Abstract: The invention relates to a radiofrequency transmission device comprising an electrical board, a transmission line, and an electroconductive fastening element which is intended to fasten the electrical board to a support, the transmission line being electrically coupled to the fastening element such that the fastening element forms at least one first radiating portion of an antenna arranged so as to emit and/or receive radiofrequency signals travelling along the transmission line.

Abstract: An electronic device is provided. The electronic device includes a first substrate, a second substrate, a liquid crystal layer, a feeding structure, and a plurality of phase shifter electrodes. The liquid crystal layer is disposed between the first substrate and the second substrate. The feeding structure is disposed on the first substrate to transmit a radio frequency signal. The plurality of phase shifter electrodes are disposed on the first substrate and at least one of the plurality of phase shifter electrodes is for receiving the radio frequency signal. In addition, at least one of the plurality of phase shifter electrodes is electrically connected to a thin film transistor.

Abstract: Disclosed are an antenna reflective net and an antenna reflective net mounting structure. Sliding slots are provided on side walls of the antenna reflective net mounting structure respectively. Protrusions of a base of the antenna reflective net slide into the sliding slots, and the size of the sliding slot is adapted to that of the protrusion. The protrusion is fixed in the sliding slot along a direction vertical to the sliding slot. A baffle block is provided at a distal end of the sliding slot. The baffle block restricts the protrusion from sliding along the direction of the distal end. Moreover, a limit part of an elastic pressing member of the antenna reflective net mounting structure restricts the protrusion from sliding along the direction of the entrance end of the sliding slot after the protrusion enters the sliding slot. Therefore, the antenna reflective net is easily mounted in the antenna reflective net mounting structure with high stability.

Abstract: Disclosed herein is a method and system for using ferrite cores to suppress harmonic radiation with microstrip patch antennas. In certain embodiments, the ferrites cores exemplified herein significantly suppressed second and third harmonic radiation generated by RF components coupled to the microstrip patch antenna.

Abstract: An indoor Yagi antenna includes an antenna body, a PCB substrate and an antenna bracket. The antenna body includes an upper shell and a lower shell which form an inner cavity containing the PCB substrate including an end connected to a signal director, an end connected to a signal reflector, a middle section connected to a main antenna oscillator, the portions of the three which are electrically contacted with the PCB substrate respectively, are wrapped by the upper shell and the lower shell, the bottom surface of the lower shell is provided with a feed line terminal block connected to the PCB substrate; the antenna bracket includes a bracket rod that can be flexibly bent, the top end of the bracket rod is provided with a universal adjusting mechanism connected to the lower shell, and the bottom end of the bracket rod is provided with a bracket base.

Abstract: A dual band antenna providing a high forward gain includes a radiator, a director disposed in front of the radiator, and a reflector disposed behind the radiator. A dual resonance notch antenna including a conducting plate and a feeding portion is used as the radiator. The director includes a conducting plate and a short-circuiting portion and the reflector includes a conducting plate and a short-circuiting portion. Each conducting plate is disposed such that the direction of a normal to the conducting plate is a front-rear direction. Two slots having different lengths are formed in each conducting plate so as to be aligned with each other. The feeding portion is disposed in one of the slots. Each short-circuiting portion is disposed in one of the two slots at a position corresponding to the feeding portion.

Abstract: A mobile device with an underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms. The portable device may be wearable.

Abstract: The outdoor antenna includes multiple directors located respectively on a main rod and two assistant rods, and an inner-swing arm and an outer-swing arm fixed on the main rod and coupled with two ends of the assistant rods. When the inner-swing arm and the outer-swing arm are expanded, the assistant rods are fixed on two sides of the main rod; when the inner-swing arm and the outer-swing arm are folded, the assistant rods are positioned in parallel with the main rod. In use, the inner-swing arm and the outer-swing arm are expanded to allow the assistant rods to move toward the two sides of the main rod and maintain in a certain spatial distance to receive as many radio signals as possible. During transportation and storage, the assistant rods can lean against two sides of the main rod, so that occupied space is reduced to achieve usability.

Abstract: An antenna device includes a first substrate, a feeder line which is disposed in the first substrate, a grounding conductor which is disposed in the first substrate, a first radiation element which is electrically connected to the feeder line in the first substrate, a second radiation element which is electrically connected to the grounding conductor and is disposed substantially in parallel with the first radiation element in the first substrate, a first reflector which is disposed in the first substrate, and a second reflector which is disposed in the first substrate so as to be separated by a predetermined distance from the first radiation element or the second radiation element in at least one of longitudinal directions of the first radiation element and the second radiation element.

Abstract: In each parasitic element array, each of parasitic elements has a strip shape substantially parallel to a longitudinal direction of a dipole antenna, and the parasitic elements are formed at predetermined intervals. For example, the interval is set to be equal to or smaller than ? of a wavelength ? of a high-frequency signal to be fed to a feeder line. The parasitic element arrays are arranged so as to form a plurality of pseudo-slot openings that allow a radio wave from the dipole antenna to propagate therethrough as magnetic currents.

Abstract: An electrically-shortened Yagi antenna includes a boom, a first electrically-shortened end element mounted on the boom, a second electrically-shortened end element mounted on the boom; and an electrically-shortened driven element mounted on the boom and electrically shortened less than the first and second electrically-shortened end elements.

Abstract: The invention relates to data transmission in radio communication networks, the object of the invention multiband directional antenna comprising a multidimensional array structure and having more than one director working in active or passive mode according to the working frequency.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A multi-band antenna is provided in the present invention. The multi-band antenna includes a substrate, a first antenna module and a second antenna module. The first antenna module with an Industrial Scientific Medical band is formed on the substrate. The second antenna module with a V band is formed on the first antenna module. A vertical projecting plane of the second antenna module on the substrate is overlapped with the substrate. The second antenna module further includes at least two antenna units. Center lines of the antenna units are coplanar and are parallel each other with a distance or crossed at a point with an included angle. A height of each antenna unit is equal to an odd multiple of one-quarter effective wavelength.

Abstract: Some embodiments provide a relatively small antenna apparatus that acts as a passive repeater. The antenna apparatus can be designed to facilitate radio frequency (RF) signal gain for a collection or range of frequencies. In some embodiments, the antenna apparatus is placed near a device with a wireless receiver and/or transmitter, where the antenna apparatus causes increased RF signal intensity at the device by coupling RF signals from a proximate area of higher RF signal intensity into the area around the device. Accordingly, in some instances, an embodiment of the antenna apparatus can be used to increase the RF signal intensity in a null spot or dead spot by coupling RF signal energy from an area proximate to the null spot that has higher RF signal intensity.

Abstract: An electromagnetic bandgap structure comprising a progressive cascade of a plurality of patterns of cells. The cells of each pattern are dimensioned so that each pattern has a reflection phase response centered at a different, but closely-spaced, frequency compared with the reflection phase response of an adjacently positioned pattern, so that the combined reflection phase response of the plurality of patterns provides a continuous wideband operational range.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A planar directional antenna including a substrate, a metal layer, a master antenna, and an auxiliary antenna is provided. The substrate has a first surface and a second surface. The metal layer is disposed on the second surface of the substrate, and an upper edge of the metal layer forms a concave parabolic curve. The master antenna is disposed on the substrate and located within a predetermined range of the focus of the concave parabolic curve. The auxiliary antenna is disposed on the substrate and opposite to the master antenna so that the planar directional antenna generates a beam toward a radiation direction.

Abstract: A dual radiation patterns antenna is provided in the present invention. The dual radiation patterns antenna includes a substrate, a first antenna unit and a second antenna unit. The substrate has a first surface and a second surface opposite to the first surface. The first antenna is formed on the first surface of the substrate and used to radiate a first radiation pattern. The second antenna is formed on the second surface of the substrate and used to radiate a second radiation pattern. A first vertical projecting plane of the first antenna unit on the second surface is overlapped with the second antenna unit completely or partially. A second vertical projecting plane of the second antenna unit on the first surface is overlapped with the first antenna unit completely or partially. The first radiation pattern and the second radiation pattern are perpendicular each other.

Abstract: A device for operating an RFID writing/reading device with transmitted signal suppression includes the RFID writing/reading device and a reflection modulator. The RFID writing/reading device includes a transmitter, a receiver with a signal processor, a directional coupler with a first, a second, a third and a fourth port, and an antenna. The reflection modulator is connected to the fourth port of the directional coupler. The reflection modulator includes a first setting element and a second setting element. The reflection modulator is configured to reflect a copy of a transmitted signal from the RFID writing/reading device, the amplitude and phase of which copy have been weighted, to the directional coupler. The directional coupler is configured to add the weighted copy of the transmitted signal to a received signal from the antenna in the directional coupler.

Abstract: Systems and methods which utilize a current null cut reflector dipole antenna configuration are shown. According to embodiments, a plurality of current null points are identified with respect to an antenna element reflector configuration whereby a reflector is provided which terminates at the identified current null points. Accordingly, a noncontiguous reflector is provided in current null cut reflector dipole antenna elements. The discontinuity in the noncontiguous reflector is utilized for disposing signal feed paths providing a feed network to the dipole antenna element of the current null cut reflector dipole antenna. Accordingly, current null cut reflector dipole antennas of embodiments may be provided in configurations which are relatively simple and inexpensive to manufacture, such as two-sided printed circuit board configurations.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A slot-fed Yagi aerial includes: a cable, a reflector, an active dipole and directors, wherein, the reflector, the active dipole, etc. are provided on a support tube; the feeding section of the Yagi aerial is of a shielded slot structure in which the distance between the ends of the slot is approximately one half of the wavelength of the electromagnetic signal desired to be received; the two pieces of thin metal rods composing the half wavelength dipole are located at two external sides of the slot; the outer conductor of the cable is connected to one side of the slot, and the inner conductor of the cable is connected to the other side of the slot or the inner conductor of the cable isolated by a dielectric layer is wound around at the other side of the slot, so as to realize a direct connection feed or a coupling feed.

Abstract: A sensor element for opening of doors and gates, with the aim being to allow production of a detection field for identification of people and/or static objects by means of an antenna element, the antenna element is intended to have a flat antenna unit, with a pin-like antenna projecting at least approximately vertically from the flat antenna unit.

Abstract: The invention relates to data transmission in radio communication networks, the object of the invention multiband directional antenna comprising a multidimensional array structure and having more than one director working in active or passive mode according to the working frequency.

Abstract: A dual polarized variable beam tilt antenna having a superior Sector Power Ratio (SPR). The antenna may have slant 45 degree dipole radiating elements including directors, and may be disposed on a plurality of tilted element trays to orient an antenna boresight downtilt. The directors may be disposed above or about the respective dipole radiating elements. The antenna has a beam front-to-side ratio exceeding 20 dB, a horizontal beam front-to-back ratio exceeding 40 dB, a high-roll off, and is operable over an expanded frequency range.

Abstract: A portable Yagi antenna kit for being frequency/wavelength adjustable by virtue of being knockdownable, wherein the Yagi antenna is for mounting to a mast. The antenna includes a boom, a reflector element, a driven element, and a director element. The reflector element, the driven element, and the director element each extend outwardly from the boom, respectively. The boom, the reflector element, the driven element, and the director element are each knockdownable so as to be portable and form the kit, and as such, are length adjustable, and as such, are frequency/wavelength adjustable.

Abstract: A wireless networking adapter integrated in an impedance-controlled manner with at least one directional antenna and, optionally, an omni-directional antenna to achieve maximum signal strength and integrity for a given antenna size for maximum distance performance.

Abstract: The invention provides a damage resistant antenna using a super-elastic flexible metallic material to form antenna radiating structures with a high damage threshold. The invention accounts for the electro-magnetic properties of the super-elastic flexible metallic material in the design of the shape and dimensions needed to form antenna radiating structures with consistent performance after repeated deploy, stow, and transport cycling of the antenna.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A slot-fed Yagi aerial includes: a cable, a reflector, an active dipole and directors, wherein, the reflector, the active dipole, etc. are provided on a support tube; the feeding section of the Yagi aerial is of a shielded slot structure in which the distance between the ends of the slot is approximately one half of the wavelength of the electromagnetic signal desired to be received; the two pieces of thin metal rods composing the half wavelength dipole are located at two external sides of the slot; the outer conductor of the cable is connected to one side of the slot, and the inner conductor of the cable is connected to the other side of the slot or the inner conductor of the cable isolated by a dielectric layer is wound around at the other side of the slot, so as to realize a direct connection feed or a coupling feed.

Abstract: A portable Yagi antenna kit for being frequency/wavelength adjustable by virtue of being knockdownable, wherein the Yagi antenna is for mounting to a mast. The antenna includes a boom, a reflector element, a driven element, and a director element. The reflector element, the driven element, and the director element each extend outwardly from the boom, respectively. The boom, the reflector element, the driven element, and the director element are each knockdownable so as to be portable and form the kit, and as such, are length adjustable, and as such, are frequency/wavelength adjustable.

Abstract: A mobile wireless communications device may include a portable housing having a surface, a printed circuit board (PCB) carried by the portable housing, and wireless transceiver circuitry carried by the PCB. The device may further include an antenna connected to the transceiver, and at least one electrically floating, electrically conductive, antenna beam shaping element secured to the surface of the portable housing for directing a beam pattern of the antenna.

Abstract: In one embodiment, a backfire antenna comprises a cup-shaped member defining an outer aperture and an interior cavity, a splash-plate disposed within a plane, and a dipole assembly comprising first and second arms. The first and second arms are both oriented non-parallel to the splash-plate towards the plane.

Abstract: An antenna device, includes a plurality of substrate type antennas arranged in a direction, each of the substrate type antennas includes a dielectric substrate, an electric supply line that includes a microstrip line and is formed on the dielectric substrate, and antenna elements each of which includes microstrip lines and formed on the dielectric substrate, and a reflector plate located along the direction that the substrate type antennas are arranged. The substrate type antennas each have different angles of inclination relative to the reflector plate.

Abstract: An antenna comprising a reflective surface; and an array of dipole antenna elements disposed adjacent to the reflective surface. Each antenna element has a pair of arms which together define a dipole axis, and the dipole axis is tilted at an acute angle with respect to the reflective surface. The pair of arms may be dipole arms, or may be Yagi director arms. In some embodiments the dipole axis is tilted at an acute angle with respect to a feed axis. In some embodiments the antenna element comprises a feed portion defining a feed axis; and the feed portion has a mounting portion which is tilted at an acute angle with respect to the feed axis.

Abstract: An antenna array system includes a launcher comprising an antenna configured to establish and steer a wavefront, and an array of Yagi-Uda director trains coupled to the launcher and located in the path of the wavefront. The array of Yagi-Uda director trains is configured to influence a beamwidth of the launcher. A method for beam steering includes launching a wavefront generated by an antenna through an array of director elements, and steering the wavefront. The array of director elements focuses the wavefront and influences gain of the antenna over plural steering angles.

Abstract: An open Yaggi antenna array is disclosed wherein the reflector element and parasitic director elements of the antenna array are opened in line with the feed point of the driven element so that the reflector and director elements do not cause a shunting effect on the driven element of the antenna.

Abstract: The present invention related an asymmetrical yagi representation of dipole UWB antenna herein, said antenna located on a substrate and able to be interconnected to a wireless communication apparatus. The antenna comprising: a first radiation arm, said radiation arm comprising a first feed point, a first branch, a second branch, and a first tail. The second radiation arm comprising a second feed point, a third branch, a fourth branch and a second tail. Said first tail and said second tail point are located at the farthest spot from the first radiation arm and the second radiation arm respectively.

Abstract: A device 20 includes a substrate 22 having an integrated circuit (IC) die 24 coupled thereto. A bond wire 28 interconnects a die bond pad 32 on the IC die 24 with an insulated bond pad 36. Another bond wire 38 interconnects a die bond pad 42 on the IC die 24 with another insulated bond pad 46. The bond wires 28 and 38 serve as radiating elements of a dipole antenna structure 64. A reflector 72 and director 74 can be located on the substrate 22 and/or the IC die 24 to reflect and/or direct a radiation pattern 66 emitted by or received by the antenna structure 64. A trace 82 can be interconnected between the insulated bond pads 36, 46 to form a folded dipole antenna structure 84.

Abstract: The present invention relates to an antenna system designed to be used in a wireless link, having polarization directions, respectively for reception and emission identical to the polarization directions, respectively for emission and reception, presented by a similar system placed in a geometric configuration of use that is different from that of the said first system. The invention enables identical devices to be implemented in separate items of equipment and in distinct positions while enabling the antenna pair to function correctly.

Abstract: A multi-input multi-output communication device can communicate with other communication device. The multi-input multi-output communication device includes: an antenna device configured to perform communication using a plurality of polarized waves; a transmitting circuit configured to divide data to be transmitted into a plurality of data streams, and transmit the data by multiplexing signals corresponding to the data streams on the plurality of polarized waves from the antenna device; and a receiving circuit configured to receive data by separating signals multiplexed at the other communication device from a signal received by the antenna device via the plurality of polarized waves.

Abstract: A portable/handheld device is provided having a processing module configured to selectively operate a reading mode selected from a far-field mode and a near-field mode, and a directional antenna array coupled to the processing module. The directional antenna array includes a first antenna element configured to radiate electromagnetic (EM) radiation in a far-field, and a second antenna element coupled to the first antenna element. The second antenna element is configured to radiate EM radiation in a near-field. The second antenna element includes an antenna transducer configured to selectively cancel far-field EM radiation from the first antenna element. A method of reading inductively coupled radio frequency identification (RFID) tags is also provided having the steps of scanning at least one frequency band to detect a RFID tag, and selectively radiating one of a near-field electromagnetic (EM) field and a far-field EM field based on the detected RFID tag.

Abstract: An antenna array system includes a launcher comprising an antenna configured to establish and steer a wavefront, and an array of Yagi-Uda director trains coupled to the launcher and located in the path of the wavefront. The array of Yagi-Uda director trains is configured to influence a beamwidth of the launcher. A method for beam steering includes launching a wavefront generated by an antenna through an array of director elements, and steering the wavefront. The array of director elements focuses the wavefront and influences gain of the antenna over plural steering angles.

Abstract: An adjustable-frequency two-element bowtie antenna includes a support member on which first and second non-conductive hollow element support arms are mounted. Each support arm includes first and second opposing segments. The first and second segments of each element support arm include a first section extending outwardly from the support member, a curved transition section, and a second section extending in a direction towards and joining the second section of the other element support arm. The spacing between the first sections of each segment of each element support arm increase as a function of the distance from the support member. A length-adjustable conductive member is disposed in each element support arm. Length adjusters are coupled to the conductive members to configure the lengths of antenna elements. A connector may be provided to couple a transmission-line to a pair of the conductive members comprising a driven element.

Abstract: An antenna device includes a first elliptic reflective surface, a first antenna and a second antenna. The first elliptic reflective surface has a first focus and a second focus. The first antenna is disposed on the first focus, and the second antenna is disposed on the second focus. The first antenna transmits a first signal and a second signal, and the second antenna receives the first signal and the second signal. The first signal is transmitted directly to the second antenna from the first antenna. The second signal is reflected by the first elliptic reflective surface and transmitted to the second antenna.

Abstract: A directive monopole antenna element with good RF performance (e.g., directivity and cross-polarization) and a low assembly cost is provided. The directive monopole antenna includes a dielectric support structure and one or more conductive directors coupled to the support structure. Each of the conductive directors is disposed parallel to every other conductive director and in a first plane of the support structure. The directive monopole antenna further includes a conductor coupled to an end of the support structure. The conductor has a feed probe section disposed in the first plane perpendicular to the one or more conductive directors and extending beyond the end of the support structure. The conductor further has a bent section disposed in the first plane parallel to the one or more conductive directors. The feed probe section and the bent section are electrically coupled. The directive monopole antenna element may be fed by a waveguide or a coaxial feed line.

Abstract: An antenna minimizes radiation from the outer conductor (44) of a coaxial cable (40) that is coupled to the antenna by providing a balancing tab (90) that lies near the connection (72) of the cable outer conductor (44) to the antenna. One antenna includes a Yagi structure (12) constructed of a plate of metal that forms a long boom (20) and a plurality of directors (28) extending laterally across the boom, with an electrical coupling loop mounted at a rear region of the Yagi structure. The coupling loop includes a folded dipole in the form of a metal coupling plate that forms a loop (54) with a gap (70), the loop having a laterally elongated front loop end (60). The Yagi structure is formed with a balancing tab (90) that lies forward of the loop, that has a lateral length (D) less than half that of one of the directors, and that extends from only one side (22) of the boom which is the side to which the outer coax conductor (44) is connected to the loop.

Abstract: A directive antenna operable in multiple frequency bands includes an active antenna element and at least one passive antenna element parasitically coupled to the active antenna element. The passive antenna element(s) have length and spacing substantially optimized to operate at (i) a fundamental frequency associated with the active antenna element and (ii) a higher resonant frequency related to the fundamental frequency. Spatial-harmonic current-distributions of the passive antenna elements are used to create the multiple frequency bands of operation. The directive antenna also includes devices operatively coupled to the passive antenna element(s) to steer an antenna beam formed by applying a signal at the fundamental resonant frequency, higher resonant frequency, or both to the active antenna element to operate in the multiple frequency bands.

Abstract: An antenna system with at least one tunable dipole element with a length adjustable conductive member disposed therein that enables the antenna to be used over a wide range of frequencies. The element is made of two longitudinally aligned, hollow support arms made of non-conductive material. Disposed longitudinally inside each element is a length adjustable conductive member electrically connected at one end. In the preferred embodiment, each conductive member is stored on a spool that is selectively rotated to precisely extend the conductive member into the support arm. The support arms, which may be fixed or adjustable in length, are affixed at one end to a rigid housing. During use, the conductive members are adjusted in length to tune the element to a desired frequency.