Abstract:
A method and system facilitate communication between a constellation of satellites and a mobile platform-mounted mobile communicator. The method and system may include the use of a first antenna suited for operation using a first frequency band in a first geographic region and a second antenna suited for operation using either the first or a second frequency band in a second geographic region. The method and system may use a controller to determine which antenna to activate based on one or more of a geographic indicator or a signal indicator. The system used by the method to facilitate the communication may have one or more enclosures over the antennas and controller for mounting to a mobile platform.
Abstract:
A cylindrically symmetric satellite antenna that provides directional and omnidirectional operating modes in a compact form factor. Feed points located at the top of the cylindrical structure provide increased platform isolation. Combining networks, disposed below or within the cylindrical structure, may be replaced with inexpensive baluns composed of coaxial line sections.
Abstract:
Ultra-wideband 180° hybrids for feeding a radiator of one band of a dual-band dual-polarization cellular basestation antenna are disclosed. The hybrid comprises: metal plates configured in parallel as groundplanes, and a dielectric substrate disposed between plates. First and second metallizations are implemented on opposite exterior surfaces of substrate and are shorted together to keep metal tracks at same potential to form conductor. Plates and first and second metallizations form first stripline circuit implementing matched splitter with short-circuit shunt stub Sum input port is provided at one end and two output ports are provided at opposite ends. Branches of matched splitter narrow to provide gap between output tracks. Third metallization is disposed within substrate. First, second and third metallizations form second stripline circuit. Tracks of third metallization comprise quarter-length transformers of different widths. Difference input port is provided at one end of second stripline circuit and at short-circuit point of short-circuit shunt stub of first stripline circuit. Metal track extends across gap of first stripline circuit.
Abstract:
A device is provided for use of an antennal base formed of two antennas which pick up the emissions present and produce two radioelectric signals S1 and S2. These two signals are used to produce at least one intermediate-frequency signal Fl by demodulation of one of the two signals by the other (autotransposition). The demodulation is carried out by firstly transposing one of the signals, S1 for example, around a given frequency F1, the signal S2 being preserved around its initial central frequency F0. Thus, whatever the central frequency F0 of the emission picked up by the antennas, the demodulation produces a signal of central frequency F1, thereafter demodulated into a given intermediate frequency Fl by a local oscillator of constant frequency F2=F1+Fl. The device is applied to the production of a device for detecting emissions and for characterizing the emissions picked up.
Abstract translation:提供了一种用于使用由两个天线形成的触角基座的装置,其拾取存在的发射并产生两个放射电信号S1和S2。 这两个信号用于通过用另一个(自动转置)解调两个信号之一来产生至少一个中频信号F1。 通过首先将信号S1之一(例如,绕给定频率F1)进行转换,信号S2围绕其初始中心频率F0保持来进行解调。 因此,无论天线拾取的发射的中心频率F0如何,解调产生中心频率F1的信号,然后由恒定频率F2 = F1 + F1的本地振荡器解调成给定的中间频率F1。 该装置适用于生产用于检测排放物和表征所拾取的排放物的装置。
Abstract:
The present invention relates to an apparatus and method for preventing unauthorized users from gaining access to a wireless network. A processor allows only data transmissions from the directions of the authorized users to access the network. Data transmissions from other directions are not allowed to access the network. The present invention also relates to a method and apparatus fore transmitting information only in selected directions, while in directions not selected, information cannot be inferred from the transmitted signal or signals.
Abstract:
A monopulse radar system for detecting an azimuth depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, includes: a transmitting array antenna and a receiving array antenna each including antenna elements forming an antenna train, at least one antenna switch disposed among the elements of the transmitting array antenna and/or the receiving array antenna, and a switch controller for turning ON/OFF the antenna switch to change an aperture length of the transmitting array antenna and/or the receiving array antenna thereby changing a beam shape thereof. The antenna elements of the transmitting array antenna and the receiving array antenna are formed on a dielectric substrate. A dielectric length between the antenna train formed by the antenna elements and the antenna switch is ½ dielectric wavelength.
Abstract:
A compact RF monopulse receiver circuit having a relatively low noise figure which is particularly useful for operation in the millimeter wave frequency range is described. The compact monopulse receiver finds use in small projectile and small missile applications. Also, a combination of transmit signal protection circuitry and receiver circuit architecture allows the RF monopulse receiver circuit to operate in a missile or other projectile which utilizes high RF power transmit signals. The RF monopulse receiver circuit can directly provide a radiation pattern for target detection and tracking or alternatively, the RF monopulse receiver circuit can function as a monopulse feed circuit which can be used, for example, in a quasi-optically fed reflector antenna.
Abstract:
A system is provided with a directional antenna having first and second antenna patterns oriented around an antenna boresight direction. The antenna boresight is oriented in a direction corresponding to a play determinative line on a playing field. Signals are emitted firm a playing object, used as a ball and detect using the two antenna patterns. Comparison of the detected signals provides an output indication when the playing object crosses the play determinative line.
Abstract:
A planar array antenna comprises a plurality of antenna elements disposed in a predetermined matrix pattern. Feeders extend from a feed to the antenna elements. High-frequency switches cooperatively open or close the feeders connected to antenna elements of at least one row of the matrix pattern located at both a right-end and a left-end regions of an antenna surface. Switching signals are supplied to the high-frequency switches from switching terminals for alternately activating the associated antenna elements, thereby providing two time-divisional array antennas offset in position by a distance corresponding to the width of at least one row of the antenna elements controlled.
Abstract:
An adaptive receiving antenna reduces interference arriving in the main beam of the antenna by redirecting the antenna beam away from the interference source. The receiving antenna projects the main beam to receive desired source signals from a source direction and may receive interfering signals from the interfering source. The antenna system measures the strength of the source signal and interference signal for controlling the direction of the main beam to marginally decrease the received desired source signal while substantially decreasing the received interfering signal to increase the desired source signal to interfering signal ratio so that the desired source signal can be received in the presence of interference.