336results about "Waveguide mouths" patented technology

A dual-band antenna matching system and a method for dual-band impedance matching are provided. The method comprises: accepting a frequency-dependent impedance from an antenna; and, selectively supplying a conjugate impedance match for the antenna at either a first and a second communication band, or a third and a fourth communication band. More specifically, the method comprises: tuning a first tuning circuit to a first frequency; and, simultaneously tuning a second tuning circuit to a second frequency. In response, a conjugate match is supplied to the antenna in the first communication band in response to the first frequency. Simultaneously, the antenna is matched in the second communication band in response to the second frequency. When the first tuning circuit is tuned to a third frequency, and the second tuning circuit is tuned to a fourth frequency, then conjugate matches are supplied for the third and fourth communication bands, responsive to the third and fourth frequencies, respectively.

Apparatus, systems and methods to transmit power and data are provided. A particular apparatus to transmit power and data includes a transmission medium. The transmission medium includes at least one first frequency selective surface (FSS) layer, at least one second FSS layer, and a dielectric layer separating the at least one first FSS layer and the at least one second FSS layer. In a particular embodiment, the apparatus also includes a first coupler coupled to the transmission medium to send a signal along the transmission medium and a second coupler coupled to the transmission medium. The second coupler may receive signals via the transmission medium, receive power via the transmission medium to power devices coupled to the second coupler, process and send data via the transmission medium, or any combination thereof.

A system and method is provided for full-duplex antenna impedance matching. The method comprises: effectively resonating a first antenna at a frequency selectable first channel in a first frequency band; generating a first antenna impedance at the first channel frequency; effectively resonating a second antenna at a frequency selectable second channel in the first frequency band; generating a second antenna impedance at the second channel frequency; supplying a first conjugate impedance match at the first channel frequency; and, supplying a second conjugate impedance match at the second channel frequency. For example, the first antenna may be used for transmission, while the second antenna is used for received communications. The antennas effectively resonant in response to: supplying frequency selectable conjugate impedance matches to the antennas; generating frequency selectable antenna impedances; and/or selecting the frequency of antenna resonance.

A dual- or quad-ridged horn antenna with an embedded impedance matching network is provided herein. According to one embodiment, the horn antenna may include at least one pair of ridges arranged opposite one another for guiding an electromagnetic wave there between. A transmission line is coupled to a first one of the ridges for supplying power to, or receiving a signal from, a feed region of the horn antenna. To reduce impedance mismatches between the transmission line and the ridges, an impedance matching network is embedded within a second one of the ridges at the feed point. The impedance matching network reduces impedance mismatch and extends the operational frequency range of the horn antenna by providing a sufficient amount of series capacitance between the transmission line and the ridges at the feed region. As set forth herein, the impedance matching network is preferably implemented as an open-circuit transmission line stub or capacitive stub.

A circularly polarized antenna has a dielectric substrate, a ground conductor which is piled up one surface side of the dielectric substrate, a circularly polarized type of antenna element formed on an opposite surface of the dielectric substrate, a plurality of metal posts whose respective one end sides are connected to the ground conductor and penetrate the dielectric substrate along a thickness direction thereof, and whose respective other sides extend up to the opposite surface of the dielectric substrate, the plurality of metal posts configuring a cavity by being provided at predetermined intervals so as to surround the antenna element, and a conducting rim which short-circuits the respective other end sides of the plurality of metal posts along an array direction thereof, and is provided so as to extend by a predetermined distance in a direction of the antenna element at the side of the opposite surface of the dielectric substrate. With the circularly polarized antenna, a radiation characteristic of the antenna can be made to be a desired characteristic by preventing a surface wave from being generated by means of the cavity and the conducting rim, and a frequency characteristic of the antenna gain can be made to have a sharp notch within the RR prohibited band by utilizing a resonance of the cavity. Accordingly, the circularly polarized antenna is effective for reducing radio interference with the EESS or radio astronomical services.

A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone.

A radio frequency coupling structure is arranged to couple a radio frequency signal between a first side of the radio frequency coupling structure to a second side of the radio frequency coupling structure opposite to the first side. The radio frequency coupling structure comprises a dielectric layer, a first electrically conductive layer comprising a first transition structure, a second electrically conductive layer comprising a second transition structure, and an integrated waveguide structure formed by an array of electrically conductive vias extending through the dielectric layer from the first to the second electrically conductive layer to enclose a portion of the dielectric layer. The portion is arranged to guide the radio frequency signal between the first transition structure and the second transition structure.

The invention provides a waveguide flat array antenna, which has the characteristics of broadband and high-efficiency feed. Rectangular open waveguides 11 are used as radiation units; four rectangular open waveguides in one group form a sub array, and are arranged in a 2*2 rectangle and supplied with broadband equal-amplitude in-phase feed by a rectangular cavity 21; and in order to ensure efficient transmission of electromagnetic wave, the joint of each rectangular open waveguide 11 and the rectangular cavity 21 is provided with matched steps 13 and 23. The center of the rectangular cavity 21 is provided with a rectangular window 22 which is connected with a feed network of the next layer. In order to ensure smooth signals, a rectangular matching block 42 is arranged at the feed network corner connected with each rectangular window 22. The feed network consists of multistage parallel E-T so as to ensure that the antenna has enough bandwidth. The transceiving capacity of circularly polarized wave is realized by arranging a circularly polarized cover. Compared with the conventional flat antenna, the waveguide flat array antenna has broader bandwidth and higher feed efficiency.

A radar level gauging system comprising a microwave unit for transmitting and receiving first microwaves having a first and second distinguishable characteristics, a microwave absorber adapted to be arranged in a bottom region of the tank and adapted to absorb electromagnetic energy of microwaves having one of the first and second characteristics, and processing circuitry adapted to determine the product level based on a relationship between transmitted and received microwaves. The system thus emits microwaves in two channels, and the absorber is arranged to absorb energy in only one of the channels. Using the absorbed channel, it is possible to obtain a measurement with very limited interference from the bottom, which thus will be accurate also for levels close to the bottom. Using the unabsorbed channel, it is possible to obtain a reference measurement of the distance to the reflecting part of the absorber, thus enabling verification of the of the system.

A slot array antenna includes: an electrically conductive member having an electrically conductive surface and slots therein, the slots being arrayed in a first direction which extends along the conductive surface; a waveguide member having an electrically conductive waveguide face which opposes the slots and extends along the first direction; and an artificial magnetic conductor extending on both sides of the waveguide member. At least one of the conductive member and the waveguide member includes dents on the conductive surface and/or the waveguide face, the dents each serving to broaden a spacing between the conductive surface and the waveguide face relative to any adjacent site. The dents include a first, second, and third dents which are adjacent to one another and consecutively follow along the first direction. A distance between centers of the first and second dents is different from a distance between centers of the second and third dents.

A dielectric loaded antenna apparatus has a column-shaped loaded dielectric which is loaded on an end portion of a feeding line of the dielectric loaded antenna apparatus. The loaded dielectric has an inclined radiation surface which is inclined from a surface perpendicular to an axial direction of the loaded dielectric. A cross section of the loaded dielectric perpendicular to the axial direction of the loaded dielectric has a shape of one of a circle, ellipse and polygon. The feeding line is a waveguide which includes a radiation waveguide and a feeding waveguide. The radiation waveguide has an axis parallel to the axial direction of the loaded dielectric and includes an opening for feeding an electromagnetic wave to the loaded dielectric. The feeding waveguide feeds the electromagnetic wave to the radiation waveguide.

The invention belongs to the technical field of design and manufacture of millimeter-wave circularly-polarized antennas, aims to solve the problem of difficulty in integration of broadband, high efficiency and arraying of existing millimeter-wave circularly-polarized antennas, and provides a broadband circularly-polarized panel array antenna. The broadband circularly-polarized panel array antenna has the advantages that a novel 90-degree phase delay line is used for feed of a cross recess, four parasitic patches added above the cross recess are used for improving antenna unit gain and 3dB axial ratio bandwidth, and the designed 90-degree phase delay line has three independent branches which are used for phase delay, amplitude compensation and matching adjustment respectively; a group of short-circuit metal holes are designed beside a strip line to effectively inhibit spreading of a TEM (transverse electromagnetic) mode outside a feed network area, unit cross coupling is reduced greatly, and arraying performance is guaranteed; the antenna made of a multilayer PCB (printed circuit board) has the advantage of low cost and is applicable to millimeter-wave large-scale circularly-polarized arraying, and the problem of difficulty in integration of circularly-polarized antenna efficiency and the axial ratio bandwidth on millimeter-wave frequency bands is solved.

A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone and with changing range gates in each of the antenna beams the coverage of the detection zone can be varied.

The invention relates to a one-point short-circuit circularly polarized antenna with a low-profile cavity-backed annular slot. The existing cavity-backed circularly polarized antenna based on one-point short-circuit of the annular slot has complex structure, large volume, inability to planar integration, and high cost. In the present invention, a metal layer is plated on both sides of the dielectric substrate, and the upper metal layer is etched with a microstrip line for power feeding and a common ground coplanar waveguide transmission line, and the middle metal strip of the coplanar waveguide transmission line extends outwards as a microstrip line . Through the upper metal layer, the dielectric substrate and the lower metal layer, a plurality of metallized through holes arranged in a circle are opened to form a cavity, and the coplanar waveguide transmission line extends into the cavity. The lower metal layer is etched with a circular radiation slit with a short circuit in the area corresponding to the cavity. Compared with the conventional cavity-backed circularly polarized antenna composed of a metal cavity, the present invention is manufactured by common PCB technology, has low manufacturing cost, can be seamlessly integrated with a microstrip circuit, and improves system integration.

The invention discloses a millimeter-wave fan beam cylindrical Luneberg lens antenna based on a metal perturbation structure. The antenna achieves a pitch beam width reaching 104 degree and azimuth plane +/- 60 degree scanning. The antenna comprises a cylindrical Luneberg lens located between an upper metal flat plate (1) and a lower metal flat plate (2); an arc feed source array (3) located on the focal line of the cylindrical Luneberg lens; and the metal perturbation structure (5) arranged on the radiating aperture of the lens circumferentially. The cylindrical Luneberg lens comprises a cylindrical filling dielectric sheet (4). The filling dielectric sheet uses a low-loss microwave substrate as a substrate material and is divided into five layers according to a concentric circle structure from inside to outside. Respective layers have through-holes with different densities. The through-holes are filled with air. The antenna is light in weight and easy to process, greatly increases the pitch surface beam width, realizes a wide beam scanning range in the horizontal plane so as to be better applied to a multi-beam directional communication and beam scanning antenna, especially the millimeter wave high-frequency band and applications requiring axial grouping.

The invention relates to a frequency variable coupling feeding device used in boardband microstrip antenna which includes coplanar waveguide and coupling slit thereon, and a varicap device whose two pins are fixed to two sides of the center of the coupling slit of the coplanar waveguide. Feeding manner is changed by regulating the varicap device, and the provided device can switch frequency resonant points of the antenna in a very wide band thereby realizing frequency conversion when feeding for the antenna; in the state of fixed antenna dimension and fixed shape of the coupling slit, the invention can improve the antenna performance such as better bandwidth and plus only by regulating the varicap device. The invention provided device is fit for the broadband or multi-frequency wireless communication field.

The invention relates to a single-point coaxial feeding low-profile cavity-backed circularly polarized antenna. Ordinary cavity-backed circularly polarized antennas have complex structures, large volumes, and high manufacturing costs. In the invention, metal layers are plated on both sides of the dielectric substrate, and the upper metal layer is etched with two mutually perpendicular rectangular slits for radiating energy. Through the upper metal layer, the dielectric substrate and the lower metal layer, a plurality of metallized through holes arranged in a circle are opened to form a circular cavity. At the appropriate position of the angle bisector of two mutually perpendicular elongated radiation slots in the cavity area, a coaxial probe is connected through the lower metal layer and the dielectric substrate as a feed structure. Compared with the existing cavity-backed circularly polarized antenna composed of a metal cavity, the cavity of the present invention is manufactured by common PCB technology, so that the antenna has a small profile and low manufacturing cost.