Radar Cross Section Analysis Research Articles

Dynamic radar cross section similarity study based on dynamic time warping

Abstract Dynamic radar cross-section (RCS) represents the radar reflectance cross-section of an aircraft at different moments during flight and is a crucial criterion for evaluating the ability of a radar to detect an aircraft. In practice, it is challenging to construct an accurate 6-DOF dynamics model for the purpose of solving its dynamic RCS. Consequently, a 3-DOF dynamics model is employed for the analysis of dynamic RCS. This paper presents a methodology for the joint simulation of the dynamic RCS under two DOF models and subsequent comparison and analysis of the resulting sequence data via the dynamic time warping algorithm. It is also concluded that the dynamic RCS values calculated using the 3-DOF dynamics model can identify the target vehicle.

Backscatter Radar Cross Section Analysis of Chaff Using the Sequential Loading Method

Backscatter Radar Cross Section Analysis of Chaff Using the Sequential Loading Method

Analysis of multi-photon quantum radar cross section for targets in atmospheric medium

Analysis of multi-photon quantum radar cross section for targets in atmospheric medium

Constructing multiple heterogeneous interfaces in one-dimensional carbon fiber materials for superior electromagnetic wave absorption

Due to impedance mismatch and a single loss mechanism, carbon fiber fails to meet the requirements for efficient absorbers in terms of lightweight construction and broad absorption band. In this study, we have successfully prepared one-dimensional beaded SiO2@SiC@C nanofiber (SSCF) composites with multiple heterogeneous interfaces by employing the electrospinning-carbothermal reduction method. The beaded SSCF composites effectively address the impedance mismatch issue by controlling silicon dioxide and silicon carbide through carbothermal reduction. This optimization enriches the defects and interfaces of carbon fibers composites, consequently enhancing the electromagnetic wave absorption performance. The SSCF composites demonstrate remarkable performance, with a minimum reflection loss of −59.53 dB at a matched thickness of 2.21 mm and a maximum absorption bandwidth of 6 GHz. This outstanding performance is attributed to the synergistic effects of the multi-phase composition, bead structure, and one-dimensional network structure. These features not only optimize impedance matching but also enhance defect loss, interface polarization loss (SiC/SiO2, C/SiO2, SiC/C, C/Air), conduction loss, and relaxation loss of the SSCF composites. Furthermore, radar cross-section analysis utilizing computer simulation technology confirms the excellent attenuation of microwave energy by the SSCF composites under realistic far-field conditions. This study provides valuable insights for designing efficient one-dimensional carbon-based electromagnetic wave absorbers.

Analysis of bistatic multiphoton quantum radar cross section for the cylindrical surface.

A closed-form model of bistatic multiphoton quantum radar cross section (QRCS) for the cylindrical surface, the main structure of typical aircraft, especially missiles, is established to analyze the system and scattering characteristics. The influence of curvature of the three-dimensional target on QRCS is analyzed. By comparing and analyzing the bistatic multiphoton QRCS for a cylinder and a rectangular plate, we find that the QRCS for the convex surface target is the extension of the QRCS for the planar target with inhomogeneous atomic arrangement intervals and patterns. The characteristics of cylindrical QRCS are discussed by combining the transceiver system and the photon number of the transmitted signal, and the influences of the cylindrical radius, cylindrical length, and incident photon number on QRCS are analyzed. The bistatic results provide guidance on potential strong scattering directions for the target under various directions of photon incidence. Compared with the plane target, the cylindrical target amplifies scattering intensity near the target surface at the scattering angle side in the bistatic system. A bistatic multiphoton quantum radar system can achieve sharpening and amplification of the main lobe of the QRCS for a cylinder in an extensive scattering angle range. Bistatic multiphoton quantum radar has better visibility for the cylinder with a smaller length. These characteristics will provide prior information for research in many fields, such as photonic technology, radar technology, and precision metrology.

Quantitative calculation of electromagnetic scattering characteristics from drag plate of aircraft afterbody

PurposeThis paper aims to discuss the electromagnetic scattering characteristics of the afterbody model with two drag plates.Design/methodology/approachThe plane shape of the drag plate model is designed as a rectangle. High-precision unstructured grid technology is used to treat the target surface. A calculation method based on multiple tracking and dynamic scattering module is presented to calculate the radar cross section (RCS).FindingsThe results show that under the given observation conditions, the RCS and surface scattering characteristics of a single drag plate change with the increase of the opening angle, which makes the forward RCS of the afterbody model change more than 8.43 dBm2. The opening of two resistance plates at different fixed angles has little effect on the peak value and position of the RCS of the afterbody model. The dynamic deflection of the two drag plates can bring 16.78 dBm2 fluctuations to the forward RCS of the afterbody model, and more than 25.59 dBm2 fluctuations to the side RCS.Practical implicationsThe installation positions of the drag plate on the aircraft are various, so the method in this paper can provide reference and support for RCS analysis of the speed brake at other positions.Originality/valueThe presented calculation method is of engineering value to analyze the electromagnetic scattering characteristics of the drag plate.

Statistical analysis of hypersonic glide vehicle radar cross section

AbstractThe capability to design, manufacture and test Hypersonic Glide Vehicles (HGVs) has been demonstrated by a number of nations, and they are increasingly forming part of military inventories, potentially offering capabilities highly unique to this technology. This article reports the simulated Monostatic Radar Cross Section of a generic HGV in five frequency ranges, HF, VHF, UHF, L, and S‐bands associated with different radar types. Full spherical datasets of complex co‐ and cross‐polar data are synthesised so that backscatter resulting from illumination by r.f./microwave energy of linear or circular polarisation can subsequently be computed from the raw dataset. Circular polarisation is commonly employed by ground‐based Ballistic Missile Early Warning Systems and Space Object Surveillance and Identification radars to avoid polarisation mis‐match losses resulting from ionospheric Faraday rotation effects. The data was generated using Ansys' Finite Element Solver at 10, 150 and 430 MHz, with the Geometric Optics/Physical Optics based SBR+ solver employed for 1.3 and 3 GHz data. All data was produced at below the Nyquist sampling interval relevant to the target's electrical size. These datasets were then imported into a Matlab routine which extracted data over limited angular ranges associated with the likely radar line‐of‐sight in particular scenarios, typically having a standard deviation of ±10° about the direction of flight, applying either a Gaussian or Uniform sampling distribution as part of a Monte Carlo analysis. These extracted data were then used to form histograms giving the probability of sampling particular RCS values. Probability density functions and cumulative distribution functions were then fitted, to aid in the representation of statistical target fluctuations for each band and angular sampling range. The HGV exists in either the ‘Rayleigh’, ‘resonance’ or ‘optical’ scattering regimes, depending on its relative electrical size. The results suggest that for this target shape at HF and VHF cases a simple Swerling 0 (fluctuation invariant) approximation is adequate in most instances, whilst a Gamma distribution may be applied for UHF band cases. At L and S‐band a Beta distribution was found to provide a good fit to the available data.

Satellite Collision and Fragmentation Probabilities Using Radar-Based Size and Mass Estimates

Most conjunctions between Earth-orbiting satellites involve unknown objects, typically debris created by explosions or collisions. This study formulates methods to estimate probabilities of collision and fragmentation for such conjunctions, which depend on the estimated sizes and masses of the unknown objects. Analysis of radar cross-section (RCS) measurements provides estimated sizes, found to be accurate at the 90% confidence level to within a factor of 0.59 for potential underestimations and to within a factor of 3.1 for potential overestimations. For satellites that experience measurable atmospheric drag orbital perturbations, combining RCS data with orbit determination ballistic coefficients provides mass estimates accurate to within factors of 0.47 to 10.9 at the 90% confidence level. For satellites with perigee altitudes above 450 km, combining RCS data with solar radiation pressure coefficients provides mass estimates accurate to within factors of 0.44 to 5.6 at 90% confidence. The collision and fragmentation risk assessment formulation accounts for these size and mass estimation uncertainties. Specifically, conjunction collision probabilities formulated as statistically expected values account for the RCS-based size estimation uncertainties. Fragmentation probabilities, which measure the likelihood of producing more than a threshold number of collision fragments, account for both size and mass estimation uncertainties.

Constructing hierarchical hollow flower-like MoO2/CoNi/NPC microspheres via water-in-oil system assisted supramolecular self-assembly for high-efficient electromagnetic wave absorption

Starting from the composition combination and structural design of materials, the novel high-efficiency absorber can be exploited. Herein, we constructed hollow flower-like MoO2/CoNi/NPC microspheres by virtue of supramolecular self-assembly in water-in-oil system and carbonization. The study found that when the mass ratio of the phosphomolybdic acid and dopamine hydrochloride was 3:4, and the oil phase solvent was glycol, microspheres presented outstanding electromagnetic wave (EMW) absorption performance. Its minimum reflection loss (RLmin) value was − 54 dB and the effective absorption bandwidth (EAB) was 4.72 GHz at 1.97 mm with the filling ratio of 35 wt%. When the thickness was only 1.7 mm, the widest EAB was up to 6.48 GHz (11.52–18 GHz), covering the entire Ku-band. The excellent EMW absorption performance was mainly attributed to the multiple scattering and enhanced impedance matching caused by the 3D flower-like hollow structure, as well as the strong polarization loss induced by the double-layer structure and Schottky contact. We also utilized the radar cross section (RCS) analysis method to simulate and calculate electromagnetic (EM) scattering performance of aluminum metal plates with absorbing coatings. The analysis results further manifested that MoO2/CoNi/NPC could be used as excellent absorber.

A trade-off analysis between lateral/directional stability and radar cross section requirements of an air-to-air combat airframe

Numerical aerodynamic and radar analyses were conducted on 3 low-radar cross-section airframes, derived from the AVT-183 diamond wing. The geometries were developed by adding different configurations of vertical stabilators, to improve lateral and directional characteristics at high angles of attack whilst minimising the deterioration of radar signature characteristics. The analyses were conducted at a Mach number of 0.30, with angle of attack varying between 0 deg to 30 deg and angle of sideslip varying from 0 deg to 6 deg. Monostatic radar cross-section analysis was conducted in L and X bands. The study explored the trade-off between radar signature control (RCS) and the spin/departure requirements typical of a modern combat aircraft designed for air-superiority. Several of the proposed configuration were shown to improve both lateral and directional stability, whilst maintaining acceptable RCS.

Automated topology design to improve the susceptibility of naval ships using geometric deep learning

AbstractThe survivability of a naval ship is defined as its ability to evade or withstand a hostile environment while performing a given mission. Stealth technology, which reduces the probability of detection by enemy detection equipment using a highly advanced detection system, is one of the most important technologies to improve the survivability of naval ships. Moreover, radar cross-section (RCS) reduction is a very important factor in stealth technology because a small RCS, which is the main parameter determining susceptibility, improves the ability of ships to evade enemy detection equipment. In this study, an automated topology design for reducing susceptibility was developed by combining geometric deep learning and topology optimization. A convolutional neural network model was used as the geometric deep-learning model, and the triangular meshes of the naval ship models and equipment models were used as datasets. To compensate for the lack of training data, randomly generated meshes were additionally used as datasets. To express the feature data of the mesh as a matrix, points at equal intervals were projected orthogonally and the distance between the plane and point was set as a matrix value. The label data were defined as the highest RCS values excluding the cardinal points. After realizing the topology design for reducing susceptibility using the developed system, verification was performed through RCS analysis of the original model and the topology-designed model.

Fast Wide-Band RCS Analysis of the Coated Target Based on PBR Using EFIE-PMCHWT and the Chebyshev Approximation Technique

The Chebyshev approximation technique (CAT) combined with the MoM based on the electric-field integral equation (EFIE) and the Poggio–Miller–Chang–Harrington–Wu–Tsai (PMCHWT) integral equation is proposed to efficiently calculate the wide-band radar cross-section (RCS) based on passive bistatic radars (PBR). The EFIE-PMCHWT equations can be used to analyze the electromagnetic scattering of coated targets. The combination with CAT only requires computing the electric and magnetic currents at a few Chebyshev frequency points, which can be employed to obtain the electric and magnetic currents over the entire frequency band. In this study, the RCS values of a coated target calculated by the hybrid EFIE-PMCHWT-CAT based on passive bistatic radar (PBR) were found to be consistent with that calculated by the MoM based on the EFIE-PMCHWT. The validity of the hybrid method is verified by several numerical examples. Compared with the conventional MoM method, the hybrid method can greatly improve the efficiency for electromagnetic scattering problems over a wide frequency band.

Screen Printed Polarization Independent Microwave Absorber for Wideband RCS Reduction

Designing and deploying a broadband microwave absorber that provides wide bandwidth radar cross section (RCS) reduction for planar and curved surfaces is challenging. We present a resistive ink-based multilayered wideband absorber using a low-priced FR4 substrate to cope with the challenge. The reflection coefficient response of the structure lies beneath −10 dB reference over the frequency span of 1.3–18.6 GHz for the normally incident electromagnetic waves. The multilayered structure incorporates the entire microwave radar frequency span with a relative fractional bandwidth of 173.86%. Moreover, to examine the applicability of the structure for a nonplanar geometrical surface, we further design the structure on a very thin FR4 substrate that can be bent easily. We performed an RCS analysis of the redesigned structure under monostatic and bistatic conditions. The structure thereby exhibits novelty in terms of wider stealth and electromagnetic compatibility applications and also a good counterbalance among different design attributes comprising thickness, bandwidth, and periodicity, unlike the earlier reported work. The proposed prototypes are fabricated and experimentally validated for planar and curved surfaces, respectively. The experimental results depict a good concurrence with the simulated results.

Research on the Influence of Model Surface Conductivity on RCS Test Accuracy

The accuracy of the RCS (Radar Cross Section) test is closely related to the conductivity of the model surface. The Chinese military standard has stringent surface resistance criteria for models. If the resistance criteria are appropriately relaxed, model processing can be more effective and expenses can be reduced. However, there are few quantitative evaluations of the relationship between surface resistance and RCS test error, making it impossible to design the model surface resistance in accordance with RCS test accuracy requirements. In this paper, firstly, the influence of model surface resistance on RCS is clarified through theoretical, simulation, and experimental research. The RCS analysis approach of the finite conductivity model is established. Subsequently, taking various typical shapes as research objects, such as the sphere, cube, flying wing aircraft, wing-body combination, and stealth aircraft, the simulation analysis of radar scattering characteristics is carried out under varied sheet resistances and multiple frequencies. A more attainable surface conductivity control standard for the RCS test model has been formulated, which is relaxed by 93% and 727% for models with average RCS of less than and higher than −30dBsm compared with the indicator in the Chinese military standard.

Novel Dual-Mode Polarization Insensitive Wide Angular Stable Circular Ring Based Deca-Band Absorber for RCS and EMI Shielding Applications

A simple concentric circular ring resonator-based nonreciprocal deca-band absorber is demonstrated in this article. The design primarily consists of two frequency selective surfaces (FSSs) among one is a compliment to the other printed on either side of the 2.4 mm thin FR-4 dielectric substrate. It exhibits near-unity absorption effectively at ten different resonant frequencies over X-Ka bands with an average absorption efficiency of 94.6%. Surface plasmonic resonances are the reason behind the multiband absorption and are illustrated with current profiles at resonant frequencies. The performance is angular stable for both transverse electric and transverse magnetic oblique incidences up to 60 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> . The design is compact with a structural periodicity of 0.210 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{\lambda }}}_{\boldsymbol{o}}$</tex-math></inline-formula> and thickness 0.07 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{\lambda }}}_{\boldsymbol{o}}$</tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{\lambda }}}_{\boldsymbol{o}}$</tex-math></inline-formula> is the lowest resonant peak's free-space wavelength. The 20×20 array of the design prototype is fabricated, and the measured results agree with the full-wave analysis. Bistatic radar cross section (RCS) analysis of the proposed absorber is evaluated along with a conventional microstrip patch antenna at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> -band. Since the absorber design is based on complementary FSSs, it can also be utilized as a reflector for the not absorbing frequencies. The novelty lies in the utilization of the dual-side of the substrate made this design compact with a greater number of absorption peaks and good angular stability, making it potential for real-time RCS, and electromagnetic interference and shielding applications.

Y-type quadrotor radar cross-section analysis

PurposeThe purpose of his paper is to study the radar stealth performance of a Y-type quadrotor with coaxial rotors and parallel rotors.Design/methodology/approachThis Y-type quadrotor is designed as an aerodynamic layout with parallel twin rotors at the front and coaxial twin rotors at the rear. The multi-rotor scattering (MRS) method based on multi-rotor dynamic simulation (MRDS) and electromagnetic scattering module (ESM) is presented. MRDS is used to simulate the complex rotation of parallel rotors and coaxial rotors. ESM is used to calculate the instantaneous radar cross-section (RCS) of the quadrotor.FindingsFor a single rotor, the minimum period of the RCS curve at a given azimuth is equal to the basic passage time of the blade, where increasing the speed can shorten this minimum period. When the elevation angle increases, the forward RCS fluctuation of the quadrotor increases, while the average RCS decreases. The change of the roll angle will affect both the mean and the maximum difference of the RCS–time curve at the given lateral azimuth. The increase of the pitch angle will enhance the dynamic amplitude of the RCS–time curve under the forward azimuth.Practical implicationsThe research in this article can provide reference for the stealth design of the Y-type quadcopter in the future.Originality/valueThe originality is the establishment of the MRS method. This method could provide value for dealing with the electromagnetic scattering problem of coaxial rotors and parallel rotors.

W-type flying wing radar cross-section analysis

To study the electromagnetic scattering characteristics of a W-type flying wing with two rotors, a computing method is presented. The method includes two modules: dynamic grid transformation and instantaneous RCS (radar cross-section) computing. The results show that the surface of the blade and the leading edge of the wing have a high level of scattering under the irradiation of forward radar waves. The scattering characteristics of the rotor support cabin are enhanced when electromagnetic waves are incident from the side. At the given positive elevation angle, the mean of aircraft RCS curve under side direction decreases first and then increases with the increase in azimuth. The fluctuation range of the aircraft RCS curve under different tail azimuths is similar at the given negative elevation angle. The computing method is effective for analyzing the RCS of the W-type flying wing.

Measurement of Nonlinear RCS of Electronic Targets for Nonlinear Detection

The conventional radar technology is based on linear detection—i.e., the same transmit and receive frequencies are used. However, with linear radars, difficulties arise when detecting electronic objects with relatively small radar cross section (RCS). To overcome these limitations, a nonlinear radar that can detect nonlinear responses (i.e., harmonic and intermodulation) scattered by electronic devices due to nonlinear interaction can be utilized. Nonlinear radars require a different analysis from linear radars for analyzing RCS. In this paper, we present an experimental analysis of the nonlinear RCS of various electronic devices. Unlike linear radars, RCS in nonlinear radars is determined by the amount of nonlinear responses backscattered to the radar. Therefore, we derive a radar equation accustomed to harmonic radars that consists of nonlinear RCS. We then obtain and analyze the nonlinear RCS of various targets from the measured harmonic responses of the targets based on the nonlinear radar equation.

Broadband Chiral-Type Linear to Linear Reflecting Polarizer With Minimal Bandwidth Reduction at Higher Oblique Angles for Satellite Applications

This work presents a broadband linear–cross polarizer for K- and Ka-band applications. The design consists of a simple asymmetric width-based meander-line metasurface printed on a thin FR-4 grounded dielectric substrate. Normal incidence demonstrates 90% polarization conversion ratio (PCR) bandwidth (BW) of 20.64 GHz from 18.31 to 38.95 GHz with 72.1% fractional BW (FBW). Due to the destructive interference involved at greater oblique angles, reflective polarizers experience severe degradation of 90% PCR BW response. The proposed polarizer’s performance is obliquely stable up to 43° for transverse electric (TE) and 45° for transverse magnetic (TM) incidence with minimal 90% PCR BW reduction of only 13.95% (TE) and 15.25% (TM) compared with normal incidence. For the first time, transfer matrix method (TMM)-based equivalent surface impedance technique is modeled for oblique incidence analytically, closely resembling the full-wave analysis. The design is compact with a periodicity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda \text{o}$ </tex-math></inline-formula> /5.98 and a thickness of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda \text{o}$ </tex-math></inline-formula> /13.69. The surface current patterns at resonant frequencies illustrate the reason behind broadband behavior. Bistatic radar cross section (RCS) analysis of the proposed converter is studied with reference to PEC. To the best of the author’s knowledge, this structure demonstrates broadband response with wide angular stability with less than 90% PCR BW reduction at higher oblique angles reported so far.

Analysis of bistatic quantum radar cross section for multi-photon illumination of typical ship structure

Analysis of bistatic quantum radar cross section for multi-photon illumination of typical ship structure