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This article presents a flexible four-element antenna for X-band applications. The proposed antenna covers the spectrum ranging from 10.6 to 11.9 GHz, including a significant portion of the X-band. The single antenna element comprises a modified E-shaped radiating patch, which is fed by a unique feeding structure consisting of a 50-Ω feeding strip connected with two rectangular stubs on both sides. All antenna elements are printed on a flexible felt 60 mm × 60 mm × 1 mm (2.12 λ × 2.12 λ × 0.035 λ at 10.6 GHz) substrate. The proposed antenna exhibits circular polarization over the desired bans of operation with an axial ratio (< 3 dB) bandwidth of 1.2 GHz, which is significant for X-band applications. The designed antenna is manufactured and practically tested. Both simulated and measured results agree well with each other, ensuring the optimal performance of the antenna. Moreover, the antenna achieves a maximum gain of up to 8 dBi in the desired band of operation. Further MIMO parameters, including envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), and mean effective gain (MEG), are calculated to validate the MIMO performance. Finally, a conformal analysis was carried out to study the robustness of the antenna in various bending scenarios. Results show that the antenna reported in this article is the correct choice for conformal X-band MIMO applications. [ABSTRACT FROM AUTHOR]

In order to achieve high‐performance gallium nitride (GaN) high‐electron‐mobility‐transistors (HEMTs) capable of operating in the X‐band, a bilayer passivation technique is employed. The technique involves creating a stacked passivation layer consisting of a 20‐nm Si‐rich silicon nitride (SixN) passivation layer and a 100‐nm N‐rich silicon nitride (Si3N4) passivation layer. This effectively reduces radio frequency scattering in GaN HEMTs without compromising the breakdown voltage (BV). On the one hand, the SixN passivation layer effectively suppresses the surface states of devices, resulting in low current collapse. On the other hand, the Si3N4 passivation layer can effectively reduce gate leakage caused by the SixN passivation layer, allowing the device to reliably operate at higher voltages. Consequently, a GaN HEMTs with SixN/Si3N4 bilayer passivation achieve a low current collapse of 5% and a high BV of 157 V. The device features a current gain cutoff frequency (fT) and maximum oscillation frequency (fmax) of 57.9 and 96.8 GHz, respectively. Additionally, it exhibits excellent radio frequency performance in the X‐band, with an output power density (Pout) of 13.7 W mm−1 and power added efficiency of 60.8% at a drain voltage (VD) bias of 50 V. [ABSTRACT FROM AUTHOR]

Reconfigurable intelligent surface (RIS) is one of the possible solutions to overcome challenges that bring up the 6G communication networks. Unit cell design for RIS is similar in many aspects to the design of artificial magnetic conductors (AMC) because both have a common nature of changing the phase of the reflected wave. However, RIS is aimed at controlling the angle of reflection to maintain requirements for the radiation pattern similar to phased antenna arrays such as low side lobes and beamwidth. The paper reviews the criteria for optimizing RIS: unit cell dimensions, phase span, frequency bandwidth, and loss. An optimization algorithm is proposed for the proper accounting of RIS optimization criteria. A new X-band unit cell is designed using the proposed optimization algorithm. [ABSTRACT FROM AUTHOR]

A ground station antenna system features a conical horn attached to a microstrip antenna as an alternate receiving feed antenna. The proposed microstrip antenna has circular polarization and operates in the X-band. The far-field parameters of the antenna are measured after developing and simulating the combination of a conical horn and a microstrip antenna. The modeling results for a microstrip antenna with a conical horn offer a working bandwidth of 930 MHz, spanning frequencies 7.44 GHz to 8.37 GHz. The axial ratio measurements for a microstrip antenna joined with a conical horn produce a working bandwidth of 150 MHz, covering frequencies ranging from 7.72 GHz to 7.87 GHz. The conical horn is attached to a microstrip antenna and has a gain of 15.1 dB. The proposed antenna is designed to meet ground station antenna requirements by pairing it with a parabolic reflector with a diameter of 3.7 meters. The primary focus antenna of the proposed design was chosen. The feed antenna and parabolic reflector should be positioned at a focus point distance of 1110 mm for a total gain of 38.9 dB at 7.8 GHz frequency. The proposed antenna can be applied on X-band remote sensing ground stations as a receiving antenna. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a meander-feed antenna system featuring circular polarization (CP) diversity and high isolation. The antenna design comprises a monopole antenna and an isosceles triangular partial ground on a single layer. This innovative structure departs from traditional antennas in three significant ways: it achieves structural asymmetry by modifying the antenna's shape and position, which enhances CP characteristics; and it transitions the feeding structure from a linear to a meander type. Experimental results show that the proposed antenna covers frequency ranges of 6.9–8.5 GHz and 9.2–10.1 GHz, with measured isolation below − 12 dB within the operating bandwidth. As a result, the single monopole antenna attains a CP bandwidth of 20.78% and 9.33%. The single-element CP antenna is then incorporated into a 4-port MIMO antenna, which is fabricated and measured, demonstrating excellent agreement between simulated and measured results. The proposed antenna system achieves an overall gain of 5 to 8 dBi across the operating spectrum, making it an ideal choice for X-band applications. [ABSTRACT FROM AUTHOR]

In this research, a quad‐band sickle‐shaped MIMO antenna of compact size 32 × 32 mm2 (0.28λ0 × 0.28λ0 at lower resonant frequency 2.6 GHz) has been proposed using partial ground and tilted isolation stub at an angle of 45°. It covers 2.40 to 2.80 GHz frequency range with bandwidth (BW) of 15.38% (0.40 GHz) which is applicable for Wi‐Fi application in first band and in second band it covers from 4.48 to 5.75 GHz frequency range with BW of 24.83% (1.27 GHz) for WLAN application. In addition, the third band starts from 9.75 to 10.43 GHz frequency range with BW of 6.74% (0.68 GHz) for the X‐band whereas in fourth band it covers from 13.07 to 15.87 GHz frequency range with BW of 19.38% (2.8 GHz) frequency, which is applicable on Ku‐band application. Moreover, the isolation is < −15 dB in the entire resonating frequency band which is an acceptable limit for reduction of mutual coupling. ECC value is <0.5 in the entire operating band of frequency. The diversity gain of the proposed MIMO antenna is approximately 9.96 dB that shows the antenna exhibits good diversity property. The channel capacity loss value is <0.4 bps/s/Hz in the entire resonating band. In view of all the diversity parameters, the proposed MIMO structure fulfills all the requirements of the MIMO antenna. [ABSTRACT FROM AUTHOR]

The technique of electromagnetic characterization of materials in free space allows for the measurement of constitutive properties without making contact with the material being measured. Characterization methods in Free Space are naturally suited for Electromagnetic Radiation Absorbing Materials (RAM) but are also important in applications where the material sample to be measured does not undergo major interventions. They consist of evaluating a received signal resulting from a free-space transmission through two horn antennas with beam collimating lenses and a Vector Network Analyzer (VNA). The characteristics of the transmitted signal are modified by a material positioned between the transmitting and receiving antennas. This work presents methods for electromagnetic characterization in Free Space, in the frequency range of 8.2 to 12.4 GHz (X-Band), in a semi-anechoic chamber, seeking the development of measurement processes that present results with repeatability and reliability. The measurements were made with standard and electromagnetic radiation absorbing materials. The measurement technique presented 95% of efficiency. [ABSTRACT FROM AUTHOR]

This article is an attempt to design and develop a metamaterial-based microwave absorber with a low profile, broad incidence angle and compactness in the microwave frequency range. Further, equivalent circuit model of the proposed structure is discussed based on circuit theory. The unit cell focuses on achieving maximum absorption at C-, X-, and K-band. The dimensions of the proposed design are ultrathin and compact, having an overall size of 8 mm × 8 mm × 0.8 mm. The dimensions are optimized in such a fashion to achieve three different peaks at three various bands (C, X and K), thereby making the triple-band behaviour of the metamaterial absorber possible. The structure provides absorption of 98.26 % absorption at 7.76 GHz (C-band) while absorption of 96.74 % is achieved at 10.26 GHz (X-band) and 99.92 % absorption at 19.32 GHz (K-band) of microwave regime. The experimental verification of design conform that the measured results are found to be in close agreement to simulated ones. [ABSTRACT FROM AUTHOR]

Copyright of Leather & Footwear Journal / Revista de Pielarie Incaltaminte is the property of INCDTP 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 latest developments in communication systems require an economical, light‐weight, compact size, and excellent performance in microstrip patch antennas in order to meet the requirements of the upcoming implementation. The optical, electrical, and physical properties of different materials have an impact on the design of antennas. An innovative composite photonic crystal microstrip patch antenna with outstanding gain has been developed. For composites of fumed silica embedded in RT‐Duroid dielectric material, the effective permittivity is calculated using the Maxwell‐Garnett model. The performance of composite antennas for different volume fractions and various dielectric substrate thicknesses is studied. The resonance frequencies of composites also shift from the X‐band to the C‐band with an increase in volume concentration, which is suitable for wireless communication systems. This investigation provides a perspective on how composite substrates can represent a communication revolution by providing an alternative to substrates that are readily accessible commercially in situations when the material qualities are insufficient. The photonic crystal composite antenna records the highest gain of 13.89 dB with the coverage of C‐band, X‐band, and Ku‐band, whereas the composite antenna reaches the best gain of 10 dB with the coverage of C‐band and X‐band. [ABSTRACT FROM AUTHOR]

Recently, the difference in the most effective competencies is considered the main competitive factor in organizations. To this end, organizations seek to improve a number of their functional capabilities, expertise, and capacities to enhance their operational area. Therefore, when an organization focuses on the quality of its services or products, it is trying to improve maintainability to gain a competitive advantage. In this study, a closed-loop, multi-objective, multi-level, multi-commodity, and multi-period mathematical model for a supply chain with producer, and distributor components is presented to locate and allocate items. The presented model can control environmental, economic, and social factors along the chain. One of the most important and unique aspects of the current study is considering different scenarios in the closed-loop supply chain (CLSC) so that the quality of the produced and transported products is paid attention to according to perishability. In addition, to control environmental effects, the model can minimize total CO2 emissions. The problem is solved on small, medium, and large scales using Epsilon Constraint and NSGA-II methods. According to the obtained results, the flow according to the boom scenario is more than the stagnation scenario. Finally, according to the sensitivity analysis, the number of centers established increases with an increase in demand. The results show that the nondominated sorting genetic algorithm (NSGA-II) model can predict the behavior of the model well in the long term. For this purpose, Mean ideal distance (MID) index, has been used for evaluation of calculation. the value of standard MID is equal to 6.56 that shows the model accuracy is adequate. [ABSTRACT FROM AUTHOR]

This letter demonstrates an X‐band transceiver front‐end in 130‐nm CMOS technology for phased‐array systems. To solve the problem that passive attenuator performance deteriorates significantly in wideband systems, a 6‐bit attenuator with source follower and common‐gate amplifier is proposed. Besides, an 8‐bit vector‐summing phase shifter is implemented in common path to realize the phase coverage of 360° with the least significant bit of 5.625°. In the frequency range of 8–12 GHz, the measured root‐mean‐square (rms) amplitude and phase errors of the attenuator in the transceiver are less than 0.36 dB and 2.2°, respectively. The rms phase and amplitude errors of the phase shifter in the transceiver are less than 4.8° and 0.56 dB, respectively. The whole chip area including pads is 3 × 2.3 mm2. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Engineering Transactions B: Applications is the property of International Journal of Engineering (IJE) 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 quality of weather radar affects the reliability and effectiveness of monitoring severe convective weather. Therefore, rigorous calibration and validation are the foundation for the quantitative application of weather radar. Among the available methods, radial velocity validation is of great significance for reducing the false alarm rate in the identification of tornadoes and thunderstorms. Based on the traditional method that utilizes internal and external instrument radar velocity measurements, we propose a weather radar radial velocity validation method that uses RTK UAV to simulate external targets. In addition, according to the characteristics of the UAV application scenarios, we introduce the evaluation parameter of optimal absolute accuracy to supplement the original parametric system. The experimental results show that the evaluation parameter of optimal absolute accuracy can effectively reduce the interference caused by the systematic deviation of the UAV due to the internal and external environment, which can affect the validation results. When the UAV velocity is not greater than 10 m/s, the optimal absolute accuracy of the radial velocity validation is less than 0.05 m/s, which is essentially consistent with the external instruments' measurement results. This method can be effectively applied to the procedural handling of weather radar radial velocity validation. It is significant for ensuring the accuracy and quality of weather radar radial velocity measurements and improving the effectiveness of radar velocity data applications. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive analysis of the design of a high-performance meta-material loaded square patch antenna arrays specifically tailored for X-band applications. To enhance the gain and front to back ratio (FTBR), a novel 1x3 series-fed linear array configuration that integrates solitary series-fed elements with metamaterial-based square patches at X-band frequencies is introduced. Later, parallelfed 1x2 and 1x4 antenna arrays are designed by considering the series-fed antenna array as a single element for further enhancement of gain and FTBR. The single element 1x3 series fed array is fabricated with dimensions of λx3.5λx0.028λ, whereas the respective 1x2 and 1x4 parallel fed antenna arrays has the dimensions of 2.86λx3.8λx0.028λ and 2.86λx4.3λx0.028λ, respectively. The Taconic substrate is chosen as the dielectric material, exhibiting a dielectric constant of 2.2 and a loss tangent of 0.0025. The empirical data presented substantiates the superior performance of the 1x4 parallel fed configuration. This is evident through the remarkable reflection coefficient of -25dB, the wide bandwidth spanning 47MHz, the substantial gain of 17.8dBi, and the FTBR of 30.7. The metrics serve to highlight the array's capacity in guaranteeing a superior level of signal fidelity, encompassing a wide frequency spectrum, amplifying incoming signals, and directing transmissions towards specific orientations. These metrics unequivocally validate its potential for advanced X-band applications. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive analysis of the design of a high-performance meta-material loaded square patch antenna arrays specifically tailored for X-band applications. To enhance the gain and front to back ratio (FTBR), a novel 1x3 series-fed linear array configuration that integrates solitary series-fed elements with metamaterial-based square patches at X-band frequencies is introduced. Later, parallel-fed 1x2 and 1x4 antenna arrays are designed by considering the series-fed antenna array as a single element for further enhancement of gain and FTBR. The single element 1x3 series fed array is fabricated with dimensions of λx3.5λx0.028λ, whereas the respective 1x2 and 1x4 parallel fed antenna arrays has the dimensions of 2.86λx3.8λx0.028λ and 2.86λx4.3λx0.028λ, respectively. The Taconic substrate is chosen as the dielectric material, exhibiting a dielectric constant of 2.2 and a loss tangent of 0.0025. The empirical data presented substantiates the superior performance of the 1x4 parallel fed configuration. This is evident through the remarkable reflection coefficient of -25dB, the wide bandwidth spanning 47MHz, the substantial gain of 17.8dBi, and the FTBR of 30.7. The metrics serve to highlight the array's capacity in guaranteeing a superior level of signal fidelity, encompassing a wide frequency spectrum, amplifying incoming signals, and directing transmissions towards specific orientations. These metrics unequivocally validate its potential for advanced X-band applications. [ABSTRACT FROM AUTHOR]

The manufacturing of active RF devices like klystrons is dominated by expensive and time-consuming cycles of machining and brazing. In this article, we characterize the RF properties of X-band klystron cavities and an integrated circuit manufactured with a novel additive manufacturing process. Parts are 3D printed in 316 L stainless steel with direct metal laser sintering, electroplated in copper, and brazed in one simple braze cycle. Stand-alone test cavities and integrated circuit cavities were measured throughout the manufacturing process. The un-tuned cavity frequency varies by less than 5% of the intended frequency, and Q factors reach above 1200. A tuning study was performed, and unoptimized tuning pins achieved a tuning range of 138 MHz without compromising Q. Klystron system performance was simulated with as-built cavity parameters and realistic tuning. Together, these results show promise that this process can be used to cheaply and quickly manufacture a new generation of highly integrated high power vacuum devices. [ABSTRACT FROM AUTHOR]

This study presents an 8∼15 GHz low noise amplifier (LNA) using a 0.25 μm GaN on SiC process. The LNA is designed in three stages with source degeneration in the first stage to optimize the noise figure and operation bandwidth. Lossy matching using a resistor is applied to the drain nodes in each stage to enhance stability. An RC parallel equalizer is applied to the output port to flatten the frequency response. The chip size of the fabricated LNA MMIC is 3.0 mm×0.9 mm. At operating frequencies of 8∼15 GHz, the small signal gain is 23 to 27 dB, return loss is lower than 10 dB, and noise figure is 1.6 to 2.8 dB. [ABSTRACT FROM AUTHOR]

This paper will propose an innovative compact, lowcost, low-profile inverted U-shaped patch antenna with a single and dual band-notched ultra-wideband (UWB) with split ring resonators (SRRs). To achieve our main goal based on the reduction of electromagnetic interference in narrowband communications (WLAN, WiMAX, and satellite), four-element rectangular split-ring resonators (SRRs) array are placed nearby the feedline to create notch band at approximately 5.15-5.35 and 5.725-5.85 GHz. The SRRs antenna's measured data indicate a directivity of 8.52 dBi, a gain of 7.18 dBi, a reflection coefficient of -27 dB, and an efficiency of 84.3%. The realized prototype, including the SRRs and CSRRs structures, were carried out using a PCB prototyping machine. Reflection coefficient measurement is obtained using a vector network analyzer (VNA) PNA-X from Agilent Technologies. The measured values of the proposed antenna, with 50 x 38 x 1.6 mm3 in total and constructed on a FR4 substrate with permittivity of er = 4.3, loss tand = 0.0024 and substrate thickness of h = 1.6 mm, correlate well with the simulated values. The proposed antenna, compared with other published work, is a good candidate to operate in WLAN, X-band. [ABSTRACT FROM AUTHOR]

The role of antennas in wireless communication is critical for enabling efficient signal transmission and reception across various frequency bands, including those associated with IoT (Internet of Things), X-band, S-band, and RFID (radio-frequency identification) systems. This paper presents a small quadruple-band antenna with 25 × 40 × 1.5 mm3 dimensions designed for diverse wireless applications. It is adept at operating in the S-band (2.2 GHz), wireless local area network (WLAN) (5.7 GHz), microwave RFID frequency band (5.8 GHz), and X-band (7.7 GHz and 8.3 GHz). While the majority of existing research focuses on antennas covering two or three bands, our work stands out by achieving quad-band operation in the proposed antenna design. This antenna is constructed on a semiflexible Rogers RT5880 substrate, making it well-suited for wearable applications. Computer Simulation Technology (CST) Microwave studio (2019) simulation package software is chosen for design and analysis. The antenna design features a comb-shaped radiating structure, where each "tooth" is responsible for resonating at a distinct frequency with an appropriate bandwidth. The antenna retains stability in both free space and on-body wearability scenarios. It achieves a low specific absorption rate (SAR), meeting wearable criteria with SAR values below 1.6 W/Kg for all resonating frequencies. The proposed antenna demonstrates suitable radiation efficiency, reaching a maximum of 82.6% and a peak gain of 6.3 dBi. It exhibits a bidirectional pattern in the elevation plane and omnidirectional behavior in the azimuth plane. The antenna finds applications across multiple frequencies and shows close agreement between simulated and measured results, validating its effectiveness. [ABSTRACT FROM AUTHOR]

An investigation of a single‐layer band‐stop frequency selective surface (FSS) is designed and analyzed for X‐band application. The proposed FSS design primarily involves a cross‐shaped conductive patch with four square slots on each corner, and it is fabricated on the 3D‐printed polylactic acid (PLA) substrate. The design is resonating at 12 GHz with an insertion loss greater than 60 dB. The 10 dB bandwidth of the designed structure is 8.3% with respect to the resonant frequency. The results show that the design has polarization‐independent and angle‐insensitive transmission characteristics for incidence angles up to 60°. The simulation is carried out using CST Microwave Studio Suite, and the results are obtained. The physical mechanism of the designed structure is evaluated using the surface current distribution. The designed FSS is fabricated using two techniques, namely inkjet printing and conventional etching. Finally, the measurements of the fabricated structure are done using a vector network analyzer setup. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Tropical Meteorology (1004-4965) is the property of Guangzhou Institute of Tropical & Oceanic Meteorology, China Meteorological Administration 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 efficient broadband metasurface-based polarization converter is investigated in this communication. The proposed embodiment works in the reflection mode. It can efficiently convert the x-polarized fields to their y-polarized counterpart and vice versa, with a good oblique incidence of up to 50° over the entire X-band. The design portrays a good polarization conversion ratio of up to 98% for normal incidence and is more than 70% considering the cases of oblique incidences. A prototype is fabricated to confirm the operation of the proposed design. Good agreement between the simulation and experimental results is observed. Ryy (co-component: y-polarized transmission and y-polarized reception) is below -10 dB, and the Rxy (cross-component: y-polarized transmission and x-polarized reception) is above – 3 dB over the entire X-band. [ABSTRACT FROM AUTHOR]

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering 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.)

In this paper, an X‐band dual‐band dual‐polarized medium‐gain antenna (MGA) is designed for deep‐space satellite applications. The MGA has isoflux radiation patterns in the 7.145–7.19 and 8.40–8.45 GHz frequency bands. The concentric ring horn qualification model named MGA is developed for TIAN WEN‐2 (TW‐2) mission. MGA is fabricated and the measurements are conducted on it and its installation on the deck of the TW‐2 Radiation Mockup (RM). The performance evaluation of MGA and its corresponding RM measurements indicate an axial ratio lower than 4.0 dB and a gain higher than 5.8 dBic on the operational bandwidth at the coverage limit of 40° for all azimuth angles (φ). The calculated and measured data align exceedingly well, confirming that MGA satisfactorily meets the requirements for the forthcoming TW‐2 deep‐space spacecraft. [ABSTRACT FROM AUTHOR]

The paper aims to utilize a metamaterial (MTM) structure, specifically the slotted plus‐shapes within a square split‐ring resonator, to analyze the characteristics of the reused oil and also used to classify different oil samples. The proposed MTM structure is designed to operate within the X‐band frequency range of 8–12.4 GHz. The MTM structure is simulated using the high‐frequency EM simulation tool, and the MTM properties are extracted using standard equations. The negative permittivity and permeability characteristics of the proposed MTM structure in the X‐band are studied to verify its suitability for X‐band applications. A sample container is designed to hold the oil samples, and the experiments were carried out using an X‐band waveguide setup with Vector Network Analyzer. The results were analyzed and presented in brief to examine reused oil and classify different oils. [ABSTRACT FROM AUTHOR]

Remote sensing of the Earth is now widely used in various fields. One of the challenges of remote sensing is the creation of inexpensive satellite systems operating in polar circular orbits. These systems require the development of a receptiontransmission system that allows tens of gigabits of video information to be transmitted to an earth receiving station within ten minutes. That is, there is a need to create a communication system that provides high speed data transmission from small satellites weighing up to 50 kg. Objective. The aim of the work is to study the features of digital signal formation in modern satellite communication lines and to develop a communication system with a high data transfer rate (usually 300 Mbit/s), which can be applied to small Earth Observation satellites. Method. Proposed concept for building a high-speed data transmitter from a remote sensing earth satellite using commercially available off-the-shelf technology. Calculations of the power flow density created at the input of the receiving earth station were performed to find out the possible power of the on-board transmitter. Results. A diagram of a communication system based on the DVB-S standard using the technology of commercially available off-the-shelf products has been developed. The high-speed data transmitter is implemented on a Xilinx® Zynq Ultrascale+ ™ MPSoC FPGA microchip, which is located on an Enclustra Mercury XU8 module with a high-performance dual 16-bit AD9174 DAC. The on-board transmitter with a power of up to 2 W meets the requirements of the ITU Radio Regulations for the power flux density on the surface of the Earth, which is created by the radiation of the space station EESS in the range 8025–8400 MHz. It is shown that the energy reserve of the communication line of 3 dB is achieved for various commands for coding and modulation changes with an increase in the elevation angle, which allows to increase the speed of information transmission. Conclusions. An original receiving-transmitting system was developed for use in small satellites for remote sensing of the Earth. It is shown that the function of adaptive modeling of ACM of the DVB-S standard allows you to automatically change the transmission parameters in real time depending on the changing conditions of the channel, providing opportunities for more flexible and effective data transmission in various conditions, which will allow to increase the volumes of information transmitted by communication session. The proposed system operates in the X-band and is built using commercially available off-the-shelf products. An antenna with double circular polarization is used as the emitter. Two physical channels represent two polarization modes: right circular polarization and left circular polarization, each of which has three frequency channels. [ABSTRACT FROM AUTHOR]

Carbon fabric-reinforced polymer (CFRP) composites have replaced most aluminum and ferrous alloys in aerospace construction owing to their attractive high strength-to-weight ratio. CFRPs used in aircraft should have electromagnetic shielding ability in addition to structural properties. Hence, the study of Electromagnetic (EM) wave shielding by hybrid CFRPs is an important topic of research. In this article, we summarize research advancements for enhancing the EM wave shielding of CFRP composites in the X-band frequency range. This study focuses on the manufacturing and performance of carbon-fabric-based composites with metals, metal oxides, and carbon-based fillers. The factors influencing the EM wave shielding ability of the CFRP composites are also discussed. The EM wave shielding of Carbon fibers (CF) was remarkably improved by coating, electroless plating, and synthesizing nanoparticles on the carbon fiber surface. It was found that the carbonious fillers and metal nanofillers such as Nickel (Ni), Iron (Fe), and Silver (Ag)-loaded multilayer CFRP composites showed better absorption modes of EM wave shielding with good structural properties. Owing to the Ag nanowire coating on the CFs, the shielding effectiveness was drastically improved. However, in addition to the type of filler, the structural properties are also influenced by the manufacturing method and type of composite. In the case of laminated composites, the absorption-laminated EM shielding is influenced by the architecture of the plys and the type and number of interplay in the composite construction. In addition, the techniques adopted for the synthesis of nanoparticles and dispersion in composites for effective EM shielding are challenging tasks. [ABSTRACT FROM AUTHOR]

In this study, we fabricated a coplanar waveguide using a novel graphene-silver nanowire composite structure (GNCS) on a polyethylene terephthalate (PET) substrate and then investigated its radio frequency (RF) characteristics. According to the measured results, the coplanar waveguide employing GNCS exhibited a substantially lower loss of transmission line than conventional waveguides. Furthermore, compared to the conventional graphene-based coplanar waveguide, the proposed structure allowed for lower skin depth and higher conductivity, resulting from the high electric conductivity of the silver nanowire. In addition, repetitive bending tests, which were performed to investigate the electric stability of the graphene-silver nanowire, showed that the coplanar waveguide employing GNCS offered substantially better electrical stability than the conventional graphene-based coplanar waveguide. These results indicate that the graphenesilver nanowire structure is a promising candidate for application in flexible wireless communication systems. Notably, this is also the first study to investigate the RF performance and electrical stability of a graphene-silver nanowire/PET structure. [ABSTRACT FROM AUTHOR]

Precise knowledge of the antenna pointing direction is a key facet to ensure the accuracy of observations from scanning weather radars. The sun is an often-used reference point to aid accurate alignment of weather radar systems and is particularly useful when observed as interference during normal scanning operations. In this study, we combine two online solar interference approaches to determine the pointing accuracy of an X-band mobile weather radar system deployed for 26 months in northern England (54.517°N, 3.615°W). During the deployment, several shifts in the tilt of the radar system are diagnosed between site visits. One extended period of time (>11 months) is shown to have a changing tilt that is independent of human intervention. To verify the corrections derived from this combined approach, quantitative precipitation estimates (QPEs) from the radar system are compared to surface observations: an approach that takes advantage of the variations in the magnitude of partial beam blockage corrections required due to tilting of the radar system close to mountainous terrain. The observed improvements in QPE performance after correction support the use of the derived tilt corrections for further applications using the corrected dataset. Finally, recommendations for future deployments are made, with particular focus on higher latitudes where solar interference spikes show more seasonality than those at mid-latitudes. [ABSTRACT FROM AUTHOR]

A single-substrate-layer Frequency Selective Surface (FSS) is designed with a 1.6 mm thick FR4 substrate for triple band-stop frequency filtering applications, that are for Bluetooth, WLAN, WiMAX, and X-band. The proposed FSS unit cell consists of two polygon loops on the front side and a square loop with four annular rings attached to its corners on the backside. The offered design covers three frequency bands: 2.3-4 GHz, 5-6 GHz, and 8-12 GHz. There are three resonances at 3.3, 5.6, and 9.9 GHz. The equivalent circuit model of the proposed structure and the formulas of the LC parameters are presented. A prototype of this structure was manufactured in size of 26 × 26 cm2 and experimentally verified in the antenna and microwave laboratory. The software used for design and simulation is HFSS from Ansys, which uses the finite element method. A comparison with similar structures was performed to demonstrate the performance of the proposed structure. The advantages of the proposed filter include adequate bandwidth, simple structure, as well as small size. In addition, it is unaffected by variant angles of incidence for TE polarization and TM polarization. Furthermore, due to its symmetrical design, it shows a polarization-independent feature. Experimental results for both polarizations verify the merits of the proposed approach, as shown before in the simulation results as well. [ABSTRACT FROM AUTHOR]

This paper presents design of a 4-element crescent-shaped two-sided multiple-input-multiple-output (MIMO) antenna, employing pattern and polarization diversity with improved element-to-element isolation, for UWB, X and Ku band wireless applications. The proposed crescent-shaped MIMO structure consists of two antennas on the top and remaining two antennas on the bottom sides of the substrate. The developed antenna operates in a frequency range from 2.8 to 15.2 GHz, covering the entire UWB 3.1–10.6 GHz, X-band and portion of Ku-band giving element-to-element isolation of more than 20 dB in most of the operating bands. Also, the proposed MIMO structure gives a maximum gain of 6.6 dBi with radiation efficiency from 75 to 95% in the operating band. The important MIMO parameters like envelope correlation coefficient (ECC < 0.005), channel capacity loss (CCL < 0.03 bits/s/Hz), mean effective gain (MEG < − 3 dB) and total active reflection coefficient (TARC < − 10 dB) are presented to estimate the performance of the developed UWB MIMO system. [ABSTRACT FROM AUTHOR]

This paper presents a dual-band bandpass filter (BPF) operating at 9.5 GHz and 11 GHz using a substrate integrated waveguide (SIW) technology. The filter was designed on the diplexer structure to enable the flexible control of the spacing of two passbands. By carefully designing the input/output cavities, spacing between two passbands can be adjusted freely. In addition, thanks to the design of each branch cavity, performance of each band is able to tune easily. The filter was designed on a cost-effective RO4003C substrate and simulated using a CST Microwave Studio 2019 simulator based on the time-domain analysis. The simulated insertion losses at 9.5 GHz and 11 GHz are 2.0 and 1.9 dB, respectively whereas the return losses at these two center frequencies are -15.7 dB and 32.8 dB, respectively. The fractional bandwidth of 1-dB insertion loss is 3.7 % and 3.6 % at the two passbands. The total size of the filter is just 2.4 x 3.5 mm² . The proposed filter aims at using for next-generation wireless communications such as satellite communication, 5G, 6G and beyond. [ABSTRACT FROM AUTHOR]

This research presents a coplanar waveguide fed elliptical-based second iterative antenna for dual-broadband applications. The antenna radiator is formed after implementing two iterations of an elliptical-shaped patch in a tree-shaped manner and a modified semi-elliptical CPW plane. The antenna provides a bandwidth of 1.87 GHz (2.49–4.36 GHz) in the lower resonating band and 1.96 GHz (7.96–9.92 GHz) in the upper resonating band with peak gains of 2.84 and 6.15 dBi, respectively. An augmented gain of 9.48 dBi is obtained by implementing a single-layer FSS (frequency selective surface) beneath the designed antenna. The simulated and experimental results of the antenna with and without FSS are very similar regarding gain, impedance bandwidth, and directional radiation patterns. The antenna described in this article is simple, inexpensive, and low profile in nature. It can be used for Wi-MAX, lower sub-6 GHz 5G (n78), and x-band applications. [ABSTRACT FROM AUTHOR]

A dual-port multiple-input multiple-output (MIMO) filtenna with minimal sizes of 80 × 45 mm2 is set up in this study. Each element in this MIMO filtenna is positioned orthogonally to the one next to it to improve isolation. For the MIMO element to achieve high-frequency selectivity and compact size, a frequency-reconfigurable filtenna that was created by fusing a band-pass filter and a monopole radiator was used. The suggested filtenna can switch between its C-band and X-band operating states with ease. On build the filtenna circuit, a band-pass filter based on defective microstrip structure is inserted to a circular monopole radiator. The developed filtenna operates in the C-band frequency range of 6.5–8 GHz and the X-band frequency range of 8–12 GHz. It is possible to use the X-band operating state for communication in a cognitive radio environment. Used as a decoupling structure, metamaterial structures can increase isolation to more than 40 dB across the bandwidth. The suggested MIMO filtenna system has an envelope correlation coefficient of 2.4e−6, a peak gain of 6 dBi, and an impedance bandwidth of 7.4–7.75 GHz. The MIMO filtenna is constructed and measured, and the findings of the measurement and simulation are in good agreement. [ABSTRACT FROM AUTHOR]

In this article, a high gain Circularly Polarized (CP) dual band 2 × 2 antenna array using sequential phase rotation technique for wireless applications is designed and investigated. The feed network utilizes four rectangular lines of equal width and three 90° arcs. The length of all elements is equal to λg/4 to provide 0°, 90°, 180° and 270° phase differences at the four outputs of feed network to increase Axial Ratio (AR) bandwidth and purity. Four corner truncated patch elements are connected to the feed network to complete 2 × 2 antenna array design. The proposed antenna array operates at two different frequency bands of 4.9–6 and 7.9–8.3 GHz (S11 < −10 dB) and also shows CP behavior at 5–5.8 and 8–8.4 GHz (AR < 3 dB) frequency bands. Very good similarity is attained between the axial ratio and impedance bandwidths. The maximum gain of the antenna array is 9.1 dB. The antenna array was prototyped and tested to validate its performance. This array is well suitable for WLAN, Wi-Fi and X-Band uplink satellite communication applications. [ABSTRACT FROM AUTHOR]

This paper proposes a planar wideband microstrip feedline to a slot-line-based patch antenna for high-frequency pattern diversity applications. The antenna consists of two adjacent rectangular patches separated by the ground slots, with a directive patch slot along the edge of the substrate. A compact common feedline-to-slot configuration is used to miniaturize the antenna. The antenna is designed in stages, starting with an in-phase feedline, followed by a slot line structure, with two radiating patches on top and a director on the side. This creates radiation diversity with directive radiation patterns. The antenna was fabricated and analyzed inside a far-field anechoic chamber. The experimental results validate the return loss, gain, and radiation performance. The measured results of the antenna within a frequency range of 8.5 to 11 GHz show good agreement with the simulation. The antenna has a maximum gain of 9.2 dBi and has the potential to be beneficial for beam steering and X-band applications due to its low profile, broad bandwidth, high gain, and good directivity. [ABSTRACT FROM AUTHOR]

Electromagnetic pollution has become a major problem affecting human health, which requires the scientific community to characterise materials that can solve this problem. In the present work, we studied the microwave absorption properties and complex permittivity of ZrB2/Al2O3 ceramic composites in the X-band by simulation. The composites studied are based on alumina and reinforced with ZrB2 particles. The concentration of ZrB2 particles by volume in these composites are 0%, 5%, 10% and 15%. The results obtained show, on the one hand, that the complex permittivity depends on the frequency, and on the other hand, the high content of ZrB2 remarkably increases the complex permittivity and improves the microwave absorption properties. The ZrB2/Al2O3 composite with 5% by volume of ZrB2 particles has better microwave absorption property than others. In this case, the minimum reflection loss is −26.36 dB at 11.5 GHz. For this composite, the RL bandwidth of less than −10 dB is 1.72 GHz, and it is obtained in the frequency range from 9.4 GHz to 10.5 GHz. The simulation results are in good agreement with the published experimental results. In addition, they indicate that the composites studied are favourable for microwave absorption applications in the X band. [ABSTRACT FROM AUTHOR]

The article presents the design and development of a metamaterial-based microwave absorber having polarisation insensitivity, broad angle of incidence, low profile, and compactness in the microwave frequency range. The unit cell focuses to achieve maximum absorption at C-, X- and broad Ku-bands. The structure is simulated and the results are analysed for different angles of polarisation and angle of incidence. The dimension of the proposed structure is ultrathin and compact having an overall dimension of 8 mm × 8 mm × 0.8 mm. The dimensions are optimized in such a fashion to achieve three different peaks at three different bands thereby making the triple-band behaviour of the metamaterial absorber possible. The structure is providing absorption of 99.14% absorption at 6.08 GHz (C-Band) while absorption of 98.29% is achieved at 9.49 GHz (X-band) and 265 MHz bandwidth with above 95% absorption from 16.57 GHz to 16.83 GHz (Ku-Band) in the microwave regime. The absorber patch is a composition of square ring patches and a central square ring annexed with triangles on four sides, the split ring providing a combinational effect witnessing the desired absorption at designated frequencies. The unit cell dimension at a lower cut-off frequency is 0.162 λlowest. The proposed structure is verified for polarisation sensitivity and has a wide angle of incidence. The structure is experimentally verified for results and is found to be in close agreement with simulated ones. The compactness of structure with the attainment of the highest form of absorption in different bands including the 265 MHz high absorption band provides the scope of applicability in various engineering applications at microwave regimes. [ABSTRACT FROM AUTHOR]

Artificially designed anisotropic materials are gaining momentum in the microwave region to cater for various wideband applications such as 5G communication, microwave imaging, etc. In this work, a metasurface-based single-layer reflective cross-polarization rotator with 90% polarization conversion has been demonstrated. The proposed structure has been examined for both transverse electric (TE) and transverse magnetic (TM) wave incidences, and the physical mechanism has been thoroughly examined using the surface current distribution. The metasurface structure has been fabricated and measured in a compact range anechoic chamber. The simulation and measurement results show a polarization conversion ratio (PCR) of above 0.9 from 6.07 GHz to 13.77 GHz. Additionally, the generalized sheet transition condition (GSTC) has been used to calculate the structure's effective electric and magnetic surface susceptibility. The proposed metasurface can be used for monostatic radar cross-section reduction, low scattering antennae, and as an antenna polarization converter. [ABSTRACT FROM AUTHOR]

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A novel metamaterial-based MIMO antenna designed with low mutual coupling and good resolution for object detection using a machine learning model (ML). This proposed design analyzed the azimuth angle variation with gain in the field of view for object detection and isolation variation with the distance between antenna elements. The machine learning model for antenna parameter optimization is discussed. The MIMO antenna used Defected Ground Structure (DGS) and metamaterial unit cell to reduce mutual coupling and bandwidth tuning. This work's originality resides in designing a miniaturized MIMO antenna and optimizing antenna parameters using a machine-learning model. It is implemented on FR4 Epoxy with 1.6mm of thickness and a size of 15 × 25mm2 with a 3.5mm distance between antenna elements. The proposed antenna operates from 7.53 to 12.58GHz with maximum isolation of -26dB at 9.5GHz and maintained above 20dB throughout the operating band. The efficiency, gain, and Miniaturization of the proposed antenna 96%,4.4dB, and 62% were achieved compared to previous works. The performance parameters of the MIMO antenna, return loss, mutual coupling, and envelope correlation coefficient (ECC) are evaluated using HFSS. The prototype of the MIMO antenna is fabricated, and the results are good arrangement with the simulated. [ABSTRACT FROM AUTHOR]

In this paper, a quad-band polarization- and incident-angle independent low-profile metamaterial absorber is proposed. The design consists of three square rings one into another and one plus-shaped slot structure. The size of the unit cell is 11 × 11 mm2 and is printed on an FR-4 substrate having a thickness of 1 mm. It provides 99.2%, 97.6%, 99.3%, and 99.9% absorption at 3.55 GHz, 5.27 GHz, 7.57 GHz, and 11.57 GHz, respectively, thus covering the S, C, and X bands. The surface current distribution of the proposed absorber is also shown at the four resonating frequencies to get a better insight into the design. Moreover, the stability of the proposed design is also validated with different incident angles (for both TE and TM modes) and polarization angles. In addition, a prototype of the proposed absorber structure is also fabricated and then verified experimentally. [ABSTRACT FROM AUTHOR]

Metamaterials are frequently employed as sensors in a wide range of applications because of their special qualities that are not present in nature. This study focus on the design, fabrication and measurement of a novel shape metamaterial absorber for moisture-sensing applications. The proposed metamaterial absorber consists of modified cross along with split square resonator shape conductor on top of a 0.6 mm thick substrate. Parametric studies are also performed on the different design parameters, such as the thickness of the substrate and split square resonator etc. to figure out the optimal value of design variables. The simulated results of the proposed absorber illustrate the maximum reflection coefficient at 9.9 GHz. The obtained reflection coefficient value is − 30.5 dB at the resonant frequency The measured results of the absorber also show good agreement with the simulated results. Furthermore, the proposed metamaterial-based absorber utilize as a sensor. The proposed sensor design demonstrates excellent results in terms of resonance shift, sensitivity, linearity, Q factor, and figure of merit, making it a good candidate for moisture-sensing applications. [ABSTRACT FROM AUTHOR]

A porous 3D cross-linked conductive network pierced by multi-wall carbon nanotubes (MWCNTs) was successfully designed from zeolitic imidazolate framework-8 (ZIF-8). Zn@NPC@MWCNTs composites were tailored by the facile regulating the mass ratios and thermal annealing treatment. Due to the combination of less eddy current loss and dielectric loss together with multiple reflection attenuation caused by a unique structure. With a 10 wt% filler loading, the Zn@NPC@MWCNTs composites carbonized at 800 °C show two high reflection loss (RL) values with different thicknesses. An RL value is -53.18 dB with 4.09 mm thickness in the C-Band (4e8 GHz), and a minimum RL can reach -74.83 dB (10.8 GHz) with a matching thickness of 2.749 mm. The effective absorption bandwidth is 4 GHz (from 8 to 12 GHz, RL = -10 dB), which just covers the full X-band. Low cost and easy preparation can also provide advantages to develop MOF-based materials as effective EMW absorbents. [ABSTRACT FROM AUTHOR]

Developing flexible electromagnetic interference shielding (EMI SE) materials is an effective strategy to protect humans from being harmed by electromagnetic radiation from electronic devices. Though the EMI SE property of such materials as graphene can exceed 100 dB, it remains a challenge to achieve high-efficiency EMI SE performance while having excellent flexibility to allow them to be wearable. Herein, we designed theoretically and fabricated experimentally the flexible multilayer structure of the poly-(vinylidene fluoride)/graphene-poly-(vinylidene fluoride) (PVDF/GNP-PVDF) composite films. The experimental results show that the film thickness and layer number play an important role in determining the EMI SE performance, and the multilayer film with a thickness of 0.3 mm and a layer number of 6 exhibits not only high EMI SE performance (69.7 dB on average in X-band) but also excellent flexibility and stability (98.85% EMI SE retention after bending of 60° for 1000 cycles). The theoretical study via COMSOL software matching well with the experimental data reveals that multiple reflection and absorption of electromagnetic waves between layers is responsible for the high EMI SE performance of the PVDF/GNP-PVDF multilayer film at a relatively low thickness that ensures flexibility. This work highlights the significance of designing the multilayer architecture via theoretical simulation for improving the EMI SE performance and also demonstrates the high EMI SE application prospect of PVDF/GNP-PVDF films in wearable electronic devices. [ABSTRACT FROM AUTHOR]

The proposed paper presents a flexible antenna that is capable of operating in several frequency bands, namely 2.45 GHz, 5.8 GHz, and 8 GHz. The first two frequency bands are frequently utilized in industrial, scientific, and medical (ISM) as well as wireless local area network (WLAN) applications, whereas the third frequency band is associated with X-band applications. The antenna, with dimensions of 52 mm × 40 mm (0.79 λ × 0.61 λ), was designed using a 1.8 mm thick flexible kapton polyimide substrate with a permittivity of 3.5. Using CST Studio Suite, full-wave electromagnetic simulations were conducted, and the proposed design achieved a reflection coefficient below −10 dB for the intended frequency bands. Additionally, the proposed antenna achieves an efficiency value of up to 83% and appropriate values of gain in the desired frequency bands. In order to quantify the specific absorption rate (SAR), simulations were conducted by mounting the proposed antenna on a three-layered phantom. The SAR1g values recorded for the frequency bands of 2.45 GHz, 5.8 GHz, and 8 GHz were 0.34, 1.45, and 1.57 W/Kg respectively. These SAR values were observed to be significantly lower than the 1.6 W/Kg threshold set by the Federal Communication Commission (FCC). Moreover, the performance of the antenna was evaluated by simulating various deformation tests. [ABSTRACT FROM AUTHOR]

This article presents a single-layer, ultra-thin and multifunctional polarization converter (PC) design using metasurface. The PC, which is proposed as a single layer, consists of a metal metasurface on the front side of a easily accessible FR-4 material and a metal termination on the back surface. The suggested PC features linear polarization (LP) characteristic within a frequency ranges of 5.21 - 5.41 GHz and 7.53 - 8.08 GHz in C-band, also 10.59 - 10.84 GHz in X-band under normal incidence. It indicates the conversion performance of linear polarization to circular polarization (LP-CP) that has the properties of left-handed circular polarization (LHCP) in frequency range of 5.74–7 GHz in C-band and right-handed circular polarization (RHCP) in frequency range of 8.63 - 10.15 GHz in X-band. Besides, the suggested PC provides more than 90 % polarization conversion ratio (PCR) value in case of normal incidence (0 ∘ ) and over 80 % PCR value in case of oblique incidence up to 45 ∘ . Again, the suggested PC offers the same CP feature in two frequency regions where CP conversion takes place under normal incidence for angle of incidence up to 60 ∘ . A prototype of suggested PC was produced, measured, and a good match was found between the results simulated via a commercial electromagnetic (EM) simulation program. Finally, the performance of suggested design is compared with existing studies in literature with its high aspects. In this context, the suggested PC may be useful for C- and X-band applications due to its simple structure, ultra-thin and compactness, low-cost, and performance of LP and CP conversion under wide oblique angles. [ABSTRACT FROM AUTHOR]

Summary: This work proposes an electrical compact triple‐bands antenna founded on a composite left‐/right‐handed approach. This structure contains a rectangular patch combined with two unit cells based on the metamaterial properties that are used to produce wide electrical lengths in miniature physical sizes. Thus, the presented antenna is designed with a lower resonant frequency and miniature physical dimensions compared to conventional antennas. The suggested antenna has been produced on top of the FR4 substrate having tan δ = 0.022, εr = 4.58, and a size of 28 × 16 × 1.6 mm3. This structure provides three bandwidths of (2.391–2.54 GHz), (3.42–3.56 GHz), and (5.02–11.40 GHz). Additionally, a multi‐input multioutput (MIMO) antenna is designed by placing two similar radiating patches in a perpendicular shape. Therefore, this design approach has been used to achieve an important isolation among ports and less than −30 dB at frequency bands. The results of radiation patterns, envelope correlation coefficient, diversity gain, and channel capacity loss are below to 0.06, 10 dB, and 0.4 b/s/Hz respectively, which confirms that the MIMO antenna is compatible with wireless MIMO devices. These antennas have been modeled and experimentally confirmed, and the results have proven that the suggested antennas are useable and can support multi‐standard wireless applications. [ABSTRACT FROM AUTHOR]

In this article, a dual circularly polarized high gain superstrate integrated X‐band antenna is designed and analyzed for CubeSat applications. The proposed antenna consists of a metallic patch, multilayer space qualified printed circuit boards, and a dielectric superstrate with a high relative permittivity on top of the patch to establish a suitable resonance condition for high‐gain operation. The driven patch is fed by a 3‐dB hybrid coupler for the generation of dual (left hand circular polarization and right hand circular polarization) circular polarization. The antenna exhibits an impedance bandwidth of >18.5% (7.75–9.4 GHz) with a peak gain of >16 dBiC. The achieved antenna performance makes it suitable for CubeSat missions at X‐band. [ABSTRACT FROM AUTHOR]