Showing papers on "Feed horn published in 2002"

Method and system in a transceiver for controlling a multiple-input, multiple-output communications channel

Abstract: The present invention makes it possible to increase a data rate between a transmitter and receiver using a multiple-input, multiple-output radio frequency channel. A multiple-stream, multiple-antenna receiver measures a composite channel between a multiple-antenna transmitter and a multiple-antenna receiver to produce a composite channel measurement. The receiver selects a plurality of antenna array weight sets for use in the multiple-antenna transmitter in response to the composite channel measurement, where each antenna array weight set is associated with one of multiple data streams. Information describing the plurality of antenna array weight sets for use in the multiple-antenna transmitter are then transmitted.

Low cost high performance antenna for use in interactive satellite terminals

Abstract: The invention relates to a Interactive Satellite Terminal antenna system comprising an antenna to which is associated a feed horn. This antenna systems characterized in that it comprises an elliptical parabolic main reflector and a corrugated feed horn ( 2 ) having an outer elliptical aperture and an inner cylindrical waveguide with an inner portion ( 7 ) and a step section ( 8 ) and in that cavity elements ( 10 ) are added to the step section ( 8 ) for compensating cross-polar components. The invention can be used in antenna systems.

Design, development, and testing of X-band amplifying reflectarrays

Abstract: The design and development of two X-band amplifying reflectarrays is presented. The arrays use dual-polarized aperture coupled patch antennas with FET transistors and phasing circuits to amplify a microwave signal and to radiate it in a chosen direction. Two cases are considered, one when a reflectarray converts a spherical wave due to a feed horn into a plane wave radiated into a boresight direction, and the other when the reflectarray converts a spherical wave due to a dual-polarized four-element feed array into a co-focal spherical wave. This amplified signal is received in an orthogonal port of the feed array so that the entire structure acts as a spatial power combiner. The two amplifying arrays are tested in the near-field zone for phase distribution over their apertures to achieve the required beam formation. Alternatively, their radiation patterns or gains are investigated.

Method of determining the capacity of each transmitter antenna in a multiple input/multiple out/put (MIMO) wireless system

Abstract: The per antenna capacity of each of the transmitter antennas in a MIMO system are individually determined from measurable information at the receiver end. Specifically, the channel capacity for each individual transmitter antenna is calculated at the receiver end as a function of measurable channel coefficients (also known as channel state information), the measurable average signal-to-noise ratio, and the number of transmitter antennas. Once the per antenna capacity of each transmitter antenna is individually determined at the receiver end, the maximum transmission rate for each data stream transmitted by each transmitter antenna is determined from that individual capacity either at the receiver end and fed back to the transmitter end, or is determined at the transmitter end from the individual transmitter antenna capacities that are fed back by the receiver end to the transmitter end. A modulation scheme that supports each maximum transmission rate is then determined based on some defined criteria.

Optical transmitter and receiver

Abstract: There is provided an optical transmitter and receiver that delivers a radio signal received from outside the optical transmitter and receiver to a wireless demodulation circuit ( 16 ). A control circuit ( 10 ) controls a drive circuit ( 4 ) according to the radio signal. The optical transmitter and receiver sends an optical signal which is emitted according to a driving current from the drive circuit ( 4 ) by a light emitting element ( 5 ) into an optical cable ( 1 a ). A regenerating circuit ( 7 ) converts an optical signal received by way of another optical cable ( 1 b ) into received data and a wireless modulation circuit ( 22 ) modulates a carrier wave with the received data so as to generate a radio signal and then outputs the radio signal to outside the optical transmitter and receiver by way of an antenna ( 15 ).

Non-planar log-periodic antenna feed for integration with a cryogenic microwave amplifier

Abstract: The bandwidth of a microwave reflector telescope is limited by the size and figure accuracy of the mirror elements and by the feed which couples focused radiation to the receiver. A single or hybrid-mode feedhorn can efficiently illuminate a telescope aperture with low ohmic loss. Its gain varies quadratically with frequency, however, limiting its effective bandwidth to less than an octave. A log-periodic antenna (LP) can illuminate a telescope aperture over multi-octave bandwidths, but it has greater spillover and ohmic loss than a well-designed feedhorn. This paper describes a non-planar log-periodic antenna feed to which cryogenic electronics can be attached without the need for a long, lossy section of transmission line. With appropriate reflector optics to minimize defocusing with phase travel and baffles to redirect sidelobes onto the sky, this antenna offers a low noise, wideband alternative microwave feed for astronomical and SETI applications. It is currently being adapted for use on the Allen telescope array.

A way to improve the field of view of the radiotelescope with a dense focal plane array

Abstract: We consider a problem of increasing the field of view (FOV) of the radio telescope by means of multi beam performance of the prime focus hybrid reflector systems. It was shown that array feeds of waveguide and horn elements currently used cannot provide closely spaced beams over a wide FOV and a high aperture efficiency in each beam due to the element spacing restrictions imposed by a size of the element aperture. We proposed a feed design in a form of an integrated dense array with a small physical size of the grid element and a volumetric form of the array element. For the feed, the original excitation system of the array elements has been developed to perform the desirable beam illumination pattern with low spillover level. The results have been obtained both for theoretical and experimental radiation patterns of the array feed. Scanning and multi beam capabilities and limitations of the hybrid reflector antenna have been investigated on the basis of the focal field distribution analysis. As an example, 0.35 F/D ratio reflector (Westerbork Telescope) has been considered. It has been shown that the proposed array antenna is a good candidate be used as the feed to improve the properties of source images by the reflector systems and therefore to increase the FOV of the radio telescope.

Dual band satellite communications antenna feed

Abstract: An antenna feed that transmits in a single vertical or horizontal linear polarization at commercial Ka-band while simultaneously receiving both vertical and horizontal polarizations at commercial KU-band is presented The antenna feed includes a metal feed horn, an integrated corrugated ring filter, an outer conductor disposed coaxially about the feed horn, a hollow inner conductor disposed coaxially within the feed horn and a polyrod disposed within the hollow inner conductor The antenna feed further includes a PCB having receive channel RF probes, 180-degree hybrid combiners and LNB circuitry The PCB is surrounded by a housing which is attached to the feed horn

Optimization of corrugated horn radiation patterns via a spline-profile

Abstract: Corrugated horns are widely used as feeds for reflector antennas [1] or as direct radiators, as in global earth illumination from a satellite [2, 3] or as source antennas in an anechoic chamber. Shaping the radiation pattern of a corrugated horn is mainly done by shaping the profile [4-6] to the required aperture dimension, and to a lesser extent, for wideband applications, by using a mode-converter [7-9] tuned to the design frequency.

Improved radiation pattern performance of Gaussian profiled horn antennas

Abstract: A new horn antenna profile is presented. This new profile based on Gaussian techniques offers the best solution when the requirements related to the radiation pattern are very stringent. Short-horn antennas with high-conversion efficiency to a fundamental Gaussian beam, and therefore, very low sidelobe and cross-pol levels in a wide-frequency band, could be obtained by using the design technique presented here. Once the theoretical principles of the Gaussian profiled horn antennas (GPHA) are presented, some other possibilities involving Gaussian profiles are studied and compared with their conventional counterparts. Finally, as an example of the design technique proposed, a particular design of a GPHA for HISPASAT 1C and now also valid for the new HISPASAT 1D satellite is presented, showing the excellent agreement between the theoretical and experimental results.

Wideband linearly or circularly polarized monopulse tracking corrugated horn

Abstract: A design of a wideband monopulse tracking corrugated horn, for either a linearly or a circularly polarized signal, is presented. Two types of suppressors are introduced to restrain the excitation of unwanted higher order modes. Parametric dependence curves of special points on the propagation characteristics are given for m=1 and m=2 modes in the ring-loaded corrugated horn. By using the suppressor and employing ring-loaded slots in the entire horn, the cross-polarization peak level of the horn can be reduced by a further 10 dB or more in the transmitting band, and its maximum level is less than -28 dB across C-band. The experimental results of return loss and sum and difference patterns validate that the feed possesses satisfactory wide-band communication and tracking characteristics.

Method of transmitting data from a transmitter to a receiver, and a radio system

Abstract: The invention relates to a method of transmitting data from a transmitter to a receiver in a radio system, and to a radio system. The method includes the following: channel-coding the data using selected channel-coding; dividing the channel-coded non-interleaved data into signals with different contents, to be transmitted via at least two different transmitter antennas; providing the signal to be transmitted via each transmitter antenna with an identifier, by means of which identifier the signals transmitted via different transmitter antennas are distinguishable from each other in the receiver; transmitting the signals to the receiver using different transmitter antennas; detecting the signal transmitted via each transmitter antenna with a receiver receiving each transmitter antenna in the receiver, and combining the detected signals into received channel-coded non-interleaved data; decoding the channel-coding of the received channel-coded non-interleaved data; and the receiver attenuating interference utilizing the decoded data.

Multi band ring focus dual reflector antenna system

Abstract: A ring focus antenna and method of using same. The ring focus antenna can have a main reflector of revolution shaped as a non-regular paraboloid about a boresight axis of the antenna. A sub-reflector/feed pair is provided comprising a sub-reflector of revolution shaped as a non-regular ellipsoid having a ring-shaped focal point about the boresight axis. A feed element is installed at a feed element location separated spaced from a vertex of the sub-reflector on the boresight axis of the antenna. The main reflector is adapted for operation with multiple sub-reflector/feed pairs having a coupled configuration, and multiple sub-reflector/feed pairs having a decoupled configuration (i.e. classical optical dual reflector system). The main reflector is operable at a plurality of spectrally offset frequency bands. For example, the antenna can be designed for operation over C-band, X-band, Ku-band, and Ka-band.

Method for securing the operation of a receiver, and a radio apparatus

Abstract: A method for securing the operation of a receiver in a two-way radio apparatus by enhancing the isolation between the transmitter and receiver, and a radio apparatus employing said method. The transmitter and receiver in a radio apparatus have separate antennas (320, 330). The transmitter has at least two mutually alternative filters which have different attenuations in the receive band. Transmitting antenna matching is monitored by measuring the strength of the field (re) reflected from the antenna (320) towards the power amplifier (PA). When the strength of the reflected field in proportion to the strength of the propagating field is above a certain threshold, the filter (312) which has a greater stop-band attenuation in the receive band will be used as the transmitting filter. Otherwise, the filter (311) which has a smaller stop-band attenuation and, hence, smaller pass-band attenuation will be used as the transmitting filter. The filters and their selection switches (SW31, SW32) can be integrated into a single component. The receiver noise level can be kept relatively low also when the matching of the transmitting antenna changes for external reasons, without substantially increasing power loss between the RF power amplifier and the antenna.

Low sidelobe contiguous-parabolic reflector array

Abstract: An antenna array of parabolic rectangular reflectors for use in satellite communications. The antenna comprises two parabolic reflectors disposed contiguously on a common outer surface. The common surface forms a continuous antenna aperture. The parabolic reflectors have rectangular side edges which permit the adjacent edges of the parabolic reflectors to be spaced closely. The mouth of each parabolic reflector is focussed on a separate feed. The focus of the feed is not located at the center of the reflector but rather offset. The antenna feeds and the reflector foci are displaced toward the center of the array such that the spacing between the antenna feeds is less than half the length of the antenna. The present invention provides the displacement of each reflector focal point and each antenna feed toward the center of the array.

On linear pre-processing in multi-antenna systems

Abstract: We study linear pre-processing for multi-antenna systems when the channel is perfectly known at the transmitter. In particular, the capacity of linear and adaptive channel inversion is compared to the optimum water-filling. When equal numbers of antennas are used at the transmitter and at the receiver, the outage probability with linear inversion is rather large. Outage is remarkably reduced when more antennas are used at the transmitter. Adaptive inversion approximates the water-filling capacity at small transmitter power and so it is robust against fading correlation. The average transmitter power with linear inversion depends on the numbers of antennas at the transmitter and at the receiver. For Rayleigh fading, we compare the bit error performance to V-BLAST.

Genetic optimization of microstrip reflectarrays

Abstract: Printed reflectarrays try to combine the advantages of both reflectors and printed arrays (see e.g. [l]) and consist in arrays of printed patches, illuminated by a primary feed horn, that re-radiate the illuminating power back into the space. Since the elements have different positions, the field that propagates from the feed to the patches covers different path lengths and therefore the contributions to the total re-radiated field coming from the different patches are not in phase. So it becomes necessary to adjust the phase of the single element to compensate the different path lengths and this may be obtained using at least one of the following different possible techniques: adding to the patches suitable differentlength transmission lines [2, 31, varying the size of the radiating elements [4], rotating the elements to different angles or finally varying the dielectric constant of the material below the radiator itself. Here we chose to combine the first two options together

High power broadband feed

Abstract: A ridged feed horn antenna for use in broadband satellite communications. This multi-ridged feed horn operates in a receive band of 10-13 GHz and a transmit band of 14-15 GHz. The ridged feed horn antenna comprises excitation conductors which excite the field between each of the ridges in the feed horn antenna. The excitation conductors are connected to each of the ridges. A waveguide, terminated at the back of the horn antenna, enables the ridges to guide the energy from their respective excitation conductors toward the mouth of the feed horn antenna. A planar balun and matching circuit, located at the back of the horn antenna, may be used to feed each of the excitation conductors. Furthermore, the cross-section of each excitation conductor is chosen so as to optimize horn antenna performance. Each excitation conductor extends outwardly from the back of the horn and is parallel to the longitudinal axes of the horn waveguide. Essentially, a dual-ridged feed horn would require two excitation conductors and a quad-ridged feed horn would require four excitation conductors.

Apparatus and method for antenna attachment

Abstract: An apparatus and method of for attaching an antenna to a mobile communication device. The apparatus can include radio frequency generation circuitry, a radio frequency feed point coupled to the radio frequency generation circuitry, a direct current voltage source coupled to the radio frequency feed point, and an antenna detection module coupled to the radio frequency feed point and the direct current voltage source. The antenna detection module is configured to detect a type of antenna coupled to the radio frequency feed point based on a detected direct current voltage. The antenna detection module can be coupled to the radio frequency feed point and a ground contact point. The apparatus can additionally include a parameter of operation adjustment module coupled to the antenna detection module. The adjustment circuitry can be configured to adjust a parameter of operation of the mobile communication device.

Adaptive vector modulation method and system

Abstract: A transceiver for implementing an adaptive vector modulation method is disclosed. In response to a binary stream assembled into groups of bits forming symbol indices, a transmitter of the transceiver generates one or more complex values symbols that are normalized over channel coefficients associated with one or more propagation channels between one or more transmitter antennas and one or more receiver antennas. The transmitter controls a transmission of the complex values symbol(s) from the transmitter antenna(s) to a selected receiver antenna. The selection of the receiver antenna is based upon a metric proportional to the average injection power or a vector norm corresponding to each receiver antenna of the receiver antenna(s).

Reflector and antenna system containing reflectors

Abstract: The invention concerns a reflector and a satellite antenna system comprising such a reflector. In the satellite antenna system, microwave radiation from one or more feed horns (5) is emitted at the reflector (1), which comprises first and second reflector elements (2, 3). Upon reflection of the radiation from the reflector elements (2, 3), a distinct beam shape for the reflected microwave energy is generated. The reflector elements (2, 3) are disposed at a fixed distance from one another so that radiation that passes the first reflector element (2) strikes the second element. The first reflector element (2) comprises a lattice structure aimed toward the feed horn, which lattice structure consists of plates (8) of electrically conductive material, wherein the distance between the plates and the depth of said plates are adapted for reflection of polarization parallel to the plates. The invention is characterized in that the extent of each respective plate toward the second reflector element is chosen so that the transmission losses in the first reflector element are minimized.

Scalar quad ridged horn

Abstract: Quad ridged horn antennas which may be individually disposed at the focal point of a parabolic reflector, or in an antenna array of parabolic reflectors. In the field of satellite communications, focus-fed parabolic reflectors are required to be compact yet provide broadband signal services. As such, the antenna horn feed structure must be very compact and provide equally broadband services. In order to provide uniform excitation of a parabolic reflector antenna, the antenna must have equal beamwidths in the E plane and the H plane. The quad ridged horn antenna of the invention equalizes these beamwidths through of a conductive ring around the mouth of the horn antenna. Matching the E plane and the H plane beam widths results in uniform excitation of a parabolic reflector. The conductive ring is advantageously effective for exciting a reflector or an array of reflectors in two closely spaced bands, such as the Ku band.

Laser alignment apparatus and method

Abstract: A method for aligning a feed horn in an antenna system (100) is disclosed. The antenna system (100) includes at least one reflector surface and one or more feed horns (141, 142, ...145). The method includes the steps of determining a desired reflection point of the central ray from the feedhorn on the reflector surface, configuring a laser beam source to be mounted on the feed horn to enable a laser beam to travel substantially coincidently along the axis of transmission of the feed horn in a direction towards the reflector surface, and adjusting the azimuth and elevation of the feed horn to align the laser beam with the desired reflection point on the reflector surface. A laser aligning apparatus (200) for practising the above method and an antenna system aligned by means of the laser alignment apparatus (200) and/or method are also disclosed.

Communication device with integration in separate transmitter and receiver antennas

Abstract: Integrated RF components in the radio frequency (RF) front end of a communication device. The RF front end includes an antenna function for converting between radiated and electronic signals, includes a filter function for limiting signals within operating frequency bands, an amplifier function for boosting signal power and a mixer function for shifting frequencies between RF and lower frequencies. The receive antenna function is separate from the transmit antenna function where two different integrated filters/antennas (filtennas) are employed, a filtenna for the receive path and a filtenna for the transmit path.

Antenna system for a level measuring device

Abstract: The present invention relates to antenna system for a level measuring device for measuring a filling level of a filling product in a receptacle by means of microwave signals. The antenna system comprises an antenna horn (2) having an inner antenna horn flaring zone, and a planar structure (4) present in the antenna horn flaring zone. The planar structure (4) couples microwave signals into the antenna horn (2) for determining the filling level of the filling product, which microwave signals are then emitted by the anetnna horn (2) into the direction of the filling product.

Capacity of multi-antenna systems with adaptive transmission techniques

Abstract: The capacity of multiple antenna systems in the presence of Rayleigh flat fading is considered under the assumption that channel state information (CSI) is available at both transmitter and receiver. The capacity expression for a general dual antenna array system of multiple transmitter and receiver antennas is derived together with an equation that determines the cut-off value for such a system. It is shown that, compared to the case in which there is only receiver CSI, large capacity gains are available with an optimal power and rate adaptation scheme.

Feed horn and antenna

Abstract: PROBLEM TO BE SOLVED: To commonly use the components of a feed horn which are used together with reflecting mirrors having different diameters as much as possible. SOLUTION: In the feed horn, horn sections 16a and 16b are detachably attached to a plurality of waveguides 8a and 8b arranged with their center axes in parallel with each other. The horn sections 16a and 16b are selected correspondingly to the diameters of the used reflecting mirrors and respectively have pluralities of horns 20a, 20b, 24a, and 24b. The horns 20a, 20b, 24a, and 24b are coincident with the center axes of their corresponding waveguide 8a and 8b. The intervals between the horns 20a and 20b and between the horns 24a and 24b at the front ends of the horns 20a, 20b, 24a, and 24b are changed correspondingly to the diameters of the used reflecting mirrors.

Analysis of a 150 GHz spatial power divider/combiner

Abstract: A five-element spatial power divider/combiner has been realized. Uniform illumination is performed by a dual offset reflector setup. Holography is applied to couple the pseudo-plane wave to an in-line rectangular horn antenna array. The theoretical power dividing/combining efficiency amounts to 85%. Corresponding measurements around 150 GHz show a maximum efficiency of 77% and a 70% -bandwidth of 4%.

Co-located antenna design

Abstract: A method and apparatus are provided for transceiving signals. The method includes the steps of providing a secondary reflector within a focal region of a main reflector in a relative spatial relationship where a first radio frequency signal processed by a first radio frequency radiator adjacent the secondary reflector is reflected from both the secondary and main reflectors and providing a second radio frequency radiator in a aperture of the secondary reflector so that a second radio frequency signal processed by the second radio frequency transceiver is reflected from the main antenna along a path that is substantially coaxial with the first radio frequency signal.

Quad-ridged feed horn with two coplanar probes

Abstract: The invention utilizes two nominally orthogonal probes to couple selectively to two orthogonal modes propagating in a microwave waveguide and horn. The waveguide and horn utilize internal ridges to obtain broad bandwidth and the two probes are located in substantially the same plane in order to avoid introducing large changes in the relative phases of the two modes propagating within the waveguide with changes in frequency over the operating bandwidth of the device. The middle portion of each probe is bent or deformed to the extent needed to avoid physical conflict and electrical contact between the probes, while still avoiding the introduction of substantial phases differences between the modes excited by the respective probes.