in printed technology on a dielectric substrate. According to the invention, this device is equipped with means for compensating the permittivity dispersions of the substrate. For this purpose, the device comprises a circuit for measuring the dielectric permittivity of the substrate able to deliver a measured permittivity value and adjustment means able to adjust the impedance of the antenna and/or the frequency response of said filter according to said measured permittivity value.

Abstract: A variable capacitance device includes a fixing member, a fixed electrode having a first end side fixed by the fixing member, an actuator element having a first end side fixed by the fixing member directly or indirectly, a movable electrode provided to connect to the actuator element directly or indirectly and disposed to approximately face the fixed electrode, and a driving section deforming a second end side of the actuator element, to change a distance between the fixed electrode and the movable electrode.

Abstract: An adjustment module, an electronic device with the adjustment module, and an antenna performance adjusting method thereof are disclosed. The adjustment module is used for adjusting an antenna module. The antenna module is disposed in the electronic device and used for radiating a wireless signal. The adjustment module includes a monitoring module, a determining module, and a capacitance adjusting unit. The monitoring module is used for detecting an alternating current signal waveform when the antenna module radiates the wireless signal. The determining module receives the alternating current signal waveform and is used for generating an adjusting voltage value when the alternating current signal waveform is a non-constant amplitude. The capacitance adjusting unit is used for changing a capacitance value according to the adjusting voltage value to adjust a resonance point coordinate of the antenna module.

Abstract: Examples disclose a printed circuit board including an antenna and a matching circuit to match an impedance of the antenna. Further, the examples of the printed circuit board provide the printed circuit board is interchangeable among various types of platforms by adjusting the impedance value of the matching circuit without replacing an electrical component of the matching circuit.

Abstract: An embodiment of the present invention provides an apparatus, comprising' an RF matching network connected to at least one RF input port and at least one RF output port and 5 including one or more voltage or current controlled variable reactive elements; a voltage detector connected to the at least one RF output port via a variable voltage divider to determine the voltage at the at least one RF output port and provide voltage information to a controller that controls a bias driving circuit which provides voltage or current bias to the RF matching network; a variable voltage divider connected to the voltage detector and implemented using a 10 multi-pole RF switch to select one of a plurality of different resistance ratios to improve the dynamic range of the apparatus; and wherein the RF matching network is adapted to maximize RF power transferred from the at least one RF input port to the at least one RF output port by varying the voltage or current to the voltage or current controlled variable reactive elemen

Abstract: An apparatus including a cover defining an exterior surface of the apparatus and including a first conductive cover portion; an antenna, connected to a feed point and configured to operate in at least a first resonant frequency band; a first conductive member; a second conductive member; and wherein the first and second conductive members are configured to couple with the first conductive cover portion, the combination of the first and second conductive members and the first conductive cover portion are operable in a second resonant frequency band, different to the first resonant frequency band and are configured to be contactlessly fed by the antenna.

Abstract: An electronic device for processing radio frequency signals includes an antenna, an RF circuit, and a matching circuit. The matching circuit provides variable impedance between the antenna and the RF circuit. The antenna is capable of operating in a first frequency band or a second frequency band according to the variable impedance The matching circuit includes a first element; a second element; a first tuning cell connected to the first element and the second element, and comprising a first tuning element, a second tuning element and a first control element, the first control element determining whether to make a first node connected between the first and second tuning elements couple to a voltage level according to a first control signal; and a selecting circuit coupled to the first control element and configured to generate the first control signal so as to adjust the variable impedance.

Abstract: A circuit arrangement includes a component having a closed signal path, that closed signal path connected to a first port, a second port and at least a third port. The component has a directed signal flow of a signal applied to one of that ports. Such a coupling device can be connected to a transmitter and to a receiver path, respectively.

Abstract: An antenna structure of a Radio Frequency (RF) device includes an antenna and a transmission line circuit coupled to the antenna. The transmission line circuit includes a plurality of transmission line circuit elements and a transmission line coupling circuit that couples at least one of the transmission line circuit elements together to form the transmission line circuit based on a transmission line characteristic signal.

Abstract: An impedance matching network comprises a first and a second signal terminal and a reference potential terminal. The network further comprises a first shunt branch between the first signal terminal and the reference potential terminal, the first shunt branch comprising a variable inductive element and a first capacitive element. The impedance matching network also comprises a second shunt branch between the second signal terminal and the reference potential terminal and comprising a second capacitive element. A series branch between the first signal terminal and the second signal terminal comprises a third capacitive element. Optionally, the first, second, and/or third capacitive element may be implemented as a variable capacitive element. The variable capacitive element comprises a plurality of transistors, wherein a combination of off-capacitances Coff of the transistors provide an overall capacitance of the variable capacitive element as a function of at least two independent transistor control signals.

Abstract: An embodiment is directed to a device comprising an antenna, a chassis configured to be electrically coupled to the antenna and comprising a slot loaded with at least one tunable component, wherein: the slot is aligned along a longitudinal edge of the chassis, the slot is formed in an area of the chassis based on an identification of currents in the area, and the antenna and chassis are electrically connected at a location based on the area.

Abstract: Disclosed is a wireless receiving apparatus, whereby inter-antenna interference can be reduced without inducing an increase of a mounting area due to an increase of the number of antennas, and the number of RFIC input terminals, circuit scale and power consumption can be reduced. In the wireless receiving apparatus (100), when a receiving antenna (110-1) and a down-converter (130) are connected with a multiplexer (120) therebetween, a capacity control unit (190-2) controls the capacity value of the capacity-variable parasitic element (180-2) connected to the receiving antenna (110-2) such that the communication capacity of the receiving antenna (110-1) is maximum.

Abstract: An antenna device includes a substrate, a first antenna element disposed on a surface of the substrate, a second antenna element disposed on the surface of the substrate, the second antenna element being a linear shape, a length of the second antenna element being shorter than twice a length of a side that determines a lowest operating frequency of the first antenna element, a grounding conductor disposed so as not to overlap with the first antenna element and the second antenna element, a feeder coupled to the first antenna element, a first switch and a second switch disposed at the feeder wire, a first matching element and a second matching element disposed between the feeder wire and the grounding conductor, respectively, a third switch configured to switch connecting states of the first antenna element and the second antenna element.

Abstract: A tunable impedance matching circuit is provided for matching a signal source to an impedance of an antenna. The tunable impedance matching circuit includes two terminals, a series path, and two shunt paths. The first terminal is coupled to the signal source, and the second terminal is coupled to the antenna. The series path is coupled between the first terminal and the second terminal and includes a first tunable capacitor and at least one tunable inductor. One of the two shunt paths is coupled between the first terminal and a ground end, and the other one of the two shunt paths is coupled between the second terminal and the ground end. Each of the shunt paths includes a second tunable capacitor.

Abstract: An electronic device and an antenna reception tuning method thereof are provided. The electronic device includes a first main body, a second main body, a sensing unit, and a processing unit. The second main body, including an antenna and a matching unit, is disposed on the first main body through a hinge and adapted for being opened or closed relative to the first main body. The sensing unit is disposed on the electronic device, adapted for detecting a distance between the first main body and the second main body, and generates a control signal according to the distance, wherein the distance includes an angle and an open/close state between the first and the second main bodies. The processing unit is electrically connected to the sensing unit and the matching unit, and adjusts the matching unit according to the received control signal.

Abstract: Adjustable impedance tuning circuitry includes a first impedance matching terminal, a second impedance matching terminal, and a plurality of passive components adapted to match the impedance of the first impedance matching terminal and the second impedance matching terminal. The plurality of passive components includes one or more tunable components adapted to adjust the impedance of the adjustable impedance tuning circuitry to maintain an impedance match between the first impedance matching terminal and the second impedance matching terminal over a variety of operating conditions. Each of the one or more tunable components includes one or more switches adapted to selectively alter the impedance of the tunable component. The one or more switches are integrated onto a single semiconductor die in order to facilitate the performance of the adjustable impedance tuning circuitry over a wide bandwidth.

Abstract: An NFC component includes a first interface that can be used in reader mode and is configured to be connected to an antenna via an impedance matching external circuit. A second interface can be used in card mode and in reader mode and is configured to be connected to the antenna and to the first interface via the impedance matching external circuit. An internal module includes a first detection circuit configured to deliver a first detection signal that represents the phase antenna matching quality when the impedance matching external circuit and the antenna are indeed connected between the first interface and the second interface. The internal module is further configured to deliver a check signal from at least the first detection signal.

Abstract: A mobile communication device and an impedance matching method thereof are provided. The mobile communication device includes an antenna, a power amplifier, a tunable matching circuit, a power detection circuit and a controller. The tunable matching circuit determines an output impedance encountered by a radio frequency (RF) signal transmitted by the power amplifier to the antenna when the RF signal enters the tunable matching circuit. The power detection circuit detects a forward power of the RF signal entering the antenna and a reflected power of the antenna. The controller tunes the tunable matching circuit according to a frequency range currently used by the mobile communication device, the forward power and the reflected power to steer the output impedance toward a corresponding load-pull impedance that the power amplifier has in the frequency range.

Abstract: A system that incorporates teachings of the present disclosure may include, for example, a tuning system for a communication device having an antenna where the tuning system includes at least one first tunable element connected with at least one radiating element of the antenna for tuning the antenna where the adjusting of the at least one first tunable element is based on a closed loop process, and a matching network having at least one second tunable element coupled at a feed point of the antenna for tuning the matching network based on an operational parameter of the communication device. Additional embodiments are disclosed.

Abstract: The antenna matching circuit control device with an antenna body includes a sensing module, a processing module, a power adjusting module and a frequency adjusting module. The sensing module senses an object that approaches the antenna body and outputs a sensing signal accordingly. The processing module is coupled to the sensing module and outputs a first control signal and a second control signal according to the sensing signal. The power adjusting module is coupled to the processing module and controls a power amplifier to couple with one of a plurality of first matching circuits according to the first control signal. The frequency adjusting module is coupled to the antenna body and the power adjusting module. The frequency adjusting module controls one of a plurality of second matching circuits to couple with one of the first matching circuits according to the second control signal.

Abstract: A planar antenna includes a ground plane on a substrate, a radiating element coupled to the ground plane on the substrate, and a feed line. An impedance tap point is defined by a connection between the feed line and the radiating element and the length of the radiating element defines the resonant frequency of the antenna. A first portion of the radiating element includes an impedance adjustment mechanism for defining the impedance tap point of the antenna and consequently the impedance of the antenna. A second portion of the radiating element includes a frequency adjustment section which adjusts the length of said radiating element and consequently the resonant frequency of the antenna.

Abstract: A wireless device is described. The wireless device includes an antenna. The wireless device also includes a hybrid transformer. The wireless device further includes a frequency matching termination port. The frequency matching termination port provides impedance matching with the antenna at multiple frequencies. The frequency matching termination port may include multiple resistors, inductors and capacitors that can be switched in/out.

Abstract: A technique for improving radio coverage involves using interdependently tuned directional antennas. An example according to the technique is a substrate including two antennas, a transceiver, and a connector. Another example system according to the technique is a wireless access point (AP) including a processor, memory, a communication port, and a PCB comprising a plurality of directional antennas and a radio. An example method according to the technique involves determining a voltage standing wave ratio (VSWR) and interdependently tuning a first and second directional antenna to reach an expected radiation pattern.

Abstract: An IC tag can be mounted without deteriorating appearance of a container, breakage or the like of the IC tag can be prevented and excellent wireless communication between a reader/writer becomes possible by eliminating influence of the metal container by ensuring a long communication distance to the reader/writer by allowing excellent communication properties to be exhibited even when an existing IC chip is used and mounting an insulated and sealed IC tag on a metallic cover having a low possibility of being brought into contact with other goods and equipment and being hidden by the adjacent metallic containers. The metallic cover is provided with an IC chip (41), which has a pull-tab (33), and an IC tag (40) for the IC chip (41) mounted on the tab (33), an antenna for the IC tab (40) and a matching circuit (50) for matching impedances between the antenna and the IC chip.

Abstract: The disclosure provides a device and a method for antenna impedance matching. The device comprises an application detection module, configured to detect a current state of an antenna of a terminal, and output a matching adjustment signal according to the state; an adaptive control module, configured to perform control over a process of matching adjustment in response to the matching adjustment signal; and a matching adjustable module, configured to, under control of the adaptive control module, perform matching adjustment on impedance of the antenna through an impedance matching network corresponding to the matching adjustment signal. Through the technical solution provided by the disclosure, the problem of single impedance matching mode in the prior art is solved, and further, the effect that differential matching can be performed for various application states of the terminal is achieved.

Abstract: Disclosed herein are a hybrid variable capacitor, an RF apparatus, a method for manufacturing a hybrid variable capacitor, and a method for tuning a variable capacitor. The hybrid variable capacitor used in a tunable matching network includes: a metal-insulator-metal (MIM) cap array including one or more MIM capacitors and having varied capacitance equivalent to values of a lower-bit region among digital values corresponding to capacitance to be tuned; and a MOS varactor connected in parallel to the MIM cap array and having varied capacitance equivalent to values of an upper-bit region among the digital values.

Abstract: A resonant circuit dynamic optimization system is described herein that can exhibit improved system charging functionality, can have multi-input charging functionality, and can improve the efficiency and speed of charging electronic devices. The resonant circuit dynamic optimization system can comprise at least one antenna configured to receive or transmit an electromagnetic signal, at least one variable component, and at least one dynamic adjustment circuit. The dynamic adjustment circuit can adjust the variable component to thereby modify the power transfer efficiency of the electromagnetic signal.

Abstract: A mobile communication device has a number of selectable states, an antenna, and a communication circuit for transmitting and receiving communication signals. The mobile device also includes an impedance matching circuit having impedance matching networks. Each impedance matching network is associated with at least one of the selectable states of the mobile communication device and is configured to optimize the impedance match between the communication circuit and the antenna based on the selectable state of the mobile communication device with which the impedance matching network is associated. A switching network is included for coupling the antenna to the communication circuit together using one of the impedance matching networks based on a selected state of the mobile communication device.

Abstract: An antenna module includes an antenna, a tunable matching circuit, a power detector and a control unit. The antenna comprises a feeding point. The tunable matching circuit, electrically connected between the antenna and the power detector and configured to provide a loading impedance, comprises a plurality of tunable impedance elements connected to each other and electrically connected to the feeding point as well. The power detector is electrically connected between the tunable matching circuit and a power amplifier and configured to detect a power indicator. The control unit, electrically connected to the tunable matching circuit and the power detector, is configured to read the power indicator and RSSI to generate a control signal for the tunable matching circuit, which consistently changes the loading impedance to achieve impedance matching.

Abstract: A mobile terminal with an antenna apparatus is provided. The mobile terminal in one embodiment includes an antenna radiator disposed at a first end of the mobile terminal; at least one antenna modifying element disposed at a second, opposing end of the mobile terminal; and a coupling unit for fastening the first and second ends and electrically connecting the at least one antenna modifying element with the antenna device when the first and second ends are fastened. In another embodiment, a deformation detector detects at least one deformation of the mobile terminal, an antenna matching unit is electrically connectable to the first antenna radiator; and a controller is coupled to the deformation detector, for controlling an electrical connection between the antenna matching unit and the first antenna radiator when the at least one deformation is detected. The antenna matching unit may include a second antenna radiator.

Abstract: An antenna device can detect the surrounding environment and appropriately corrected and maintain stable antenna characteristics. The antenna device includes at least first and second antenna element electrodes, an antenna matching circuit provided along a wireless communication signal path for the first antenna element electrode, a capacitance detection circuit connected to the second antenna element electrode and operable to detect stray capacitance of the antenna element electrode using a sensing signal. A matching control circuit controls the antenna matching circuit in accordance with an output signal of the capacitance detection circuit.

Abstract: A system that incorporates teachings of the present disclosure may include, for example, a matching network for a communication device having first and second antennas, where the matching network includes a first variable component connectable and a detector. The first variable component can be connectable along a first path between the first antenna and a front end module of the communication device, where the first antenna is configured for transmit and receive operation. The detector can be connectable along a second path between the second antenna and the front end module of the communication device, where the detector obtains an RF voltage associated with the second path, where the second antenna is configured for a diversity receive operation, and where the first variable component is adjusted based on the detected RF voltage to tune the matching network. Additional embodiments are disclosed.

Abstract: A logging while drilling tool includes a directional resistivity antenna and an antenna shield having. The shield has at least one slot having at least one electrically open end formed therein. The antenna shield may include a base portion and a plurality of spaced apart fingers extending away from the base portion such that the finger ends are electrically isolated from the tool body and from one another. The antenna shield may alternatively include a plurality of spaced apart plates that are electrically isolated from the tool body and from one another. These antenna shields have been found to provide suitable physical protection for sensitive antenna components while at the same time being substantially transparent to both z-mode and x-mode electromagnetic waves.

Abstract: A communication system is provided, including an antenna, a matching network coupled to the antenna, a controller configured to host an algorithm for controlling the matching network, and a look-up table coupled to the controller. The look-up table includes characterization data according to frequency bands and conditions. The controller is configured to refer to the look-up table to determine optimum impedance for a frequency band selected under a condition detected during a time interval, and adjust the matching network to provide the optimum impedance. Part or all of the sections related to the tunable matching scheme can be integrated on a chip.