Showing papers on "Feed horn published in 2012"

The Cosmology Large Angular Scale Surveyor (CLASS): 40 GHz Optical Design

Abstract: The Cosmology Large Angular Scale Surveyor (CLASS) instrument will measure the polarization of the cosmic microwave background at 40, 90, and 150 GHz from Cerro Toco in the Atacama desert of northern Chile. In this paper, we describe the optical design of the 40 GHz telescope system. The telescope is a diffraction limited catadioptric design consisting of a front-end Variable-delay Polarization Modulator (VPM), two ambient temperature mirrors, two cryogenic dielectric lenses, thermal blocking filters, and an array of 36 smooth-wall scalar feedhorn antennas. The feed horns guide the signal to antenna-coupled transition-edge sensor (TES) bolometers. Polarization diplexing and bandpass definition are handled on the same microchip as the TES. The feed horn beams are truncated with 10 dB edge taper by a 4 K Lyot-stop to limit detector loading from stray light and control the edge illumination of the front-end VPM. The field-of-view is 19 deg x 14 deg with a resolution for each beam on the sky of 1.5 deg. FWHM.

Millimeter-Wave Integrated Pyramidal Horn Antenna Made of Multilayer Printed Circuit Board (PCB) Process

Abstract: Due to the low atmospheric absorption over W-band, numerous applications are expected, which should be developed at low cost. Short wavelength makes the dimension of antennas in this frequency range small, which usually requires sophisticated and expensive fabrication process. This communication presents a class of integrated wideband pyramidal horn antennas which can be made of low-cost multilayered printed circuit board (PCB) process. The proposed horn antenna radiates along the broadside to the substrate and uses substrate integrated waveguide (SIW) as its feeder. Transverse slot on the top metallic surface at the end of SIW is deployed to drive the horn antenna. Metalized via holes are used to synthesize the horn walls. The opening of the horn antenna is discretely flared from the bottom to the top layer. Measured bandwidth of the antenna is 35 GHz (70-105 GHz) while a relatively constant gain of 10 ± 1 dB is obtained over most of the bandwidth.

Multi-chroic Feed-Horn Coupled TES Polarimeters

Abstract: Multi-chroic polarization sensitive detectors offer an avenue to increase both the spectral coverage and sensitivity of instruments optimized for observations of the cosmic-microwave background (CMB) or sub-mm sky. We report on an effort to adapt the Truce Collaboration horn coupled bolometric polarimeters for operation over octave bandwidth. Development is focused on detectors operating in both the 90 and 150 GHz bands which offer the highest CMB polarization to foreground ratio. We plan to deploy an array of 256 multi-chroic 90/150 GHz polarimeters with 1024 TES detectors on ACTPol in 2013, and there are proposals to use this technology for balloon-borne instruments. The combination of excellent control of beam systematics and sensitivity make this technology ideal for future ground, ballon, and space missions.

Ku-band dielectric-loaded SIW horn for vertically-polarized multi-sector antennas

Abstract: This paper presents a compact and lightweight Ku-band dielectric-loaded H-plane sectoral horn antenna, using the substrate integrated waveguide (SIW) technology, suitable to be utilized as an element of a steerable multi-sector antenna with the ability of scanning a full 360° on the horizon. A dielectric loading together with metallic strips in front of the SIW horn aperture are utilized to optimize the performances in terms of bandwidth, gain and front‐to‐back ratio (FTBR). To experimentally demonstrate the performance of the proposed design, a three‐element prototype, intended later to be a part of an eight‐sector antenna, has been fabricated. The measurement process of different characteristics of the prototype is discussed in detail and a comparison between simulated and measured results is given.

Quad-ridge horn antenna with elliptically shaped sidewalls for use as a reflector feed for radio astronomy

Abstract: We present a quad-ridge horn antenna as a feed for a reflector antenna for use in radio astronomy applications. The antenna uses elliptically shaped sidewalls to limit the variation of beamwidth over a wide frequency range and to obtain greater radiation pattern rotational symmetry. The antenna is dual-polarized and matched over more than a 4:1 bandwidth. A design procedure is presented and a prototype designed according to this procedure is shown. Measured and simulated results of the prototype agree with each other well. The antenna is analyzed with a prime focus reflector to determine the range of efficiencies that can be expected.

Multi-Chroic Feed-Horn Coupled TES Polarimeters

Abstract: Multi-chroic polarization sensitive detectors offer an avenue to increase both the spectral coverage and sensitivity of instruments optimized for observations of the cosmic-microwave background (CMB) or sub-mm sky. We report on an effort to adapt the Truce Collaboration horn coupled bolometric polarimeters for operation over octave bandwidth. Development is focused on detectors operating in both the 90 and 150 GHz bands which offer the highest CMB polarization to foreground ratio. We plan to deploy an array of 256 multi-chroic 90/150 GHz polarimeters with 1024 TES detectors on ACTPol in 2013, and there are proposals to use this technology for balloon-borne instruments. The combination of excellent control of beam systematics and sensitivity make this technology ideal for future ground, ballon, and space missions.

The design of the MeerKAT L-band feed

Abstract: The design methodology of the MeerKAT L-band feed which consists of a wide flare angle axially corrugated conical horn, a horn matching section and a compact orthomode transducer (OMT) is presented. The dish is a classical Gregorian offset dual-reflector antenna system. The predicted results show stable radiation patterns over the frequency band with an ideal antenna efficiency above 73 %. The feed has losses below 0.05 dB resulting in very good system sensitivity.

A High Performance 700 GHz Feed Horn

Abstract: We present a design of a high performance horn operating at 700 GHz. The feed, which comprises three smooth-walled conical sections, is easy to machine and yet has comparable performance to a corrugated horn. The measured radiation patterns show high main beam circularity, low sidelobe level and good agreement with theoretical predictions. The cross-polar level is below −20 dB across a frequency bandwidth of 140 GHz. The new design allows the fabrication of high performance, large format feed arrays cheaply and rapidly.

Pattern synthesis for multi-feed reflector antenna using IWO algorithm

Abstract: In this paper, a new optimization algorithm to design shaped beam antenna is proposed. It is shown that by using offset parabolic reflector antenna and a linear array of horn antennas with one-wavelength spacing in focal point, Invasive Weed Optimization (IWO) algorithm can be used for amplitude and/or phase of source antennas to provide desired cosecant squared radiation patterns. To achieve a simple cosecant squared radiation pattern, amplitudes and phases of 11 source antennas (22 parameters) are optimized with no constraint by IWO and the results are compared with Particle Swarm Optimization (PSO) algorithm. Convergence diagram and radiation pattern results confirm the capability of IWO algorithm in shaped beam antenna design.

Electromagnetic Design of Feedhorn-Coupled Transition-Edge Sensors for Cosmic Microwave Background Polarimetry

Abstract: Observations of the cosmic microwave background (CMB) provide a powerful tool for probing the evolution of the early universe. Specifically, precision measurement of the polarization of the CMB enables a direct test for cosmic inflation. A key technological element on the path to the measurement of this faint signal is the capability to produce large format arrays of background-limited detectors. We describe the electromagnetic design of feedhorn-coupled, TES-based sensors. Each linear orthogonal polarization from the feed horn is coupled to a superconducting microstrip line via a symmetric planar orthomode transducer (OMT). The symmetric OMT design allows for highly-symmetric beams with low cross-polarization over a wide bandwidth. In addition, this architecture enables a single microstrip filter to define the passband for each polarization. Care has been taken in the design to eliminate stray coupling paths to the absorbers. These detectors will be fielded in the Cosmology Large Angular Scale Surveyor (CLASS).

A planar passive dual band array feed antenna for Ku band satellite communication terminals

Abstract: A planar passive array feed antenna for bidirectional Ku band satellite communication was designed, fabricated and measured. The feed antenna achieved 50 dB isolation between transmit and receive ports across the transmitting band. An on-reflector test was conducted by mounting the array feed with external low noise amplifier and block downconverter (LNB) on a 90 cm dish to verify the feed radiation efficiency and illumination pattern. The measured signal to noise ratio (SNR) with the planar feed including loss in test connectors was within 2 dB of that of a commercial horn feed.

A novel lower frequency dual-polarized broadband horn antenna for use as a source in tapered anechoic chambers

Abstract: A novel dual-polarized broadband horn antenna working at 75–500 MHz with coaxial input feed section is investigated. Some new structures are introduced to support the huge dimensions and reduce the weight based on the precondition that the effect of these solutions to the low end performance is minimization. And an adjustable shorting plate is inserted on the bottom of the horn antenna to improve the return loss performance. Details of the horn antenna design and experimental results are presented and discussed.

Quad-ridge dual polarized antenna for use in the 2–32GHz band

Abstract: Ridge horn have been utilized in antenna test ranges for different measurement applications for many years. These horns offer stable performance on a bandwidth that can exceed 16:1 as reported in [1–2]. The quad-ridge horn offer dual polarization in the same horn but often at the expense of bandwidth [1]. The open boundary horn concept investigated in [3] is preferred since it avoid the frequency dependent influence of the horn walls that often lead to pattern deformation. The design task is often a compromise between pattern shape, matching and polarization purity but also mechanical issues needs to be considered to arrive at a robust design with repeatable and stable performance. This paper describes the design of a 2–32GHz dual polarized quad ridge horn with a 16:1 bandwidth with high polarization purity.

Arrangement to measure the deflection of an object

Abstract: A reflector is arranged at a first position, which is assigned to a first end of the object. An antenna-system is arranged at a second position, which is assigned to a second end of the object. The antenna system contains a transmit antenna and a receive antenna, while the reflector and the antenna-system are coupled by a radio signal. The radio signal is sent from the transmit antenna via the reflector towards the receive antenna. The receive antenna is connected with an evaluation unit, which is prepared to measure the deflection between the first end of the object and the second end of the object based on the received radio signal.

Accurate gain measurement for millimeter-wave horn and open-ended waveguide antennas

Abstract: The pyramidal horn and open-ended waveguide (OEG) antennas are widely used on millimeter-wave bands as the standard or wideband antenna. These aperture antennas are normally calibrated in the far-field ranges by using the three-antenna method. However, even if the antenna separation distance satisfies the usual far-field criterion 2D2/λ (D: maximum aperture size), the gain of horn antennas is reduced by the order of 1 dB. The separation distance needed for accurate measurement, i.e., to obtain a gain reduction within 0.05 dB, is 32D2/λ or more [1]. Newell et al. [2] developed the extrapolation technique for reducing the distances required for conventional far-field measurements. As another approach for the same purpose, the efficacy of considering the phase center of an antenna in the three-antenna method has been shown [3] [4]. In this paper, we discuss the determination of the gain of millimeter-wave pyramidal horn and OEG antennas by considering the phase center, and evaluate experimentally the effect of measurement distance on the gain.

Radiation and matching characteristics of a novel dual-band dielectric loaded coaxial horn

Abstract: Copolar and crosspolar radiation as well as matching characteristics of a novel dual-band coaxial hybrid-mode feed horn with partial dielectric loading [1] for reflector antennas have been numerically and experimentally investigated. In comparison with dual-band corrugated horns this horn has higher crosspolar level, but provides larger band separation and rather good electrical performances over a wide frequency range (20% and more) within each operational frequency band. Furthermore, the main concept of the coaxial feed system can be easily extended for multi-band cost-effective applications in reflector antennas with polarization diversity.

Design and characterization of a simplified planar 16×8 RF MEMS switch matrix for a GEO-stationary data relay

Abstract: This paper presents the design and measurements of a simplified design approach for a 16 × 8 switch matrix based on Radio Frequency Microelectromechanical System (RF MEMS) switches. The operational frequency range is between 25.5 GHz and 26.5 GHz for data links between a Geostationary Earth Orbit (GEO) relay satellite and several Low Earth Orbit (LEO) satellites. The switch matrix implements a key functionality for tracking the incident signals of the LEO satellites on the receive feed antenna array of the GEO satellite's reflector antenna. A maximum insertion loss of 8.5 dB, isolation of higher than 45 dB and a minimum return loss of 18 dB have been measured.

Designing horn antennas based on variable metasurface concept

Abstract: Concept of variable or non-uniform metasurfaces allows a very high level of control over the electromagnetic wave paths. In this paper this control is achieved by gradually modifying the geometry of subresonant printed patches on a grounded dielectric substrate. This allows us to change the phase velocity or the propagation path of the guided wave. This property was used to design a Luneburg lens which was then inserted into an H-plane horn to improve the horn's radiation characteristics. The results of this idea are demonstrated using full wave simulations, showing the applicability of this concept.

A Novel Ultra Wideband horn feed for parabolic reflector antennas

Abstract: An Ultra Wideband (UWB) parabolic reflector horn antenna system is designed to cover frequency range from 2 GHz to 18 GHz The feed structure is redesigned for the ridged horn antenna to overcome the problem of its radiation pattern deterioration at higher frequencies, thus the designed feed maintains a single main lobe in the direction of horn axis Also, the modifications are made in the shape of ridges to achieve better voltage standing wave ratio (VSWR) over the whole frequency band This new modified horn antenna is then used as a feed for a prime-fed parabolic reflector design The radiation pattern of designed parabolic reflector is also not divided into four large side lobes and has a single main lobe This study is investigated using reliable commercial 3D EM simulation software CST solvers based on both Multi-level Fast Multipole Method (MLFMM) and Finite Integration Technique (FIT) The simulations result in high gain, low side lobe level with a VSWR less than 2 over the entire frequency band

Cancellation of High Cross-polarization of an Offset Parabolic Reflector Antenna using a Rectangular Matched Feed

Abstract: This paper presents the design and the experimental results of a dual-mode rectangular-matched feed. This type of feed cancels the unwanted high cross-polarization generated by the offset parabolic reflector antenna. In order to design this feed, higher order TE11 mode has been added in correct amplitude and phase with the fundamental TE01 mode in a rectangular structure. The proposed feed was then used as a primary feed to illuminate a linearly polarized offset parabolic reflector antenna. Through experimental results, it is verified that such a feed suppresses the undesired high cross-polarization introduced by the offset geometry of an offset reflector antenna. This kind of feed is very much suitable for monopulse tracking radar.

Experimental evaluation of polarimetric beamformers for an L-band phased array feed

Abstract: A novel method to form multiple high-sensitivity beams with a reflector based radio telescope is to use a phased array feed (PAF). To accurately reconstruct the polarization state of the incident radio waves, the beam patterns of the PAF are of crucial importance. The co- and cross-polar element patterns of an oversampled L-band PAF prototype system have been measured in an interferometric setup. It is demonstrated that, although the antenna elements sampling the two orthogonal polarizations of the focal field are not co-located, dual polarized beams can be formed by combining the element responses in a beamformer. The capability of the PAF to optimize its beams in terms of sensitivity, sidelobes and polarization characteristics is demonstrated.

Hybrid elliptic TEM horn with symmetric main beam

Abstract: The structure of a TEM horn with new plate separation and width profiles is described. It is shown that the combination of a superellipse for the separation function, and a new function for the pate width, results in a horn with nominally frequency-independent properties to beyond 42 GHz. The new separation function has elliptic properties at the throat of the horn, and gradually opens to an almost linear taper.

B12. Dual polarized dual feed aperture-coupled DRA reflectarray

Abstract: In this paper, a new application of aperture coupled dielectric resonator as a cell element in design of a dual linear polarized reflectarray at X-band is investigated The reflectarray has two feed horn antennas, one for each linear polarization The radiation patterns for each polarization are achieved by adjusting the phase of the reflected wave at each reflectarray element independently for each linear polarization with varying the strip line length The design is carried out independently for each polarization at 10 GHz A 441-element reflectarray is designed The offset feed was used to minimize the feeding blockage and improve the total efficiency The verification of reflection coefficient phase of cell element is satisfied by CST microwave studio and HFSS software Maximum gain of 246 dB is obtained The 15 dB gain bandwidth of the reflectarray is about 15 %

Fork shoe used in industrial truck, has antenna that is arranged along lengthwise direction of transmitter and receiver

Abstract: The fork shoe has a transmitter that wirelessly transmits the data received by a receiver (5). The transmitter and the receiver are located within a radio frequency identification (RFID) transponder. An antenna is arranged along the lengthwise direction of transmitter and receiver. The battery (12) is charged by the energy stored in a power source.

Recent advances in microwave reflector antenna technology

Abstract: This paper presents some recent developments in microwave reflector antenna technology The main focus of this research is on novel reflector antenna designs to overcome the challenges caused by the rising communication systems Prototype implementation will be described in this paper; published microwave reflector antenna frequency range, low profile and compact designs, wideband reflector antennas, low sidelobe level, low cross polarization and enhanced gain microwave reflector antenna's review is brought up

A dual band array-fed reflector ScanSAR antenna

Abstract: The paper presents the array-fed reflector antenna of the CoReH2O (Cold Regions Hydrology High-resolution Observatory) SAR instrument currently being investigated within Phase-A under ESA contract The antenna is a dual linearly polarized single-offset reflector, illuminated by two side linear arrays operating in X and Ku band respectively Each array comprises seven compact multimodal horns in quasi rectangular waveguide These are sequentially excited, a couple at a time, for optimum antenna pattern synthesis and secondary beams overlap Each horn is a multiple step rectangular waveguide structure that provides the right modal content at aperture, very close to the analytical patterns synthesized through benchmarks The Ku band feed has been subjected to a pre-development activity aimed at validating the design The measured results at feed level show good agreement with predictions Measured pattern has been used as primary source in the antenna model and satisfactory performance have been predicted on radiated beams The X band feed has been designed with the same electromagnetic model adopted for Ku band and all performances are predicted with the same accuracy Further breadboarding activities are foreseen in X band, finalized to characterize a reduced dual band feed cluster and the relevant switching systems, taking into account the effect of mutual coupling between the two frequency bands

Multiobjective Optimization and Design of a Luneberg Lens Antenna with Multiband Multi-Polarized Feed-System

Abstract: A general multiobjective optimization and design proce- dure of a Luneberg lens antenna (LLA) with a compact multiband multi-polarized feed-system for a broadband satellite communication terminal is presented. The LLA utilizes a compact multiband feed horn, consisting of an inner dielectric loaded circular horn for the K/Ka-band (dual-circular polarization) and a coaxial waveguide with axially corrugated ∞ange for the Ku-band (dual-linear polarization). Measurements show good agreements with simulations. Moreover, an e-cient multiobjective evolutionary algorithm based on decomposition (MOEA/D) with difierential evolution operator and objective normal- ization technique is flrstly coupled with the vector spherical wave func- tion expansions (VSWE) for the optimal design of a 7-layer 650mm diameter LLA, which provides higher aperture e-ciency at Ku/K/Ka- band simultaneously. The frequency dependence of the LLA is also investigated. Finally, the gain and sidelobe level of a 5-layer design are jointly evaluated and compared with previous works. The pro- posed design procedure provides much better radiation performances and greater design freedom to the designers, as a group of Pareto- optimal LLA solutions can be obtained with just one simulation.

Design of modified dual mode horn antenna to improve E/H-plane radiation pattern symmetry

Abstract: Dual mode horn antenna is widely used in reflector antenna systems to illuminate symmetric E/H-plane radiation patterns to a reflector surface. Symmetric E/H-plane radiation pattern can improve the total gain of the reflector antenna system and allows a design of a reflector to be symmetric [1]. Dual mode horn antenna was developed by Potter [2] and many designs have been proposed to have symmetric E/H-plane radiation pattern [3]-[7]. The mode at the aperture of the dual mode horn antenna is hybrid mode (HE 11 mode) which consists of approximately 85% of TE 11 mode and 15% of TM 11 mode [8] and the antenna radiates gaussian-like beam pattern, and therefore the E/H-plane radiation patterns are symmetric ideally. However, if the aperture size of a dual mode horn antenna is increased to attain the desired gain or beamwidth for the reflector antenna system, ideal HE 11 mode is difficult to be attained at the aperture because undesired high order modes which lead asymmetric E/H-plane radiation patterns are generated. In this paper, modified dual mode horn antenna with rectangular aperture is proposed to improve the E/H-plane radiation pattern symmetry in oversized aperture horn. Simulation and experimental results show that the proposed dual mode horn antenna has the improved E/H-plane radiation pattern symmetry compared to a conventional circular dual mode horn antenna.

Printed circuit board based feed horn

Abstract: A new class of feed horns is provided based on the use of metamaterial printed circuit board (PCB) liners on the walls of the feed horns. These feed horns may be implemented to achieve low cost operation. PCBs making up the metamaterial liner may be assembled together in such a manner as to form a feed horn with a square or rectangular aperture shape, although other suitable shapes are possible. These PCBs may be fabricated from standard low cost, off-the-shelf dielectric material. A conductor artwork pattern on the PCB surface forming the interior surface of the feed horn can be designed such that the PCB feed horn yields radio frequency (RF) properties similar to that of a corrugated feed horn. A simple flat plate ground plane bonded to the back side of the PCB can serve as the feed horn structure.

Wideband matching the dual frequency coaxial waveguide feed

Abstract: An effective technique to the design of dual band coaxial waveguide feed horn for reflector antenna excitation has been developed and tested Matching the feed horn with free space in upper frequency range is achieved by dielectric insert disposed inside the circular waveguide fabricated in interior conductor of open ended coaxial waveguide The presence of dielectric insert causes the high level of reflection in lower frequency range from the boundary between the open end of coaxial waveguide and free space A novel technical solution of highly complicated matching problem has been proposed The matching design was performed as the series of finite thickness diaphragm arranged on outer surface of interior conductor of coaxial waveguide To obtain the rigorous solution of given electromagnetic problem for the complicated structure consisting of a great number of connected coaxial waveguide sections and dielectric insert, a new effective approach has been proposed The distinctive feature of this approach consists in combination of rigorous procedure based on computation of generalized scattering matrices and another rigorous procedure based on the finite difference time domain method To combine these essentially different approaches, the metallic discontinuity equivalent to overall investigated structure was employed An optimization of equivalent matching structure has been performed by the variant of the evolution strategy method The obtained design with metallic discontinuities was converted into real structure comprising the dielectric insert The final calculations of real structure were performed by the finite difference time domain method The effectiveness of proposed technique was confirmed by the results of testing the developed feed horn in reflector antenna system