Showing papers on "Feed horn published in 2008"

Design of High Efficiency Circular Horn Feeds for Multibeam Reflector Applications

Abstract: Design aspects of high efficiency profiled circular horns with thin walls as feeds for multibeam reflector antennas for satellite applications are presented in this paper. The modal content at the circular aperture of the horn necessary to closely approximate a unipolarized uniform distribution is first established. Slope discontinuities along the length of the horn are then used to generate the necessary aperture modes with the appropriate amplitudes and phases. The performance of the horn is calculated using the mode matching technique. Significant improvement in the horn aperture efficiency and reduction in the cross-polar level over a straight conical horn can be achieved over a single band or two bands that are widely separated in frequency. This conclusion is supported by the good agreement between predictions and measurements of a high efficiency dual-band horn.

Method and apparatus of codebook-based single-user closed-loop transmit beamforming (SU-CLTB) for OFDM wireless systems

Abstract: A method includes broadcasting, at a transmitter, messages comprising antenna configuration, antenna spacing and a number of antenna of the transmitter and reference signals; generating, at a receiver, a codebook comprising a plurality of antenna beams based on the broadcasted messages; receiving, at the receiver, the broadcasted reference signals; selecting, at the receiver, an antenna beam among the plurality of antenna beams within the codebook in dependence upon a predetermined performance criteria of a data communication system and in dependence upon the broadcasted reference signals; feedbacking to the transmitter, at the receiver, information comprising the antenna beam selected by the receiver; optimizing, at the transmitter, a beamforming process by utilizing the feedback information from the receiver; transmitting, at the transmitter, data signals by utilizing the optimized beamforming process; and receiving and processing, at the receiver, the data signals in dependence upon the selected antenna beams within the codebook.

Reply to “Comments on `Design of High Efficiency Circular Horn Feeds for Multibeam Reflector Applications'”

Abstract: The above paper (Chan and Rao, 2008), has been read with considerable interest. We wish to point out that the design, including radiation and wide-bandwidth characteristics, of multiflared high-efficiency horns has already been published in an invention disclosure (Bhattacharyya and Sor, 2004) which has been in the public domain since June 8, 2006. The high-efficiency multiflared horn structure was first designed in 2003 at the company of the first author. Since then, the structure has been used as radiating elements for arrays and as reflector feeds in several communication satellite projects.

Apparatus method and computer program for configurable radio-frequency front end filtering

Abstract: A radio use case is determined for concurrently operating radios of a multi-radio device and/or transmitter and receiver of a FDD radio. A local memory is accessed with the determined use case to find a high and/or a low frequency cutoff for the concurrent operation radio or transmitter/receiver. Control signals are applied to impose the high and/or the low frequency cutoff to a pair of frequency adjustable diplexers that are in series with one another in one of a transmit branch or a receive branch of a duplexer circuit that is disposed between the radio and an antenna. Then, a receive signal is passed through the antenna and the receive branch of the duplexer circuit to the radio or receiver of the FDD radio, or a transmit signal is passed from the respective radio or transmitter of the FDD radio through the transmit branch of the duplexer circuit to the antenna.

A vehicle mounted antenna and methods for transmitting and/or receiving signals

Abstract: An antenna for communicating with a satellite from a moving vehicle. The antenna comprises a transmitter for generating a transmission signal, main and sub reflectors, and a waveguide associated with the transmitter for conducting the transmission signal toward the sub reflector. The sub reflector is configured for redirecting the transmission signal toward the main reflector; the main reflector is configured for projecting the redirected transmission signal as an antenna beam toward the satellite.

Development of ALMA Band 8 (385-500 GHz) Cartridge

Abstract: We have developed a cartridge-type receiver covering from 385 to 500 GHz for pre-production of ALMA Band 8. It receives two orthogonal polarizations and down-converts the sideband-separated signals to intermediate frequencies (IF) between 4 and 8 GHz. The cartridge-type receiver consists of a cold optics, a feed horn, an OMT, two sideband-separating SIS mixers, cryogenic multipliers of local oscillator (LO). These components were individually tested and then the cartridge was integrated and tested as a complete assembly. We have also developed equipment to test both components and the integrated receiver. The single sideband (SSB) noise temperature of this receiver is 130 K at the band center and 180 K at the band edges. The beam pattern and cross-polarization pattern are consistent with physical optical calculation. These results are promising for receiver production to the Atacama Large Millimeter/submillimeter Array (ALMA).

Electronically steered, dual-polarized, dual-plane, monopulse antenna feed

Abstract: A method and apparatus for electronically steering a RADAR beam across an array of feed horns by moving the phase center of the beam to different origination points on the array—each origination point being the phase center of a feed horn pair. Variations include polarized beams, polarized feed horns, dual-beam systems, dual direction steering, diagonal steering, and cross-polarized wire grids to control beamwidth.

Antenna for compact satellite terminal

Abstract: An antenna for a compact satellite terminal. Antenna is a rigid parabolic structure of metal matrix composite capable of disassembly into segments affording a high degree of portability such as for man-packable satellite terminals and the like. A shallow feed horn assembly is joined to an orthomode transducer by a common hub, the hub also serving as the attachment point for a plurality of antenna segments, where a quick release means joins the segments to the hub. The feed horn, hub, orthomode transducer and antenna segments are designed for extremely compact stowability in a variety of applications.

Antenna System Supporting Multiple Frequency Bands and Multiple Beams

Abstract: A multiband antenna system supporting multiple communication services and multiple beams is presented. Key component of the antenna is the smooth-walled horn that has efficient radiation patterns over three frequency bands that are spread over an octave bandwidth and provides optimal illumination on the reflector at all the frequency bands. Results of the feed horn and the antenna are discussed.

Antenna Performance of a Directly Dug Corrugated Feedhorn for the 150-GHz Band

Abstract: We have developed a 150 GHz band corrugated feed horn. These corrugated feed horns have been established by a new machining method, which involves digging corrugations through a metal material. We were able to realize E plane and H plane symmetry, low side lobe level, and low cross-polarization level. Measured co-polarization beam patterns above − 35 dB were consistent with the simulated patterns within a designed frequency range. The peak levels of cross-polarization beam patterns were less than − 30 dB. And, the performances were uniform in several horns. In the present paper, we describe the corrugated horn produced by this methods.

Automatic Satellite Tracking System

Abstract: A satellite tracking system for tracking a synchronous satellite includes a satellite antenna system movably supported on a roof of a vehicle via a roof frame to move between an operation position and a folded position. At the operation position, the satellite antenna system is rotated on the roof frame to adjust a horizontal orientation of a parabolic reflector of the satellite antenna system while the parabolic reflector is pivotally lift at a predetermined inclination angle to align with the satellite. At the folded position, the parabolic reflector is pivotally dropped down until the parabolic reflector faces downwardly to the roof of the vehicle to conceal a signal transmitting device of the satellite antenna system between the parabolic reflector and the roof of the vehicle. Therefore, the satellite antenna system provides a relatively low profile at the folded position when the vehicle travels.

A modified Bow-Tie Antenna for Microwave Imaging Applications

Abstract: Due to the growing demand for traffic communication, the requirement for reconfigurable antennas for future generation of satellites is growing steadily. This article presents designs examples of reconfigurable satellite contour beam reflector antennas via multi-objective evolutionary optimization. One configuration is composed of shaped reflector illuminated by a single feed horn. To explore the concept, we consider the case of a satellite that can be placed in three orbital positions to provide different coverage: Europe, North America and South America. A second example considers a single shaped reflector illuminated by two feed horns to simultaneously provide dual coverage with frequency reuse

Frequency variable power transmitter and receiver in Fresnel region and power transmitting system

Abstract: An object is to achieve a radio power transmitting system capable of adaptively controlling power transmission efficiency, and the following means for achieving it is proposed. The power transmitting system includes a receiver having a loaded antenna and a transmitter whose transmitting frequency is variable, and it controls power transmission efficiency by using a modulated electromagnetic wave reflected from the receiver. A capacitive element and an inductive element are formed in the antenna, the transmitting frequency of the transmitter is set to be variable, the electromagnetic wave transmitted from the transmitter and reflected by the receiver is modulated, and the power transmission efficiency between the transmitter and the receiver is controlled by using the modulated reflection wave.

Ka-Band Shaped Reflector Hybrid Antenna Illuminated by Microstrip-Fed Horn Array

Abstract: The numerical simulation and experimental results of a shaped reflector hybrid antenna (SRHA) structure are presented. The SRHA design was optimized for a scan range of plusmn3deg for a broadside of 45deg in elevation to maintain a gain of more than 38 dBi and low side-lobes. The designed SRHA has an aperture size of less than 60 times 70 m2 and an offset structure for a low profile to meet the need for a mobile satellite platform. The antenna geometry and reflector surface was determined by a geometrical optic (GO) method and the radiation pattern was obtained by physical optic (PO) analysis. A microstrip horn array was used as a feeder and was composed of eight elements. The number of array elements was chosen so as to maximize antenna performances, such as gain and efficiency, without overdesign. The SRHA breadboard, including a shaped reflector and a feed horn array, was fabricated and measured. The measured results showed good agreement with the simulation and met the performance required of SRHA.

Low cost design & development of conical horn feed for parabolic reflector antenna

Abstract: We have designed the unusual types of feed antenna for parabolic dish that is used for both reception and transmission purpose. This different frequency band performance having horn and helical feed, works for the parabolic reflector antenna. We have worked on frequency band between 4.8 GHz to 5.9 GHz for horn type of feed. Here function of the horn is to produce uniform phase front with a larger aperture than that of the waveguide and hence greater directivity. Parabolic dish antenna is the most commonly and widely used antenna in communication field mainly in satellite and radar communication.

Performance comparison of a matched feed horn with a potter feed horn for an offset parabolic reflector

Abstract: The present paper deals with the comparison of matched feed performance with that of the conventional potter horn when used with an offset parabolic reflector. The effect of TE21 mode amplitude on the cross polarization has been studied in order to ascertain the suitable TE21 modal amplitude. Followed this, the behavior of change of TE21 modal amplitude with offset angle (thetas0) has been investigated. The effect of cross-polarization variation as a function of (F/D) ratio has been studied for both the matched feed and the potter horn. Finally, the beam squinting phenomenon in case of circular polarization has been studied for the matched feed and the results were compared with that of the potter horn.

Development of a 385-500 GHz Orthomode Transducer (OMT)

Abstract: —We report on the development of an orthom ode transducer (OMT) for ALMA Band 8 (385-500 GHz). The OMT is a scaled model of that of ALMA Band 4 (125-163 GHz), which has a Bφifot junction and a double ridge. The transmission loss of the OMT at 4 K was derived to be 0.4-0.5 dB from noise measurements with an SIS mixer. The polarization isolation was measured to be la rger t han 20 dB from quasioptical measurements. For electromagnetic d esign, effe cts of mechanical errors have been studied and then a robust design with allowable mechanical errors of 10 μm has been obtained. I. I NTRODUCTION An orthomode transducer (OMT) is a passive waveguide device that separates a received signal by a feed horn into its two orthogonal linearly polarized components. For submillimeter receivers, the conventional way to separate orthogonal polarizations is to use a wire grid, which is a quasioptical device that consists of free-standing wires. Optical systems of a dual polarization receiver with a wire grid or an OMT are shown in Fig.1. The merits and demerits of an OMT compared with a wire grid are the following: Merits 1) Optical system of a receiver can be quite simple and compact. An ellipsoidal mirror, a corrugated horn, and a wire grid can be removed from that with a wire grid. 2) There is no beam squint between two polarizations. 3) A problem of the life time of a wire grid can be solved. Demerits 1) A Fabrication is relatively difficult. 2) The Joule loss of the waveguide is added, although an ideal wire grid has almost no loss. These demerits can be solved if we can design mechanical robust OMT, and if waveguide is gold-plated. The transmission loss at 4 K is calculated as 0.5 dB/ 25 mm at 385 GHz when the OMT is cooled down to 4 K. We assume the conductivity of gold film at 4 K is 1.0 x 10

Simulation study of a 4 – 28 GHz double ridged conical horn antenna

Abstract: The design and simulation-based analysis of a 4-28 GHz double ridged conical horn is presented in this work. While the horn offers a VSWR of less than 1.6 over the entire bandwidth, it also exhibits desirable radiation patterns. More importantly, as per the simulation study, the ridged conical horn gives neat radiation and gain patterns throughout the band unlike the conventional ridged pyramidal horns whose patterns deteriorate at higher frequencies.

Radio frequency tag and method for manufacturing radio frequency tag

Abstract: According to an aspect of an embodiment, a radio frequency tag comprising: a base; a radio frequency antenna disposed on the base; a circuit chip mounted on the base and electrically connected to the radio frequency antenna, the circuit chip performing radio communication via the radio frequency antenna; and a protection sheet disposed on the radio frequency antenna, the protection sheet comprising a flexible material and rigid bodies dispersed in the flexible material so as to prevent the protection sheet from being collapsed when the radio frequency tag is bent and compressed.

Satellite Reconfigurable Contour Beam Reflector Antennas by Multi-objective Evolutionary Optimization

Abstract: Due to the growing demand for traffic communication, the requirement for reconfigurable antennas for future generation of satellites is growing steadily. This article presents designs examples of reconfigurable satellite contour beam reflector antennas via multi-objective evolutionary optimization. One configuration is composed of shaped reflector illuminated by a single feed horn. To explore the concept, we consider the case of a satellite that can be placed in three orbital positions to provide different coverage: Europe, North America and South America. A second example considers a single shaped reflector illuminated by two feed horns to simultaneously provide dual coverage with frequency reuse.

Effects of quasi-optical components on feed-horn co- and cross-polarisation radiation patterns

Abstract: Astrophysical experiments dedicated to the study of the Cosmic Microwave Background are in needs of very welldefined beam shape in order to get an accurate re-construction of the anisotropies power spectrum. These beams have tobe carefully designed, but also properly characterised. Some of these instruments will be located in a cryostat for whichfilters and windows are necessary, and the effects of these additional optical components on the beam shape need to betaken into account. We present here, measurements of such effects on the co- and cross-polarisation radiation patterns ofcorrugated horns using a Vector Network Analyser

Optics Design and Verification for the APEX Swedish Heterodyne Facility Instrument (SHeFI)

Abstract: We present the design and verification of the receiver optics for the Single-Pixel Heterodyne Facility Instrument (SHFI) of the APEX telescope [1]. The SHFI is designed to cover the frequency band 211 – 1390 GHz in 6 receiver channels. Four of the receiver channels have been designed, installed and characterized: 211-275 GHz (Band 1); 275-370 GHz (Band 2); 385- 500 GHz (Band 3); 1250-1390 GHz (Band T2). The first three bands employ 2SB SIS mixer technology and Band T2 employs HEB mixers in a waveguide balanced mixer configuration. The entire optics design was driven by the receiver position in the telescope Nasmyth cabin “A” (Fig.1) and the aperture limit of O150 mm, introduced by the elevation encoder inside the Nasmyth tube A. This layout and the telescope geometry (~ 6 m distance from the focal plane to the Cabin A) lead us to choose a single-pixel configuration and required using intermediate optics with long focal distances. The common optics path, coupling the receivers to the Cassegrain sub-reflector, consists of the three offset ellipsoidal mirrors, M3, M6, M8s, and three flat mirrors, F4, F5, and F7s. The combination M3 and M6 via flat F4, F5, creates a Gaussian telescope, providing frequency-independent re-imaging of the antenna focal plane from the Cassegrain cabin into the Nasmyth cabin A. Switching between channels is achieved by the precision rotating of the active mirror M8s. The mirror M8s in combination with each channel active mirror M10 provides re-imaging of the secondary onto the feed horn aperture of the selected channel. Such a configuration provides frequency independent illumination of the secondary with the edge taper -12dB. The angular position of the flat mirrors F9 is adjustable and gives additional possibility of fine-tuning of the beam alignment from the common optics to every receiver channels. Verification of the optical design through measurements is essential in order to align the beams from the cryostat windows to the common optics to minimize loss in the quasioptical guiding system. In order to verify the design of the cold optics (corrugated horn + M10) in terms of Gaussian beam parameters, a new wideband vector field measurement system was developed [2]. Vector field measurements were performed for band 1, 2, and 3, and scalar measurements were employed for the THz band.

Hybrid ultrasonic and radio frequency identification system and method

Abstract: A radio frequency identification system and method includes a tag reader and radio frequency identification tag. The tag reader includes an ultrasonic transducer capable of transmitting tones at selected ultrasonic frequencies and a radio transmitter capable of transmitting signals at selected radio frequencies. The tag reader includes a radio receiver capable of receiving signals at selected radio frequencies. The tag reader determines if a received radio frequency signal is modulated at a selected ultrasonic frequency. The radio frequency identification tag includes an array of combination resonator/reflectors. Each combination resonator/reflector of the array includes an ultrasonic resonator coupled to a radio reflector. Each resonator/reflector of the array is tuned to a unique pair of selected ultrasonic frequencies and selected radio frequencies.

Compact Dual Polarization Feeding System of HY-2 Calibration Radiometer

Abstract: A new double-septums in main wave guide and single septum in side waveguide ortho-mode transducer (OMT) is proposed in this paper. Finite difference method in time domain (FDTD) and genetic algorithms (GAs) are combined to analysis and optimize this new OMT. The simulation results of the OMT together with the feed horn validate the better characteristics of the new OMT than that of the common structure. The VSWR of this OMT is less than 1.1 in the bandwidth, the cross-polar level of the feed can reach -25 dB, while the length of the main waveguide can be reduced at least 30%. On the other hand, in order to reduce the weight and length of the feed, a compact conical corrugated horn is also employed.

Alignment Verification of the PLANCK Reflector Configuration by RCS Measurements at 320 GHz

Abstract: In the Flight Model (FM) of the PLANCK telescope, the feed horns are connected to either HEMTs or bolometers operating at cryogenic temperatures to detect the Cosmic Microwave Background radiometric signal. For the purpose of an overall alignment verification at ambient temperature, RCS measurements have been performed using an auxiliary feed horn that is terminated with a switching diode. This verification test has been conducted at 320 GHz, to benefit from the narrow beam and a high sensitivity to misalignment. To perform the RCS measurements, an additional "circulator" with low propagation loss and high isolation from transmit to return channel had to be developed. Besides that, the circulator also co-locates the phase centres of both Tx and Rx range antennas on the focal point of the CATR, which allows mono-static RCS measurements. Quasi-optical techniques have been used to design a circulator that meets these requirements. To test the feasibility of determining the feed location from the RCS measurements with an uncertainty of plusmn1 mm, a test campaign was conducted with the so called RF Qualification Model (RFQM). In this campaign, 9 feed locations with 1 mm separation were tested. With the Flight Model, the test was on the critical path of the planning and only one test could be conducted to verify the overall alignment.

Low-Loss Feedome Design for Axially Displaced Ellipse (ADE) Reflectors

Abstract: To address the continuing demand for high-performance advanced extremely high frequency (EHF) antennas for satellite communications, we developed a low-loss feedome for the axially displaced ellipse (ADE) reflector antenna for improved aperture efficiency To examine the feasibility of the approach, a feedome is designed and a prototype is built in the frequency range of 435455 GHz (Q-band) Simulation results using a linear feed horn correlate very well with experimental results employing an right-hand circularly polarized (RHCP) feed horn

Study on a parabolic reflector fed by L-band multi-port eleven antenna

Abstract: The paper studies the properties of the far field of a primary-fed parabolic reflector fed by a four-port L-band Eleven antenna. The sum beam as well as difference beams in two orthogonal planes after the reflector, which are necessary for the mono-pulse tracking, have been numerically evaluated. In addition, the relationship between the spacing between two parallel folded dipoles and the matching as well as radiation properties has been investigated.

Effect of design parameters on sidelobe level of short-focus parabolic reflector antenna

Abstract: In this paper, a low sidelobe short-focus parabolic reflector antenna fed by a half-wave dipole with a disk secondary reflector is presented. Effect of focal length to diameter ratio and secondary reflector parameters on sidelobe level has been explored. Electromagnetic simulations and theoretical analysis of parameters variation were performed. The tendency and degree of the effect of each parameter on sidelobe level have been given. This low sidelobe short-focus parabolic reflector antenna has the advantages of low cost, small size, simple structure and perfect electrical properties. It can be applied to special occasions as life detection radar systems which in need of low cost and small-size.

High speed monopulse tracking radar antenna

Abstract: A high speed monopulse tracking radar antenna is provided to track a high speed flying object by reducing a weight thereof to rotate at high speed by using feed line pipes as a feed horn support. A parabolic reflector(10) is formed by filling honeycomb or expandable resin cells between a parabolic metal film and a parabolic insulator. A monopulse feed horn(20) is supported by feed line pipes(5), installed in a focus position(F) of the parabolic reflector, and supplies a total sum signal, a horizontal difference signal, and a vertical difference signal. A transceiver(30) is installed at a center of a back side of the parabolic reflector to receive the total sum signal, the horizontal difference signal, and the vertical difference signal. A housing(40) protects the transceiver. A driving unit tracks an object by rotating the parabolic reflector at high speed.

Modal Analysis of a Single-Aperture Monopulse Feed Horn

Abstract: In this paper, we present a modal analysis of a single-aperture monopulse feed horn. The horn aperture is of square type and it is assumed that necessary higher-order modes can be generated by suitable means. First we consider the type of higher-order modes that can be employed in the realization of the sum and difference patterns for the monopulse feed. The principle of choosing mode ratios for the sum and difference channels is presented and an optimum set of mode ratios are derived. With the derived mode ratios, we compute and plot the aperture electric field distribution and the resultant radiation patterns.