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Until recently, full-wave electromagnetic (EM) primary beam simulation results for MeerKAT’s offset-Gregorian reflector antennas in $L$ -band (856–1711 MHz) differed systematically and inexplicably from high-precision field measurements. The measured beam patterns exhibit unexpected frequency- and polarization-dependent pointing offsets (squint) in both horizontal (H) and vertical (V) directions for the copolarization patterns, as well as distinctive asymmetries in the horizontal direction for the cross-polarization patterns in the upper half of the band. These effects were not predicted by design stage simulations that are based on the excitation of the fundamental waveguide mode only. Conventional large reflector simulation strategies used in the literature idealize the orthomode transducer (OMT) and waveguide and exclude this module from primary beam simulations entirely. This research shows that the inclusion of MeerKAT’s wide-bandwidth OMT and waveguide in the simulation is critical to the excitation of the TE21 mode, which results in the asymmetric features observed in the measurements. It is found that the characteristic frequency-dependent asymmetries of the primary beams are a consequence of the design of the OMT and cannot be attributed to manufacturing tolerances, reflector collimation errors, nor the coupling to conductive structures near the feed horn.

In this work, we propose a new dual-band and dual-circularly polarized spin-decoupled reflectarray (RA) combined with frequency selective surface (FSS)-back that ensure the RA independently operating at Ku / Ka dual-band. First, a double-layer FSS with four concentric square loops is designed to inhibit the mutual coupling between the Ku - and Ka -bands. Second, at each Ku - and Ka -band, the 3 bit coding crossed dipole element is used to realize the spin-decoupling. Moreover, each circularly polarized feed horn generates reflected beam operating with left-hand circular polarization (LHCP)/right-hand circular polarization (RHCP) at Ku - and Ka -bands, respectively. Finally, the RA with a square size of 340 mm is designed, manufactured, and measured to verify its performance. At 12.45 GHz, the measured cross-polarization levels (XPLs) are better than 16.5 and 18.5 dB for LHCP and RHCP radiations, respectively, which show the great spin-decoupling between the two circular polarizations. The measured XPLs are better than 21 and 22.5 dB for LHCP and RHCP at 30 GHz, respectively. The well-performed RA has the perspective in satellite communication systems at both Ku - and Ka -bands.

International audience; A low-cost dual linearly-polarized transmitarray antenna (TA) is presented for 5G and beyond networks at D-band. This TA is made of 40 40 unit-cells (UCs) and is illuminated by a stepped feed horn with a F/D ratio equal to 0.75. The flat lens panel is based on UCs with six different phase states at the center frequency of 150 GHz (thus leading in average to a 2-bit phase quantization and 0.7-dB insertion loss from 130 to 175 GHz). Each UC is made of only three metal layers and does not include any via connection to guaranty performance robustness with respect to fabrication dispersions. The measured1-dB and 3-dB TA gain bandwidths equal 16.8% and 19.8%, respectively, with a peak gain of 32 dBi, corresponding to an aperture efficiency of 32% at 150 GHz. The measured sidelobe and cross-polarization levels in E and H planes remain below -21 and -37 dB, respectively. An excellent agreement between measured and simulated radiation patterns was observed.

A ultra-wideband feed having the form of a three-layer metal-dielectric conical horn was proposed and investigated. The horn has a double-layer dielectric filling, and the third layer is the air. The electromagnetic simulation and optimization of the radiator parameters are performed with the use of the finite element method and the finite difference method in the time domain. As the result of numerical simulation, it is shown that the optimized feed provides for the matching at the level below –15 dB in the frequency band 76%. The level of the main lobe of the amplitude pattern is within –10…–15 dB at the boundaries of the irradiation angle (56°). In this case, the nonuniformity of the phase pattern is less than 7°.

In this article, the design and development of a novel twin conjugate matched feed horn at Ku-band is presented. This type of multimode feed cancels the undesired high cross-polar components genera...

This letter presents a low radar cross section (RCS) reflectarray antenna consisting of a feed horn and a spoof surface plasmon polariton (SSPP) reflector. The mesh-type reflector, composed of ${\rm{14\ \times \ 14}}$ bandstop elements, is transparent in the optical band. Owing to the SSPP modes excited by the metallic grating structures (MGSs), each element has high reflectivity in its stopband and high transmittivity in its passband. Moreover, the reflection phase of each element can be adjusted by varying the length of the MGSs. Therefore, the reflector can convert spherical waves into plane waves in the working band and transmit the out-of-band incident waves, thus obtaining low RCS properties. The simulated results indicate that the proposed antenna has a maximum gain of 25.2 dBi, a maximum aperture efficiency of 44.5%, and a 1 dB gain bandwidth of 13.9% (9.4–10.8 GHz). Compared to the reference antenna, the RCS of the proposed antenna is obviously reduced in the frequency ranges of 1.0–8.5 GHz and 12.0–19.0 GHz.

A large-scale 1-bit reconfigurable reflectarray with the feature of fast steerable monopulse patterns has been designed and tested at ${X}$ -band. The reflectarray element integrates one PIN diode to reconfigure the reflective phase between 0° and 180°. The entire reflectarray is composed of $160\times64$ elements, with a total size of 2.56 m $\times1.024$ m. Critical design issues, including element modeling, subarray optimization, and feed horn selection, are investigated to achieve good radiation performance. For the purpose of realizing fast beam steering, 160 field-programmable gate arrays (FPGAs) are adopted to control “ON/OFF” states of every p-i-n diodes in parallel. Digital beam forming methods have been applied to scan both the sum and difference beams. The reflectarray has been fabricated and measured in an anechoic chamber, and a high gain (37.4 dBi) with relatively good aperture efficiency (17.1%) has been realized in such a large-aperture size. Precise monopulse beam steering within ±60° azimuth range has been achieved with the switching time of only $2~\mu \text{s}$ . This large-aperture reflectarray shows promising applications for tracking and detecting systems.

For the first time, a millimeter-wave dual-polarized dielectric resonator (DR) reflectarray fabricated by three-dimensional (3D) printing with high relative permittivity materials is presented. The unit cell of the reflectarray is composed of two elliptical DRs orthogonally placed in the center. A base layer of dielectric slab at the bottom of the unit cell is for fixture and connection with its adjacent elements. For each polarization, only the length of the long axis of one elliptical DR is varied independently to obtain the required reflecting phase response. Due to the orthogonality, high isolation and design independence between the two polarizations can be also obtained. A dual-polarized square DR reflectarray with $16\times16$ elements working in the Ka-band was designed, printed, and measured for demonstration. A measured peak antenna gain of 22.53 dBi was obtained, achieving a gain enhancement of 7.43 dB as compared with that of the feed horn.

This article proposes a novel nondiffractive Bessel beam launcher based on discrete dielectric lens (DDL) antenna with 2-D beam-scanning capability operating at 300 GHz. The terahertz (THz) Bessel beam launcher consists of two identical in-plane rotatable DDLs fed by a commercially available pyramid horn. First, the two thin and lightweight DDLs can transform the quasi-Gaussian beam with spherical phase front from the feed horn into a well-collimated and confined pseudo-Bessel beam. Second, we demonstrate that simultaneous in-plane rotation of the two DLLs in the same and opposite directions can steer the generated Bessel beam in the azimuth and elevation, respectively. Hexagonal dielectric post is employed as the element of the DDL, whose height is tuned from pixel to pixel to realize the required aperture phase distribution. 3-D printing technology was utilized to fabricate the two DDLs aiming at simplifying the manufacturing process and reducing the cost. The theoretically calculated, simulated, and measured results reveal that the designed THz DDL can generate 2-D scanning nondiffractive Bessel beam with a large field of view (FoV) of 86.2° and full azimuth coverage. The proposed 2-D scanning THz Bessel beam launcher can find widespread applications in THz fast noncontact detection, tracking, and imaging systems.

This article describes the design and prelaunch performance of the antenna subsystem of the low-cost 118.75 GHz temperature sounding radiometer payload used in the PolarCube and GEMS-IOD 3U CubeSat missions. Radiometric sounding measurements used for providing data for weather prediction are strongly affected by the main beam, ohmic, and spillover efficiencies of the optics, as well as by inhomogeneities in the scene and background radiation fields. The interpretation of radiometric data is affected by the accuracy with which these antenna efficiencies can be determined, particularly for radiometers that do not permit full main beam external calibration. To this end, an HE11 mode full wave Fourier–Bessel electromagnetic field analysis was developed for determination of an optimal feed horn and reflector geometry such that the main beam and spillover efficiencies of the system are maximized, and these and the antenna phase center location that maximizes phase efficiency are precisely known. The efficacy of employing a sub-millimeter wave 3-D-printed corrugated conical horn operable between 110 and 127 GHz as the feed for an offset paraboloidal reflector due to its very low cost and rapid manufacturability is also addressed. Horn measurements indicate a reflection coefficient below −15 dB and far-field radiation patterns that compare closely to simulation. Although there is some asymmetry in the horn pattern, the average main beam efficiency is 89% for a main reflector subtending a 16° half-angle. Initial performance obtained from airborne measurements over Antarctica on the NASA DC-8 during Operation IceBridge in Oct–Nov 2016 suggests a well-focused scanning antenna subsystem. After final payload assembly, the antenna’s 3 dB beamwidth extracted from a bridge-scan field experiment was broader by ~ 0.1° compared with the idealized simulated pattern.

Various feasible solutions of Irbene RT-32 secondary focus feed antennas are designed and compared in the present study. The examined feed antennas include smooth wall and corrugated horns with linear and shaped profiles. Mode matching technique is employed for simulation of scattering parameters and radiation patterns. Genetic algorithm is used for optimisation of horn profile for the best cross-polarization, and aperture efficiency performance. Although the presented horns are valid for any frequency band, different solutions allow choosing the best combination of factors, such as electrical parameters, bandwidth, physical size and complexity of manufacturing.

In this study, the authors present a beam scanning lens antenna for 30 GHz applications, which is composed of a feed horn and a planar lens with parabolic phase distribution. Due to the parabolic phase compensation, the lens antenna can perform the scanning coverage of ±60° with a gain tolerance of 3 dB. The fabricated lens has a size of 10λ0 × λ 0 × 0.2 λ 0 ( λ 0 is wavelength at the centre frequency of 30 GHz) and the focal length of 24 mm. The beam steering mechanism and the phase error of the lens antenna are analysed in detail. The total system has the advantages of wide scan angle, low profile and lightweight, and it can be readily applied to multi-beam or beam-scanning antenna designs.

In this article, a class of wideband transmit arrays (TAs), composed of cascaded anisotropic impedance surfaces (AISs), for circularly polarized (CP) multibeam generation from a single feed horn are reported. The dispersionless phase compensation is achieved by the Berry phase (BP) via imposing a spatially dependent rotation angle on the TA unit cells. A homogenized model for the BPTA unit cell is proposed and utilized for obtaining a wideband response by tailoring the dispersive properties of the AIS layers. Two modeling methods, an analytical vectorial field analysis and a full-wave strategy incorporating the homogenized model, were employed to efficiently evaluate the performance of the BPTAs. In order to validate the proposed unit cell and the modeling methodologies, a Q-band single-beam BPTA is demonstrated, which achieves a peak gain of 30.2 dBi and a 1 dB bandwidth of 11.1% within which the axial ratio is smaller than 2 dB. Furthermore, by employing the intersection approach for pattern synthesis, several Q-band BPTAs supporting multiple concurrent symmetric/asymmetric CP pencil beams and circular-shaped flat-top beams are designed. A BPTA prototype for producing quad CP pencil beams with unequal gain values was fabricated and characterized, yielding good performance with an overall operational bandwidth of about 11%. The proposed BPTAs are promising candidates for point-to-multipoint communication and point-to-multiregional coverage in wideband millimeter-wave communications for wireless and satellite applications.

Corrugated horn is a kind of key feed component of antenna system, which could be fabricated by electroforming method. However, the feed horn is becoming more difficult to electroform with the increase of frequency. In the terahertz band, which is now of great interest in military and social safety application, the widths of the corrugation teeth and gaps decrease to the micrometer scale, and their depth-width ratios are higher than 2:1. It is really a challenging, time-consuming work to directly machine a terahertz feed horn or make a metal mandrel for electroforming of that. To solve the difficulties in the normal process of terahertz feed horn, a novel discrete fabrication method based on UV-LIGA technology is put forward avoiding the need of mandrel machining. In this method, the manufacturing of a 3D corrugated horn is transformed into 2D slices forming, that is, the corrugation structure is separated into discrete slices according to the width of each tooth or gap. The slices are formed through UV-LIGA technology, in which electroforming is an essential process. Consequently, slices with micro hardness higher than 250HV(200g) and internal compress stress less than 20MPa were electroformed. After assembly and vacuum bonding of slices, typical nickel micro-structure of a conical corrugated horn operating at frequency 2.5THz was fabricated successfully. This layer-by-layer method breaks though the traditional solution of direct machining of metal feed horn or its mandrel by coupling UV-LIGA and vacuum hot bonding technology, which is feasible for vacuum electronic devices like rectangular folded waveguide and multilayer MEMS components moreover.

A K -band (18–26.5 GHz) two-dimensional (2-D) beam scanning antenna is proposed. The hyperbolic lens is fed by an array of focal-shifted horns with nonuniform aperture. The feed at the focal point of the lens generates the boresight vertical beam, while the off-focal feeds are responsible for tilted beams. The nonuniform horn aperture helps to mitigate the gain decrement from the lens aperture tapering. It is fabricated taking full advantage of dielectric and metallic 3-D printing technologies. The lens is printed by stereolithography apparatus (SLA) in resin. The feed horn array is printed by selective laser melting (SLM). Process-wise, it features low cost, short turnaround time, and the capability to implement complex geometries versus traditional computer numerical control machining and mold casting. Simulation and measurement indicate that the antenna features desirable matching below −15 dB and mutual coupling between adjacent port below −25 dB. The gain is above 23 dBi across the K -band. Multiple beams at ±32°, ±12°, and 0° are observed on E- and H-planes. The proposed design can either function as multibeam antenna or a beam-scanning antenna together with switches. It is a capable candidate for applications such as multiple target tracking and wide region monitoring.

The Radio Instrumentation Team (RIT) team at NRC Herzberg in Victoria, Canada, is developing a dual linear polarization, cryogenic radio astronomy receiver covering the frequency range of 30.5 to 50.5 GHz for the next generation Very Large Array (ngVLA) project. The specification of this receiver development is aligned with ngVLA Band 5 requirements. This receiver is designed for a noise temperature of less than 25 K over the bandwidth. The proposed receiver uses a vacuum vessel and a two-stage cryopump system for a cryogenic environment which provides 16 K and 70 K stages. The proposed receiver consists of a cryostat with a cooled feed horn, a turnstile OMT plus two integrated noise couplers for noise calibration, two mHEMT MMIC cryogenic low noise amplifiers with noise temperature lower than 14 K, IR filters, and a vacuum window to create a low-loss transmission of electromagnetic fields into the cryostat. The RIT team is also working on designing and developing various high-efficiency and wideband feed horns, vacuum windows, and OMTs. So far, a compact, low noise octave band OMT, multiple octave band feed horns, and a vacuum window covering the frequency range of 25-50 GHz have been designed. Most of the waveguide components designed and developed for the ngVLA Band 5 and octave band receiver are scalable to higher and lower frequency bands. &nbsp

We present an improved axial ring feed horn using a logarithmic spiral flare opening and tapered groove geometry that is suitable for wide-angle feeding, as required for offset Gregorian telescopes. To enable a design with maximum aperture efficiency, full 2-D field integration was calculated as part of the optimization loop. Since aperture efficiency includes the contributions of cross-polarization, phase, amplitude, and taper, directly optimizing against these terms will result in excellent wideband performance. An example design is shown and optimized for the 30–51 GHz band.

Long distance communication has developed leaps and bounds where it is possible to communicate across the solar system and beyond. This demands the use of large antennas with very high gain for successful link between the transmitter and receiver. To achieve this, in the recent times a new category of antennas have emerged having low mass and low profile. This type of antenna is known as the Reflect Array. This provides low cost and high gain solution. The reflect array combines the favorable features of reflectors and printed arrays. The parabolic dish is difficult to fabricate with tight tolerances at mm wave frequencies, in the case of the conventional phased arrays it is very expensive due to the presence of thousands of T/R modules to obtain the high gain required. Hence the reflect arrays are gaining more attention as an alternative to more mature technologies in the Synthetic Aperture Radar (SAR) Applications as it mitigates the drawbacks of these two types of antennas. In this paper a 1616 element offset fed array is designed at Ku-band. Feed horn is designed using CST Microwave studio, 400mm diameter reflect array is designed that consists of rectangular patches using Ansoft HFSS and the reflect array as a whole is simulated using Integral Equation Method in CST. The phase compensation is performed by varying the patch width and keeping the length fixed at resonance. The simulated gain for the offset fed reflect array is 31.3 dB and the measured gain is 30.5 dB.

This paper presents an additive manufactured dielectric reflectarray antenna for mm-wave communication applications. A dielectric mirror structure is used to reflects the EM-wave instead of conventional metal ground. Meanwhile, the dielectric mirror is properly arranged in the vertical direction to form the reflectarray. Thus, the air layer is used as the phase tuning to achieve stable and broadband radiation. A circularly polarized feed horn is used to illuminate and test the performance of the proposed dielectric reflectarray.

Both the SKA and ngVLA radio telescopes (will) use shaped offset Gregorian reflector antennas, in the feed low configuration, with a variety of different feeds to cover their full operating bandwidth. It is foreseen that both systems will most likely employ variations of quad-ridge flared horns (QRFH) to cover receiver bands with about 3.5:1 bandwidth – possibly wider [1] , [2] . For both systems, the most important performance parameter is the receiving sensitivity, and it is critical that any feed horn employed in the telescope has a carefully controlled radiation pattern, which is specifically designed to maximize the receiving sensitivity over the entire operating bandwidth.

We present the design of a compact dual frequency feed horn optimized to operate at Ka-band (35.75 GHz) and W-band (94.05 GHz). The feed horn consists of a single spline profile horn along with a diplexer having orthogonal Ka- and W-band ports and a band pass filter at the Ka-band port. The filter is used to achieve high isolation between the Ka- and W-band ports. A directivity of 21 dB and - 12 dB beam width of 31 degrees was achieved at Ka-band and a directivity of 26 dB and -12 dB beam width of 21 degrees was achieved at W-band. The overall feed horn assembly is compact and easy to machine. The dual frequency horn will be tested as part of a Ka/W-band breadboard radar.

A compact front-end design, including an axial-ring corrugated feed horn and a vacuum window, has been designed for a proposed ngVLA Band-5/ Q-band receiver. The electromagnetic performance, optical propagation, and mechanical analysis of the proposed front-end model are presented in this paper. Our design work achieved an optimized compact feed with an aperture efficiency higher than 95%, using shaped optics, and a "top-hat" shaped vacuum window with excellent performance covering the frequency range 30 - 51 GHz for the wide opening-angle ngVLA antenna optics.

Traditionally, corrugated conical horn antennas have been the main choice for use in astronomical receivers in the range of millimeter and submillimeter waves. They present low cross-polar level and high coupling efficiency into the fundamental Gaussian mode. However, this type of antenna is difficult to manufacture, inevitably increasing its price and extending the production process. In this article, we present two kinds of feed horn antennas, aimed for use in a frequency range equivalent to atacama large millimeter/submillimeter array (ALMA) Band 6 (211–275 GHz), which can be fabricated in a much simpler way with the conventional machining tools. Specifically, we present the design and performance comparison of smooth-walled spline-profile horns in two geometries, diagonal, and conical. Optimization of the designs has been made by means of an algorithm that allowed us to obtain models whose electrical and mechanical characteristics make them competitive when compared with corrugated horns. In particular, they are $\text{40}\%$ shorter than the conventional corrugated horns suited for this band, representing an advantage given the stringent space constraints of most astronomical receivers. We also demonstrate that they can be coupled efficiently to an astronomical-grade optical system, using ALMA Band-6 receiver as an example. Furthermore, we have constructed the diagonal horn and characterized it thoroughly. Experimental results of the radiation pattern at room temperature show a good cross-polar performance with levels below −20 dB and Gaussicity above $\text{96}\%$ . Our calculations show a good antenna-efficiency level with losses less than $\text{1}\%$ . All these properties demonstrate the feasibility of this type of horns to become the main option at the time of choosing a feed system for cutting-edge astronomical applications.

A novel conformal transmitarray with beam steering ability is presented. First, an ultra-thin transmitarray element consisting of three layers of identical square ring slots is developed. The element has a thickness of 0.508 mm (0.04 wavelength in the free space at 25 GHz), achieving a transmission phase range of 330° with a maximum 3.6 dB loss. The element is then applied to a curved transmitarray conformal to a cylindrical surface fed by a standard gain horn with about a 10-dBi gain. A prototype is fabricated radiating a boresight beam with a peak measured gain of 19.6 dBi and an aperture efficiency of 25.1%. Second, when the transmitting surface of the above array is divided into two parts from the middle with different main beam directions, the combined beam can be radiated to an oblique angle with respect to the boresight direction. Using this method, a mechanical beam scanning conformal transmitarray antenna is designed. Its size is about 2.5 times larger than the fixed-beam one and consists of six transmitting surfaces with main beams directed to different angles. By rotating the feed horn to different positions, the main beam of the array can be switched to ±15°, ±10°, ±5°, and 0°. A prototype is fabricated with a stable gain of about 18.7 dBi at all beam angles.

A two-dimensional (2-D) beam-scanning lens antenna is proposed for Ka-band satellite applications, which is composed of a feed horn that can move in plane and a metasurface lens with elliptical paraboloid phase distribution. Due to the paraboloid phase compensation, the lens antenna possesses wide scanning angles in the azimuth and elevation. The fabricated lens has a size of 10.5 λ 0 × 10.5 λ 0 × 0.2 λ 0 ( λ 0 is wavelength at the center frequency of 30 GHz) and the focal-to-diameter ratio of 0.2. The total system can realize the boresight gain of 18.5 dB, and the scanning coverage of ±60° with a gain tolerance of 3.7 dB. The design methodology features the advantages of low cost, compact size, and light weight. It can find potential applications in multibeam or beam-scanning antenna systems that are comparable with array antennas.

A dielectric–metallic jointly three-dimensional (3D) printed V-band (50–75 GHz) lens antenna with preliminary surface roughness modelling is proposed. It takes full advantage of both the dielectric and metallic 3D printing technologies which help effectively to control the cost of the lens antenna. The stereolithography apparatus is used to form the lens using Somos Imagine 8000 resin, while the selective laser melting is used to fabricate the feed horn using aluminium alloy. A λ 0 /4 matching layer is adopted between the feed and lens for reduced reflection. The surface roughness of the lens and the feed horn are characterised under a surface profilometer. Owing to the material and process, the surface roughness of the 3D-printed device demonstrates distinctive properties. A preliminary conjecture is made on the surface roughness distribution of 3D-printed devices that are helpful to predict roughness-related performance degradation. The antenna is characterised by electromagnetically and materialwise. It has impedance bandwidth of | S 11| 32 dBi and symmetric radiation patterns on both E and H planes, which agrees well with simulation.

In this paper, the design of an axially corrugated conical horn antenna is presented for the application in a transportable polarimetric Doppler Weather Radar (DWR) at X-Band. Such types of applications require very low cross-polarization and the same is achieved for the current feed horn. Additionally, since it is to be used for transportable weather radar and the actual operating frequency depends at the corresponding site condition, the horn has been designed to operate the commonly used weather radar band of 9.3 GHz to 9.5 GHz. The proposed feed horn has five corrugations with variable depth and linear profile for the ease of fabrication. The horn was fabricated using aluminium material and measurements were carried out in Compact Antenna Test Facility (CATF). Measurement result confirms −18 dB of edge taper as requirement with a cross polarization of better −30 dB which are in good agreement with the simulated one. Measured data of the feed pattern is used to simulate in GRASP9 software package and the overall antenna performance ensures the fulfilment of required specifications for the polarimetric Doppler weather radar system.

A novel $W$ -band left-hand circular polarized (LHCP) cylindrical waveguide feed horn antenna is proposed. The proposed antenna features an inbuilt polarizer structure and a single side-fed linear polarized input to offer symmetric LHCP radiation pattern. The internal polarizer structure consists of nine pairs of circular cavities to generate a circularly polarized wave, eliminating the need for an orthomode transducer or a complex septum. The side-fed horn reduces the overall length by eliminating the rectangular to circular waveguide transition. The proposed horn antenna’s electrical dimension is $7.2\lambda \times 3.9\lambda \times 1.4\lambda $ at 84 GHz. The antenna has impedance matching ( $S_{11}$ below −15 dB) and axial ratio below 1.2 dB from 79.5 to 88 GHz. The horn is used as a feed source for an offset parabolic reflector of 10 cm diameter and small $f/D$ ratio 0.25, which can fit inside a CubeSat. The reflector antenna provides the simulated right-hand circular polarization (RHCP) directivity of 36.6 dBic at 86 GHz with spillover loss of 0.83 dB. The feed reflector assembly is also simulated with the complete aluminum CubeSat chassis. The measurement of the prototyped feed horn and the offset parabolic reflector antenna validates the analysis and simulation results.

Orthogonal Polarized Horn Antenna with high port to port isolation at millimeter wave frequencies is presented. WR-34 waveguide is used as feed at two ports for horn antenna. Dual-polarization with good port to port isolation is achieved by using redesigned Magic-T structure in the feed horn. The simulated results show that the port isolation is more than 60 dB and the gain is 16dB for both ports at 28GHz. The Proposed dual polarized antenna is modelled using HFSS 3D EM software. Simulated results on radiation pattern, gain and frequency response of S-parameters at two ports are presented.

The robot-based antenna measurement system at the Institute of High Frequency Technology at RWTH Aachen University is put into operation and its measuring capability is proven by preliminary spherical measurement data. For this purpose, near- and far-field measurement data of a standard gain horn antenna are shown and compared with measurement data of the institute’s compact antenna test range. The influence of the scalar feed horn used as the probe is compensated by a full high-order probe correction. It is shown that the deviation in the E-plane of the antenna is mainly ≲ −40 dB in wide parts of the angular range of the radiation pattern. In view of the fact that the construction of the measurement range is not yet completed and no absorbers are mounted, the deviations are, thus, within the range of the expected tolerance.

An ultra wide band two polarizations four ridge conical metal-dielectric feed horn has been proposed and investigated. The horn has a three-layer dielectric filling and is excited by a circular metal-dielectric waveguide, which is excited by two orthogonally located coaxial lines. Electrodynamic modeling and optimization of horn parameters were carried out using finite element and finite difference in time domain methods. As a result of numerical simulations it is shown that the optimized feed horn provides a reflection coefficient below -15 dB, a stable beamwidth (56°) at the level of -10 to -15 dB, and a stable position of the phase center in the 85% frequency band.

This communication presents the experimental validation of independent and wide beam scanning with a dual-band transmitarray antenna (TA) in Satcom up- and down-links at Ka -band. The TA consists of two subarrays: one operates in the down-link with central frequency at 19.5 GHz, while the other one operates in the up-link centered at 29 GHz. Both subarrays share a common radiating aperture to obtain the compact configuration. The TA layout is made of 1 bit unit-cells and its design relies on the bifocal technique to extend the beam-scanning capability. The proposed bifocal prototype includes 1500 up-link unit-cells in a $30\times50$ matrix and 1581 down-link unit-cells arranged in a $31\times51$ rectangular lattice. The 1-D scanning is validated by displacing the feed horn along one direction. We show that the TA beam can be scanned in a ±40° and ±30° independently in each band while keeping a very low scan loss (

A high-performance feed horn antenna with dual circular polarization (CP) is proposed at 5G millimeter-wave band (26.5 – 29.5 GHz) for multiple switched beam spherical reflector antenna application. This horn antenna is designed using a circular waveguide and has an inbuilt polarizer made of radially opposite rectangular grooves. The horn antenna has corrugated teeth and choke at the aperture to achieve wide axial ratio beamwidth and high front-to-back ratio. The simulated inter-port isolation is below -25 dB, port reflection coefficients is below -15 dB, and axial ratio is below 1 dB in the 27.5 – 28.35 GHz of the 5G communication band. Five of these feed horn antennas are placed along the focal-arc of the offset spherical reflector to achieve high gain dual-CP stable switched beams. The peak simulated realized gain of the reflector is more than 30 dBic for both the polarization and for different beam switched angles.