Abstract: An ultrasonic transducer, including a piezoelectric element with physical characteristics of radial resonant frequencies and thickness resonant frequencies, and with an upper surface and a lower surface opposite to each other through the piezoelectric element and a lateral surface connecting the upper surface and the lower surface, and an acoustic matching layer set on the upper surface of the piezoelectric element and having a first resonant matching part and a second resonant matching part, wherein a thickness of the first resonant matching part in a direction perpendicular to the upper surface is greater than a thickness of the second resonant matching part in the direction, and the thickness of the first resonant matching part matches one radial resonant frequency of the piezoelectric element and the thickness of the second resonant matching part matches another radial resonant frequency or one of the thickness resonant frequency of the piezoelectric element.

Abstract: An ultrasonic transducer includes a piezoceramic element with a first surface and a second surface opposite to each other through the piezoceramic element and a lateral surface connecting the first surface and the second surface, an acoustic matching layer with a third surface and a fourth surface opposite to each other through the acoustic matching layer and the third surface connecting with the second surface of the piezoceramic element, a first damping element with a fifth surface and a sixth surface opposite to each other through the first damping element and the sixth surface connecting with the first surface of the piezoceramic element, and a second damping element encapsulating the first damping element and the lateral surface of the piezoceramic element.

Abstract: An ultrasonic transducer includes a carrier with a first surface and a second surface which are opposite to each other, a piezoceramic element attached on the first surface of the carrier, a first acoustic matching layer with a third surface and a fourth surface which are opposite to each other, the third surface is attached on the second surface of the carrier, wherein the first acoustic matching layer includes a mesh with openings, and the thickness of first acoustic matching layer is smaller than ¼ wavelength of an ultrasonic wave emitted by the piezoceramic element in the first acoustic matching layer in an operating frequency, and a total area of the openings of mesh is larger than 30% area of the third surface of first acoustic matching layer, and a second acoustic matching layer disposed on the fourth surface of the first acoustic matching layer.

Abstract: An ultrasonic transducer includes a piezoceramic element, a first acoustic matching layer with extending sidewall attaching the lateral surface of the piezoceramic element, wherein the thickness of the first acoustic matching layer is smaller than ¼ wavelength of an ultrasonic wave emitted by the piezoceramic element in the first acoustic matching layer in an operating frequency of the ultrasonic transducer, and the height of the sidewall of the first acoustic matching layer is larger than 1/20 height of the lateral surface of the piezoceramic element, and a second acoustic matching layer attaching the first acoustic matching layer.

Abstract: An antenna device includes a circuit board and at least one chip antenna. The circuit board includes a clearance area and at least one signal feeding line disposed in the clearance area. The chip antenna includes a substrate and at least one resonance unit partially or wholly disposed on the surface of or within the substrate. The chip antenna is disposed in the clearance area of the circuit board and the resonance unit of the chip antenna is connected to the signal feeding line. A shortest distance from an edge of the clearance area to a nearest edge of the circuit board is greater than 1/10 of a smallest width of the circuit board. Therefore, the polarization direction of the chip antenna is approximately perpendicular to the upper surface of the circuit board, as well as the direction of the strongest signal strength of the radiation pattern is approximately parallel to the upper surface of the circuit board.

Abstract: A multiple-frequency antenna device includes an antenna unit and a frequency switch unit. The antenna unit includes an insulating substrate on which grounded first and second conductive layers are disposed. The first conductive layer is further connected to a radio-frequency (RF) circuit. The frequency switch unit is connected to the antenna unit in parallel, and includes a switching component, and a frequency adjustment: component connected to the antenna unit. The multiple-frequency antenna device is resonant at a first resonant frequency when the switching component is switched to a first state, and is resonant at a different, second resonant frequency when the switching component is switched to a second state.

Abstract: The present invention is a multi-frequency antenna device comprising a first electrode layer and a second electrode layer disposed on a first surface of an insulating substrate, wherein the second electrode layer is located outside periphery of the first electrode layer. A third electrode layer is disposed on a second surface of the insulating substrate, and the first surface and the second surface are separated by the insulating substrate. A conductive element penetrates the insulating substrate and is connected to the first electrode layer. A groove is disposed on a side surface and/or the second surface of the insulating substrate, and a projection of the groove on the first surface completely or partially overlaps the second electrode layer. An effective dielectric constant between the second electrode layer and the third electrode layer is changed through arrangement of the groove to adjust a resonance frequency generated by the second electrode layer.

Abstract: A multi-frequency antenna comprises a substrate disposed on a clearance area of a circuit board, and a first resonance unit and a second resonance unit located on the surface of the substrate or within the substrate. The first resonance unit is connected to a signal feeding terminal of the circuit board and connected to the second resonance unit via a first filtering element. The first resonance unit forms the first resonance frequency of the multi-frequency antenna, and the first resonance unit, the first filtering element, and the second resonance unit all together form the second resonant frequency. The first filtering element shows a high impedance towards the signal with the first resonant frequency and a low impedance towards the signal with the second resonant frequency. Thus, an antenna with multiple resonant frequencies can be obtained. The material and manufacturing costs of the multi-frequency antenna can thereby be reduced.

Abstract: A radio frequency device with mechanisms for adjustment of the impedances and frequencies of its antennas comprises a first circuit board, a radio frequency module and a second circuit board. The radio frequency module is disposed on the first circuit board that is disposed on the second circuit board. The radio frequency module comprises an antenna unit, a first frequency tuning element and a radio frequency circuitry. The antenna unit is disposed within a clearance area of the first circuit board, and connected to the radio frequency circuitry via a feeding circuit. The second circuit board comprises a second frequency tuning element that is electrically connected to the antenna unit via a ground circuit and the first frequency tuning element on the first circuit board. Thus, the resonance frequency of the antenna unit can be adjusted according to the first and the second frequency tuning element.

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.

Abstract: A miniature multi-frequency antenna, comprising at least one dielectric substrate, at least one signal electrode and at least one ground electrode. The signal electrode and the ground electrode are disposed on a substrate. The signal electrode contains at least two branches and at least one branch is partially overlapped with the ground electrode. Each interlayer region between the partially overlapped electrodes forms a specific capacitance. By utilizing this interlayer capacitive effect, the resonant frequency of lower frequency band is achieved while the size of the antenna is effectively reduced. For obtaining the resonant frequency of the high frequency bands, the design concept of PIFA is applied on other branches of the signal electrode. A miniature antenna thus obtained is capable of transmitting/receiving multi-frequency signals having the benefits of easily adjusting impedance and resonant frequency.

Abstract: A wide bandwidth antenna, wherein, at least an antenna module is provided on a substrate, said antenna module includes a plurality of antenna elements having spiral geometric patterns, that are connected one by one in series. Each antenna element is formed by an electrically conductive trace winding from outside said spiral geometric pattern to inside, then it winds back from inside to outside. A first antenna element in the antenna module is connected to a signal input terminal, and that is connected electrically to a signal transmission line.

Abstract: The present invention discloses a miniature antenna that has a simple structure, compact dimension and high efficiency. The miniature antenna is comprised of a dielectric element made of a dielectric material, having a first surface and a second surface opposite to the first surface, a first electrode layer being laid on the first surface, and a second electrode layer being laid on the second surface. The first electrode layer connected to a signal feeding line and the second electrode layer, connected to a ground plane, are partially overlapped to form a region that functions as a capacitor. Thereby, the miniature antenna can transmit and receive signals. The capacitance and resonant frequency of the miniature antenna can be adjusted via varying the pattern of the electrode layers, varying the thickness or permittivity of the dielectric element or via varying the size of the overlapping areas of the two electrode layers.

Abstract: An antenna structure includes a substrate, a signal transmission unit and at least one fixing unit. The substrate is made of a dielectric material and has at least a through hole. The signal transmission unit has a transmission path and goes through the through hole. The fixing unit is made of a flexible or deformable material, and is in contact with the signal transmission unit and the inner surface of the through hole to fix the signal transmission unit on the substrate.