Showing papers on "Feed horn published in 2003"

Analysis and Simulation of a 1-18-GHz broadband double-ridged horn antenna

Abstract: A 1-18-GHz broadband double-ridged horn antenna with coaxial input feed section is investigated. For the ridged horn antenna it is found that the radiation pattern, contrary to common belief, does not maintain a single main lobe in the direction of the horn axis over the full frequency range. Instead, at frequencies above 12 GHz, the main lobe in the radiation pattern starts to split into four large side lobes pointing in off-axis directions with a dip of up to 6 dB between them along the main axis. Although this type of horn is the preferred test antenna, which is in common use for over four decades, no explanation for this unwanted behavior was found in the open literature. To investigate this phenomenon in detail, a method of moments approach has been adopted to simulate the complete antenna system. The simulations are in good agreement with the measurements over the 1-18-GHz operational bandwidth and indicate that the use of this type of horn antenna in EMC applications remains questionable.

Coaxial horn antenna system

Abstract: An antenna feed system includes a plurality of RF horn antennas ( 201, 202 ) for operating on a plurality of RF frequency bands. A first one of the feed horns ( 202 ) can have a boresight axis and is configured for operating at a first one of the frequency bands. A second one of the feed horns ( 201 ) is positioned coaxially within the first one of the feed horns ( 202 ) and is configured for operating at least at a second one of the frequency bands. Further, the first one of the feed horns ( 202 ) is a corrugated horn that has a plurality of corrugations ( 204 ) formed on an interior surface defining a profile. The profile extends substantially from a throat ( 205 ) of the first feed horn and along a tapered portion of the first feed horn. The profile substantially minimizes an interaction of the corrugations with the second feed horn.

Diplexing feed assemblies for application to dual-reflector antennas

Abstract: We investigate possible configurations for dual-band waveguide diplexing assemblies appropriate for use as feed systems for dual-reflector antennas. Specific applications are where the bands are well separated and, individually, have relatively wide bandwidths. Two crucial problems are addressed: the demanding bandwidth requirements of the feed horn and the subsequent means of diplexing the signals. We present results arising from the analysis of candidate systems and discuss a preferred option in detail.

Digital video broadcast-terrestrial (dvb-t) receiver interoperable with a gsm transmitter in a non-interfering manner using classmark change procedure

Abstract: A method and a device used for displaying information from at least one radiofrequency (RF) distributed service through a cellular mobile terminal (CMT). The RF distributed service may provide interactivity through a return channel. The device (10) has a first antenna (12) and a second antenna (20), a receiver (14,16) that is coupled to the first antenna and a transmitter (24) that is coupled to the second antenna. The method includes, prior to receiving information with the receiver in a first band of radio frequencies, generating a notification of reception with the receiver by asserting a receiver on signal and, in response to the notification, requesting a change of transmitter transmission frequencies from a second band of radio frequencies to a third band of radio frequencies that is predetermined to avoid interference with the reception of the information in the first band of radio frequencies. The transmitter is preferably a cellular mobile terminal transmitter, and the request for a change can be made by initiating a Classmark Change procedure with a cellular mobile terminal wireless network. In one embodiment, the RF distributed service includes GPS data. In other embodiments, the RF distributed service includes DV13-T or ACTS.

Random surface error effects on offset cylindrical reflector antennas

Abstract: The focus of this paper is to characterize the average power pattern of an offset cylindrical parabolic reflector antenna subject to random surface errors. A novel computational method is developed for studying the random surface error effects on the boresight gain loss and the sidelobe levels of the average power pattern. The particular antenna dimensions used for this study are similar to the specifications for the second generation precipitation radar (PR-2) mission. In keeping with the requirements in the PR-2 mission, both the Ku and Ka frequency bands are considered. Random surface error effects are also studied for different edge taper levels. In addition to analysis of a reflector with uniform random surface errors, a nonuniform surface error case is presented in this study. This is an important consideration for evaluating the suitability of large deployable membrane reflector antennas for the PR-2 mission.

Small reflector antenna with low sidelobes

Abstract: A prime focus low sidelobe parabolic reflector antenna with self-supported feed is designed for low sidelobe applications. The parabolic reflector diameter is between nine and twelve wavelengths. A simple design is achieved to satisfy the required first sidelobe level. The design is performed numerically using a computer code for bodies of revolutions (AKBOR2). The measured radiation patterns of 18 inch and 24 inch reflector systems at 5.75 GHz. are presented. Good agreement between computed and measured radiation patterns is obtained.

Compact micro-concentrator for photovoltaic cells

Abstract: A reflector array comprises a plurality of partial parabolic reflectors arranged in rows and columns with each reflector directing radiation to a receiver or from a transmitter located at the focus of the reflector. In a compact photovoltaic cell arrangement, each cell is shielded from direct radiation by the adjacent reflector. The reflectors can be formed as one unit with reflective material or with the reflecting surfaces coated with aluminum, silver, or other suitable reflecting material. A secondary reflector can be positioned at the focus of a reflector for directing radiation to a receiver or from a transmitter located at a more accessible location in the array.

Feed horn coupled bolometer arrays for SPIRE - design, simulations, and measurements

Abstract: In this paper, we present the design, modeling, and measurements of feed horn coupled large bolometer arrays being developed for the Herschel Space Observatory's Spectral and Photometric Imaging REceiver (SPIRE) instrument. SPIRE has five arrays of feed horn coupled silicon-nitride micromesh "spider-web" bolometers in two instruments, a three-band photometer, and a two-band Fourier transform spectrometer, each covering the 430-GHz-1.5-THz band. The optical coupling efficiency, bandwidth, and crosstalk between adjacent pixels of the arrays were investigated with numerical electromagnetic-field simulators, and prototype arrays were measured extensively in a test facility. The measured results were found to be in good agreement with simulation predictions, and the simulation results were used as a benchmark for the design goals of the instrument.

Multi-beam and multi-band antenna system for communication satellites

Abstract: An antenna system includes a reflector having a modified-paraboloid shape; and a multi-beam, multi-band feed array located at a focal point of the reflector so that the antenna system forms a multiple congruent beams that are contiguous. The system has a single reflector with non-frequency selective surface. The reflector is sized to produce a required beam size at K-band frequencies and is oversized at EHF-band frequencies. The synthesized reflector surface is moderately shaped and disproportionately broadens EHF-band and Ka-band beams compared to K-band beams. The synthesized reflector surface forms multiple beams each having a 0.5-degree diameter at K-band, Ka-band, and EHF band. The multi-beam, multi-band feed array includes a number of high-efficiency, multi-mode circular horns that operate in focused mode at K-band and defocused mode at Ka-band and EHF-band by employing “frequency-dependent” design for the horns.

Sector antenna apparatus and vehicle-mounted transmission and reception apparatus

Abstract: A sector antenna apparatus mounted on a vehicle has a casing, in which six horn antennas having apertures over an angular range of 180 degrees and extending radially are accommodated. The proximal ends of the horn antennas are connected to an antenna changeover switch. A portion of the horn antennas which emits beam radiation in the forward and backward direction and diagonal direction of the vehicle have large apertures, and a portion of the horn antennas which emits beam radiation to the right and left of the vehicle have a small aperture. Thus, the required antenna characteristics, such as angular resolution, beam width, antenna gain, are achievable in the required direction.

High gain wideband compact microstrip antenna with quasi-planar surface mount horn

Abstract: We report a new compact square microstrip antenna with a surface mounted quasi-planar horn. The horn is made of plastic sheet and painted with silver epoxy. The horn improves the gain of the patch by 3-4.5 dB without adversely affecting bandwidth which is 2.3-9%.. Also the horn improves the isolation between array elements by 10 dB. The total thickness of antenna, including the horn, is only 6.94 mm.

Antenna receiving system

Abstract: A receiving antenna system includes an antenna unit, a receiver unit, a down converter and a DC power/control supply. The antenna unit includes a parabolic reflector, a feed horn and an orthomode transducer, which are configured to capture, isolate, and output respective first and second polarized RF signals. The receiver unit is coupled to the antenna unit and is configured to amplify the respective RF signals and output a selected one of the respective amplified RF signals in response to a DC control signal. The down converter is coupled to the receiver unit via a transmission line and is configured to further amplify, down convert and output the selected amplified RF signal as an intermediate signal. The DC power/control supply is coupled to the receiver unit via the same transmission and is configured to produce a power/control signal that is transmitted over the same transmission line in which the selected amplified RF signal is transmitted, thereby providing power and control to the receiver unit.

Adaptive communications system and method

Abstract: An arrangement where a transmitter has multiple transmitting antennas that simultaneously transmit, and where the signals delivered to each transmitting antenna is processed by a space-time transmitter based on the side information that is related to the channel coefficients found between the transmitting antennas and multiple receiving antennas. The receiver's receiving antennas simultaneously receive the transmitted signals, and the signal from each receiving antenna is processed by the space-time receiver to extract the information symbols that have been transmitted. Alternative systems are possible, such as those employing frequency or code diversity, as well as those employing only one transmit antenna and multiple receive antennas (or visa versa).

Comprehensive analysis and simulation of a 1-18 GHz broadband parabolic reflector horn antenna system

Abstract: A 1-18 GHz parabolic reflector horn antenna system featuring a broadband double ridged primary horn with a coaxial feed line is investigated. For the ridged horn antenna it is found that the radiation pattern, contrary to common belief, does not maintain a single main lobe in the direction of the horn axis over the whole frequency range. Instead, at frequencies above 12 GHz the main lobe in the radiation pattern starts to split into four lobes pointing in off-axis directions with a dip of up to 6 dB between them along the center axis. To investigate this phenomenon in detail, a combined method of moments and physical optics approach has been adopted to simulate the complete antenna system.

Circularly polarized receive/transmit elliptic feed horn assembly for satellite communications

Abstract: The present invention provides a feed horn for use in an antenna assembly having a non-circular reflector. The feed horn is capable of transmitting and receiving circularly polarized signals. The feed horn includes a circular waveguide section for connection to a transmitter and receiver of the antenna assembly. A conical waveguide section is connected to an opposed end of the circular waveguide section for creating a smooth transition from the circular waveguide section to a non-circular corrugated waveguide section. The corrugated waveguide section includes a plurality of corrugations that transition for a circular shape adjacent to the conical waveguide section to an increasing non-circular shape at an end proximal to the reflector of the antenna assembly. The corrugations have individuals depths defined in the inner wall of the corrugated waveguide section. These depths compensate circularly polarized signals propagating in the feed horn for distortions due to the non-circular reflector.

Radio wave receiving converter and antenna device

Abstract: A radio wave receiving converter in accordance with the present invention is for receiving satellite broadcast, and includes a body portion having a first feed horn portion, a second feed horn portion connected to first feed horn portion, and a sheet sandwiched between first feed horn portion and second feed horn portion and maintaining air tightness at a connected portion of first feed horn portion and second feed horn portion. An antenna device in accordance with the present invention includes the radio wave receiving converter as described above and a reflective parabolic portion reflecting a received radio wave and leading it to the radio wave receiving converter.

Using multiple receive antennas to determine the location of a transmitter with respect to a receiver in ultra wideband systems

Abstract: An apparatus, system, method, and computer program product for determining a location of at least an image of a transmitter transmitting a signal is disclosed. The location of at least the image of the transmitter is determined by receiving a signal transmitted by the transmitter at at least three receiver antennas separated by known distances. Differences in time are then determined between receipt of the signal at one of the receiver antennas and at least two other receiver antennas. The known distances and the determined differences in receipt times are then processed to determine the location of the transmitter.

Analysis of a hard strip-loaded conical horn by the method of generalized scattering matrices

Abstract: A hard-walled conical horn fed in the TE/sub 11/-mode from a regular circular waveguide is analyzed. The hard wall is formed by a dielectric layer with cylindrical inner surface loaded with longitudinal conducting strips. The analysis is carried out by using a stepwise representation of the horn with subsequent application of the method of generalized scattering matrices in combination with the method of factorization. The approach used refines values of the limiting aperture efficiency by 5 to 15% for diameters up to 3.2 wavelength in comparison with the underrated data based on the Kirchhoff method, and reveals the effect of the sharp worsening of the hard horn performance at some values of the horn length caused by resonances of the strip-line mode excited in the loaded section. Beyond the resonance points, the aperture efficiency remains relatively high (from 80 to 85%), and the crosspolar level is a few decibels lower than that of a standard smooth-walled horn.

Landmine neutralizer using a high power microwave device

Abstract: An apparatus to neutralize landmines using high power microwaves has a blast hardened dish antenna mounted on a vehicle along with a microwave generator and power generator A waveguide from the microwave generator feeds microwaves to a feed horn for the antenna. Plugs that are transparent to microwaves are located in the waveguide to prevent the blast wave generated by a detonated landmine from propagating inside of the waveguide and damaging the microwave generator. Flexible sections in the waveguide dampen any shock wave produced by a detonated mine from traveling along the waveguide towards the microwave generator.

Multi-band coaxial ring-focus antenna with co-located subreflectors

Abstract: A multi-band ring focus antenna system includes a main reflector ( 408 ) that is operable at a plurality spectrally offset frequency bands A first feed ( 301, 403 ) includes a first feed horn ( 301 ) and a first sub-reflector ( 403 ), which are positioned spaced apart from each other at respective locations along a boresight axis of the main reflector The locations are selected so that the first feed horn and the first sub-reflector share a commonly located first phase center ( 401 ) A second feed ( 302, 404 ) designed for operation on a second RF frequency band includes a second feed horn ( 302 ) and a second sub-reflector ( 404 ), each positioned at a location along the boresight axis of the main reflector so that they share a commonly located second phase center

Hybrid-mode horn antenna with design-specific aperture distribution and gain

Abstract: Horn antennas with high directivity or high aperture efficiency are required as feed horns in multibeam reflector antennas and as an element in limited scan arrays. Candidate high directivity horns for circular polarization often suffer from limited bandwidth, complex design or limited aperture size. In this paper a relatively simple dielectric-loaded hybrid mode horn with high efficiency under balanced hybrid conditions (low cross-polarization) is presented. The horn meets the so-called hard boundary conditions, supporting a TEM mode inside the horn at the design frequency. Like other hybrid mode horns this horn is not limited in aperture size, and works for linear and circular polarization. The concept also allows for the design of any boundary conditions between soft and hard.

Collapsible antenna assembly for portable satellite terminals

Abstract: A collapsible antenna assembly for portable, outdoor satellite communication systems is provided. When connected to complementary electronics, the apparatus enables the transmission and reception of communications signals from any selected terrestrial location by means of a satellite link. The apparatus is implemented in a physical form that minimizes the overall physical dimensions such that portability is improved. The apparatus consists of an antenna reflector, transmit assembly, feed horn assembly, a boom, a tripod, and a mounting platform, which permits the antenna reflector to be oriented to operate with any selected satellite. The entire apparatus can be folded and disassembled to fit inside of a suitcase.

Focal field analyses for front-fed and offset reflector antenna

Abstract: In this paper, we present results of focal field analyses carried out for front-fed and offset parabolic antennas. Such analyses are needed and especially important for hybrid antenna configurations with arrays in the focal zone. The front-fed configuration relates to work carried out for radio telescope applications within the FARADAY project. The offset geometry relates to potential applications for instance for Earth observation or telecommunication satellites. The focal field analysis is necessary as an intermediate step, before focal field matching procedures are applied, to derive suitable excitations for a focal array. But also such an analysis gives insight from another point of view for antenna operations in the generic sense.

High gain linearly polarised dual band horn for multi-feed reflector antenna

Abstract: A simple linearly polarised dielectric-loaded horn with high aperture efficiency over two separate frequency bands is presented. The horn operates as a fundamental-mode dielectric-lined horn at the low frequency, and as a dual mode horn at the high frequency. Aperture efficiency better than 92.7% has been measured over the dual 4/6 GHz frequency band.

Dielectric spherical lens antenna for wireless millimeter‐wave communications

Abstract: A simplified theoretical model based on geometrical optics (GO) in combination with physical optics (PO) in its vector form is used to analyze the performance of a homogeneous dielectric-sphere lens fed by a feed horn. The proposed model provides physical insight and sufficient accuracy for the initial design cycle. The computed results are also compared to measured data acquired from a prototype model and the agreement is satisfactory. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 28–33, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11117

Switch circuit especially suitable for use in wireless LAN applications

Abstract: A switch circuit selectively connects either a transmitter or a receiver to an antenna. The switch circuit has a transmitting pathway connecting the transmitter to the antenna 300 and containing only non-semiconductor elements (such as a first quarter-wave transmission line 313 ), and a receiving pathway connecting the antenna to the receiver and containing only non-semiconductor elements (such as a second quarter-wave transmission line 303 ). The switch circuit also has a switching arrangement ( 314 A/B/C/D, 304 A/B/C/D) configured to isolate the transmitter from the antenna while enabling the receiving pathway from the antenna to the receiver, and to isolate the receiver from the antenna while enabling the transmitting pathway from the transmitter to the antenna. Preferably, the transmitting pathway and receiving pathway include only elements having a very low insertion loss. A wireless local area network (WLAN) includes the transmitter, receiver, antenna and switch circuit.

Beam steering apparatus for a traveling wave antenna and associated method

Abstract: Steering of an electromagnetic beam of energy in the upper plate of a plate waveguide of a traveling wave antenna concurrently with the formation of a flat phase front and collimation of the electromagnetic beam is achieved by providing a second waveguide beneath the lower plate of the first waveguide and providing a 180% bend parabolic main reflector to reflect the energy beam to the upper plate of the upper waveguide. A feed horn is located in the lower waveguide and illuminates a pivotal subreflector which reflects the energy to the parabolic main reflector. By rotating the subreflector about its pivot point, the beam which is radiated to the upper waveguide is angularly shifted or steered.

Horn antenna system having a strip line feeding structure

Abstract: A horn antenna system having a strip line feeding structure of which size is reduced while cross polarized characteristics are kept. The horn antenna system, includes: a first horn antenna unit having a first horn antenna and a first ground made of metal, for radiating a signal; a second horn antenna unit having a second horn antenna and a second ground made of metal, for reflecting the signal to allow the second horn antenna unit to radiate the signal; and a feeding unit located between the first horn antenna unit and the second horn antenna unit, for feeding the energy to the first horn antenna unit and the second horn antenna unit, wherein the feeding unit is a stripe line.

A phase hologram based compact RCS range for scale models

Abstract: A compact radar cross section (RCS) test range for scale model measurements is being developed. The test range is based on a phase hologram that converts the feed horn radiation to a plane wave needed for RCS determination. The measurements are performed at 310 GHz using continuous wave operation. A monostatic configuration is realized using a dielectric slab as a directional coupler. The main advantage of a scale model RCS range is that the dimensions of radar targets are scaled down in proportion to the wavelength. Therefore, RCS data of originally large objects can be measured indoors in a controlled environment. So far simple test objects such as metal spheres have been measured. The feasibility of the phase hologram RCS range has been verified. The basic operation and first measurement results of the monostatic measurement range are reported here.