Showing papers on "Feed horn published in 2017"

Dual-Mode Transmissive Metasurface and Its Applications in Multibeam Transmitarray

Abstract: A novel triple-layer dual-mode meta-atom wherein an H-shaped structure is combined with a pair of symmetric patches is proposed. The composite structure substantially lowered the operation frequency, and balanced phase agility with transmission magnitude bandwidth. The transmission phase limit of the proposed composite structure approaches the theoretical limit. Because this structure has appealing features, we employed a set of these ultrathin meta-atoms to implement the phase distribution of an optimized array using the alternating projection method. An X-band single-feed quad-beam transmitarray consisting of $25 \times 25$ elements, each carefully designed to exhibit the desired transmission phase, was designed, simulated, physically implemented, and measured. Feeding the meta-array using a horn at its focus, four-beam radiation patterns with satisfactory sidelobe levels and gain were numerically and experimentally demonstrated. The peak gain was found to be 18.8 dB at 9.6 GHz, and the aperture efficiency was calculated as 38.3%. Moreover, the half-power beamwidth of the array antenna was approximately 7°, which was 50° narrower than that of a bare feed horn. Moreover, the gain of each beam was higher than 17 dB in all studied cases, which was at least 7 dB higher than that of a bare feed horn.

Dual Polarized Reflectarray Transmit Antenna for Operation in Ku- and Ka-Bands With Independent Feeds

Abstract: A reflectarray antenna capable of operating independently in the transmit frequencies (from a satellite) in Ku-band (11–13 GHz) and Ka-band (19–20 GHz) has been proposed and demonstrated. To prove that independent beams can be optimized in each frequency band using separate feeds, a 25-cm demonstrator that generates a focused beam in dual polarization (linear or circular) has been designed, manufactured, and tested. The reflectarray cells comprise two stacked sets of coupled parallel dipoles for each polarization, which permits an independent optimization of the phase for each frequency and polarization. The simulated and measured radiation patterns for both copolar and cross-polar components are in good agreement in Ku- and Ka-bands.

On the Use of Single-Layered Subwavelength Rectangular Patch Elements for Broadband Folded Reflectarrays

Abstract: The feasibility of using single-layered subwavelength rectangular patch elements for broadband folded reflectarrays is studied in this letter. The antenna is made of a feed horn, a planar lower reflector, and an upper polarizer. Different to existing folded reflectarray designs in the literature where a halfor near-halfwavelength unit cell is used for lower reflectors, this work employs subwavelength rectangular patch elements on a single-layered substrate for achieving a wide bandwidth of folded reflectarrays. The design is conducted at 10 GHz and composed of 1976 elements on a 405 × 405-mm 2 aperture. The effect of the polarizers on the antenna's performance is also examined when they are integrated with folded reflectarray structures. The proposed folded reflectarray features a broadband performance with a compact and lowprofile structure. The measured results show that the folded reflectarray with a 0.3λ grid spacing realizes a 1-dB gain bandwidth of 16% with an aperture efficiency of 44%, which demonstrates better behavior than various existing folded reflectarrays. In addition, this superior performance is also comparable to the previous traditional reflectarray design, whereas the antenna depth has been reduced in half.

Substrate Integrated Horn Antenna Loaded With Open Parallel Transitions

Abstract: The substrate integrated H-plane horn antenna has been struggling with very limited impedance bandwidth since its invention, which is coming from its natural aperture discontinuity. Apart from a variety of series transitions introduced so far, here, parallel transitions are applied to the antenna aperture in addition to narrow slots on the horn walls around the aperture to widen the antenna impedance bandwidth. It is shown that the depth of the transitions can easily determine the center frequency of the matching bandwidth. The new parallel transitions also reduce the antenna back radiation since they act as chokes around the horn aperture.

Design of a High-Isolation 35/94-GHz Dual-Frequency Orthogonal-Polarization Cassegrain Antenna

Abstract: In this letter, a novel high-isolation 35/94-GHz dual-frequency orthogonal Cassegrain antenna is designed. The antenna consists of a D = 800 mm main reflector, a subreflector, and a dual-band orthogonal-polarization feed. In order to get similar feed horn's E – H radiation patterns and similar phase center positions at the dual frequencies separately, the dual-mode conical horn is designed in the feed. For obtaining a high isolation, a three-order low-pass filter is designed in the Ka-band waveguide feed port. The measured antenna gains are 43.6 and 51.3 dBi, and the sidelobe levels are −27.5 and −26.5 dB at 35 and 94 GHz, respectively. The isolation between the two ports is −61.0 dB in the Ka-band and −63.5 dB in the W-band. The proposed antenna is a suitable candidate for a dual-band radar system.

Terahertz High-Gain Offset Reflector Antennas Using SiC and CFRP Material

Abstract: Two high-gain terahertz (THz) offset reflector antennas are proposed. The silicon carbide material and thermally stable carbon fiber-reinforced plastic are selected as reflectors for high specific stiffness and low thermal expansion coefficient which are helpful for space use. Dual polarization is achieved by introducing a wire-grid polarizer which can separate the two THz polarization waves provided by multimode horns fabricated in electroforming technology. Furthermore, three-coordinate test system and theodolites are employed to detect the surface error of dishes and alignment of antenna subsystem. The physical optics analysis based on the measured reflector surface data is introduced referring to the large aperture antenna patterns by virtue of its accuracy and high efficiency. The results of this novel method are compared to that of the near-field test. Measurements show that the sidelobe levels (SLLs) of the single polarization silicon-based reflector are below −32 dB while the gain is 55.3 dB at 330 GHz, and the dual polarization carbon fiber-reinforced plastic reflector antenna suppresses the SLLs to −28 and −29 dB in two principal planes while the gain is 57.2 dB at the same frequency, respectively. The good performances of the proposed antennas indicate the potential for the application of space THz radiometer.

Ka band 3D printed horn antennas

Abstract: This paper presents pyramidal horn antennas operating at 28 GHz, which are manufactured by 3D printing technology. A printed antenna based on a WR-28 waveguide standard gain horn designed for 20 dBi gain is then metalized using two different methods. Copper tape and conductive copper paint are applied to the 3D printed geometry surface. A full-wave electromagnetic simulator, HFSS, is used to design the horns and predict the gain. Through simulation, we observe that dielectric loss impacts the copper tape metallized structure. The measured input reflection coefficient for the 20 dBi horns is presented along with the simulated radiation pattern. The dielectric and metallic loss impact the overall radiation patterns of the antennas. Measured gain for an X band horn is compared with a reference.

An All-Metal, 3-D-Printed CubeSat Feed Horn: An assessment of performance conducted at 118.7503 GHz using a robotic antenna range.

Abstract: Three-dimensional (3-D) printing is finding applications across many areas and may be a useful technology for antenna fabrication for cube satellites (CubeSats). However, the quality of an antenna produced using 3-D printing must be considered if this technology can be relied upon. We present gain and far-field pattern results for the feed horn of the radiometer payload of the CubeSat PolarCube. The corrugated feed horn is constructed from AlSi10Mg alloy and fabricated using powder bead fusion (PBF). Measurements were performed at the atmospheric oxygen line of 118.7503 GHz with the National Institute of Standards and Technology (NIST) Configurable Robotic Millimeter-Wave Antenna (CROMMA) facility in Boulder, Colorado. A comparison of these measurements to theoretical predictions provides an assessment of the performance of the feed horn.

An adjustment method for active reflector of large high-frequency antennas considering gain and boresight

Abstract: The design of the Qitai 110 m Radio Telescope (QTT) with large aperture and very high working frequency (115 GHz) was investigated in Xinjiang, China. The results lead to a main reflector with high surface precision and high pointing precision. In this paper, the properties of active surface adjustment in a deformed parabolic reflector antenna are analyzed. To assure the performance of large reflector antennas such as gain and boresight, which can be obtained by utilizing an electromechanical coupling model, and satisfy them simultaneously, research on active surface adjustment applied to a new parabolic reflector as target surface has been done. Based on the initial position of actuators and the relationship between adjustment points and target points, a novel mathematical model and a program that directly calculates the movements of actuators have been developed for guiding the active surface adjustment of large reflector antennas. This adjustment method is applied to an 8 m reflector antenna, in which we only consider gravity deformation. The results show that this method is more efficient in adjusting the surface and improving the working performance.

A Low-Profile Wideband Surface-Mountable Substrate-Integrated Waveguide Horn Antenna

Abstract: A low-profile surface-mountable substrate-integrated waveguide (SIW) horn antenna with wideband performance is proposed in this letter. In order to reduce the serious impedance mismatch at the SIW horn aperture resulting from the thin substrate (0.12 λ0), a semi-open SIW horn is designed by gradually detaching upper broadwall while maintaining another one. Furthermore, in order to realize wide bandwidth for the SIW horn antenna, air-vias are drilled into the semi-open horn to realize smooth transition from semi-open horn to free space. Finally, a fabricated prototype is measured, and results indicate that a 35.7% impedance bandwidth ranging from 19.1 to 27.4 GHz and a 31.8% 3 dB gain bandwidth ranging from 19.3 to 26.6 GHz are obtained, respectively. Stable end fire radiation patterns are observed across the operating band.

Design of a Multimode Feed Horn Applied in a Tracking Antenna

Abstract: This paper proposes a multimode feed horn applied to a Cassegrain antenna operating at W-band. The horn is easily fabricated due to the simple structure. Comparisons are made between the performances of a four-mode feed horn and a seven-mode feed horn. The seven-mode feed horn is finally adopted for two reasons. First, the construction size is larger, and thus, it is easier to machine. Second, the active voltage standing-wave ratio is acceptable lower. A good compromise between the sum and difference beams is also achieved. The multimode feed horn is fabricated as part of the Cassegrain antenna. The simulation and measurement results of the Cassegrain antenna have shown good performances. The antenna efficiency reaches up to about 47%, and the 3-dB beamwidths are approximately 1.5° at operating frequencies. The sidelobe level is less than −15 dB in azimuth plane and less than −18 dB in elevation plane.

An Active 20-MHz to 2.5-GHz UWB Receiver Antenna System Using a TEM Horn

Abstract: An ultrawideband receiver antenna system is proposed. The radiating element is a transverse electromagnetic horn antenna, featuring a negative impedance converter at lower frequencies. The voltage standing-wave ratio (VSWR) is less than 2.0 in the bandwidth from 20 MHz to 2.5 GHz. A good agreement between the measurements of the fabricated system and the simulated results is observed. Sample applications include direction finding, broadband communication systems, radar systems, and electromagnetic compatibility measurement systems.

Antenna Deembedding for mmWave Propagation Modeling and Field Measurement Validation at 73 GHz

Abstract: In field measurements at millimeter-wave (mmWave) frequencies, the spatial propagation characteristics are usually obtained by using steerable high-gain horn antennas to compensate the large path loss. However, it is a challenging issue to deembed antenna patterns from the observed channel responses. This paper has two contributions. First, according to the steering-antenna sounding process, a spatial channel response model is designed, where the multipath propagation profile, antenna pattern, and channel response are spatially sampled and combined in a discrete convolutional form. Then, a low-complexity antenna deembedding algorithm, including two steps of deconvolutions, is proposed. Second, a field measurement campaign on the frequency-space mmWave channels in an office is presented to validate the method. The channels were sounded at 72.5 to 73.5 GHz using three horn antennas with different beam widths and gains. The omnidirectional angular channel responses (ACRs) were measured by rotating the receiver antenna. The observed and reconstructed ACRs are consistent, and the estimated antenna-free angular propagation profiles by using different horn antennas are also highly correlated, which validate the proposed antenna deembedding approach. Furthermore, the omnidirectional transfer functions in the mmWave band obtained using different horn antennas are compared, and the channel coherence bandwidth is analyzed based on the autocorrelation of the transfer functions.

Radiometer payload for the temporal experiment for storms and tropical systems technology demonstration mission

Abstract: The Temporal Experiment for Storms and Tropical Systems Technology Demonstration (TEMPEST-D) instrument is a five-frequency millimeter-wave radiometer capable of observing thermal radiation from the Earth at 89, 165, 176, 180, and 182 GHz. The direct-detection architecture of the radiometer reduces its power consumption and eliminates the need for a local oscillator and mixer, reducing complexity. The instrument includes an ambient blackbody calibration target and a scanning reflector. The reflector rotates to scan the antenna beams in the cross-track direction so that the TEMPEST-D feed horn and receiver view first the blackbody calibration target, then the Earth over a range of nadir angles from −45° to +45°, and finally the cosmic microwave background radiation at 2.73 K. This enables precision end-to-end calibration of the millimeter-wave receivers every scan period. The TEMPEST-D millimeter-wave radiometers are based on 35-nm InP HEMT MMIC low-noise amplifiers and related technology developed under extensive investment by the NASA Earth Science Technology Office (ESTO).

Performance validation of the 19-element multibeam feed for the five-hundred-metre aperture spherical radio telescope

Abstract: The performance of an L-band 19-element multibeam feed for the five-hundred-metre aperture spherical radio telescope is verified here. Radiation patterns have been measured in an anechoic chamber in the radiating near field of the array and compared with simulated radiation patterns from HFSS for the same conditions. Very good agreement is observed between the measurements and simulations.

W-band feed horn with polarizer structure for an offset reflector antenna for cubesat applications

Abstract: A compact W-band cylindrical waveguide horn antenna with polarizer structure is designed which offers wideband left-hand circular polarization (LHCP) and symmetric radiation pattern. It has wideband impedance matching below S 11 = −15 dB and axial ratio below 1.8 dB from 79.5 GHz to 87.5 GHz. This horn is used as a feed source for an offset parabolic reflector. The reflector antenna provides peak RHCP (right-hand circular polarization) directivity of 37.3 dBic at 86 GHz.

Feed source locating and focus offset device for compact range measurement

Abstract: The invention provides a feed source locating and focus offset device for compact range measurement. The device is used for precise location and focus offset motion of a feed horn in an electromagnetic measurement process of a compact range. The device mainly comprises left and right transverse movement along the X axis, front and back longitudinal movement along the Y axis, rotation and translation around the Z axis and pitching movement around the phase center of a feed source. Accurate locating and focus offset of the feed source are realized through movement of five freedom degrees, and focus offset measurement is completed. By means of servo control, polarization rotation and uniform rotation at a certain rotation speed of the feed horn can be realized, and RCS (radar cross-section) measurement or antenna measurement is completed. The device comprises an X-axial moving unit, a Y-axial compensation unit, a Z-axial rotating and height adjusting unit, an offset arm, a feed source pitching unit and a feed source polarization unit. Different from a fixed feed source locating device, the device can not only be used for precise location of the feed source during measurement of the compact range in a traditional manner, but also be used for measurement of new demand ways such as focus offset and the like; the device has the advantages of high measurement efficiency, high locating precision and simple and reliable control process.

High Power Metasurface Reflectarray Antennas Using Switched Shorted Circular Elements

Abstract: A metamaterial design that can rapidly reconfigure its reflection phase angle and safely operate under high incident field strengths is presented for use in a high power microwave (HPM) reflectarray system. The design offers switching between reflection phase angles to allow for beam control with a stationary reflector and feed horn. Two variations of the design are presented which offer (a) fixed (but selectable) reflection phases with high-power operation and (b) on-the-fly reconfigurable reflection phases with low-power operation. For design (b), reconfiguration is easily and quickly accomplished though simple relay-style switching operation. The designs are developmental steps towards a fully on-the-fly reconfigurable reflectarray which can operate with several megawatts of peak input power. Fabrication and testing of the prototype antennas and metasurfaces were carried out and presented.

Design of mm-Wave transmitter and receiver for 5G

Abstract: Millimeter wave compact RF transmitter and receiver for 5G communication system are designed in this paper, which could be typically applied in massive MIMO system of 16 channels. The transmitter and receiver are designed using multilayered structure and highly-integrated chips to decrease the module size. The antenna feeding transition structure are designed using electromagnetic field simulation software, and integrated in RF module. The size of fabricated RF modules is 2cm–2cm. IF and power supply circuits are also designed separately for both of them to support the RF array with 16 channels configuration. Performance of single channel transmitter and receiver are measured which could be applied in Q-band millimeter wave massive MIMO system.

Quad band X/Ka horn antenna and feed chain designs

Abstract: This paper proposes the performance comparison of two different corrugated feed horn designs and their corresponding feed chains working simultaneously in the X and Ka frequency bands. One of the solutions is composed of an X band coaxial corrugated horn that combines axial and radial corrugations fed laterally by an OMTJ formed by four branches to allow dual polarization and a smooth-walled spline-profile Ka band horn antenna placed inside the inner coaxial of the corrugated X band horn. The second solution is formed of a radial corrugated horn antenna for Ka band connected directly to another horn antenna that combines axial and radial corrugations for X band. The X band horn antenna part is also fed by an OMTJ formed by four branches. Both results which have been optimized for a science mission communication satellite specification requirement are very compact, allowing dual pol operation, combining both frequency bands in the same profile and making the system ideal for space applications. Each approach will present some advantages and disadvantages that can decide the one to be used in a mission of this type. The main contribution of this research has been the final optimization of the whole component achieving nicer results than the ones proposed in the scientific literature for this kind of solution.

Focal-Plane Multibeam Dual-Band Dielectric Lens for Ka-Band

Abstract: A shaped double-shell dielectric lens is evaluated as a primary feed for a multibeam single-reflector system operating in the satellite uplink and downlink Ka-bands, complying with gain and edge-of-coverage (EoC) directivity requirements. An assembly of dual-band printed feeds is integrated at the base of a single lens, each feed producing a virtual focus far behind the lens base and coincident with the reflector focal arch. The used double-shell lens approach, instead of a single-material lens, allows an extra degree of freedom to accommodate an aberration mitigation condition. This primary feed system is proposed as a low-complexity solution to enable fitting more beams per solid angle than conventional single-feed-per-beam systems based on a cluster of focal-plane horns. A proof-of-concept lens prototype with 87 mm diameter and 62 mm height, fed by a linear arrangement of five dual-band printed feeds, was fabricated and tested at the Ka-band. The lens measured radiation patterns were post-processed to evaluate the combined performance of the lens with an offset F/D ≈ 1 reflector system designed for 45-dBi EoC directivity. It is shown that it duplicates the reflector aperture efficiency compared to horn-fed systems with same feed separation.

ALMA Band 1 Optics (35-50 GHz): Tolerance Analysis, Effect of Cryostat Infrared Filters and Cold Beam Measurements

Abstract: The Atacama Large Millimeter/Sub-millimeter Array (ALMA) is currently the largest (sub-)mm wave telescope in the world and will be used for astronomical observations in all atmospheric windows from 35 to 950 GHz when completed. The ALMA band 1 (35–50 GHz) receiver will be used for the longest wavelength observations with ALMA. Because of the longer wavelength, the size of optics and waveguide components will be larger than for other ALMA bands. In addition, all components will be placed inside the ALMA cryostat in each antenna, which will impose severe mechanical constraints on the size and position of receiver optics components. Due to these constraints, the designs of the corrugated feed horn and lens optics are highly optimized to comply with the stringent ALMA optical requirements. In this paper, we perform several tolerance analyses to check the impact of fabrication errors in such an optimized design. Secondly, we analyze the effects of operating this optics inside the ALMA cryostat, in particular the effects of having the cryostat IR filters placed next to the band 1 feed horn aperture, with the consequent near-field effects. Finally, we report on beam measurements performed on the first three ALMA band 1 receivers inside test cryostats, which satisfy ALMA specifications. In these measurements, we can clearly observe the effects of fabrication tolerances and IR filter effects on prototype receiver performance.

Integrated single-piece antenna feed

Abstract: The invention is an integrated single-piece antenna feed, turnstile polarizer and antenna system suitable for satellite communications. One embodiment of the integrated single-piece antenna includes a circular waveguide input, a circular polarizer, a coaxial feed horn, subreflector and subreflector support. One embodiment of the circular polarizer features four branches of wrapped-single-ridged waveguide.

Design Approach for Multiband Horn Antennas Mixing Multimode and Hybrid Mode Operation

Abstract: The design of a quad-band (18, 28, 38, and 48 GHz) feed horn is presented. Corrugations are used for a good polarization purity at the higher frequencies. At the lower frequency, they act as a smooth wall and the horn profile is tuned to achieve a high aperture efficiency.

Design of Millimeter-Wave Monopole Yagi-Uda-Fed Waveguide Pyramidal Horn Antennas

Abstract: Recently, radar technology to support safe driving is one of the sectors receiving a lot of attention for auto-navigation system of a vehicle. In particular, adaptive cruise control (ACC) radar in the W-band is important. The horn antenna has advantages to achieve high gain and low VSWR in the millimeter-wave band because it is commonly simple structure. In this paper, the monopole Yagi-Uda-fed waveguide pyramidal horn antennas are designed with an optimum size 20x20x30mm3 to operate at the W-band. As a result, this paper presented the possibility of the design of a millimeter-wave pyramidal horn antenna for automotive radar systems.

Wide-flared corrugated horn designed for the SKA dish

Abstract: In this paper, the optimization of the feed horn for the SKA (Square Kilometre Array) dish is presented, and an optimization method based on the antenna sensitivity for wide-flared corrugated horn is proposed A prototype of the corrugated horn is developed and the return loss and the radiation patterns are tested The measured results show a good agreement with the calculated ones, which validates the analysis and design method

Shaped reflector antennas for outdoor BTS of 4G/5G mobile communications

Abstract: This paper presents an effective design of reflector antennas to radiate beam patterns fulfilling the coverage need of base station antenna (BSA) system in the 4G/5G mobile communication. A mechanical feed's titling mechanism has been implemented in conjunction with the synthesis of reflecting surface to provide remote beam tilting function for dynamic cell adjustments. The numerical and experimental results are shown to demonstrate the design concept.

Feed system optimization for convex conformal reflectarray antennas

Abstract: In this communication, the possibility of enhancing the performances of Convex conformal Reflectarray Antennas (CRA) adopting an ad-hoc feed system properly designed is investigated. In particular, a feed horn with proper illumination of the here considered CRA has been designed, exploiting particular tecniques. The results show an increase of the efficiency (from 28% to about 46%), with respect to the case in which the same reflector is illuminated by a rectangular horn [4]. Further enhancement of SLL and bandwidth have also been obtained.

Corrugated (2 × 2) silicon platelets horn antenna array at 560 GHz

Abstract: We designed and microfabricated a (2×2) silicon platelet horn antenna at 560 GHz, which is the highest frequency ever among silicon corrugated horn antennas. This was enabled by a silicon compression pin alignment technique of which inaccuracy is less than ± 2 μm in layer-to-layer. The simulation results show that the return loss and gain across the operation frequency of 490–600 GHz are approximately 25 dB and 22 dBi, respectively. The cross-polarization level is below −40 dB. The feature of batch processing will enable us simultaneously to build hundreds or thousands of horn antennas.

Substrate integrated horn antennas with improved aperture efficiency

Abstract: The tapered aperture distribution of the substrate integrated horn antenna always limits its aperture efficiency and widens the antenna beam width. Therefore, the integrated H-plane horn has rarely been considered for the applications where fan-beam types of radiation pattern are required. Here, the amplitude distribution of the integrated horn aperture has been improved to be almost uniform by the three methods of applying hard boundary conditions to the lateral walls of the horn. Among these three methods, air-filled integrated horn in which the internal substrate is removed by keeping a thickness of the dielectric on the walls shows wider improvement over the bandwidth.