Ku Band Research Articles

Compact Ultra-Wide Band Two Element Vivaldi Non-uniform Slot MIMO Antenna for Body-Centric Applications

This work presents a novel compact two-port Vivaldi Non-uniform Slot MIMO Antenna (VNSMA) to overcome the challenges of traditional ultra-wideband (UWB) antennas, such as large size, limited bandwidth (BW), high mutual coupling, and suboptimal performance in wearable devices. Designed based on Vivaldi non-uniform slot profile antenna (VNSPA) theory, this antenna offers superior performance metrics and significantly advances wearable antenna technology. The novelty of this work is investigating different positions for the two compact UWB VNSA to get better performance with smaller sizes, wider impedance matching BW, and lower mutual coupling (MC) where side by side at an angle of 180ᵒ is determined to be the best configuration. Detailed parametric studies were performed on this configuration for better performance, where the MC was further reduced by etching the ground plane with a vertical slot between the two antennas and L slots around the Microstrip to Slot (M/S) transition, respectively. Furthermore, BW and gain enhancements were obtained by etching exponential tapered and triangular slots at its two edges. Using the Finite Integration Technique (FIT), Computer Simulation Technology (CST) software is used for the simulations in this work. The VNSMA is tested on a CST Gustav human phantom and gives excellent results with low specific absorption rate (SAR) values at several UWB frequencies. The proposed VNSMA provides good, measured outcomes of S11 < -11.08 dB with wide BW of 12.5 GHz (2.33–14.83 GHz) covering high isolation of -23 dB (for most of frequency band), moderate-high gain of 5.89 dBi, radiation efficiency of 66-90%, low Envelope Correlation Coefficient (ECC) of 0.002 and high diversity gain (DG) of 9.99 dBi, stable radiation patterns, and average group delay of 1.2 ns. This innovative design, which optimizes antenna positioning and incorporates ground plane modifications, achieves remarkable improvements in BW, which covers multiple bands, including WLAN (2.4–2.485 GHz), X-band (8-12 GHz), and part of Ku band (12-18 GHz). The findings demonstrate the antenna's potential for various high-resolution microwave imaging applications, particularly in medical diagnostics like breast and brain cancer detection, showcasing its impact in wearable technology and healthcare.

Regulation of PPy Growth States by Employing Porous Organic Polymers to Obtain Excellent Microwave Absorption Performance.

Regulating the different growth states of polypyrrole (PPy) is a key strategy for obtaining PPy composites with high electromagnetic wave (EMW) absorption properties. This work finds that the growth states of PPy is regulated by controlling the amount of pyrrole added during the preparation of composites, so as to regulate the development of conductive networks to obtain excellent EMW absorption performance. The POP/PPy-200 composite achieves an effective absorption bandwidth (EAB) of 6.24GHz (11.76-18.00GHz) at a thickness of only 2.34mm, covering 100% of the Ku band. The minimum reflection loss of -73.05dB can be demonstrated at a thickness of only 2.29mm, while at the same time showing an EAB of 5.96GHz to meet the requirements of "thin", "light", "wide", and "strong". Such excellent EMW absorption performance is attributed to the conductive loss caused by the regulation of the growth states of PPy and the polarization loss caused by the heterostructure. This work also addresses the key challenge that porous organic polymers (POPs) cannot be applied to EMW absorption due to poor conductivity and providing new insights into the candidates for EMW absorbing materials.

Multi-band ultrathin reflective metasurface for linear and circular polarization conversion in Ku, K, and Ka bands

Linear polarization (LP) and circular polarization (CP) holds paramount importance in Ku, K, and Ka bands for satellite based communication, and remote sensing applications. Satellite based remote sensing applications face challenges like atmospheric attenuation, noise & interference, and signal degradation. Moreover, satellite based communication application demands CP in two distinct, non-adjacent frequency bands with orthogonal polarizations at greater oblique angles, considering the unpredictable incidence angles of electromagnetic (EM) waves. Addressing these challenges, an innovative metasurface polarization converter is proposed to operate efficiently across the Ku-band (13.5–18.0 GHz), K-band (18.0–26.5 GHz), and Ka-band (26.5–38.5 GHz) frequency ranges. The converter achieves left-handed circular polarization (LHCP) in the Ku- and Ka-bands within the frequency ranges of 14.57–15.65 GHz and 27.47–33.85 GHz for y-polarized incident EM waves. Additionally, it provides right-handed circular polarization (RHCP) in the K- and Ka-bands at 17.27–23.92 GHz and 35.87–38.32 GHz for y-polarized incident EM waves. The LP conversion ratio exceeds 95% in the frequency bands of 15.97–16.85 GHz, 24.70–26.65 GHz, and 34.37–35.45 GHz for y-polarized, LHCP, and RHCP incident EM waves, respectively. The metasurface exhibits robust performance up to incidence angles of 45 degrees under oblique conditions. Experimental validation using traditional board-circuit manufacturing demonstrates close agreement between measured co- and cross-polarized reflection coefficients and simulations in the 13.5–18 GHz, and 24–38.5 GHz frequency range. Thin metasurface with a thickness of only 0.64 = 0.013λo mm, the proposed design outperforms existing studies in the literature, establishing its competitive edge in terms of structure and performance.

Exploring Broadband Electromagnetic Absorption Characteristics and Composition Optimization in Novel Synthesized Ni2Fe1+xGe1−x Alloy Powders

This study reports for the first time the successful synthesis of a novel series of Ni2Fe1+xGe1−x (x = 0.25, 0.50, 0.75, 0.90) polycrystalline alloy materials with L21 austenite structure using the mechanical alloying method. Notably, the Ni2Fe1+xGe1−x alloys demonstrate excellent electromagnetic wave absorption performance across the entire 2–18 GHz frequency range, and by adjusting the composition ratio of iron and germanium, it is possible to effectively regulate their complex permittivity () and permeability (), thereby adjusting the reflection loss. All Ni2Fe1+xGe1−x samples show an effective electromagnetic wave absorption effect of more than −10 dB, indicating that 90% of the electromagnetic waves are efficiently absorbed. Among them, the Ni2Fe1.5Ge0.5 sample achieves an outstanding −43.5 dB reflection loss at 3.2 GHz, and the maximum effective absorption bandwidth reaches 5.8 GHz (11.8–17.6 GHz) with just a 1.6 mm thickness, fully covering the Ku band. This excellent absorption ability comes from the strong ability of the material to reduce signal strength and its perfect impedance matching. This study first shows the high potential of Ni2Fe1+xGe1−x ferromagnetic alloys as effective, wide‐range electromagnetic wave absorbers. It suggests the ferromagnetic Ni2Fe1+xGe1−x alloys hold promise as appealing candidates for broadband and high‐efficiency electromagnetic wave absorption.

Lightweight Carbon Fiber Aerogel@Hollow Carbon/Co3O4 Microsphere for Broadband Electromagnetic wave Absorption in X and Ku bands

The increasing proliferation of modern communications, radar systems, and military equipment operating in the X and Ku bands (8–18 GHz) has exacerbated the issue of electromagnetic wave (EMW) pollution, highlighting the urgent need for lightweight, broadband EMW-absorbing materials. In this paper, the lightweight carbon fiber aerogel@hollow carbon/Co3O4 microsphere (CFA@H-C/Co3O4) were composed by ZIF-67 derived hollow carbon/Co3O4 microsphere and bamboo cellulose fiber derived carbon fiber aerogels and constructed by in-situ chemical deposition, dopamine treatment and pyrolysis. Carbon fiber aerogels form a lightweight three-dimensional (3D) interconnected conductive network, which expands the multiple reflection and absorption paths of EMW and increases the dielectric loss. The hollow carbon/Co3O4 microsphere inhibits the collapse of the structure by forming a polydopamine shell through the self-polymerization effect of dopamine on the surface of ZIF-67 during pyrolysis, showing dipole polarization loss, interface polarization loss and magnetic loss, which plays an important role in improving EMW polarization loss and optimizing impedance matching. The minimum reflection loss (RLmin) of CFA@H-C/Co3O4 reaches -43.5 dB at frequency of 12.88 GHz with thickness of 3.0 mm and the effective absorption bandwidth (EAB) of CFA@H-C/Co3O4 reaches 7.84 GHz (10.08∼17.92 GHz) with thickness of 3.0 mm, covering most of X and Ku bands at a low filling ratio of 15 wt%. The radar cross-section (RCS) value of CFA@H-C/Co3O4 is 22.68 dB m2 lower than the perfect electrical conductor (PEC). This study provides valuable insights into materials that can improve the absorption bandwidth of electromagnetic waves in the X and KU bands.

Dimensional Self‐Assembled Magnetic Coupling via Embedding Ferromagnetic Nanoparticles in Multi‐Channel Fibers for Microwave Absorption

Abstract1D magnetic fibers with significant morphological diversity and magnetic anisotropy are highly desirable for optimizing magnetic properties and electromagnetic responsiveness. However, it remains challenging for the precise control over internal magnetic interactions within each fiber. Herein, a strategy for self‐assembled magnetic coupling is taken to achieve the controllable reconstruction of continuous multiple coupling networks within a single fiber. High‐density ultrafine cobalt nanoparticles are uniformly embedded inside a carbon framework with a 1D multi‐channel structure (Co@MCF). This structure establishes a complex magnetic response system characterized by inherent inter‐fiber interactions and refined intra‐fiber self‐assembling coupling. The distinctive distribution of magnetic flux lines demonstrates enhanced magnetic sensitivity. This results in a minimum reflection loss of −57.65 dB and a broadband absorption frequency range of 7.28 GHz at 1.9 mm, effectively covers the entire Ku band and a substantial portion of the X band. The multi‐channel structure enhances the understanding of the relationship between microstructure and performance in magnetic fibers. Additionally, it positions Co@MCF as a highly competitive candidate for microwave absorption applications.

“Assessment of combined wind and wave energy in European coastal waters using satellite altimetry.”

In this study, the combined wind and wave energy potential assessment is presented for various locations in European coastal waters. The objective is to investigate the feasibility of satellite altimetry-based assessments of combined wind/wave renewable energy potential on the European shelf. The study is motivated by the potential reduction in energy supply variability by combining wind and wave. The method consists of using a homogenized multi-mission altimeter database available by the European Space Agency Sea State Climate Change Initiative (Sea_State_cci) that comprises 26 years of data, from January 1991 to December 2018, that allows extending the time range and spatial coverage to estimate site wind and wave power densities. An empirical model is used to estimate the wave energy period from the altimeter Ku band significant wave height and radar backscatter coefficient required to compute the wave power density. The results show that wind/wave energy is relatively correlated in the Mediterranean but not in the North Atlantic sites studied. Thus, the Western North Atlantic sites are the most adequate places for wind and wave farms, from the point of view of combined exploitation.The different characteristics of the studied sites show some correspondence between variability and mean wave power, which is an essential input to a marine renewable energy strategy in any jurisdiction. The level of overall variability decreases with an increase in mean wave power, related to the higher power swell waves are not highly correlated with the local wind.

Design and development of a compact, wide-angle metamaterial electromagnetic energy harvester with multiband functionality and polarization-insensitive features

This article presents a compact, wide-angle, polarization-insensitive metamaterial harvester that can efficiently harvest electromagnetic (EM) energy in the S, C, X, and Ku bands. The harvester's unit cell consists of a split ring resonator, two strip lines, and two split strip lines, giving it a total size of (10 × 10) mm2. Each split gap is filled with a 50 Ω resistive load. The input impedance of the harvester is precisely designed to match that of free space, allowing for efficient absorption of EM power and appropriate redirection towards the resistive loads. The harvester's performance is also evaluated for various polarization and incident angles, considering the Transverse Electric and Transverse Magnetic modes. The simulation results reveal that the proposed harvester exhibits a notably greater conversion efficiency of around > 95%. The simulation outcomes were carefully validated through experimental tests conducted in an anechoic chamber using a 3 × 3 cell array of the proposed design. This ensured the accuracy and reliability of the results. The strong correlation between the experimental data and the full-wave simulations strongly supports the effectiveness of the proposed harvester. Therefore, the demonstrated efficiency and compact size make it a perfect fit for energy harvesting systems in wireless sensor networks.

Performance Analysis of an Aerial Remote Sensing Platform Based on Real-Time Satellite Communication and Its Application in Natural Disaster Emergency Response

The frequency of natural disasters has increased recently, posing a huge threat to human society. Rapid, accurate, authentic, and comprehensive acquisition and transmission of disaster information are crucial in emergency response. In this paper, we propose a design scheme for an aerial remote sensing platform based on real-time satellite communication. This platform mainly includes a civilian heavy-duty unmanned aerial vehicle, ground observation system with the self-developed orthographic image stabilization device, wireless communication system with an airborne mobile communication device using Ku band, ground satellite information receiving station, and data processing and application analysis system. The image stabilization capability of the ground observation system and the communication capability of the wireless communication system were verified through ground and flight tests respectively. The results showed that the stability accuracy of the platform was better than the theoretical threshold, the system transmission rate was not less than 2 M bandwidth, the data packet loss rate was low, and the time delay was not more than 2 s. The images captured in the experiment were clear, with a resolution of less than 1cm and an overlap rate of more than 70%. These all results meet the emergency observation requirement, which indicates that the aerial remote sensing platform based on real-time satellite communication has great potential for application in natural disaster emergency response.

Multifunctional electromagnetic wave absorbing carbon fiber/Ti3C2TX MXene fabric with ultra-wide absorption band

In order to provide electronics and aerospace equipment with effective immunity to electromagnetic interference and to improve their adaptability to very harsh electromagnetic environments, high-performance electromagnetic wave-absorbing materials are urgently needed for civil and military applications. Unfortunately, their effective absorption bandwidth width is still unsatisfactory (<10 GHz) due to the insufficient regulation of their component mixing and microstructure. By employing nanocage-structured UiO-66 as a doping phase, MXene/ZrO2/tungsten-doped carbon (MXene/ZrO2/W-C) interpenetrating fiber networks were prepared by the electrostatic spinning method. According to the experimental results, the introduction of the dopant phase and the formation of the interpenetrating network significantly improves impedance matching, resulting in a wide absorption bandwidth of 11.12 GHz for the composites, completing the coverage of the X and Ku bands. The radar scattering cross section of MXene/ZrO2/W-C has been simulated using three-dimensional electromagnetic field simulation, and as a result of its excellent stealth performance, it is able to generate corresponding electromagnetic responses in radar detection environments that exhibit different far-field emission bands. Further, MXene/ZrO2/W-C exhibits outstanding hydrophobicity, corrosion resistance, and temperature resistance. These characteristics allow it to be used for the preparation of electromagnetic wave (EMW) absorbing devices for complex environmental applications. It is important to note that the results of this study will be extremely useful in the development of composites based on MXene with ultra-wide absorption bands as well as in the analysis of EMW absorption mechanisms.

Resistive ink based polarization and incident angle independent wideband absorber for RCS reduction at KU and K band

In this paper, a thin, single layered, wideband, polarization-insensitive, frequency selective surface absorber for radar cross section reduction (RCS) at KU and K bands has been studied analytically and experimentally. The lossy resistive patterns on unit cell is printed using resistive ink and arranged periodically over a low-cost metal-backed FR-4 dielectric substrate. Through appropriate design and optimization, the proposed absorber demonstrates above 90 % absorption for broadband ranging from 15 GHz to 26.6 GHz, with multi-absorption peaks at 15.7, 18.5, and 22.9 GHz. The structure shows a high absorptivity of 96.8 % in the KU band and 95.7 %, and 99.3 % in the K band at the above mentioned frequencies. A fractional bandwidth of 55.8 % has been obtained at the expense of a thickness of 0.0835 λ1 (λ1 being the wavelength associated with the lower absorbing frequency). The absorption mechanism has been described with the help of surface current distribution, induced electric field, and equivalent circuit. Further, for both TE and TM waves, analysis of various polarization angles and oblique incidence angles have been investigated. It shows polarization insensitivity to normal incidence and a stable response up to 60° for oblique incidence to TM wave. The proposed absorber’s novelty comes through its thin, single-layered structure with wide band response at the KU and K frequency bands via a unique resistive ink pattern on a low cost FR-4. A prototype of the absorber has been fabricated and measured results have been validated with simulated results. A proposed single layered, wideband, thin, polarization, and angular stable absorber using resistive ink is commercially viable for RCS reduction applications at the KU and K band.

CSA-doped PANI-CNT nano composites for Ku band microwave shielding applications

The major concern in high-frequency communication is electromagnetic interference. To address this, there are several material composites developed. This article focuses on a cost-effective development method for synthesizing CSA-doped PANI-CNT nanocomposites for microwave shielding applications. The nanocomposite is prepared using chemical polymerization. The chemical structure, surface characteristics and atomic structure of the material are characterized using FTIR, XRD, SEM, and TEM, respectively. The EMI shielding characteristics of the synthesized material are investigated as a function of weight percentage of CNT in PANI. The efficacy of the developed material is studied using the waveguide method. The analysis reveals good improvement in the shielding at the X and Ku-band frequencies.

High-gain H-plane SIW horn antenna loaded with dielectric slab for ku band low RCS applications

This article presents the design, simulation and experimental measurements of an H-Plane substrate-integrated waveguide (SIW) Horn Antenna Loaded with FR-4 Slab for Low RCS (radar cross section) applications like defence sector at Ku band (12-16 GHz). The design facilitates high gain and good impedance bandwidth (IBW). Also, the proposed structure has simple feed, planar structure with low-cost FR-4 substrate as dielectric material and decomposed into two parts. The former part of the antenna is the feeding part, which consists of two metallic plates filled with air substrate and a 90-degree corner reflector designed by shortening the metallic plates. The later part of the antenna is loaded with the FR-4 substrate that enhance the peak gain of the structure significantly. A simple coaxial probe is employed for the excitation of the corner reflector antenna. After the design is conferred by simulations, the same is fabricated and the performance measured experimentally. The experimental results are in close agreement with the simulated results. The design has yielded a 10 dB bandwidth of 30% (11.6–16 GHz), and a stable endfire radiation pattern over the entire bandwidth with a peak gain of 18.5 dBi at 14 GHz. Also, the design has F/B ratio > 20 dB over entire 10 dB bandwidth. Moreover, the antenna produced low RCS < 20 dB(m2) from −30° to +180° of elevation angle. Therefore antenna can’t easily detected from the radar system and suitable for defence applications.

A Compact Sinusoidally Tapered Slot Vivaldi Linear Antenna Array for X and Ku Band Applications

A Compact Sinusoidally Tapered Slot Vivaldi Linear Antenna Array for X and Ku Band Applications

Joule heat induced ultrafine ZrO2/C composites for enhanced microwave absorption

Lightweight absorbers with effective broad absorption and high thermal stability are highly desirable in the field of electromagnetic wave absorption. In this work, we introduce a facile carbon thermal shock method to prepare ZrO2/C composites using UIO 66 (Zr) as the precursor. The instant heating and cooling process ensures the uniform deposition of nano-sized ZrO2 (ca. 5–15 nm) on graphene, exhibiting an ultrahigh interfacial number density of ca. 1015 m−2 that favors polarization loss. Due to the synergetic effect of dielectric loss and impedance matching, the prepared ZrO2/graphene composites show tunable wide-microwave absorption performance by adjusting the heat temperature, and possess a wide absorption band covering the entire X and Ku band. Notably, the ZrO2/graphene composites show high thermal stability up to 1000 °C, which presents great potential for microwave absorption applications.

Hierarchical Magnetic Carbon Nanoflowers for Ultra-Efficient Electromagnetic Wave Absorption.

Porous carbon nanomaterials are widely applied in the electromagnetic wave absorption (EMWA) field. Among them, an emerging flower-like carbon nanomaterial, termed carbon nanoflowers (CNFs), has attracted tremendous research attention due to their unique hierarchical flower-like structure. However, the design of flower-like carbon nanomaterials with different magnetic cores for EMWA has rarely been reported. Herein, a general template method is proposed to achieve a set of high-quality magnetic CNFs, namely Co@Void@CNFs, CoNi@CNFs, and Ni@CNFs. The prepared magnetic CNFs have highly accessible surface area and internal space, rich heteroatom content, multi-scale pore system, and uniform and highly dispersed magnetic nanoparticles, as a result, deliver superior EMWA performance. Specifically, when the thickness is 2.6mm, the Co@Void@CNFs exhibit a maximum refection loss (RLmax) of -56.6dB and an effective absorption bandwidth (EAB) from 8.0 to 12.1GHz covering the whole X band. The CoNi@CNFs have an RLmax of up to -57.6dB and a wide EAB of 5.6GHz at just 1.9mm. For the Ni@CNFs, possess an ultra-broad EAB of 6.1GHz, covering the entire Ku band at 2.0mm. Overall, the hierarchical magnetic carbon nanoflowers proposed here offer new insights toward realizing multifunctional integrated carbon nanomaterials for EMWA.

Multifunctional electromagnetic wave absorbing carbon fiber/Ti3C2TX MXene fabric with superior near-infrared laser dependent photothermal antibacterial behaviors

Developing multifunctional materials which could simultaneously possess anti-bacterial ability and electromagnetic (EM) absorption ability during medical care is quite essential since the EM waves radiation and antibiotic-resistant bacteria are threatening people’s health. In this work, the multifunctional carbon fiber/Ti3C2Tx MXene (CM) were synthesized through repeated dip-coating and following in-situ growth method. The as-fabricated CF/MXene displayed outstanding EM wave absorption and highly efficient photothermal converting ability. The minimum reflection loss (RL) of −57.07 dB and ultra-broad absorption of 7.74 GHz could be achieved for CM composites. By growth of CoNi-layered double hydroxides (LDHs) sheets onto MXene, the absorption bandwidth for carbon fiber/Ti3C2Tx MXene layered double hydroxides (CML) could be reach 5.44 GHz, which could cover the whole Ku band. The excellent photothermal effect endow the CM composites with excellent antibacterial performance. The antibacterials tests indicated that nearly 100 % bactericidal efficiency against E. acoil and S. aureus was obtained for the CM composite after exposure to near-infrared region (NIR) irradiation. This work provides a promising candidate to combat medical device-related infections and EM pollution.

Polar Sea Ice Monitoring Using HY-2B Satellite Scatterometer and Scanning Microwave Radiometer Measurements

The Ku band microwave scatterometer (SCA) and scanning microwave radiometer (SMR) onboard HaiYang-2B (HY-2B) can simultaneously supply active and passive microwave observations over the polar region. In this paper, a polar ice water discrimination model and Arctic sea-ice-type classification model based on the support vector machine (SVM) method were established and used to produce a daily sea ice extent dataset from 2019 to 2021 with data from SCA and SMR. First, suitable scattering and radiation parameters are chosen as input data for the discriminant model. Then, the sea ice extent was obtained based on the monthly ice water discrimination model, and finally, the ice over the Arctic was classified into multiyear ice (MYI) and first-year ice (FYI). The 3-year ice extent and MYI extent products were consistent with the similar results of the National Snow and Ice Data Center (NSIDC) and Ocean and Sea Ice Satellite Application Facility (OSISAF). Using the OSISAF similar product as validation data, the overall accuracies (OAs) of ice/water discrimination and FYI/MYI discrimination are 99% and 97%, respectively. Compared with the high spatial resolution classification results of the Moderate Resolution Imaging Spectroradiometer (MODIS) and SAR, the OAs of ice/water discrimination and FYI/MYI discrimination are 96% and 86%, respectively. In conclusion, the SAC and SMR of HY-2B have been verified for monitoring polar sea ice, and the sea ice extent and sea-ice-type products are promising for integration into long-term sea ice records.

Compact Dual-Band Circularly Polarized Shared-Aperture Antenna for Satellite Communication Systems

A compact dual-band circularly polarized (CP) shared-aperture antenna is proposed for satellite communication. The antenna enables simultaneous dual-band functionality and CP radiation with right-handed CP in the Ku band and left-handed CP (LHCP) in the Ka band. The shared-aperture is implemented by integrating two independent subapertures, which function through frequency-multiplexed, resulting in a minimized profile (0.04 λ 0 ) and reduced complexity, making it an ideal choice for array applications. To enhance inter-frequency isolation, a circular arrangement of metal vias is incorporated. The measured results indicate that the antenna effectively encompasses a 3 dB axial ratio (AR) bandwidth of 15.6–16.5 GHz in Ku and 26.5–27.5 GHz in Ka bands. Additionally, it exhibits a broader 10 dB impedance bandwidth (IBW) and superior port isolation bandwidth exceeding 30 dB.

Hot-pressing-oriented graphene in Si3N4 composites for enhanced electromagnetic wave absorption in X and Ku bands

In this study, the oriented graphene within graphene/Si3N4 composites was successfully achieved by two-step hot-press sintering. Microstructure analysis revealed that the graphene sheets were well dispersed in the Si3N4 matrix and oriented perpendicular to the applied stress. The composites exhibited effective electromagnetic wave (EMW) absorption capabilities and good mechanical properties. The effective absorption bandwidth (EAB) was 9.63 GHz, nearly covering the entire X and Ku bands (8.2–18 GHz), and the minimum reflect loss (RL) was −24.23 dB when the graphene content reached 7 wt% at a thickness of 2.02 mm. Meanwhile, the oriented graphene/Si3N4 composites demonstrated a bending strength of 576.66 MPa and a fracture toughness of 8.40 MPa·m1/2. The EMW absorption in these composites should be primarily due to polarization relaxation loss and conductivity loss, and the toughening mechanism should involve the graphene pull-out, crack bridging, and crack deflection. The graphene/Si3N4 composites have a promising application in structurally integrated functional materials.