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This paper presents a novel approach for designing a reconfigurable and steerable antenna utilizing plasma dielectric slabs along the aperture of a pyramidal horn antenna. The antenna provides electronic control over the radiation gain and the direction of the main beam. The proposed configuration consists of four plasma slabs aligned perpendicular to the horn aperture along the horn axis, supplemented by four diagonally connected plasma slabs. Each plasma slab can be independently switched on or off, enabling dynamic adjustment of the radiation gain and steering of the main beam.Numerical investigations demonstrate that toggling the plasma slabs or controlling the plasma frequency allows precise control over the pyramidal horn antenna's radiation gain and beam steering. Selecting appropriate dimensions and angles for the plasma slabs is crucial in achieving the desired beam steering angle and radiation gain control. To validate the concept, the proposed antenna configuration is designed and numerically simulated at a frequency of 10 GHz. The results indicate that the radiation gain of the antenna can be significantly enhanced, reaching up to 6.5 dBi, and the main beam direction can be steered within a range of ±12°.This research presents a promising approach for achieving reconfigurability and beam steering capabilities in antenna systems by utilizing plasma dielectric slabs. The proposed design offers enhanced performance and flexibility, making it suitable for various applications in antenna technology. The ability to control beam steering and radiation gain without mechanical devices is essential in satellite and space communications. [ABSTRACT FROM AUTHOR]

We present a dual-orthogonal circularly polarized waveguide antenna for modeling real GNSS signals in a shielded chamber. The proposed antenna consists of a septum structure for a circular polarization radiation pattern and a coaxal-to-waveguide transition for broadband characteristics. The designed antenna has dual orthogonal characteristics and forms RHCP and LHCP radiation patterns through the two ports. The fabricated antenna had gain characteristics higher than 12 dBic, an axial ratio of less than 3 dB, and a return loss higher than 10 dB in the GNSS band. [ABSTRACT FROM AUTHOR]

A choke ring horn antenna has been designed for use as an RF applicator in a compact range in vitro 28 GHz bioelectromagnetic exposure system. The 30 mm × 50 mm horn antenna was fabricated and measured to operate from 27.75 GHz to 34.5 GHz with a −20 dB measured S11 and a measured antenna gain of more than 10 dBi. A wide sectoral (flat top) and symmetric E- and H-plane pattern with a half-power beamwidth of more than 60 degrees was achieved with a cross-polarization discrimination of better than 28 dB. Electromagnetic slots were introduced in the antenna to suppress excess cavity mode radiation which inherently impacts the cross-polarization levels of choke ring antennas. The proposed antenna was successfully integrated into the compact measurement chamber in partnership with the Korea Telecommunication Research Institute (ETRI) and is currently in use for real-time 5G millimeter-wave dosimetry studies. [ABSTRACT FROM AUTHOR]

This paper demonstrates the design, modeling, and analysis of a small size 180 × 165 × 1.6 mm3 printed broadband Vivaldi antenna for electromagnetic compatibility measurements. The proposed antenna is intended to be utilized as a reference antenna for emission and immunity tests inside the EMC Chamber through the band (0.8–5.5 GHz). Exponentially tapered slots were created based on mathematical equations to form an end-fire radiation antenna. Furthermore, microstrip and slot line stubs were employed to tune the impedance bandwidth. This antenna could be considered a 2-D Horn antenna with a size reduction of 64% and 67% since both antennas, Vivaldi and Horn are based on the same principle. Two rectangular slots were engraved near the feeding point to reshape and enhance the gain at lower frequency bands. Furthermore, the realized gain has been improved by approximately 3.5 dB and reached up to 10.7 dBi by introducing a pair of triangular reversal slots at the top edges of the structure. Moreover, this antenna has specifications that make it a suitable candidate to work as a reference antenna inside the EMC chamber compared to the classical Horn antenna offered for sale (PowerLOG® PRO 30800 and TBMA4). [ABSTRACT FROM AUTHOR]

In this study, a wideband circularly polarized (CP) H‐plane horn antenna based on Gap Waveguide (GW) technology in K‐band is presented. The proposed antenna consists of two unconnected metal planes. To produce broadband CP radiation, two main methods are utilized. First, two antipodal tapered plates (ATPs) are added in front of the horn. The ATPs are carefully designed for dissimilar polarization orientations. By this technique, the orthogonal electric fields can be prepared. Then, by embedding three metal square pins near the center of the aperture in both inner plates, the impedance bandwidth (BW) and BW of CP radiation of the proposed horn is entirely improved. Its BW for target |S11| < −10 dB is 18–28 GHz. Also, the peak gain fluctuates between 11.5 and 13 dB. This antenna can provide a 3 dB polarization axial‐ratio BW of about 28.5% (20–26 GHz). Total radiation efficiency is higher than 94%. To verify the design, the proposed structure is manufactured and tested. The proposed horn antenna result has an appropriate agreement between measurement and simulation. Its miniaturized dimensions, easy and cheap fabrication, and broadband CP capability make it a proper volunteer for broadband communication systems. Key Points: We apply Gap Waveguide technology in sectoral horn antenna to reduce the size, bulk, and cost of conventional horn antennasSymmetrical radiation patterns and wideband circular polarization are achieved from two added antipodal tapered plates and three embedded pinsAn antenna is designed for 5G or vehicular satellite communication fields [ABSTRACT FROM AUTHOR]

With the continuous development of electromagnetic detection systems, the working frequency of radar gradually expands towards the low-frequency band such as P- and L-band, and the low-frequency horn antenna has also attracted more and more attention. Given the problems of miniaturization, lightweight and ultra-wideband design of low-frequency horn antenna, this paper presents the optimal design for the feed balun, ridge curve, back-feed cavity and sidewall of the traditional horn antenna, and proposes a performance-enhanced double-ridged horn antenna covering 0.21-2.3 GHz. In the entire working band, the antenna has stable radiation patterns and good port-matching characteristics; its VSWR is less than 2 and the main lobes of patterns do not split or deteriorate. The proposed horn antenna can be used as a standard calibration or measurement antenna in antenna or material measurement systems. [ABSTRACT FROM AUTHOR]

We have developed an affordable horn antenna at St. Stephen's College, which has been used to perform various research-based activities in the college astronomy lab. In this article, we present three of our experiments performed in our undergraduate lab with respect to radio frequency interference in the campus and provide the relevant data. We also present and analyse our results for the 21-cm Hydrogen line emission data collected using our affordable horn antenna. In the third experiment, we study the radiation pattern of our horn antenna. The aim of the article is to present experiments to explore radio astronomy in the lab that can be done by undergraduate students with minimum cost. [ABSTRACT FROM AUTHOR]

This paper presents the design of a 60 GHz millimeter-wave (MMW) slot array horn antenna based on the substrate-integrated waveguide (SIW) structure. The novelty of this device resides in the achievement of a broad impedance bandwidth and high gain performance by meticulously engineering the radiation band structure and slot array. The antenna demonstrates an impressive impedance bandwidth of 14.96 GHz (24.93%), accompanied by a remarkable maximum reflection coefficient of −39.47 dB. Furthermore, the antenna boasts a gain of 10.01 dBi, showcasing its outstanding performance as a high-frequency antenna with a wide bandwidth and high gain. To validate its capabilities, we fabricated and experimentally characterized a prototype of the antenna using a probe test structure. The measurement results closely align with the simulation results, affirming the suitability of the designed antenna for radar sensing applications in future global industrial scenarios. [ABSTRACT FROM AUTHOR]

This paper presents a model, design, and implementation of a metasurface electromagnetic (EM) wave absorber for operation in the frequency range of the X-band. The model of the metasurface was constructed with a split ring resonator (SSR) and a stripline and it was designed with a single unit cell, whereby the results were approached with transmission line theory for patch impedance extraction. Implementation of a metasurface EM wave absorber was deployed on an FR4 Epoxy dielectric substrate with dimensions of 80-unit cells x 80-unit cells and characterized with two horn antennas, which were connected to a signal generator as the transmitter and a spectrum analyzer as the receiver. In front of the horn antennas a device under test (DUT) was installed, i.e., a metasurface EM wave absorber and a metal plate with similar dimensions. The metal plate was expected to perform full reflection at the same distance and antenna orientation. The same condition was used as a normalization factor to optimize the absorption of the metasurface EM wave absorber. The characterization results showed that the minimum normalized absorption of the SRR and stripline at the designated measurement distances was 0.99, 0.99, 0.99, and 0.97, at frequencies of 8.85 GHz, 9.08 GHz, 9.15 GHz, and 9.10 GHz, respectively, and a 0° antenna orientation. [ABSTRACT FROM AUTHOR]

In this communication, a pyramidal horn antenna is proposed and investigated to operate in the sub-THz region at a centre frequency of 0.245 THz. The antenna has five layers such as coupling layer, air cavity layer, excitation layer, pyramidal horn, and extended side wings. The coupling layer is responsible to couple the electromagnetic (EM) wave from waveguide feed. The excitation layer consists of a plus shape slot which is responsible for the excitation of the proposed antenna. The air cavity is designed such that it can efficiently excite the plus-shaped slot of the excitation layer. In order to achieve high gain and efficiency, the pyramidal horn and the extended side wings are used in combination. The proposed horn antenna has a significant efficiency and gain of 97.1 % and 19.2 dBi respectively and gives a wide impedance bandwidth of 32.3 % (0.205–0.284 THz). When compared to the literature, the proposed novel design demonstrates significant improvement in terms of bandwidth, directivity, and gain. The antenna finds its suitability for Sub-THz 6G wireless communication. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the L.N. Gumilyov Eurasian National University. Technical science & Technology series is the property of L.N. Gumilyov Eurasian National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An ultrawideband 3D printed aperture‐shared conformal dual‐horn antenna that is mounted on a cylindrical metal surface is proposed. The antenna system consists of an H‐plane horn antenna working at 0.5–5.5 GHz, namely Antenna A, an H‐plane horn antenna working at 5.5–16 GHz, namely Antenna B, and a diplexer. To validate the proposed aperture‐shared antenna, a prototype is 3D printed with surface metallization. A diplexer is used to connect Antenna A and Antenna B. Measured results show a 32:1 impedance bandwidth for the dual‐horn antenna system with |S11| < −6.8 dB. Good radiation patterns are also obtained for most of the bandwidth. [ABSTRACT FROM AUTHOR]

In today's competitive market, it is crucial to continually improve antenna manufacturing technologies to keep up with the increasing demands. Researchers can utilize numerical methods to create novel and highly effective antenna designs, pushing the boundaries of antenna engineering. This paper considers two approaches to efficiently model and design sparse wire-grid antennas. The main idea is to create an optimal wire structure that closely approximates the current paths in the antenna while maintaining its integrity with minimal mass. This structure can be used in further simulations with controlled characteristic accuracy and less resources. In this study, these approaches were applied to modelling horn, conical horn, and reflector antennas. The verification was conducted by comparing their results with those obtained from numerical and experimental tests for the same antenna designs. The findings demonstrated good agreement between the results. In addition, we investigated the impact of using these approaches on the antenna characteristics and found that they can enhance the performance of certain characteristics while reducing costs in manufacturing and modelling. [ABSTRACT FROM AUTHOR]

In this paper, we propose a streamlined design and automation of a horn antenna and its rectangular waveguide-based feeder using computer simulation-based optimizations and additive manufacturing. The approach enables time-effectiveness with a holistic design of the two components, while achieving advantageous results of the antenna parameters. The approach is described in comparison to other works and the results presented and discussed on the antenna models manufactured for two midband frequencies: at 2437 MHz and 5250 MHz. The optimum-search algorithm was able to find the parameter values that resulted in more than 25 dB improvement in S11-parameter values in comparison to the initial design based on the textbook theory. For the 2437-MHz antenna, the achieved bandwidth, using the optimized parameters, was 16.52% wide comparing to 5.14% bandwidth that was the result based on the analytical expressions. In case of the 5250-MHz antenna, the optimized antenna bandwidth reached 25.47%. The fabricated antenna gain was close to the design value.

ObjectiveThis paper aims to study the coupling response law of an electromagnetic pulse acting on a pyramid horn antenna under the condition of the random distribution of incident parameters. Methods First, a statistical analysis model of the electromagnetic pulse response of the horn antenna is established on the basis of a computer simulation technology (CST) and Matlab co-simulation. A simulation model of the antenna electromagnetic impulse response is then established by CST, and the rationality of the model is verified by the voltage standing wave ratio (VSWR) and gain curve. The impedance characteristics of the radio frequency port of the communication system under different states such as transmitting and receiving are considered. The coupling response indexes of antenna ports such as open circuit voltage (OCV), short circuit current (SCC) and load current are obtained under high-altitude electromagnetic pulse (HEMP) irradiation with a peak field strength of 50 kV/m. Finally, the azimuth, elevation and polarization angles are set in the spherical coordinate system to obey the uniform distribution, and Matlab is used to fit the main signal indicators such as the peak value and waveform energy of the antenna load response waveform. ResultsThe results show that the probability distribution of the main signal indicators is mostly convex. Taking the waveform peak value as an example, there is a 90% probability that the peak value of the response waveform is less than 0.13A, which is only 16.2% of the maximum peak value of 0.8A; that is, except in the specific electromagnetic pulse incident range, the signal indicators of the pyramid horn antenna response waveform are kept at a low level in most cases.ConclusionThe results of this study lay the foundation for the electromagnetic pulse vulnerability analysis of communication systems.

A method for generation of ultra-wideband electromagnetic pulses with a nanosecond length and a picosecond rise time has been proposed and studied. A horn antenna with a photoconductive switch irradiated by laser pulses has been used as an emitter. It is shown that the length of ultra-wideband electromagnetic pulses is determined by the antenna length and the semiconductor material and the rise front is determined by the front of laser pulses used to initiate a photoconductive switch. Typical pulse lengths of ~1 ns with a rise front of up to ~34 ps are reported. [ABSTRACT FROM AUTHOR]

A novel E‐plane horn antenna fed with E‐plane Tee junction, conceptualized using the substrateintegrated waveguide (SIW) technology is introduced and investigated. Conventional SIW‐inspired horn designs are mostly limited to H‐plane sectoral horns, portraying confined radiation along the H‐plane while unconfined, fan‐beam‐shaped radiation along the principal E‐plane. Such radiation characteristics restrict its usage to designs requiring an electric field parallel to the structure and ultimately narrow confined radiation along the principal E‐plane of the embodiment. The proposed design provides a glue‐less solution to designing an E‐plane horn fed by an E‐plane Tee junction, both conceptualized by the SIW technology, having relative ease of fabrication on dual copper clad Printed Circuit Boards. Such a design operates from 17.15 to 18.8 GHz (~9.2% operating bandwidth) with a realized gain greater than 10.5 dBi, making it suitable for applications requiring light‐weighted high‐gain E‐plane sectoral horn antennas. [ABSTRACT FROM AUTHOR]

This paper is considered to be a continuation of a previous publication devoted to applications of digital transformations and simulation modeling in aerospace engineering and security (IJITS, No3, 2023). The aim of the paper is to present methods and means for conducting microwave measurements and practical learning of real antennas, which are expressed in the design, modeling, and validation of the models and contribute to obtaining reliable simulation results. The theoretical framework of the study is supported by classifications of the main types of microwave devices and technologies used in innovative laboratories. [ABSTRACT FROM AUTHOR]

In this paper, we propose a streamlined design and automation of a horn antenna and its rectangular waveguide-based feeder using computer simulation-based optimizations and additive manufacturing. The approach enables time-effectiveness with a holistic design of the two components, while achieving advantageous results of the antenna parameters. The approach is described in comparison to other works and the results presented and discussed on the antenna models manufactured for two mid-band frequencies: at 2437 MHz and 5250 MHz. The optimum-search algorithm was able to find the parameter values that resulted in more than 25 dB improvement in S11-parameter values in comparison to the initial design based on the textbook theory. For the 2437-MHz antenna, the achieved bandwidth, using the optimized parameters, was 16.52% wide comparing to 5.14% bandwidth that was the result based on the analytical expressions. In case of the 5250-MHz antenna, the optimized antenna bandwidth reached 25.47%. The fabricated antenna gain was close to the design value. [ABSTRACT FROM AUTHOR]

To determine the local inhomogeneities of a rotating plasma, the method based on microwave refraction was used. The method is based on spectral and correlation analysis of the reflected signals from the rotating plasma layer at normal and inclined microwave incidence. This method allowed us to determine local inhomogeneities of plasma electron density, angles of azimuthal displacement of grooves, and its angular frequency of rotation. Using an additional 4th horn antenna, in contrast to previous works, it was possible to find and analyze two regions with azimuthal inhomogeneities in the rotating plasma. Analysis of the reflected signals shows the presence of four grooves, and the angular frequency of rotation ω = 1.16 × 104 rad/s was also determined.

This paper presents the design of a 60 GHz millimeter-wave (MMW) slot array horn antenna based on the substrate-integrated waveguide (SIW) structure. The novelty of this device resides in the achievement of a broad impedance bandwidth and high gain performance by meticulously engineering the radiation band structure and slot array. The antenna demonstrates an impressive impedance bandwidth of 14.96 GHz (24.93%), accompanied by a remarkable maximum reflection coefficient of −39.47 dB. Furthermore, the antenna boasts a gain of 10.01 dBi, showcasing its outstanding performance as a high-frequency antenna with a wide bandwidth and high gain. To validate its capabilities, we fabricated and experimentally characterized a prototype of the antenna using a probe test structure. The measurement results closely align with the simulation results, affirming the suitability of the designed antenna for radar sensing applications in future global industrial scenarios.

Two types of cost-efficient antennas based on dielectric gradient index dielectric lens have been designed for 5G applications at 28   G H z . The first is a linearly polarized flat lens antenna (LP-FLA) for terrestrial 5G communications. The second is a novel circularly polarized stepped lens antenna (CP-SLA) for 5G satellite services. An efficient design method is presented to optimize and conform the lens topology to the radiation pattern coming from the antenna feeder. The LP-FLA is fed by a traditional linearly polarized pyramidal horn antenna (PHA). The CP-SLA is fed by an open-ended bow-tie waveguide cavity (BCA) antenna. This cavity feeder (BCA), using cross-sections with bow-tie shapes, allows having circular polarization at the desired frequency bandwidth. The two types of presented antennas have been manufactured in order to verify their performance by an easy, low-cost, three-dimensional (3D) printing technique based on stereolithography. The peak realized gain value for the flat (LP-FLA) and stepped (CP-SLA) lens antennas have been increased at 28   G H z to 25.2 and 24.8   d B i , respectively, by disposing the lens structures at the appropriated distance from the feeders. Likewise, using an array of horns (PHA) or open-ended bow-tie waveguide cavity (BCA) antenna feeders, it is possible to obtain a maximum steering angle range of 20° and 35°, for a directivity over 15   d B i and 10   d B i , in the planar and stepped lens antennas, respectively. [ABSTRACT FROM AUTHOR]

In the era of digital transformation, Radio Frequency Identification (RFID) technology has emerged as a powerful enabler for a myriad of applications, from inventory management and supply chain logistics to access control and contactless payments. At the heart of this transformative technology lies the RFID antenna, a crucial component that facilitates wireless communication between RFID tags and readers. In this article, we delve into the intricacies of RFID antennas, their design principles, applications, and their profound impact on modern-day industries. [ABSTRACT FROM AUTHOR]

E-plane sectoral horn antenna based on printed ridge gap waveguide (PRGW) technology is designed for 5G applications. It is implemented on the top plate of the PRGW structure to avoid the losses and dispersion associated with conventional feeding mechanisms. The quasi-transverse electromagneticPRGW-based antenna is excited through a planar microstrip transition. First, the single horn antenna element is introduced with the microstrip feeding section. It shows an impedance bandwidth of fractional bandwidth 26% from 45.7 to 55.4 GHz with the realized gain of 12.7 dBi and radiation efficiency of 90%. In order to maximize the realized gain, a four-element linear horn array is introduced. The same impedance bandwidth is maintained with the array having a gain of 18.6 dBi from 45.7 to 55.4 GHz. The overall antenna array performance in the entire operating frequency range is stable with a radiation efficiency around 85%. Three matching sections are implemented to achieve better impedance matching. One is used to match the horn with the feeding aperture via the PRGW line. Another section is designed to match microstrip transition with PRGW ridge. Finally, two-stage quarter wavelength transformers are required to match the power divider with the array feeding network. A prototype of single-element horn antenna was fabricated to verify the concept of the design. Simulated and measured results show that the proposed antenna can operate in the frequency band of 45–55 GHz with good agreement of radiation performance. Moreover, the proposed designs are implemented and simulated using two microwave simulation tools (CST and HFSS) to verify the radiation performance, which exhibits good agreement. The design of an E-sectoral horn antenna and its array with high gain based on PRGW is demonstrated for the first time which is considered a novel issue. It can be integrated with other passive and active elements in communication systems. Thus, it can be a valuable component in 5G communication due to its high gain, compact size and ultra-wide band. [ABSTRACT FROM AUTHOR]

In this article, the periodic pulse diffraction from the circular dielectric object radiated by the horn antenna is investigated and experimental verification is provided. The pulse spectrum with Hamming weight function (Hamming window) form occupies the frequency band of 38 – 52 GHz. The problem is solved using the Method of Auxiliary Sources, and the results of the computer simulation are obtained. The fundamental advantage of the method is to eliminate the singularity problem during the solution of the integral equation obtained by boundary conditions on each scatterer. The comparison is done with the experimental data, which shows good agreement between the simulation outcomes and the experimental ones. The correctness of the determination of the electric size of the object by the analysis of the scattered pulse echo serves as the verification of the approach. The outcomes reveal that less than a 3% deviation is observed between numerical and experimental analysis. [ABSTRACT FROM AUTHOR]

This letter presents a wideband high gain substrate integrated waveguide horn antenna (SIWHA) loaded with half Maxwell fish‐eye (HMFE) fabricated by 3‐D‐Printing. The impedance bandwidth of the SIWHA is narrow, mainly caused by the discontinuity between the substrate with the air. By introducing the HMFE and a match layer between the SIWHA with HMFE, the impedance continuity can be realized, which can not only improve the impedance bandwidth but also enhance the antenna gain. Experimental results show that the proposed antenna can achieve more than 6 dBi gain and 60.9% relative impedance bandwidth with reflection coefficients lower than −10 dB. [ABSTRACT FROM AUTHOR]

This paper proposes a method to add an additional phase compensation to conventional phased arrays to achieve flat-topped beam forming, which can convert the spherical waves emitted by common conical horn antennas into cylindrical flat-topped beams, at the same time, there is also a certain power enhancement. A centrosymmetric unit composed of four layers of F4B and metal patches is designed. By changing the value of the parameters, a 360? phase change can be achieved, and it has the advantages of small size and low-profile. To validate the design concept, a prototype of the transmitarray (TA) was designed, fabricated, and measured by calculating the phase distribution of the front. The measurement results show that the designed TA can achieve flat-topped beams at 5.2GHz, the maximum gain is 1.15dB higher than that of the horn antenna, and the flat-topped range is about ±10?. The results are in good agreement with the simulation within the test range. [ABSTRACT FROM AUTHOR]

A compact, wideband, low cost, high radiation efficiency and planar half mode substrate integrated waveguide (HMSIW) horn antenna is proposed in this work. For the first time, HMSIW is used to design a horn antenna. By using HMSIW waveguide structure instead of Substrate Integrated Waveguide (SIW), the impedance bandwidth of antenna is increased significantly. The use of this waveguide structure in the design of the horn and its feeding system has increased the impedance bandwidth of the antenna. In fact, leaking the electromagnetic waves gradually along the horn increases the bandwidth of antenna. By applying the design equations of the H-plane horn antenna and half mode substrate integrated waveguide, the initial dimensions of the antenna have been obtained, then the best possible solution has been extracted by parametric study and optimization. Simulation results exhibit an impedance bandwidth of 50% from 24GHz to 40GHz. Also, the proposed design shows a gain between 7dB and 10 dB together with radiation efficiency higher than 95% over the frequency band of 25 to 35GHz. The innovation of this work is in providing a new horn structure based on HMSIW with wide impedance bandwidth. In the previously presented works, which are mainly based on SIW, the antenna suffers from a narrow impedance bandwidth. [ABSTRACT FROM AUTHOR]

In this study, a high-gain and dual-polarized Quad Ridged Horn Antenna (QRHA) is proposed and designed to be used in Obstacle Penetrating Imaging Radar (OPIR) applications. The quad ridged design is developed and then optimized by using the antenna design simulator software; CST Microwave Studio. The antenna parameters including the center frequency, frequency bandwidth and the antenna radiation pattern beam width are considered based on the requirements of OPIR applications. The final design is obtained for the center frequency of 2.785 GHz with a -10 dB bandwidth of at least 2.5 GHz. The final designed QRHA is able to provide a gain of 12.4 dB with a beam width of 36° at the center frequency of 2.785 GHz. [ABSTRACT FROM AUTHOR]

A theoretical model is proposed to preliminary assess the performance of plasma-based reflecting and transmitting surfaces. The model has been verified and, subsequently, exploited in a feasibility study to implement beam steering and polarization control. Theoretical findings laid the basis for the numerical design of a reconfigurable plasma-aided horn antenna. Notably, the solution proposed is capable of both beam steering and polarization control relying on a plasma-based transmitting surface. Specifically, the main lobe can be steered in the range 0° – 50° maintaining the gain >10 dBi, the relative side lobe level < −10 dB, and the reflection coefficient < −10 dB. The bandwidth is 1 GHz for an operation frequency of 10 GHz. Polarization conversion is feasible maintaining values of the plasma parameters and magnetic induction field compatible with the technology at the state of the art.

A dually symmetric orthomode transducer (OMT) and horn antenna are presented for both single port linearly polarized operation and dual port circular polarization use. The feed uses two waveguide splitters and a feed bend to feed a four-port horn antenna that has the two groups of ports orthogonal to each other to produce a symmetric radiation pattern. The feed is printed from 316L stainless steel while the horn is printed from a plastic polymer and metallized using aluminum tape. The structure is based on WR 90 waveguide and covers the guide’s full operating band of 8.2 GHz to 12.4 GHz. Peak realized gain values of 20.5 dBi were measured with cross polarization rejection of over 40 dB. Here linearly polarized and circularly polarized results are presented, the latter using an off-the-shelf hybrid to control the phase for the two ports. Enabled by the symmetric feed, both the linear and circularly polarized radiation patterns were highly symmetric.

This study aims to increase horn antenna gain and aperture efficiency in a way that are compatible with aperture electric field distribution similar to TE10 rectangular waveguide mode using analytical calculation method. The proposed analytical approach can be useful to calculate the performance of a horn antenna design with thin (r«λ) perfect electric conductor (PEC) cylinder placed on the antenna aperture dividing H‐plane. In the analytical solution, the aperture field distribution is obtained by solving the electromagnetic scattering from an infinitely long cylinder placed in front of the aperture. This structure not only improves the aperture electric field amplitude distribution but also corrects phase errors in the horn antenna. An X‐band pyramid horn antenna is manufactured by using three‐dimensional (3‐D) printer and coated with aluminum tape. The measurement results of the 3‐D printed antenna are also compared with the simulation results. The antenna gain is measured with and without the PEC cylinder on the aperture. It is found that, the antenna gain is increased by 1 dB. The results of the proposed analytical calculation method are compared with the simulation and measurement results and justified. [ABSTRACT FROM AUTHOR]

Millimeter-wave (mmWave) antennas are indispensable components in the fifth-generation (5G) wireless communication systems. With the inherent advantages of integration capability, substrate integrated waveguide (SIW) antenna is an excellent choice for applications in the mmWave frequency bands. However, reflection losses occur at dielectric-filled thin apertures of SIW antennas. These reflections can be overcome by impedance matching between the aperture and the free space. In this study, we introduce an mmWave SIW horn antenna having impedance matching transitions (IMTs) across the horn's aperture width. The designed antenna, operating in the 24-28 GHz band, is simulated with a full-wave analysis tool. The simulation results of the modified SIW horn have been confirmed by the experimental results and shown to be satisfactory. The IMTs result in an enhancement of the front-to-back ratio (FTBR). The modified SIW horn antenna with a novel printed transition achieves sidelobe levels (SLLs) of better than -9 dB at 27 GHz, with an enhanced FTBR above 15 dB. In the 24-28 GHz band, the antenna has a reflection coefficient variation of better than -10 dB. [ABSTRACT FROM AUTHOR]

In this article, a lens is applied to reduce the horn antenna's Side Lobe Level (SLL) based on controlling the phase and amplitude distribution of the electromagnetic fields over the aperture of the horn antenna in the X band (8−12 GHz) for radar applications. By locating the metasurface lens inside the standard X band pyramidal horn, the SLL is decreased by 4–15 dB in E-plane and 0.8–7 dB in H-plane. The measured results with metasurface lenses demonstrate the reduction of SLL over the entire bandwidth. Good agreement between measurement and simulation results shows the tapering of field distribution over the aperture of the horn antenna. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The object of research is the process that forms an elliptical directional diagram of the H-sector horn antenna for flow irradiation of seeds with the electromagnetic field. The emitter of electromagnetic energy is presented as one of the main elements of installations for irradiating seeds with an electromagnetic field before sowing. This parameter was investigated by taking into account the values of the biotropic parameters of the low-energy electromagnetic field under the conditions of flow processing. This paper reports a study into the parameters of the H-sector horn emitter for irradiation of sugar beet seeds with a low-energy electromagnetic field at a frequency of 73...75 GHz in continuous flow. Thus, one should use the H-sectoral horn emitter with the following parameters: aperture width aa=20 mm; horn length RH=35 mm; b=1.8 mm. It is determined that in order to irradiate sugar beet seeds on the conveyor plane with a power flow density of P=100 μW/cm², it is necessary to place two horns 1200 mm above the conveyor at a distance of 2540 mm from each other. It was checked that the treatment of sugar beet seeds with electromagnetic radiation in a continuous flow with a capacity of 300 kg/h is possible with a power of up to 2 W supplied to two horn antennas; the speed of the conveyor is 15 cm/s. The parameters of the sectoral horn for an elliptical directional diagram were studied by dividing the main task into internal and external. According to the results of the research, it is possible to build a base of geometric presets for adjusting installations for different types of seeds, the desired performance, the structural features of installations, as well as existing emitters. [ABSTRACT FROM AUTHOR]

A circularly polarized pyramidal horn antenna based on substrate integrated waveguide (SIW) technology is proposed and developed for Ku‐band applications. The proposed horn antenna is excited by the upper and lower SICL differential feed networks placed vertically to each other, so that two orthogonal waveguide modes with the equal amplitude are generated at the horn aperture. A 90° coupling network based on SICL technology is proposed to achieve a 90° phase difference between the two orthogonal waveguide modes, thus realizing the function of left‐hand circular polarization (LHCP) and right‐hand circular polarization (RHCP) of the horn antenna. In addition, in order to make the phase distribution of the horn aperture more uniform, a cross metal strip structure at the horn aperture is proposed, thereby improving the radiation efficiency. The proposed horn antenna is manufactured by using low‐cost printed circuit boards (PCBs) process. The measured results show that the proposed circularly polarized pyramidal horn operates at center frequency 12.5 GHz, the measured gain is 8.4 dBi, the relative standing wave and axial ratio (AR) bandwidth are approximately 24% and 5%, respectively. And the radiation aperture efficiency is as high as 78.5%. The developed circularly polarized pyramidal horn antenna can be applied in the field of satellite communications. [ABSTRACT FROM AUTHOR]

Design and assessment of THz communications systems, which will form an essential part of 6G, require an understanding of the propagation channels the systems will operate in. This paper presents investigations of the channel characteristics in various scenarios at 145 GHz, which is the band currently envisioned for the first round of deployments. In particular, we review several extensive measurement campaigns performed by the University of Southern California in both outdoor and indoor environments. We present the measurement and evaluation methodology and sample results that illustrate the dominant propagation effects in different environments. We then summarize the parameters of the statistical channel models for path loss, delay dispersion, and angular dispersion. Based on these results, we find that even in NLoS (non-line-of-sight) situations, Gbit/s communications can be sustained over a 100 m distance; that (for an antenna gain of 20 dB), there is considerable delay dispersion, requiring tens of equalizer taps, and that angular dispersion is significant in both LoS and NLoS situations. The channel parameters can be thus used as a basis for system design and evaluation under realistic operating conditions.

A fast and convenient method to 3D print and metalize circular waveguide components is demonstrated using polylactic acid (PLA) and aluminum adhesive backed tape. A gradient index (GRIN) lens, an externally metalized thin-walled conical horn, and a WR90 rectangular to linearly polarized circular waveguide transition are simulated, fabricated, and measured. The horn and lens were both monolithic prints that were externally metallized to simplify the metallization process. Both the horn and lens have a measured operational bandwidth of 8.2 GHz to 12.4 GHz with an input reflection less than −15 dB and peak gain of 18.7 dBi at mid-band. The walls of the thin-wall horn are printed at a thickness such that the dielectric layer does not impact the performance of the horn while being robust enough to support external metallization. The lensed horn functioned as the support for the aluminum foil while also improving the radiation pattern by improving the $\vec {E}$ SLL by up to 15 dB compared to the thin-walled horn antenna.

In this paper, the relay antenna was designed in consideration of the performance of the 28GHz band 5G mobile communication relay horn antenna, such as radiation pattern and return loss. A horn array for 5G mobile communication repeater was designed by arranging the antenna elements in phase, and the performance was analyzed. Unlike conventional WCDMA (3G) and LTE (4G), in millimeter wave band communication, high path loss occurs between transmission and reception. In the design of a 5G millimeter wave horn antenna, antenna performance such as isolation and gain between antenna elements as well as gain and bandwidth of the antenna must be additionally considered. The antenna gain of the single horn antenna (1×1) and the array horn antenna (2×4) in the 28GHz band is about 10.44d Bi and 19.58dBi, respectively, and the return loss is designed to be less than -18dB. It has proven its validity and has been shown to be suitable for application to 5G mobile communication relay system. [ABSTRACT FROM AUTHOR]

A novel W-band 2-D monopulse sparse array antenna with suppressed sidelobe levels is proposed in this article. The 2-D monopulse antenna is composed of a radiation sparse array, an irregular interconnected waveguide -based network, a power divider network, and a sum–difference network. The sparse array uses a box-horn as the radiation element and is optimized based on the genetic algorithm, which exhibits low sparsity and low sidelobe levels. The whole aperture of the antenna is divided into four subarrays. To feed all the radiating elements that are randomly distributed in the subarrays with the same amplitude and equal phase, an irregular interconnected waveguide -based network and a power divider network are designed. Finally, a sum–difference network is connected to the end of the four subarrays to obtain the sum and difference radiation performance results for the monopulse antenna. A 2-D monopulse sparse array antenna with 32 radiating elements is fabricated and measured. The measured $\vert \text {S}_{\mathbf {11}}\vert \le -10$ dB bandwidth of the antenna is over 6 GHz (from 90 to 96 GHz). At the center frequency, the maximal gain of the sum radiation pattern is approximately 24.0 dBi, with low sidelobe levels (both E-plane and H-plane) less than −19.0 dB. In addition, the null depth of the difference radiation pattern is less than −30.0 dB. [ABSTRACT FROM AUTHOR]

The single-antenna technique proposed in this paper was developed for measuring the radar cross-section at near-field distances in a real environment, from reflection coefficient measurements on the antenna. The near-field radar cross-section is corrected with an analytical factor calculated as a ratio between the radar cross-section computed at far-field and near-field. The analytical correction factor takes into account the effects of the diffraction at the edges of the target at incidence angles higher than 20°. An improved, distance averaging technique is proposed to reduce the multipath propagation effects. A time-gating procedure is additionally used in order to better isolate the reflection from the target and to remove the real environment contributions. The method was successfully tested on a rectangular metallic plate as a target over a wide frequency band, at normal and oblique incidence angles; however, it might also work for arbitrarily shaped targets, because they can actually be divided into small rectangular patches. [ABSTRACT FROM AUTHOR]

In this paper, a tunable polarization converter based on multi-layer metasurface is proposed. It consists of a metal grating, a tunable polarization conversion surface (PCS) and a tunable polarization selective surface (PSS). By changing working states of the PIN diodes embedded on the layers, states of the polarization converter can be switched in real time between co-polarization transmission and cross-polarization conversion. The PSS is not only utilized to construct a Fabry–Perot resonant cavity which helps to achieve polarization conversion, but also can filter out components at undesired polarization to obtain high polarization isolation. To verify the design, a prototype is fabricated and tested. Its overlapping operational bandwidth is 29.3% (2.39–3.21 GHz), and the polarization isolation is higher than 20 dB. In addition, the proposed polarization converter is compatible with the 10-dB standard gain horn antenna. The measured results show that the main lobe of the horn antenna is basically constant within operational band with/without the loading of polarization converter. Meanwhile, the transmittance of the polarization converter is higher than − 3 dB and polarization isolation is higher than 20 dB within 2.49–2.97 GHz. [ABSTRACT FROM AUTHOR]

In this letter, a hybrid wideband decoupling method based on far-field radiation regulation by employing the specially engineered periodic near-field resonators, which consist of split-ring resonator (SRR) arrays, is presented for the two collinear transceiving horn antennas with extremely large element spacing. Two E-plane-coupled antennas operating at X-band are arranged with center-to-center distance of 8 m (over 200λ). By allocating the SRR arrays in close proximity to each horn antenna, the radiation power in the specified horizontal directions pointing to each other could be significantly reduced without disturbing their radiation characteristics in the broadside thus leading to the conspicuous port isolation enhancement. It is validated that more than 25 dB mutual coupling level reduction is achieved over the frequency range of 8–11.5 GHz (∼35.9% fractional bandwidth) when the SRR arrays are integrated. Finally, a prototype was fabricated and measured. Corresponding measurement results are in good agreement with the simulated ones. [ABSTRACT FROM AUTHOR]