280 results about "Antenna isolation" patented technology

A wireless repeater with features that improve the server-donor antenna isolation including multi-purpose server and donor mounting plates that each carry an antenna feed circuit board and associated antenna elements mounted in a back-to-back arrangement with the duplex repeater electronics board sandwiched between the server and donor mounting plates. To improve the server-donor antenna isolation, one or both mounting plates may include corner, side tabs, which may be asymmetric, and raised walls around one or both mounting plates. In addition, the radomes covering the donor antenna and/or the server antennas may carry one or more parasitic conductors, such as a two parasitic strips arranged in parallel lines or for parasitic strips arranged in a square configuration.

An antenna configuration includes two closely spaced antennas each positioned so as to be orthogonally polarized with respect to the other. The antenna configuration increases antenna isolation and reduces electromagnetic coupling between donor side antenna and repeat side antenna. The antennas include printed dipoles connected to respective transceivers through respective baluns to balance the non-symmetrical portions of the antenna feed paths to reduce unwanted radiation therein. Printed features such as chokes and non-symmetrical and non-parallel structures are preferably included in the ground plane of a multi-layer circuit board to reduce or eliminate circulating ground currents.

When first and second housings are in an open state, first and second switches are electrically opened, and thus, a first antenna element and a ground conductor operate as a first dipole antenna, and a second antenna element and the ground conductor operate as a second dipole antenna with isolation from the first dipole antenna by the slit. When the first and second housings are in the closed state, the first and second switches are electrically closed, and thus, the first antenna element operates as a first inverted F antenna on the ground conductor, and the second antenna element operates as a second inverted F antenna on the ground conductor with isolation from the first inverted F antenna by the slit.

A noise canceler for use in a transceiver is disclosed. In an exemplary embodiment, an apparatus includes a split amplifier to output an amplified transmit signal, the split amplifier providing a first noise attenuation factor in a receive band. The apparatus also includes a transmit antenna to transmit the amplified transmit signal, the transmit antenna being isolated from a receive antenna by an antenna isolation factor that provides a second noise attenuation factor in the receive band. The apparatus also includes a noise canceler configured to subtract a detection signal from a received signal to obtain an adjusted received signal, wherein subtraction of the detection signal provides a third noise attenuation factor in the receive band, and wherein the first, second, and third noise attenuation factors combine to provide a selected amount of noise attenuation in the receive band.

A doubly balanced transceiver system having a transmit terminal (TX), a receive terminal (RX), and an an antenna terminal (ANTENNA), 180° hybrids (201, 240), 90° hybrids (204, 304, 235 and 335), a power amplifier (230, 330) and a RX/TX switch (220) for disabling the power amplifier so that signals received at the transmitter are reflected to the receive terminal (RX). The 180° hybrids (201, 240) preferably split and re-combine signals into parallel paths. A loopback test mode is preferably provided by use of an antenna isolation switch (302) to enable a power detect terminal (POWER_DETECT). This eliminates pricey and problematic GaAs switches, and allows the use of low cost silicon for the power amplifier. The doubly balance architecture also has the advantage of eliminating common-mode noise, and reflection problems with the PA gain stages. Additionally, greater power can be extracted from the power amplifier. Further the arrangement has less insertion loss compared to a GaAs switch. Also, dependant upon system specifications, it may be possible to eliminate harmonic filtering at the power amplifier output.

The invention discloses an antenna system, which comprises a first antenna, a second antenna, a third antenna, a first signal source, a second signal source, a third signal source, a first separator, a second separator and a ground plane, wherein the first antenna is connected with the first signal source and the ground plane; the second antenna is connected with the second signal source and the ground plane; the third antenna is connected with the third signal source and the ground plane; a first gap is formed between the first antenna and the second antenna; a second gap is formed between the second antenna and the third antenna; the first separator is arranged between the first gap and the ground plane, is connected with the ground plane, and is used for improving the isolation degree between the first antenna and the second antenna; and the second separator is arranged between the second gap and the ground plane, is connected with the ground plane, and is used for improving the isolation degree between the second antenna and the third antenna. The antenna system has relatively good antenna isolation degree. The invention further provides a communication terminal.

The invention combines FSO (Free Space Optical) technique with mobile communication relay technique, giving full play to the characters of the two techniques, and the products can be widely applied to mobile communication network buildup and optimization. The near end device of the system modulates mobile communication downgoind signal RF to infrared laser signal and transmits the infrared laser signal, the far end device receives the infrared laser signal and then converts it to signal of mobile communication network, which can effectively extend network signal to blind area of mobile communication and solve covering problem of mobile communication. The upgoing and downgoing principles are the same. It adopts FSO technique to implement near-far end transmission in mobile communication relay system, able to avoid the disadvantages of high cost of wireless transmission, long construction cycle, difficulty in wiring, etc, eliminate limitations of isolating degree of receiving-transmitting antenna to construction and installation of a wireless cochannel transmission repeater and avoid occupying extra limited wireless frequency spectrum resources for wireless different frequency transmission.

This invention describes a method for improving antenna isolation in an electronic communication device using grounded RF microwave elements and patterns (structures). According to embodiments of the present invention, the RF microwave element can be implemented as a short-circuited section of a quarter-wavelength long transmission line (such as a stripline), or the RF microwave element can contain a metallic coupler and two thin striplines with different lengths, or the RF microwave element can be implemented using a balun concept.

A removable antenna assembly and wireless access point including the same is disclosed in which a plurality of antenna elements are provided for transmitting and receiving wireless signals over a plurality of wireless channels. A sectorized mounting structure is provided for retaining each of the plurality of antenna elements substantially in an antenna isolation configuration, so as to enable simultaneous sectorized signal communication of the antenna elements over the wireless channels. A removable network interface is provided for selectively enabling a signal connection between a radio digital interface component and the plurality of antennas.

An aircraft avian radar is implemented using an existing aircraft transponder, Mode S, or TCAS installation as the radar transmitter. To eliminate self jamming of low level avian target signals by high level transmitter signals, the ending period of the transmission signal is digitized and cross correlated with the ending period of reflected avian target signals received after the transmission signal has ended. In a first implementation, the current transponder antenna is used for both transmission and reception. In a second implementation, an external receive only antenna is mounted in a position that maximizes the transmit antenna to receive antenna isolation. In a third implementation, a signal canceller and sample of the transmit signal are used to cancel or null out as much transmit signal as possible that couples directly to the receive antenna.

A wireless repeater having dual cancellation loops is presented. A first cancellation loop is configured to remove an undesirable signal resulting from a design or manufacture of the repeater. A second cancellation is configured remove undesirable signals cause by a real-time changing environment where the repeater is deployed.

Methods and apparatus are provided for per-antenna training in a multiple antenna communication system having a plurality of transmit antenna branches. A long training sequence is transmitted on each of the transmit antenna branches such that only one of the transmit antenna branches is active at a given time. The active transmit antenna branch is configured in a transmit mode during the given time and one or more of the inactive transmit antenna branches are configured in a receive mode during the given time. The transmit and receive modes are configured, for example, by applying a control signal to one or more switches.

The invention relates to a short-wave frequency searching device which comprises a broadband receiving unit, a digital down-conversion module, a digital signal processing module, a main control module, an interface module and a power supply module; wherein the broadband receiving unit comprises an antenna isolator and a short-wave broadband receiving module; the digital down-conversion module is used for collecting an intermediate frequency signal provided by the broadband receiving unit, and transforming the intermediate frequency signal into a baseband signal to be provided to the main control module and the digital signal processing module; the digital signal processing module is used for achieving usable frequency searching and frequency optimizing, selecting an idle channel as a local optimal frequency through perceiving a frequency spectrum in a set frequency range, and selecting a sky wave usable frequency range through estimating the maximum usable frequency and the minimum usable frequency of the sky wave channel; the main control module is used for monitoring the working state, the usable frequency range, the optimal frequency and the frequency spectrum energy of the short-wave frequency searching device, presetting a communication frequency range or communication frequency and realizing man-machine interaction and controlling external devices; the interface module is used for providing a video interface, a remote control interface, a data communication interface, a GPS interface and a network interface; and the power supply module is used for providing a DC power for each module, device and unit.

The invention discloses a navigation radar for an FMCW (frequency-modulated continuous wave) ship. The navigation radar comprises a display and control terminal subsystem, an antenna feeder subsystem, an exciter and timer subsystem, a receiver subsystem and a signal processing subsystem, wherein the receiver subsystem is connected with the antenna feeder subsystem, the signal processing subsystem and the display and control terminal subsystem, the signal processing subsystem is connected with the display and control terminal subsystem, the display and control terminal subsystem is connected with the exciter and timer subsystem, and the antenna feeder subsystem is connected with the exciter and timer subsystem. A microstrip antenna which is independently researched and developed is used in the navigation radar, so that the isolation degree of the antenna is improved, the leakage problem of a transmitter is basically solved, and a good foundation is laid for late-stage echo receiving and signal processing; SFC (synthesizable frequency calibration) filtration is used at second intermediate frequency for performing attenuation on echoes of a short-range target, so that the dynamic range of a receiver can achieve 100dB; and through a signal modulation way, distance-Doppler coupling is avoided within the using range of the navigation radar, and the navigation radar further has very high reliability and is particularly suitable for small and medium-sized ships.

This invention relates to an automatic testing technology for antenna isolation degree of wireless transmitting station containing a detecting module which is composed of RF signal generator, RF signal treatment and background control analyzer display, antenna 1 and 2, among which RF generator generates a RF signal controlled by background analysis, transmitton via antenna 1 and received by antenna 2 than enters into the background analysis unit after being treated by RF signal treatment unit and finally displays so as to test antenna isolation degree of direct transmitting station timely by monitors. This invention suits the production of the present stations (containing GSM900MHz, DCS1800MHz, CDMA800MH-z and other frequency bands)

Provided in the embodiments of the present invention and relating to the field of communications are an antenna and a terminal, the antenna comprising: a first antenna, a grounding unit, a ground wire and a second antenna; the grounding unit is positioned between the first and the second antennae but does not contact either antenna; one end of the grounding unit is connected to the ground wire; the grounding unit is symmetrical in structure and the axis of symmetry thereof is perpendicular to the ground wire; the first and the second antennae are connected respectively to the ground wire by corresponding electrical feed ports. The present invention utilizes two antennae in a small space and provides between said two antennae a symmetrical grounding structure; the isolation of each antenna from the other provides excellent complementarity of the two antenna patterns, enhances the degree of isolation and the correlation coefficient of the two antennae, and reduces the difficulty of antenna development.

The invention discloses a silicon-based small-sized common-caliber dual-frequency dual-polarized broadband array antenna. The antenna comprises a plurality of dual-frequency dual-polarized antenna units, and each dual-frequency dual-polarized antenna unit adopts a laminated structure and consists of a low-frequency band radiation unit, a high-frequency band radiation unit, two frequency band feedstructures and a metal grounding plate. The low-frequency-band radiation unit is provided with a square hole and is placed in the high-frequency-band radiation unit to achieve the common caliber. Thehigh-resistance silicon is adopted as a dielectric substrate, so that the array element size is greatly reduced, and the miniaturization requirement is met. The bandwidth of the antenna is broadened in a manner of hollowing out a silicon-based air introduction layer. The common-caliber dual-frequency dual-polarization broadband array antenna can work in two frequency bands with the frequency ratiobeing about 2 at the same time, the characteristics of the two frequency bands are dual polarization, the antenna array layout is reasonable, and the common-caliber dual-frequency dual-polarization broadband array antenna has the advantages of being simple in structure, small in size, good in polarization performance, high in antenna isolation and the like.