Abstract: At a transmitting end, first and second dipole antennas are crossed each other by right angles and are arranged in a plane perpendicular to a propagating direction of radio wave. In first and second balanced modulators, a carrier signal is modulated with respective modulation signals having a phase difference of 90.degree. to produce balanced-modulated signals, which are then supplied to the first and second dipole antennas, respectively. Then a plane of polarization of a composite vector of radio waves transmitted by the dipole antennas is rotated at a frequency of the modulation signals, said frequency being higher than a fading frequency. The modulation signals are controlled by a state of a digital signal to be transmitted. At a receiving end, the digital signal is reproduced by receiving the transmitted radio wave by a conventional single side band receiver.

Abstract: A crossed polarization antenna system including a substantially flat and rectangular reflector and at least one radiating cell carried by the reflector, each cell including at least two first conductor elements assembled tail-to-tail and energized by a first external power supply forming a first dipole. Each radiating cell includes two second conductor elements mounted in exactly the same way as the first elements and energized by a second external power supply forming a second dipole. The conductor elements are V-shape bent elements with the second elements mounted orthogonally to the first elements. Applications include mobile telephones.

Abstract: A satellite based signal transmission and reception system which generates multiple beams with low side lobes and minimal crossover losses. The system includes a focusing device and an array of signal generator elements coupled to feed radiator elements. The feed radiator elements are assigned into overlapping beam sub-arrays characterized by a frequency and radiated beam polarization. Each overlapping sub-array generates a transmission beam signal which is orthogonally polarized with respect to the beam generated by the other overlapping sub-array. The use of beam orthogonality provides for physically overlapping beam sub-arrays without the use of analog combining networks which are inherently lossy structures. This allows beams to be generated having a highly tapered amplitude distribution to simultaneously achieve low side lobe levels and low beam cross over losses.

Abstract: Substantial improvements in frequency reuse in microwave communications systems is achieved by canceling co-channel interference and transmitter leakage. Interferometric beam-narrowing reduces beamwidth without reducing peak magnitude of the beam pattern. Frequency-dependent beam-shaping compensates for frequency-dependent distortions of the beam pattern thereby improving bandwidth. A spatial demultiplexing technique utilizes spatial gain distributions of received signals to separate signals, even from co-located transmit sources, and uses microwave lensing to enhance received spatial gain distributions. Predetermined cross-polarization interference is used to separate differently-polarized receive signals. A reference branch provides a cancellation signal to a receiver to cancel transmitter leakage signals. An error signal controls an impedance-compensation circuit that is responsive to changes in antenna impedance but not to receive signals.

Abstract: Communications equipment for use in a combat vehicle with at least one transmitting antenna and at least one receiving antenna and with more communications terminals than transmitting antennas or receiving antennas. Control logic accordingly contains a signal-path matrix by which any communications terminal can be connected, depending on its operating state "transmit" or "receive", either to a transmitting antenna along a high-frequency transmission path that includes a power adder or to the receiving antenna along a high-frequency reception path that includes a level distributor.

Abstract: Millimetric wave device, capable of operating as a signal transceiving antenna, with an optimum image definition even at extremely short distances (about 1 mm). Depending on the more or less concentration of the waves, the so realised radar antenna adopts, in its different configurations, a curved front optics, or an optics of hemispherical, aspherical, parabolic, concede, convex, biconcave, biconvex or stepped optics. The real focal length of the radar is shorter than that of the lens utilised in the antenna. The standard dimensions of the electronic transception and processing circuit part are very limited and contained.

Abstract: An antenna driving circuit for connecting an antenna to two transmitters is disclosed. The antenna driving circuit includes a hybrid combiner that has two isolated inputs. The hybrid is configured so that when a first signal is input to the first input, substantially one half of the energy of the first signal is output at the first output and the first signal is phase shifted by about -90 degrees at the first output. Substantially one half of the energy of the first signal is output at the second output and the first signal is phase shifted by about 0 degrees at the second output. When a second signal is input to the second input, substantially one half of the energy of the second signal is output at the second output and the second signal is phase shifted by about -90 degrees at the second output. Substantially one half of the energy of the second signal is output at the first output and the second signal is phase shifted by about 0 degrees at the first output.

Abstract: A radio station for transmitting and receiving digital information in a mobile communications system is provided having transmission and diversity reception implemented via a single antenna. For this purpose, the antenna has at least two exciter systems with different polarization. The transmitting and receiving units are connected to the exciter systems in a suitable manner, for example, via duplexers.

Abstract: In a radio station for mobile communication systems, the reception branches of at least two antenna units having different polarization are monitored in order to acquire statements about the polarization direction of the incident wave. Corresponding to the polarization direction of the incident wave, an adaptive fashioning of the radiation characteristic ensues, this fashioning the polarization direction of the emitted wave according to the weighting of the reception signals of the reception branches for the same communication connection. The connection from a base station to a mobile station in a mobile communication system therefore can be improved with an inventive radio station.

Abstract: The multidimensional cellular mobile telecommunication system extends the usage of existing cellular mobile telecommunication radio frequencies allocated for ground-based communications to non-terrestrial mobile subscriber stations by adding an overlay of non-terrestrial cells of predetermined geometry and locus in space to the existing ground-based cellular cell site network. The polarization of the signals produced by the non-terrestrial antenna elements is a polarization that is different than and preferably substantially orthogonal to the polarization of the cellular radio signals produced by the ground-based antennas, such as a horizontal polarization, to thereby minimize the possibility of interference with the vertically polarized ground-based radio signals.

Abstract: An antenna system is comprised of a plurality of independently constructed and operated antenna units, upon which are mounted a plurality of transmit and receive antenna pairs. This structure provides a means for the antenna system to be arranged to provide substantially hemispherical radio coverage. By adjusting the phase of each version of a radio signal to the transmitter or received, the signal may be formed into a beam according to known techniques of directional beam forming providing the antenna system with directional gain. Additionally, using a plurality of transmit and receive antenna pairs reduces the energy transmitted by each transmit antenna alone to a level which permits a branch line coupler to be sufficient to orthogonally polarize the transmitted and received radio signals negating the requirement for the duplexing filter for duplex operation.

Abstract: The multidimensional cellular mobile telecommunication system extends the usage of existing cellular mobile telecommunication radio frequencies allocated for ground-based communications to non-terrestrial mobile subscriber stations by adding an overlay of non-terrestrial cells of predetermined geometry and locus in space to the existing ground-based cellular cell site network. The polarization of the signals produced by the non-terrestrial antenna elements is a polarization that is different than and preferably substantially orthogonal to the polarization of the cellular radio signals produced by the ground-based antennas, such as a horizontal polarization, to thereby minimize the possibility of interference with the vertically polarized ground-based radio signals.

Abstract: A transmitter/receiver unit and a reflector unit are installed at opposite ends of a region to be monitored. The reflector unit consists of a receiving antenna whose signal is sent to a surface wave transit time element via a Wilkinson divider or a circulator. The signal returned from the latter is sent by the Wilkinson divider or the circulator to an amplifier that supplies a transmitting antenna, which in turn sends the signal back to the transmitter/receiver unit. Objects in the field of the beam cause a change in amplitude of the reflected signal, so the object can be detected with the help of an analyzer unit, namely an amplitude discriminator in the simplest case. The signals may be pulsed radar signals. It is advantageous, however, to use frequency-modulated signals corresponding to FMCW radar, so the frequency difference between the transmitted and reflected signal can also be used as a criterion for objects present in the monitored region in addition to using the amplitude of the reflected signal.

Abstract: A base station includes first and second antenna arrays for receiving first and second rotational polarizations, and a polarization diversity receiver connected to the first and second antenna arrays for processing respective first and second receive signals from a mobile station to generate an enhanced quality output receive signal based upon polarization diversity reception. Polarization isolation between the transmit and receive antenna elements may also provided by having a first plurality of transmit antenna elements for the second polarization mounted on a substrate carrying the first receive antenna elements. The second antenna array includes a second plurality of antenna elements of second polarization on a substrate carrying the second receive antenna elements.

Abstract: An adaptive polarization diversity system for radio link communication. The system includes a base station antenna for transmitting either a clockwise polarized transmission or a counterclockwise polarized transmission, the transmission including a training pilot signal. The system further includes at least one subscriber unit for receiving the transmission, the unit including a first subscriber unit antenna for receiving a clockwise polarized transmission, a second subscriber unit antenna for receiving a counter-clockwise polarized transmission, and a dual channel receiver for adaptively combining the clockwise polarized transmission with the counterclockwise polarized transmission in proportion to first and second weights, respectively, the dual channel receiver determining the first and second weights so as to substantially optimally receive the training pilot signal.

Abstract: A transponder used in a remote identification system requiring an interrogator and a transponder. The transponder which is thin and compact includes a transmit/receive antenna which is thin for receiving an interrogating signal and a rewrite signal emitted from the interrogator, and for emitting a response signal towards the interrogator. There is a modulator/demodulator for modulating a signal according to a code inherent in the transponder to emit the same from the antenna as the response signal without newly applying energy to the interrogating signal, and for demodulating the rewrite signal. A controller for applying a modulating signal generated according to the inherent code to the modulator/demodulator and for storing a signal demodulated by the modulator/demodulator. A liquid crystal display is used for displaying data including bar codes which can be read by a bar code reader. The bar code can be rewritten.

Abstract: A communication system for identifying, locating, tracking and communicating for other purposes with large numbers of tags in a time and energy efficient manner. The tags are associated with items located in a communication region that is interrogated by an interrogator on a one-to-many basis using broadcast commands, on a one-to-one basis using directed commands or on a combination basis using both methods. Identification occurs through organized transmission and reception of signals between the tags and the interrogator. A batch collection protocol uses a combined one-to-many and one-to-one communication system that effectively resolves communication contentions. The batch collection protocol employs a plurality of collection periods which communicate with large or unknown numbers of portable tags.

Abstract: A wide bandwidth radio wave communication system having a dual feed pair of cross-polarized antennas having a common axis and being at orthogonal angles to each other. A source of RF signals is coupled to the antennas and a shifter device is between at least one of the pair of cross-polarized antennas and the source of RF signals for modulating the polarization of RF signals launched by the pair of cross-polarized antennas.

Abstract: In an earth station terminal, a cascaded arrangement of downlink half- and quarter-wave polarizers receives a downlink communication signal and a mono-polarized beacon signal from a communications satellite and separates the communication signal into respective polarization components. A receiver is connected to the cascaded polarizers for detecting the in-phase and orthogonal-phase components of a cross-polarization of the beacon signal with respect to the phase of its copolarization. For cross polarization compensation, first and second polarization offset values of the beacon signal are derived from the angular positions of the polarizers, and subtracted from the beacon's in-phase and orthogonal-phase components, respectively, to produce target values. By controlling the polarizers until their angular positions are respectively equal to the target values, the polarization components of the downlink communication signal assume zero vectors.

Abstract: An integrated circuit for use in a phased array antenna system having a central processing unit. The integrated circuit is associated with one of a plurality of antenna elements of the phased array antenna system. The integrated circuit includes an ID memory for storing a unique ID addressable by the central processing unit, and receives global commands from the central processing unit globally transmitted over a distributed serial bus. Upon detecting a global command, the integrated circuit compares an ID address associated with the global commands with the ID stored in the ID memory. The integrated circuit recognizes global commands as local commands to be executed locally when the ID address associated with the global commands is the same as the ID stored in the ID memory. In response to the local commands, the integrated circuit generates and provides control signals to the associated one of the antenna elements of the phased array antenna system.

Abstract: On receiving a symbol sequence carried by a first-polarization and a second-polarization signal of two orthogonally polarized signals and in order to cancel a cross polarization interference (XPI) component which leaks from the second-polarization signal into the first-polarization signal, a first decision feedback XPI canceller (43) is supplied with a before processed signal derived from the second-polarization signal and with a decided signal which is produced by a decision circuit (22) and which represents the symbol sequence carried by the second-polarization signal with an intersymbol interference component and another XPI component cancelled from the before processed signal. Another decision feedback XPI canceller (44) is similarly operable.

Abstract: A fractionally spaced cross-polarization interference canceller, wherein a compensation signal is generated through an adaptive filter operating in a frequency that is an integer multiple of a transmission data frequency. The cross-polarization interference canceller includes a mechanism for generating an error signal used to control coefficients of the adaptive filter in the integer multiple frequency. The mechanism is realized, for example, by using a waveform generator generating an estimate of a baseband signal in the integer multiple frequency using a plurality of estimates of transmission data and coefficients determined by an impulse response of a transmission path.

Abstract: An automatic transmit power control (ATPC) method and system for radio equipment of a cross polarization interference canceler system (XPIC system) wherein two orthogonally polarized waves of the same frequency channel are used independently of each other. The transmit powers of the polarized waves of the object frequency channel are simultaneously increased when a drop of the receive signal level of at least one of the two polarized waves of the object frequency channel is detected.

Abstract: A satellite communications system includes a feed array and reflector receiving antenna coupled to a dual-mode network, for generating two channels, with independent signals representing two beams, one for each channel. Each output channel of the dual-mode network contains redundant information relating to a plurality of information channels. In the absence of an interfering signal or intrusion, the combined signals are amplified and block frequency-converted, then de-multiplexed into separate channels, which are each applied through selection switches to a transmitter multiplexer for retransmission. An alternate signal is tapped from each of the two received signal channels, phase controlled, and combined, to produce a combined signal representing a receive antenna beam with a null controllable in position in response to phase. The combined signal is demultiplexed into separate information channels.

Abstract: An active transmit phased array antenna system for generating multiple independent simultaneous antenna beams to illuminate desired regions while not illuminating other regions. The size shape of the regions is a function of the size and number of elements populating the array and the number of beams is a function of the number of beam forming networks feeding the array. All the elements of the array are operated at the same amplitude level and beam shapes and directions are determined by the phase settings. The active transmit phased array antenna includes a plurality of antenna elements disposed in a hexiform configuration. Each antenna element is identical and includes a radiating horn capable of radiating in each of two orthogonal polarizations. The horn is fed by a multi-pole bandpass filter means whose function is to pass energy in the desired band and reject energy at other frequencies. The filter means is coupled into an air dielectric cavity mounted on substrate.

Abstract: Disclosed is a method and an apparatus which act as a retroreflector of circularly polarized electromagnetic radiation over a broad range of incident angles. The apparatus includes dipole antenna pairs which are orthogonally disposed in relation to one another about a central point to create antennas which consist, for example, of crossed dipoles but can be other circular polarization sensitive antennas. Antenna pairs are then arranged symmetrically in an array and interconnected by means which control the circular polarization of the returned signals to provide retroreflection of impinging signals while maintaining the same sense of polarization. The array thereby provides enhancement of the radar cross-section of a target when circularly polarized radar is employed. Conversely, the array can be connected so as to enhance opposite-polarization returns should there be any desire to do so.

Abstract: A transmission/reception module suitable for use in electronically phase-controlled antennas for a synthetic aperture radar includes a circulator provided for each individual radiator element terminal to achieve vertical and horizontal polarization. A low-noise amplifier is connected to the circulator in the reception path. A high-power amplifier is connected to the circulator in the transmission path. The two separate polarization reception channels each include a low-noise amplifier. The two separate polarization transmission channels each include a high-power amplifier. The reception channels and transmission channels are respectively connected to a polarization change-over. Switching arms of the polarization change-over are then connected to either the reception contact or the transmission contact of the transmission/reception switch.

Abstract: A multiplexing system combines a plurality of electromagnetic signals to propagate along a common path, preferably a square waveguide which can be connected to an antenna feed horn of square cross section which can support both circularly and linearly polarized electromagnetic waves. The system is operative with a plurality of sets of signal channels including a first set of A-channel signals and a second set of B-channel signals. A circular polarizer connects with a first end of the waveguide. All of the A-channel signals are fed into an input port of the polarizer. The B-channel signals are coupled into the waveguide by a plurality of couplers located at positions arranged serially along the waveguide, individual one of the couplers operating at different ones of the B-channel frequencies for selectively coupling respective ones of said B-channel signals into the waveguide to propagate toward the second end of the waveguide.

Abstract: A method of reducing in a digital time multiplex mobile telephony system the risk of poor reception as a result of the occurrence of points of low signal strength, so-called zero points. Transmission from fixed stations is performed with a polarization direction which is changed stepwise between different parts of the transmitted information. This causes the fading patterns around receiving stations to change in time, and also causes any zero points to be moved in the geography, therewith making it improbable that more than a small part of an information frame will be lost. In the case of a GSM-type system, the polarization direction is changed for each new TDMA-frame.

Abstract: A data transmission and/or acquisition device and method are disclosed. The said device and method use two cross polarizations of an electromagnetic wave and a magnetic recording device. The invention pertains to phase/amplitude modulation using two phase-modulated signals transmitted on two orthogonal polarizations. At reception, the vector sum of the two signals is added taken. The resultant signal is amplitude-modulated and/or phase-modulated. The invention can be applied especially to television and radio transmitters, radars and telecommunications equipment.

Abstract: A high-efficiency active printed-circuit antenna system for pulsed frequency-hopping space radar electronically scanned in two planes encompasses in its timing diagram the transmission of a horizontal polarization pulse, the reception of echoes from a previous horizontal polarization pulse, the transmission of a vertical polarization pulse and the reception of echoes from a previous vertical polarization pulse. The system comprises several thousand MMIC modules distributed over the antenna and each connected to a printed-circuit radiating element comprising a plurality of dual polarized square patches connected by microstrip lines which excite them with the same amplitude and the same phase at two perpendicular ports. Switching between the two ports procures transmission or reception with horizontal or vertical polarization.

Abstract: The apparatus is an antenna system for autoadaptive direction and polarization filtering of radio waves traveling through an HF ionospheric channel and generating an output signal for coupling to a receiver. First and second crossed loop antenna elements having first and second output terminals, respectively, are disposed around a common axis. A filar antenna element has a longitudinal axis along the common axis. The filar antenna element has a first end terminal situated at the same phase center as the first and second output terminals. A multiplier circuit multiplies each value output from the first and second output terminals and the first end terminal by a corresponding complex weighting coefficient. The complex weighting coefficients are adjustable as a function of variations of polarization of a radio wave, and azimuthal and site arrival directions of the radio wave.

Abstract: An apparatus for determining the roll position of a spinning projectile with the aid of polarized electro-magnetic radiation comprises a transmitter for emitting polarized radiation in a direction towards the projectile and a polarization-sensitive receiver disposed in the projectile for receiving the polarized radiation. The polarized radiation emitted from the transmitter has an asymmetric wave-form which is formed by superimposing at least two mutually phase-interlocked radiation components of the wavelength relationship of 2:1 and/or multiples thereof, and the polarization-sensitive receiver includes a single receiver antenna.

Abstract: A single- or dual-circularly polarized earth station antenna is converted into a single- or dual-linearly polarized earth station antenna for accessing linearly polarized satellites. In a first embodiment, a free-space meander line polarizer providing a 90.degree. differential phase shift between two orthogonal polarizations is disposed in front of the earth station antenna feed system. In a second embodiment, a power dividing (transmit) or power combining (receive) network operates in conjunction with differential phase shift circuits to achieve the polarization conversion.

Abstract: A dual polarization transmission system for transmitting digital modulated signal each having a particular bandwidth by use of two polarized waves which have the same center frequency and are orthogonal to each other. The receiver side of the system demodulates radio frequency signals sent by a horizontally and a vertically polarized wave and coming in through a receiving antenna into IF signals. From the received signal of one polarization, an interference component of the other polarization generated on the basis of the cross-polar IF signal or demodulated signal is removed.

Abstract: Adaptive phase and amplitude distributor for use with satellite antennae which require distribution of transmitter-generated microwave power over many elementary radiators having predetermined amplitude and phase characteristics thus achieving required radiation patterns. It consists essentially of two polarizers three circular waveguide rotating joints, all interconnected in a joint-to-polarizer-to-joint-to-polarizer-to-joint relation and followed by an orthomode.TM. transducer output which serves to separate the orthogonal components of the electromagnetic field. By rotating the two polarizers around the waveguide axis independently and by suitable choice of the rotating angles, it is possible to distribute the power entering at one port, say in the TE.sub.11 mode, on the two orthogonal components, still in TE.sub.11, with any amplitude and phase relationship at the output. The two components are separated by the orthomode.TM. transducer.

Abstract: A monopulse antenna feed system utilizing multiple modes within the feed. A TEM mode and two TE.degree..sub.11 modes that are orthogonal and in phase quadrature are utilized in the antenna feed system to provide tracking information and data communication from a far-field source of circularly polarized radiation. The output from a port that is responsive to the TEM mode is compared with the output from a port that is responsive to the TE.degree..sub.11 modes to obtain tracking information and the output from the latter port also provides a channel for communication of data. The phase of the TEM mode relative to the phase of the TE.degree..sub.11 modes is indicative of the angular rotational position of a far-field source relative to the axis of the feed system and the relative amplitude of the TEM mode is indicative of the angular displacement of the far-field source away from the axis of the feed system.

Abstract: A polarization diversity system (10) including an adaptive polarization combiner (14) is disclosed. The combiner receives input signals V.sub.i1 and V.sub.i2 of arbitrary relative phase and amplitude, produced in response to orthogonally polarized components of an incident electromagnetic field. The combiner includes a hybrid network (18) that performs the combination of the input V.sub.i1 and V.sub.i2 based on phase adjustments initiated by a feedback circuit (20). The feedback circuit includes a limit set and sensing circuit (26) that allows feedback signals V.sub.c1, V.sub.c2, V.sub.c3, and V.sub.c4 to be swept through a range suitable to phase shifters (28, 32, 36, and 38) included in the hybrid network, thus allowing different components to be more easily used in the hybrid network. Further, the combiner is constructed to function properly in the absence of one of the signals input to the combiner.

Abstract: A pulse radar for operation at 94 GHz and higher frequencies is shown to include an antenna, a diplexer and first detector that are each optically fed so that radio frequency signals may be, when transmitting, passed through the diplexer to the antenna and, when receiving, from the antenna through the diplexer to the first detector.

Abstract: A satellite communication system particularly suited for trans-Atlantic communications is provided wherein a communications satellite is placed in geosynchronous orbit somewhere between Western European continent and Eastern American continent. The satellite includes an antenna adapted for orthogonal linear polarization and the antenna elements oriented at an acute angle with respect to orbit normal to result in polarization arrival angles as close to local vertical and horizontal as possible at the earth stations in the high rain rate regions of southeastern United States and Mediterranian region in Europe.

Abstract: During multipath fading in a terrestrial digital radio system, off-axis arrival of signals excites higher-order modes in a horn reflector antenna. In the disclosed system specified ones of these higher-order modes and the fundamental mode are allowed to propagate in a main waveguide connected to the antenna. At least one of the higher-order modes is abstracted from the main waveguide and fed to a standby receiver while the fundamental mode is propagated intact to a main receiver.Error occurrences in the fundamental and higher-order modes due to multipath fading are substantially uncorrelated. Hence, upon detecting an error in the signals delivered to the main receiver, the system switches to the standby receiver thereby to provide in a single-antenna a significant improvement in performance against multipath fading.

Abstract: A data transmission and/or acquisition device and method are disclosed. The said device and method use two cross polarizations of an electromagnetic wave and a magnetic recording device. The invention pertains to phase/amplitude modulation using two phase-modulated signals transmitted on two orthogonal polarizations. At reception, the vector sum of the two signals is added taken. The resultant signal is amplitude-modulated and/or phase-modulated. The invention can be applied especially to television and radio transmitters, radars and telecommunications equipment.

Abstract: In a satellite communications system, a rotatable 90.degree. phase shifter and a rotatable 180.degree. phase shifter introduce variable phase shifts to a single pilot signal, which is transmitted to the satellite. Downlink cross-polarization interference cancelling control signals are derived from a beacon signal received from the satellite. A pulse sequence is generated to modulate the amplitude of a carrier to produce an ASK signal as the pilot signal. A correlation calculator provides coarse mode interference cancellation by estimating uplink cross-polarization interference components from the downlink cross-polarization cancelling control signals and adjusting the angle settings of the 90.degree. and 180.degree. phase shifters with the estimated components. The pilot signal is transmitted back to the earth and synchronously detected with the pulse sequence to derive a DC signal which represents an uplink cross-polarization interference.

Abstract: The radio system embodying the invention comprises a central station and a terminal stations or passive end. Data signals are transmitted between data processing units which are respectively connected to the central and terminal stations. The radio system is essentially characterized in that the terminal station comprises a square two-dimensional antenna and a microwave switcher so as to phase modulate, by means of a data signal, a microwave transmitted from the terminal station to the central station. This phase modulated microwave is produced from an incident microwave transmitted by the central station and issued to the terminal station by the square two-dimensional antenna. The design of the terminal station is very simple and compact and can be included, as well as the corresponding data processing unit, in a contact-free chip card.

Abstract: A method of feeding out field power from a circularly polarized antenna (2), mounted on a conductive aircraft surface (1). All power is normally fed out in circular polarization to the receiver, irrespective of the elevation angle (.theta.) and the azimuth angle (.alpha.). For increasing the antenna amplification at elevation angles .theta. greater than or approximately equal to 60.degree., where substantially only the vertical polarization can be seen, it is proposed in accordance with the method that all power is fed out in linear polarization with the aid of a polarization switch (4).

Abstract: A radio-frequency identification (RF-ID) system including a master unit and a sub unit connected thereto by radio-communication, and used for identifying a moving article on which the sub unit is mounted. The master unit transmits a circularly polarized wave having two carrier components (CW1, CW2), and the sub unit, which does not include carrier generators and branching filters, is powered by a battery provided therein. The sub unit receives the circularly polarized wave, separates the two carrier components by a hybrid circuit, and transmits another circularly polarized wave base upon the received carrier component. The sub unit may be operated in response to a starting command from the main unit, and the main unit may have first and second detecting units separated by n.multidot..lambda.g/8, n: an odd integer, and .lambda.g: effective wave length, to eliminate the occurrence of null point phenomenon.

Abstract: In an angle diversity receiving system, the primary and diversity signals are produced by a waveguide signal separator coupled to a single receiving antenna.The separator operates by converting selective higher order modes in the antenna into fundamental modes that will propagate in its two output waveguides. The result is a robust system that operates over a frequency band wide enough to cover both the 4 GHz and 6 GHz common carrier bands with both horizontally and vertically polarized signals, and that can use a wide variety of antennas.

Abstract: A multi-element antenna formed of symmetrical paired elements symmetrically positioned in a concentric arrangement. The proximate ends of the elements are interconnected through a switching network which, when properly biased, permits exciting the element of the antenna to obtain right-hand or left-hand circularly polarized radiation.

Abstract: This invention reduces the weight and bulk of shipboard-mounted microwave antenna systems by achieving horizontally and vertically polarized radar return signals without the need for a rotary joint.

Abstract: Polarization Control Networks (PCNs) are used in active solid-state array transmitters. Polarization ECM requires precise polarization control of the transmitted signal. Prior polarization control networks (vector modulators) use ferrite phase shifters to achieve low loss and wide bandwidth, but because of their large size they must be placed before the RF power distribution network of the array. By implementing the polarization control networks in MMIC technology for each antenna element, and integrating each PCN with a 2-3 watt amplifier at its input, it is possible to eliminate half the required feed network and active amplifiers from the system. Each polarization control network unit includes a plurality of thin film superconducting phase shifters, hybrids and transmission lines enclosed in a cryogenic package. If more power is required than the superconductive PCN can accommodate, the amplifiers can be placed after the PCNs, and still maintain size and performance advantages over current implementations.