Showing papers on "Feed horn published in 1988"
TL;DR: In this article, a smooth profiling horn using a series of discrete conical sections is proposed to eliminate most of the mode conversion and a horn designed in this way is presented and shown to possess improved performance characteristics in comparison to a smoothly profiled design.
Abstract: The design principles used to realize smoothly profiled corrugated horns are described. The smooth profiling causes power to be converted to higher order HE/sub 12/ modes which radiate to produce high sidelobes in the copolarization patterns. A computer-aided spherical modal-matching technique is used to study the higher-order mode conversion. The results show good agreement with measurements. A profiled horn using a series of discrete conical sections is proposed to eliminate most of the mode conversion. A horn designed in this way is presented and shown to possess improved performance characteristics in comparison to a smoothly profiled design. >
62 citations
TL;DR: An antenna consisting of a flat printed reflector and a feed horn was investigated at mm-wave frequencies in this paper, where the dielectric material is fully metal covered at the side opposite to the feed, whereas the side facing the feed is provided with a number of metallic annular rings forming a Fresnel zone plate.
Abstract: An antenna consisting of a flat printed reflector and a feed horn was investigated at mm-wave frequencies. The dielectric material is fully metal covered at the side opposite to the feed, whereas the side facing the feed is provided with a number of metallic annular rings forming a Fresnel zone plate. >
53 citations
TL;DR: In this article, the design of a multimode feed horn for use in a monopulse feed system is summarized and the amplitude and phase patterns are computed in consideration of achieving the desired aperture distributions for the sum and difference beams.
Abstract: The design of a multimode feed horn for use in a monopulse feed system is summarized. Both amplitude and phase patterns have been obtained and compared with measurements. The far-field amplitude and phase patterns are computed in consideration of achieving the desired aperture distributions for the sum and difference beams. The phase center of the horn is discussed in relation to the multimode excitation and frequency dispersion. It is shown that the phase center location moves as the mode content changes, and proper adjustment of the mode content will result in design optimization. Some tradeoff curves are also presented for design optimization. >
37 citations
01 Aug 1988
TL;DR: In this article, an analytical Gaussian beam model for the radiation field of a corrugated horn antenna is presented, which describes how the beam width and the location of the phase centre depend on the dimensions of the horn, and how they vary as a function of the distance from the horn aperture to the observation point.
Abstract: An analytical Gaussian beam model for the radiation field of a corrugated horn antenna is presented. The model describes how the beam width and the location of the phase centre depend on the dimensions of the horn, and how they vary as a function of the distance from the horn aperture to the observation point. The model includes both the near-field and the far-field of the horn. These properties make the Gaussian feed model much better, for use in general work on reflector antennas, than the conventional cosnθ pattern. The Gaussian model is also used to define aperture-controlled and flareangle controlled horns, depending on whether the radiation patterns are frequency-sensitive or not.
26 citations
Patent•
04 Oct 1988
TL;DR: In this article, the phase positions of the direct and 90° phase-shifted signals are changed in dependence on the phase difference between the respective intermediate frequency mixed signal and the overall summed signal in a direction to maximize the summed signal.
Abstract: To increase the fidelity of radio reception in a moving receiver, for example a car radio, the signals received from various antennas on the radio are mixed with a carrier in the receiver, and the resulting mixed signals, directly and 90° phase-shifted, are added to a summing signal, in which, additionally, the phase positions of the direct and 90° phase-shifted signals are changed in dependence on the phase difference between the respective intermediate frequency mixed signal and the overall summed signal in a direction to maximize the summed signal (us).
23 citations
Patent•
08 Feb 1988
TL;DR: In this article, a lens antenna (10) having four phased array apertures (12, 14, 16, and 18) positioned for hemispherical coverage is disclosed, each of which is interconnected with four radiating elements (54, 56, 58, and 60), one on each of the four aperture.
Abstract: A lens antenna (10) having four phased array apertures (12, 14, 16, and 18) positioned for hemispherical coverage is disclosed. An array of phase shifters (52) is disclosed, each of which is interconnected with four radiating elements (54, 56, 58, and 60), one on each of the four apertures. A feed horn (30) is used to feed the lens and switches (48, 50) in the lens are used to switch the energy received from the feed horn to the phase shifter, and after phase shifting, to a selected aperture for radiation. The switches also perform a reciprocal function by switching energy received at an aperture to the phase shifter and then to an aperture for radiation to the feed horn. In a further embodiment, the mounting of transmitting and receiving components, such as a high power amplifier (70) and a low noise amplifier (72), with a combination of DPDT switches in the lens is disclosed and results in a solid state T/R type antenna array. In one embodiment, the switches enable the lens to radiate from three of the apertures for a scan angle of 270 degrees from a single feed horn. The addition of mor efeed horns per face results in multiple radiated beams from a single face.
11 citations
01 Oct 1988
TL;DR: The paper describes a means to change the coverage zone of a spacecraft antenna by reconfiguration of the reflector surface by using a realistic model for an offset mesh reflector.
Abstract: The paper describes a means to change the coverage zone of a spacecraft antenna by reconfiguration of the reflector surface. By using a realistic model for an offset mesh reflector, reconfiguration is successfully demonstrated for the case of two future INTELSAT regional beams. Suggestions are made concerning both the mesh characteristics and the means by which it might be controlled.
10 citations
06 Jun 1988
TL;DR: In this paper, the design, development, and testing of a dual-polarized waveguide-fed horn antenna is highlighted, which is to be used for the wind scatterometer radar, NSCAT, to be placed upon the NROSS satellite.
Abstract: The design, development, and testing of a dual-polarized waveguide-fed horn antenna is highlighted. The antenna is to be used for the wind scatterometer radar, NSCAT, to be placed upon the NROSS satellite. The dual polarized NSCAT antenna consists of a pair of slotted waveguides fed through horns. The edge-wall 202-element slot array excites an H-plane flared horn; the broad-wall 202-element slot array excites a corrugated E-plane flared horn. The antennas are designed to have nearly identical far-field patterns. It is noted that careful attention to all construction tolerances was extremely important for maintaining proper beam pointing and scale lobe levels. This was particularly true for the edge-wall slot design. >
8 citations
06 Jun 1988
TL;DR: In this paper, the synthesis of offset dual-reflector antennas is reduced to solving nondifferential equations, which is made possible by approximating a known solution for the geometrical optics (GO) field reflected from a surface, and using local parabolic expansions of the reflector surfaces.
Abstract: An approach is presented by which synthesis of offset dual-reflector antennas is reduced to solving nondifferential equations. This is made possible by approximating a known solution for the geometrical optics (GO) field reflected from a surface, and using local parabolic expansions of the reflector surfaces. The advantages of this approach are that the calculation is easy to carry out, the condition of low cross-polarization is included, and the question of existence clearly can be answered. The synthesis method can also readily be extended to the synthesis of multireflector antennas. >
8 citations
TL;DR: In this article, a system consisting of two quarter-wave polarisers in tandem for polarisation alignment of linearly polarised satellite signals is described, where the signal can be received with the correct polarisation simply by rotating the polariser which is closest to the feed horn.
Abstract: The letter reports on a system consisting of two quarter-wave polarisers in tandem for polarisation alignment of linearly polarised satellite signals. The signal can be received with the correct polarisation simply by rotating the polariser which is closest to the feed horn. The required isolation in the frequency bands 10.95–12.75 GHz (Rx) and 14.0–14.5GHz (Tx) is 35 dB on the axis for the total antenna system consisting of reflectors, horn, polariser system and orthomode transducer. This requirement cannot be met when existing polarisers are used and when a ±90° rotation is required. By using a new type of polariser, 38 dB isolation has been measured for the polariser system over the entire frequency band and over the entire range of rotation, with transmission loss below 0.15dB and return loss below −25dB (VSWR < 1.12). The total length of the system is approximately 300 mm.
7 citations
TL;DR: A compound taper feed horn structure is described that was used to move the phase center of a corrugated feed horn without any significant degradation in its other major characteristics and has been designed for use in the National Aeronautics and Space Administration's (NASA) 70-m antennas.
Abstract: A compound taper feed horn structure is described that was used to move the phase center of a corrugated feed horn without any significant degradation in its other major characteristics. Based on this technique, an X-band feed horn has been designed for use in the National Aeronautics and Space Administration's (NASA) 70-m antennas. The compound taper structure consists of a conventional corrugated flared section (a standard 22-dB feed horn) and a corrugated straight section. This feed horn is designed to move the phase center of the standard feed horn to a desired location without the addition of significant loss to the system. The feed horn was checked extensively by a computer program. Excellent agreement between theoretical and measured results was established, and the feed horn was shown to perform as well as the standard feed horn for all practical purposes. >
01 Oct 1988
TL;DR: In this paper, the authors present a method to improve the calculation of the directivity and the radiation pattern of a primary-fed reflector antenna, by including the contribution due to multiple reflections between the feed and the reflector.
Abstract: This paper presents a method to improve the calculation of the directivity and the radiation pattern of a primary-fed reflector antenna, by including the contribution due to multiple reflections between the feed and the reflector. These multiple reflections are controlled by introducing a feed scattering pattern, which is the scattered field from the feed when illuminated by a plane wave. The method is applied to a reflector with a self-supported dipole-feed, showing good agreement with both the measurements and a moment method solution of the complete antenna including the feed as well as the paraboloidal reflector. The results show that the multiple reflections may have stronger effect on the directivity and the cross-polar sidelobe level than the centre blockage has.
TL;DR: In this paper, the on-axis cross-polarisation of a reflector antenna illuminated by a feeding system with an asymmetric crosspolar radiation pattern was examined, and a graph was presented from which the cross polarisation discrimination (XPD) of the antenna can be simply obtained.
Abstract: The on-axis cross-polarisation of a reflector antenna illuminated by a feeding system with an asymmetric cross-polar radiation pattern is examined. A graph is presented from which the cross-polarisation discrimination (XPD) of the reflector antenna can be simply obtained.
06 Jun 1988
TL;DR: In this article, a single offset parabolic reflector fed by a planar array feed was used for future mobile satellite communications, such as frequency reuse and reconfigurable coverages.
Abstract: Results are presented for a single offset parabolic reflector fed by a planar array feed. The reflector system can be any of the well-known types of focused reflectors: paraboloid, spherical, or shaped: symmetrical or offset: single, dual, or multiple reflectors. The antenna system complies with the expected requirements of future mobile satellite communications, such as frequency reuse and reconfigurable coverages. The payload can be accommodated within the Ariane 4 fairing, and the layout is fully compatible with current European platforms such as EUROSTAR and SPACEBUS. The system makes use of advanced technology such as solid-state amplifiers and deployable reflectors. >
06 Jun 1988
TL;DR: In this paper, an 18 in. diameter zoned dielectric lens for a 271 beam multiple-beam antenna (MBA) was fabricated and tested with a Potter feed horn, both with and without resistive tapering.
Abstract: The design of multiple-beam antenna (MBA) systems for EHF communication satellites involves tradeoff studies of coverage gain, sidelobe level and beamwidth as a function of the number and sizes of the lens aperture and the feed directivity. The author defines those parameters that are common to any MBA system. Results are presented of parametric studies in which the lenses are assumed to be simple apertures with ideal transducers that convert the spherical wavefront from the feed into a plane wave without introducing any aberrations. An 18 in. diameter zoned dielectric lens for a 271 beam MBA was fabricated and tested with a Potter feed horn, both with and without resistive tapering. Measurements of its on-axis radiation patterns and gain show that they are correctly predicted by the aperture theory used for optimization. These results indicate that optimum dimensions for a lens or reflector MBA may be determined through straightforward analytic techniques and the use of the parametric curves. >
Patent•
10 Jun 1988
TL;DR: In this paper, a reflector-type microwave antenna includes a paraboloidal reflector (10) and a feed horn (11) located at the focal point F of the reflector.
Abstract: A reflector-type microwave antenna includes a paraboloidal reflector (10) and a feed horn (11) located at the focal point F of the reflector (10). A supporting frame (13, 14, 15) for the reflector (10) and feed horn (11) includes three arms (13, 14, 15) extending along the rear side of the reflector (10) to three spaced mounting locations (30, 40, 50) on the rear side of the reflector (10). The arms (13, 14, 15) are fastened to the spaced mounting locations (30, 40, 50) on the rear side of the reflector (10) by fastening means having a loose condition in which the arm (13, 14, 15) is attached to the reflector (10) but free to move relative to the reflector (10), and a tightened condition in which the respective arm (13, 14, 15) is rigidly attached to the reflector (10). The fastening also includes swivel means (32, 33, 36) for permitting tilting movement of the arm (13, 14, 15) relative to the reflector surface (10) when the fastening means is in the loose condition, and permitting the arm (13, 14, 15) to assume different positions relative to the reflector (10) when the fastening means is in the tightened condition. In its preferred form, the fastening means includes a cupped member (30) having a peripheral flange (60) secured to the rear side of the reflector (10) so that forces transmitted between the respective arms (13, 14, 15) and the reflector (10) are distributed over the area of the reflector (10) encompassed by said flanges (60).
TL;DR: The theoretical study and model measurements on a high-power, steerable shortwave antenna covers a spherical reflector, a parabolicreflector, and a log-periodic switch-steerable-type antenna, which provides high-gain switch-Steerable antenna suitable for over-the-horizon radar detection.
Abstract: The theoretical study and model measurements on a high-power, steerable shortwave antenna covers a spherical reflector, a parabolic reflector, and a log-periodic switch-steerable-type antenna. The scale modeling facilities are described and the modeling results are presented. The spherical reflector gives reasonable good azimuth and elevation steering over the shortwave band from 5.8 MHz to 27 MHz. The parabolic reflector gives good azimuth steering, with higher gain but no vertical steering. The log periodic antenna provides a high-gain switch-steerable antenna suitable for over-the-horizon radar detection. >
28 Nov 1988
TL;DR: The use of higher order modes in a horn reflector antenna to achieve pattern diversity is discussed and a candidate mode coupler is analyzed, and the measured performance for a one-fifth-scale model is reported.
Abstract: The use of higher order modes in a horn reflector antenna to achieve pattern diversity is discussed. During multipath fading, off-axis arrival of signals excites higher-order modes in the antenna feed. The separation of the appropriate modes and their proper recombination can be used to generate two orthogonal antenna patterns for both vertical and horizontal polarizations. A candidate mode coupler is analyzed, and the measured performance for a one-fifth-scale model is reported. >
Patent•
27 Dec 1988
TL;DR: In this paper, the authors proposed a simple and accurate way to control the direction of a parabolic antenna for reception of the satellite broadcast in a simple, quick and accurate manner by controlling the antenna first in the reference direction set artificially and then turning the antenna toward a desired satellite based on the calculated value.
Abstract: PURPOSE:To control the direction of a parabolic antenna for reception of the satellite broadcast in a simple, quick and accurate way, by controlling the antenna first in the reference direction set artificially and then turning the antenna toward a desired satellite baed on the calculated value CONSTITUTION:When an antenna 10 is turned toward a desired satellite, an azimuth magnet is first put on the upper surface of a feed horn attachment part of the antenna 10 together with a pointer attached onto the side face of a flange Under such conditions, the latitudinal and longitudinal values of the antenna installing point and other values are supplied with operation of keys set at a keyboard input part 50 Then the DC motors 29 and 33 of 1st and 2nd drive parts 28 and 32 are driven with operation of keys of a setting input part 52 Thus the antenna 10 is turned to the due south or in the just horizontal direction Then a selection key is pushed at a selection input part 54 for a desired satellite and the displacement value of the selected satellite is calculated against the reference direction based on a program Then both motors 29 and 33 are driven by the extents equivalent to said calculated displacement value Thus the antenna 10 is turned to the desired satellite
01 Oct 1988
TL;DR: The design and the measured performance of the antenna system for the TELE-X satellite is described, with good aperture efficiencies combined with low sidelobe and crosspolarization levels.
Abstract: The paper describes the design and the measured performance of the antenna system for the TELE-X satellite, the Scandinavian direct broadcast and communication satellite. The two antennas are shaped, astigmatic double reflector systems. Good aperture efficiencies combined with low sidelobe and crosspolarization levels are demonstrated.
Patent•
10 Jun 1988
TL;DR: In this paper, the authors proposed to improve the working efficiency by supporting a waterproof packing to either a low noise frequency converter and a coupling face of a feed horn by means of exfoliated adhesives so as to support the packing surely.
Abstract: PURPOSE:To improve the working efficiency by supporting a waterproof packing to either a low noise frequency converter and a coupling face of a feed horn by means of an exfoliated adhesives so as to support the waterproof packing surely. CONSTITUTION:In mounting the low noise frequency converter 1 and the feed horn 2, the waterproof packing 3 is set to a slot 1b of the converter from the face provided with an adhesives 4 to be exfoliated or set in a slot 2b of the born 2. Then the packing 3 is supported into the slots 1b, 2b by the member 4 surely. Thus, while the converter 1 and the horn 2 or the line are carried to a working place or during the work, the packing 3 is not deviated from the slot 1b or 2b or fallen down. Thus, the working efficiency is improved.
06 Jun 1988
TL;DR: In this paper, a microwave lens or an offset reflector instead of a front-fed reflector is used to focus the incident field on the other side of the antenna under test.
Abstract: A method is proposed which uses a microwave lens or an offset reflector instead of a front-fed reflector. The lens focuses the incident field on the other side of the antenna under test. Thus the feed and the probe do not interfere with each other. For the offset reflector case to work, the reflector has to have analogous focal region properties to a front-fed parabolic reflector. Using M. Hoque et al.'s (1984) model, the authors show how the offset reflector scheme is possible. The technique is expected to be valuable for compact ranges although the feasibility of the method and practical near-field separation distance between the two reflectors are still to be determined. >
TL;DR: In this article, a dual-model feed horn was proposed for low-cost satellite earth stations, which is considered particularly suitable for application in receive-only reflector antennas, and some experimental and theoretical results were presented, which are in good agreement and demonstrate the performance achievable with this class of feeds.
Abstract: This paper describes a version of the dual-model feed horn that is considered particularly suitable for application in receive-only reflector antennas. Even though it was originally presented many years ago, to the authors' knowledge this type of biconical feed horn has not previously been analyzed or utilized. The present paper aims to describe the potential advantages of this feed horn for low-cost satellite earth stations, and then briefly to illustrate the design methodology that was adopted. Finally, it presents some of the experimental and theoretical results, which are in good agreement and demonstrate the performance achievable with this class of feeds.
06 Jun 1988
TL;DR: The numerical results show that the gain is increased and the sidelobe levels are greatly reduced for strip, corner, circular, and parabolic reflector antennas by using three line sources with proper choice of their positions, amplitudes, and phase.
Abstract: The radiation characteristics of a class of two-dimensional reflector antennas is investigated. An array of radiators is used to control the aperture field distribution and hence the gain and the sidelobe levels of the far radiated fields. The method of moments is used to find the induced surface current distribution, the aperture field, and the far-field pattern. Since the problem is two-dimensional, all radiators are considered to be line sources. The numerical results show that the gain is increased and the sidelobe levels are greatly reduced for strip, corner, circular, and parabolic reflector antennas by using three line sources with proper choice of their positions, amplitudes, and phase. >