Abstract: An electronic device and a method a provided. The electronic device includes a first surface, a second surface opposite to the first surface, and a side surface that surrounds at least part of a space between the first and second surfaces; a Radio Frequency (RF) communication circuit; an antenna radiator that forms at least part of at least one of the first surface, the second surface, and the side surface and is connected to the RF communication circuit; a sensor that detects whether an external object contacts the antenna radiator; a switching circuit connected to the antenna radiator and the sensor; and a processor configured to receive a first value from the sensor when the antenna radiator and the sensor are connected to each other and to receive a second value from the sensor when the antenna radiator and the sensor are separated from each other.

Abstract: An RFID system in which at least one of the RFID tag antenna and the RFID reader antenna has an impedance matching network associated therewith in order to better match the impedances of the two antennas. This impedance matching places the antennas into an over-coupled regime once they are within a reasonable distance of each other (e.g., 2 to 50 mm). It also increases the Q-factor of the improved antenna, which can greatly increase the range at which the RFID reader can read the RFID tag. This improved RFID system may be used in any of a variety of application, including operating a door lock mechanism.

Abstract: An electronic device is provided. The electronic device includes a housing including a first face, a second face, and a side face that at least partially encloses a space between the first face and the second face, a conductive member configured to form at least a portion of the side face, a ground member, at least one communication circuit, and a conductive pattern positioned within the housing, the conductive pattern electrically connected to the communication circuit and the ground member, a first electric path positioned within the housing, and configured to electrically interconnect another end of the conductive member and the communication circuit, a second electric path configured to electrically interconnect the first electric path or the conductive member and the ground member, and a third electric path configured to electrically interconnect the first electric path or the conductive member and the ground member, and including a switching circuit.

Abstract: An electronic device may be provided with control signal generation circuitry that generates a differential pair of control signals, power supply circuitry that generates a bias voltage, and an antenna having a tuning circuit. First switching circuitry may be coupled to the power supply circuitry and the control signal generation circuitry. Second switching circuitry may be coupled to the tuning circuit. A pair of control lines may be coupled between the first and second switching circuitry. In a first switching mode, the power supply circuitry may transmit the bias voltage to the tuning circuit over one of the control lines. The bias voltage may charge storage circuitry coupled to the tuning circuit. In a second switching mode, the control signal generation circuitry may transmit the differential pair of control signals to the tuning circuit. The tuning circuit may be powered by the storage circuitry in the second switching mode.

Abstract: A FET-based RF switch architecture and method that provides for independent control of FETs within component branches of a switching circuit. With independent control of branch FETs, every RF FET in an inactive branch that is in an “open” (capacitive) state can be shunted to RF ground and thus mitigate impedance mismatch effects. Providing a sufficiently low impedance to RF ground diminishes such negative effects and reduces the sensitivity of the switch circuit to non-matched impedances.

Abstract: A PCB (Printed Circuit Board) structure at least includes a power layer. The power layer includes a first power shape and a plurality of ground elements. The first power shape is surrounded by the ground elements. The distance between any two adjacent ground elements is shorter than 0.1 wavelength of a predetermined frequency, so as to reduce electromagnetic noise radiation at the predetermined frequency.

Abstract: An antenna equipment includes an antenna and a board on which the antenna is disposed, and includes an area that is disposed on the board and that is not covered by a metal layer. A first edge of the board is a longer edge of the board in two edges of the board that are close to the antenna, a point that is on the first edge and whose distance with a current maximum point on the first edge is ?/4 is a first point, the current maximum point is on the first edge and that is closest to a feed point of the antenna, and ? is an operating wavelength of the antenna. The area that is not covered by a metal layer includes the first point, and a maximum distance from an edge of the area to the first edge of the board is ?/4.

Abstract: A system that incorporates the subject disclosure may include, for example, a method for electrically coupling a first lower frequency radiator of a first antenna to a first upper frequency radiator of a second antenna via a shared first port, electrically coupling a second lower frequency radiator of the first antenna to a second upper frequency radiator of the second antenna via a shared second port, suppressing, at least in part, with at least one first filter, first signals of the first lower frequency radiator from entering the first upper frequency radiator, second signals of the first upper frequency radiator from entering the first lower frequency radiator, or both, and suppressing, at least in part, with at least one second filter, third signals of the second lower frequency radiator from entering the second upper frequency radiator, fourth signals of the second upper frequency radiator from entering the second lower frequency radiator, or both. Other embodiments are disclosed.

Abstract: The present disclosure discloses a tunable antenna and a terminal. The tunable antenna includes a circuit board, an antenna body configured to transmit and receive a signal of a first frequency band and including a feed end and a ground pin, where the feed end is disposed on the circuit board, and an electrical tuning network, where a ground point disposed on the circuit board is connected to the ground pin of the antenna body by using the electrical tuning network, and the electrical tuning network includes an inductor and a first tunable capacitor with a tunable capacitance value, where a load value of the inductor is changed by tuning a first capacitance value of the first tunable capacitor, so that a first effective electrical length of the antenna body is changed.

Abstract: A variable capacitance device includes: capacitors coupled in series between first and second signal terminal electrodes, each of the capacitors having a dielectric layer, a lower electrode and an upper electrode, a permittivity of the dielectric layer changing according to a voltage applied to the dielectric layer, the lower and upper electrodes sandwiching the dielectric layer; resistance films coupled between the capacitors and a bias terminal electrode; a first insulating film that contacts the resistance films; and a second insulating film that covers the capacitors, the resistance films and the first insulating film, wherein: a thermal conductivity of the first insulating film is larger than that of the second insulating film; and at least one of the resistance films has a pair of connection patterns provided on both ends thereof and resistance patterns that are coupled in parallel between the connection patterns.

Abstract: The invention relates to a method for automatically adjusting one or more tunable passive antennas and a single-input-port and single-output-port tuning unit. The invention also relates to an apparatus for radio communication using this method, for instance a radio transceiver. An apparatus for radio communication of the invention comprises: a tunable passive antenna; a feeder; a single-input-port and single-output-port tuning unit; a sensing unit; a transmission and signal processing unit which applies an excitation to the input port, which delivers one or more antenna adjustment instructions, and which delivers one or more tuning unit adjustment instructions; and a control unit which delivers one or more antenna control signals to the tunable passive antenna, and one or more tuning control signals to the single-input-port and single-output-port tuning unit.

Abstract: The present document discloses an antenna unit and a terminal. The antenna unit disclosed by the present document includes an antenna circuit board, at least two neighboring antennas and an electromagnetic coupling module used for isolating coupling signal transmission between two neighboring antennas, wherein the electromagnetic coupling module is connected in series between the two neighboring antennas. The present document uses the electromagnetic coupling module to isolate signal transmission between the two neighboring antennas, i.e., electric signals in the two antennas are unable to be transmitted to opposite end, thereby reducing signal coupling between the neighboring antennas and improving the isolation between the two neighboring antennas.

Abstract: A memristive radio frequency (RF) switch circuit comprises a first metal electrode and a second metal electrode arranged on an insulating substrate and separated by an air gap, wherein the air gap is fifty nanometers (50 nm) or less, and wherein applying and removing an enabling voltage to the memristive RF switch enables the memristive RF switch to pass RF signals between the first electrode and the second electrode even when the enabling voltage is removed from the memristive switch, and wherein applying and removing a disabling voltage to the memristive switch disables the memristive switch.

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 metamaterial system of a wireless transmission apparatus comprises a metamaterial layer. The metamaterial layer comprises an array of unit cells wherein each of the unit cell comprises a surface having a metal patch with an aperture. The aperture is defined such that a periphery of the aperture is within a periphery of the surface by a spacing distance and an element is disposed within the aperture. The metamaterial system further comprises at least one input RF port placed on a backing layer disposed below the metamaterial layer such that there is no short-circuit between the conductive backing layer and the metamaterial layer; and at least one set of vias connecting the array of unit cells with the at least one input RF port.

Abstract: Provided is an electronic device in which, if an antenna element is formed on the surface of a housing, restrictions on the formation of the antenna element are less likely to arise. The following are provided: a rear case, an antenna element, and a power supply unit that supplies power to the antenna element. The antenna unit comprises a first section that is formed by applying a conductive material onto a first main surface of the rear case, and a second section. A dielectric or an insulator is interposed between the first section and the second section.

Abstract: An antenna structure includes a ground element, a first radiation branch, a first ground branch, a second radiation branch, and a second ground branch. A first end of the first radiation branch is coupled to a signal source. A first end of the first ground branch is coupled to the ground element. A second end of the first ground branch is coupled to a second end of the first radiation branch. A first end of the second radiation branch is coupled to the second end of the first radiation branch. A first end of the second ground branch is coupled to the ground element. A second end of the second ground branch is coupled to a second end of the second radiation branch.

Abstract: Provided is an electronic device in which, if an antenna element is formed on the surface of a housing, restrictions on the formation of the antenna element are less likely to arise. The following are provided: a rear case, an antenna element, and a power supply unit that supplies power to the antenna element. The antenna unit comprises a first section that is formed by applying a conductive material onto a first main surface of the rear case, and a second section. A dielectric or an insulator is interposed between the first section and the second section.

Abstract: Antenna structures and methods of operating the same of a dual-feed antenna of an electronic device are described. A dual-feed antenna includes a first antenna element coupled to a controllable circuit that is coupled a first radio frequency (RF) feed, and a second antenna element coupled to a second RF feed. The controllable circuit is configured to electrically connect the first antenna element to the first RF feed in a first antenna configuration and to electrically connect the first antenna element to ground in a second antenna configuration. During the second antenna configuration, the second antenna element is driven by the second RF feed.

Abstract: An antenna-matching device includes a first antenna terminal that is connected to a first radiating element, a second antenna terminal that is connected to a second radiating element, power feeding terminals and that are connected to a power-feeding unit C, an antenna coupling circuit (coupling inductance element L) that is connected in series between the antenna terminals, and a matching unit B that is connected between the antenna terminals and the power feeding terminals. The coupling inductance element L and the matching unit are integrally provided in a substrate. The matching circuit B is connected in series with the signal lines and includes a first resonant circuit and a second resonant circuit that have different resonant frequencies from each other and are coupled with each other. The matching unit B is connected to a power-feeding circuit that includes an RF circuit.

Abstract: A tunable antenna structure includes an antenna, a first switch circuit and a second switch circuit. The antenna structure includes a feeding point configured to feed current signal and a grounding point configured to be grounded. The first switch circuit includes a first plurality of loads and a first switch electronically coupled to the feeding point and the first plurality of loads. The first switch is configured to selectively couple one of the first plurality of loads to the feeding point. The second switch circuit includes a second plurality of loads and a second switch electronically coupled to the grounding point and the second plurality of loads. The second switch is configured to selectively couple one of the second plurality of loads to the grounding point.

Abstract: An apparatus including a plurality of radio ports for interconnection with radio circuits, a plurality of antenna ports for interconnection with antennas, interconnection circuitry configured to enable interconnection of each of one or more radio ports to different non-overlapping sets of P antenna ports, where P is controllable and P=2p, p being a whole number; and at least one control port configured to receive a control signal for determining P.

Abstract: Embodiments of the present disclosure provide a single radio frequency double-stream transmission apparatus, wherein the apparatus includes: a radio frequency link, a reactance control circuit, a parasitic reactor, an active antenna and an even number M of parasitic antennas, wherein M is larger than 2; the radio frequency link is configured to generate a radio frequency signal; the active antenna is connected with the radio frequency link, the parasitic antennas are respectively connected with the parasitic reactor, the distances from the parasitic antennas to the active antenna are the same, and the radian between adjacent parasitic antennas is 360 M ? ? degrees ; the parasitic reactor may be adjusted by the reactance control circuit to make the reactance values of any pair of parasitic antennas in mirror symmetry via the active antenna be different and the reactance values of the rest pairs of parasitic antennas in mirror symmetry via the active antenna be equal respectively.

Abstract: Embodiments of systems and methods for providing in-mold laminate antennas are generally described herein. Other embodiments may be described and claimed.

Abstract: An apparatus is disclosed configured for receiving a first alternating signal and for transmitting a second alternating signal. A detector is configured to receive a third alternating signal which is a reflection of at least a portion in power of the second alternating signal. The detector is further configured to convert the third alternating signal into a rectified signal and measure the power of said rectified signal. The measured power of the rectified signal is indicative of a power of the reflected third signal.

Abstract: A multiband switchable antenna structure includes a feeding element, a first radiation element, a second radiation element, circuit branches, and a switch circuit. A first end of the feeding element is a feeding point. A first end of the first radiation element is coupled to a second end of the feeding element. A second end of the first radiation element is open. A first end of the second radiation element is coupled to the second end of the feeding element. The circuit branches have different impedance values. The switch circuit selects one of the circuit branches as a matching branch according to a control signal. A second end of the second radiation element is coupled through the matching branch to a ground voltage.

Abstract: An electronic device may have an antenna for providing coverage in wireless communications bands of interest such as a low frequency communications band and a high frequency communications band. The antenna may have an antenna ground and an antenna resonating element. The antenna resonating element may have a high band arm that contributes to a first high band resonance in the high band and may have a low band arm that exhibits a low band resonance in the low band. A passive filter that is coupled between first and second portions of the antenna resonating element may be configured to exhibit a short circuit impedance associated with a bypass path that allows the antenna resonating element to contribute to a second high band resonance in the high band.

Abstract: An antenna apparatus is provided. A control unit adjusts an adjustment voltage outputted to a parasitic ground antenna unit according to a first voltage generated by a sensing unit and a second voltage generated by a frequency detecting unit.

Abstract: A system that incorporates the subject disclosure may include, for example, a circuit for obtaining a desired bandwidth of operation of the antenna structure, adjusting a bandwidth of the antenna to achieve the desired bandwidth of operation of the antenna structure, and tuning the antenna to a new resonant frequency to accommodate transmitting or receiving RF signals at a desired band of operation. The antenna at the new resonant frequency is at least approximately at the desired bandwidth of operation of the antenna structure. Other embodiments are disclosed.

Abstract: Electronic devices may be provided that contain wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry and antennas. An antenna may be formed from an antenna resonating element arm and an antenna ground. The antenna resonating element arm may have a shorter portion that resonates at higher communications band frequencies and a longer portion that resonates at lower communications band frequencies. A short circuit branch may be coupled between the shorter portion of the antenna resonating element arm and the antenna ground. A series-connected inductor and switch may be coupled between the longer portion of the antenna resonating element arm and the antenna ground. An antenna feed branch may be coupled between the antenna resonating element arm and the antenna ground at a location that is between the short circuit branch and the series-connected inductor and switch.

Abstract: A dual mode detection device provides both radio frequency identification and electronic article surveillance functionality. The device includes a dual mode microchip including a logic circuit and a non-volatile memory, the dual mode microchip having an electronic article surveillance (EAS) capability and a radio frequency identification (RFID) capability. An antenna is operatively coupled to the microchip for operation of the RFID capability. A coil is operatively coupled to the microchip and a capacitor is integrated into the microchip such that the coil resonates at a specific frequency, wherein exceeding a breakdown voltage of the capacitor alters a state of a memory location in the non-volatile memory.

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: An RF device includes a substrate and a series circuit of a tunable RF component and a DC blocking capacitor. The series circuit is arranged on the substrate and couples an RF signal terminal to a fixed voltage terminal that is electrically isolated from the RF signal terminal. The tunable RF component is coupled to the RF signal terminal, the DC blocking capacitor is coupled to the fixed voltage terminal and a driver terminal is coupled to the tunable RF component.

Abstract: An antenna system, which is coupled to one or more first transceivers for processing signals according to one or more protocols, respectively, and to a second transceiver for performing a function in conjunction with at least one of the one or more protocols, is provided. The antenna system includes a first antenna, a second antenna, a circuit coupled to the first and second antennas, and a controller configured to control the circuit for enabling beam forming and beam steering or for enabling the function in conjunction with the at least one of the one or more protocols. The circuit includes a phase shifting block configured to provide multiple phase shifts between a first radiation pattern associated with the first antenna and a second radiation pattern associated with the second antenna to generate multiple combined radiation patterns corresponding to the phase shifts, respectively, for the beam forming and beam steering purposes.

Abstract: A wireless communication apparatus for performing wireless communication using an antenna selected from a plurality of antennas. A received power detection unit detects received power received by an antenna selected from the plurality of antennas. A reflected power detection unit detects transmitted reflected power of the selected antenna. A switching unit switches an antenna used for communication to another antenna based on a variation of the received power detected by the received power detection unit and an amount of electric power of the reflected power detected by the reflected power detection unit.

Abstract: An antenna device includes an impedance-matching switching circuit connected to a feeding circuit, and a radiating element. The impedance-matching switching circuit matches the impedance of the radiating element as a second high frequency circuit element and the impedance of the feeding circuit as a first high frequency circuit element. The impedance-matching switching circuit includes a transformer matching circuit and a series active circuit. The transformer matching circuit matches the real parts of the impedance and matches the imaginary parts of the impedance in the series active circuit. Thus, impedance matching is performed over a wide frequency band at a point at which high frequency circuits or elements having different impedances are connected to each other.

Abstract: An antenna structure includes a feed section, a ground section, a common section, a first radiator, a second radiator, and a third radiator. The common section is electrically connected to the feed section, and the third radiator is electrically connected to the ground section. The first radiator, the second radiator, and the third radiator are all connected to the common section. The second radiator is spaced from the third radiator to allow current to be coupled from the second radiator to the third radiator.

Abstract: Disclosed is a beam steering antenna structure, including two parallel metallic boards, an antenna perpendicularly disposed between the two metallic boards, a plurality of substrates perpendicularly disposed between the two metallic boards and radially disposed around the antenna, and a bias voltage circuit. Each of the substrates has a plurality of metal units cyclically aligned thereon, and each of the metal units includes two metallic regions oppositely disposed and in no contact with each other and a transistor disposed between the two metallic regions for coupling the two metallic regions. The transistors are electrically connected to the bias voltage circuit to thereby control the steering direction of beam radiation by switching the transistors.

Abstract: A wireless communication device includes a cover, an antenna, and an adjusting member. The adjusting member is slidably mounted to the cover and is made of non-conductive materials. The antenna includes a radiator, the radiator is mounted on the cover and is shielded by the adjusting member. The adjusting member slides relative to the cover to shield different areas of the radiator.

Abstract: A distributed load monopole antenna system is disclosed that includes a monopole antenna comprising a radiation resistance unit coupled to a transmitter base, an adjustment unit, a current enhancing unit and a conductive mid-section. The radiation resistance unit includes a radiation resistance unit base that is coupled to ground, and includes a plurality of windings of an electrically conductive material. The adjustment unit is coupled to at least one of the plurality of windings of the radiation resistance unit, and is coupled to ground for selectively adjusting an operating frequency of the antenna. The current enhancing unit is for enhancing current through the radiation resistance unit, and the conductive mid-section is intermediate the radiation resistance unit and the current enhancing unit.

Abstract: A method and apparatus for providing power to e.g., a chargeable device via a radio frequency link. In one aspect, a method of providing power to a chargeable device via radio frequency link comprises generating a substantially un-modulated signal. The method further comprises radiating a substantially un-modulated radio frequency (RF) signal to the chargeable device via a transmit antenna based on the substantially un-modulated signal. The method further comprises powering or charging the chargeable device with power delivered by the substantially un-modulated RF signal.

Abstract: An apparatus and method for measuring the concentrations of oil, water and/or hydrates in a multiphase production fluid flow comprises measuring the complex permitivities, both real and imaginary parts, of the flow at at least two frequencies. One dispersive and one non-dispersive frequency are used. In one embodiment at least three frequencies may be selected, one of which is below about 1 MHz while the other two are within the dispersive and non-dispersive ranges for water. In this embodiment water may be distinguished from hydrates and both measured simultaneously.

Abstract: An antenna arrangement includes a switch having an open state and a closed state, a first antenna that operates as a first active driven element in a first frequency band in response to the switch being in the open state, and a second antenna that operates as a second active driven element in a first frequency band in response to the switch being in the open state. The closed state configures the first antenna and the second antenna to operate in a second frequency band different from the first frequency band by operatively coupling a first impedance between the first antenna and a radio frequency ground, and by operatively coupling a second impedance between the second antenna and the radio frequency ground. The first antenna functions as a parasitic element in the second frequency band and the second antenna functions as an active driven element in the second frequency band.

Abstract: A transmitter front-end for wireless chip-to-chip communication, and for other, longer-range (e.g., several meters or several tens of meters) device-to-device communication is disclosed. The transmitter front-end can include a plurality of reflector power amplifiers implemented on an IC chip and an on-chip or on-package antenna for wireless transmitting a signal to another IC chip or device. The plurality of reflector power amplifiers can reflect the radiation of the on-chip or on-package antenna in a particular pattern such that the effective radiation pattern is reinforced in a desired direction and suppressed in an undesired direction. This helps to reduce the required output power of the transmitter front-end and mitigate interference with other potential wireless chip-to-chip or longer-range communications.

Abstract: A three-dimensional multiple spiral antenna includes a substrate, a plurality of spiral antenna sections, and a feed point module. The substrate has a three-dimensional shaped region and each spiral antenna section is supported by a corresponding section of the three-dimensional shaped region and conforms to the corresponding section of the three-dimensional shaped region such that, collectively, the spiral antenna sections have an overall shape approximating a three-dimensional shape. The feed point module is coupled to a connection point of at least one of the spiral antenna sections.

Abstract: An electronic device may include an adjustable power supply, at least one antenna, and associated antenna tuning circuitry. The antenna tuning circuitry may be an integral part of the antenna and may include a control circuit and at least one tunable element. The tunable 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. The power supply may provide power supply voltage signals to the antenna tuning circuitry via inductive coupling. The power supply voltage signals may be modulated according to a predetermined lookup table during device startup so that the control circuit is configured to generate desired control signals. These control signals adjust the tunable element so that the antenna can support wireless operation in desired frequency bands.

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: A built-in antenna apparatus for a electronic device is provided. The antenna apparatus comprises a PCB with conductive and non-conductive areas. An antenna radiator is disposed at the non-conductive area of the PCB; the antenna radiator has a feeding portion and at least a first radiating portion configured in a first pattern branched from the feeding portion and has an end portion electrically connected to the conductive area. At least one capacitor is electrically connected in series within the first radiating portion. A resonant frequency of the first radiating portion is a function of a capacitance value of the at least one capacitor. The antenna can be provided in a smaller size for a given frequency band due to the capacitance. A second antenna radiator branched from the feeding portion can also be provided for operation at a different frequency band.

Abstract: In a typical system a combination of filters (BAW, SAW, etc) and an antenna are configured to achieve frequency filtering effect and efficient transmission and reception of communication signals. Wireless communication systems require specific bandwidth and out-of-band rejection; typically this metric is characterized in frequency roll-off in units of dB/MHz. This number is distributed between the antenna and filter, with the antenna contributing little to date to the filtering effect. Loss and cost penalties are incurred when multi-mode systems are designed which require additional rejection from the filter elements. Described here is a method of designing antennas to reduce the amount of rejection and complexity from the filter system. A superposition of a symmetrical frequency response from the antenna structure coupled with a non-symmetrical frequency response from a counterpoise structure generates increased rejection of out-of-band components.

Abstract: A multi-frequency antenna includes a ground layer, at least one antenna unit and at least one antenna network. The antenna unit has its one end electrically connected to the ground layer and its other end electrically connected to the antenna network for generating at least one first resonance frequencies. The antenna network includes at least one feeding circuit, and at least one resonance unit. Each resonance unit includes at least one resonant segment. Each resonant segment is electromagnetically coupled with the adjacent ground layer to generate at least one second resonance frequency. Thus, the multi-frequency antenna is capable of generating multiple different resonance frequencies.