Showing papers on "Physical optics published in 2021"

A Dielectric Dome Antenna With Reduced Profile and Wide Scanning Capability

Abstract: The design and experimental validation of a wide scanning dome antenna with reduced profile is presented The antenna is based on the combination of a planar phased array with limited scanning capabilities and a dielectric lens which allows to broaden the field of view The angular variation of the scan loss can be almost arbitrarily designed if no constraint is imposed on the size of the dielectric lens However, the focus of this article is on the size minimization of the dome as required for applications where the form factor is critical Therefore, a lower boundary of the height of the dome is derived and imposed as a design constraint The antenna is analyzed using in-house ray tracing and physical optics software tools It is shown that, when the array is combined with the dielectric dome, a significant directivity enhancement can be achieved for wide scanning A demonstrator of the lens is designed, manufactured and combined with an available phased array working in $Ku$ -band The experimental tests confirm the theoretical predictions, validating the analysis tools, and show a scanning range of 70° in all scanning planes over a 15% bandwidth The directivity is enhanced by approximately 2 dB at the limits of the scanning range compared to the standalone illuminating array The active element pattern is rotationally symmetric, thus, the radiation performance is almost independent on the scanning plane Moreover, the dielectric lens allows to preserve the cross-polarization performance of the illuminating array without adding a significant contribution

Performance simulations for the ground-based, expanded-beam x-ray source BEaTriX

Abstract: The BEaTriX (Beam Expander Testing X-ray) facility, being completed at INAF-Brera Astronomical Observatory, will represent an important step in the acceptance roadmap of Silicon Pore Optics mirror modules, and so ensure the final angular resolution of the ATHENA X-ray telescope. Aiming at establishing the final angular resolution that can be reached and the respective fabrication/positioning tolerances, we have been dealing with a set of comprehensive optical simulations. Simulations based on wave optics were carried out to predict the collimation performances of the paraboloidal mirror, including the effect of surface errors obtained from metrology. Full-ray-tracing routines were subsequently employed to simulate the full beamline. Finally, wavefront propagation simulation allowed us assessing the sensitivity and the response of a wavefront sensor that will be utilized for the qualification of the collimated beam. We report the simulation results and the methodologies we adopted.

Breaking the mass-sheet degeneracy with gravitational wave interference in lensed events

Abstract: The mass-sheet degeneracy is a well-known problem in gravitational lensing that limits our capability to infer astrophysical lens properties or cosmological parameters from observations. As the number of gravitational wave observations grows, detecting lensed events will become more likely, and to assess how the mass-sheet degeneracy may affect them is crucial. Here, we study both analytically and numerically how the lensed waveforms are affected by the mass-sheet degeneracy, computing the amplification factor from the diffraction integral. In particular, we differentiate between the geometrical optics, wave optics, and interference regimes, focusing on ground-based gravitational waves detectors. In agreement with expectations of gravitational lensing of electromagnetic radiation, we confirm how, in the geometrical optics scenario, the mass-sheet degeneracy cannot be broken with only one lensed image. However, we find that in the interference regime, and, in part, in the wave-optics regime, the mass-sheet degeneracy can be broken with only one lensed waveform, thanks to the characteristic interference patterns of the signal. Finally, we quantify, through template matching, how well the mass-sheet degeneracy can be broken. We find that, within present GW detector sensitivities and considering signals as strong as those that have been detected so far, the mass-sheet degeneracy can lead to a $1\ensuremath{\sigma}$ uncertainty on the lens mass of $\ensuremath{\sim}12%$. With these values, the MSD might still be a problematic issue, but in case of signals with higher signal-to-noise ratio, the uncertainty can drop to $\ensuremath{\sim}2%$, which is less than the current indeterminacy achieved by dynamical mass measurements.

Edge diffraction, plasmon launching, and universal absorption enhancement in two-dimensional junctions

Abstract: Exact solutions to diffraction problems in wave optics are scarce though strongly demanded for accurate knowledge of electromagnetic fields in the immediate vicinity of scatterers. Here, we obtain and analyze an exact analytical solution for plane-wave diffraction at a lateral junction of two-dimensional (2D) conductors with dissimilar surface conductivities. We find that the junction near fields possesses a dipolelike radiative component and 2D surface-plasmon polaritons launched by the edge. We show that a junction between a perfect metal and an ohmic 2D conductor enhances the local absorbance, which is the ratio of absorbed power density and light intensity. It reaches a universal value of 200% near the 2D edge at normal incidence, independent of absorbance in the bulk. A junction between metal and a 2D conductor also acts as an efficient coupler between photons and 2D plasmons. Its amplitude conversion efficiency demonstrates an unbounded growth with increase in 2D impedance. Our results set the fundamental limits for field enhancement by edges and should change the strategies for design of subwavelength radiation detectors.

Improving Physical Optics Approximation Through Bessel Beam Scattering

Abstract: In this letter, the scattering of a nondiffractive Bessel beam (BB) incident field by a perfect electric conducting circular cylinder is investigated and compared with the standard scattering solution by a plane wave It is proven that the BB incident field improves the validity of standard physical optics approximation and possibly extends its range of applicability to cylinders, or more general scatterers, whose curvature radius is not much larger than the operating wavelength This offers new effective possibilities in the solutions of different electromagnetic scattering problems

On the integration of reconfigurable intelligent surfaces in real-world environments

Abstract: The use of reconfigurable intelligent surfaces (RISs) for optimization of propagation channels is one of the most promising and revolutionizing techniques for improving the efficiency of the next generation of communications systems. In this work, we combine the physical optics approximation and the theory of diffraction gratings to study the scattering properties of finite-size metasurfaces mounted on partially reflecting walls and illuminated by directive antennas. We consider both reflective and refractive metasurfaces designed to control both reflection and transmission of waves. We start the analysis under the assumption of uniform, plane-wave illumination, and then discuss non-uniform illuminations by directive antennas.

Fractional Schrödinger equation in gravitational optics

Abstract: This paper addresses issues surrounding the concept of fractional quantum mechanics, related to lights propagation in inhomogeneous nonlinear media, specifically restricted to a so-called gravitati...

Exact transformation optics by using electrostatics

Abstract: We present a novel method for designing transformation optical devices based on electrostatics. An arbitrary transformation of electrostatic field can lead to a new refractive index distribution, where wavefronts and energy flux lines correspond to equipotential surfaces and electrostatic flux lines, respectively. Owing to scalar wave propagating exactly following an eikonal equation, wave optics and geometric optics share the same solutions in the devices. The method is utilized to design multipole lenses derived from multipoles in electrostatics. The source and drain in optics are considered as corresponding to positive charge and negative charge in the static field. By defining winding numbers in virtual and physical spaces, we explain the reason for some multipole lenses with illusion effects. Besides, we introduce an equipotential absorber to replace the drain to correspond to a negative charge with a grounded conductor. Therefore, it is a very general platform to design intriguing devices based on the combination of electrostatics and transformation optics.

Coherent Fourier Optics Model for the Synthesis of Large Format Lens-Based Focal Plane Arrays

Abstract: Future sub millimeter imagers are being developed with large focal plane arrays (FPAs) of lenses to increase the field of view (FoV) and the imaging speed. A full-wave electromagnetic analysis of such arrays is numerically cumbersome and time-consuming. This article presents a spectral technique based on Fourier optics combined with geometrical optics for analyzing, in reception, lens-based FPAs with wide FoVs. The technique provides a numerically efficient methodology to derive the plane wave spectrum (PWS) of a secondary quasi-optical component. This PWS is used to calculate the power received by an antenna or absorber placed at the focal region of a lens. The method is applied to maximize the scanning performance of imagers with monolithically integrated lens feeds without employing an optimization algorithm. The derived PWS can be directly used to define the lens and feed properties. The synthesized FPA achieved scan losses much lower than the ones predicted by standard formulas for horn-based FPAs. In particular, an FPA with scan loss below 1 dB while scanning up to ±17.5° (~±44 beam-widths) is presented with directivity of 52 dBi complying with the needs for future sub millimeter imagers. The technique is validated via a physical optics code with excellent agreement.

Tailoring the light distribution of micro-LED displays with a compact compound parabolic concentrator and an engineered diffusor.

Abstract: We propose a novel optical design to tailor the angular distribution of a micro-LED (µLED) display system and use vehicle display as an example to illustrate the design principles. The display system consists of a µLED array with a tailored LED structure, a small formfactor compound parabolic concentrator (CPC) system, and a functional engineered diffusor. It provides high efficiency, high peak brightness, and small formfactor. In the design process, a mix-level optical simulation model, including the angular distribution of polarized emission dipole (dipole emission characteristics), Fabry-Perot cavity effect (wave optics), and light propagation process (ray optics), is established to analyze the angular distribution of µLEDs. Such an optical design process from dipole emission to display radiation pattern can be extended to other µLED display systems for different applications.

Hybrid PO-SBR-PTD method for composite scattering of a vehicle target on the ground.

Abstract: In this paper, a hybrid method of physical optics (PO) shooting and bouncing ray (SBR) physical theory of diffraction (PTD), is adopted to investigate the composite scattering of a vehicle target on the ground. Where the scattering of ground is calculated by the PO method, the scattering of the vehicle target is computed by the SBR-PTD method, and the mutual couplings between them are solved by the ray tracing technique. In addition, an octree data structure is used to accelerate the ray tracing progress. A forward-backward ray tracing technique is employed to ensure the accuracy of the illuminated facet identification. In numerical simulation, the monostatic and bistatic scattering of a reduced-scale vehicle target are calculated by the SBR-PTD method and compared with the simulation results with the multilevel fast multipole method (MLFMM) in commercial software FEKO. And the composite scattering from a reduced-scale vehicle target on the planar ground by our PO-SBR-PTD method is also compared with the MLFMM. The results show that our methods can greatly reduce the computational time and memory requirement while keeping a satisfactory accuracy. Finally, the composite scattering from the vehicle target on the rough ground is demonstrated and analyzed for different incident parameters.

Wave-optics simulation of dynamic speckle: II. In an image plane.

Abstract: This two-part paper demonstrates the use of wave-optics simulations to model the effects of dynamic speckle. In Part II, we formulate closed-form expressions for the analytical irradiance correlation coefficient, specifically in the image plane of an optical system. These expressions are for square, circular, and Gaussian limiting apertures and four different modes of extended-object motion, including in-plane and out-of-plane translation and rotation. Using a phase-screen approach, we then simulate the equivalent scattering from an optically rough extended object, where we assume that the surface heights are uniformly distributed and delta correlated from grid point to grid point. For comparison to the analytical irradiance correlation coefficient, we also calculate the numerical irradiance correlation coefficient from the dynamic speckle after propagation from the simulated object plane to the simulated image plane. Overall, the analytical and numerical results definitely demonstrate that, relative to theory, the dynamic speckle in the simulated image plane is properly correlated from one frame to the next. Such validated wave-optics simulations provide the framework needed to model more sophisticated setups and obtain accurate results for system-level studies.

Scattering Prediction of Target Above Layered Rough Surface Based on Time-Domain Ray Tracing Modeling

Abstract: In the past, most of the transient electromagnetic (EM) analyses focused on the scattering from the target. The transient scattering from rough surface was rarely studied, especially for the layered rough surface. When the target is above the rough surface, it needs to solve the composite transient scattering from the rough surface and the target above it. In this article, we mainly focus on the time-domain (TD) analysis for transient scattering from the target and layered rough surface based on time-domain ray tracing (TDRT) modeling. Applying geometrical optics (GO), the multiple bounces of the transient EM waves between layered rough surfaces and target are traced to obtain the incident field of the irradiated surfaces. Then considering the particularity of the layered rough surface, we modify TD Gordon integral and reduce the TD physical optics (TDPO) integral to closed-form expressions to improve the computing efficiency. To demonstrate the efficiency and accuracy of the proposed algorithm, the transient scattering simulations of the composite model involving target and layered rough surface are compared with frequency-domain ray tracing (FDRT) with inverse fast Fourier transform (IFFT), as well as the results obtained by the multilevel fast multipole algorithm (MLFMA) of FEKO in conjunction with IFFT (IFFT-MLFMA). The characteristics of transient scattering from the composite model are further studied to show the physical phenomenon of scattering mechanisms. Specifically, the transient scattering from the composite model for different parameters is simulated for sensitivity investigation of the transient scattering to the variations in the related parameters.

A Fast, Hybrid, Time-Domain Discontinuous Galerkin-Physical Optics Method for Composite Electromagnetic Scattering Analysis

Abstract: To accelerate the solution of transient electromagnetic scattering from composite scatters, a novel hybrid discontinuous Galerkin time domain (DGTD) and time-domain physical optics (TDPO) method is proposed. The DGTD method is used to solve the accurate scattering field of the multi-scale objects region, and a hybrid explicit-implicit time integration method is also used to improve the efficiency of multi-scale problems in the time domain. Meanwhile, the TDPO method is used to accelerate the speed of surface current integration in an electrically large region. In addition, the DGTDPO method considers the mutual coupling between two regions, and effectively reduces the number of numerical calculations for the other space of the composite target, thereby significantly reducing the computer memory consumption. Numerical results certified the high efficiency and accuracy of the hybrid DGTDPO. According to the results, in comparison with the DGTD algorithm in the entire computational domain, the DGTDPO method can reduce computing time and memory by 90% and 70% respectively. Meanwhile, the normalized root mean square deviation (NRMSD) of the time-domain, high-frequency approximation method is over 0.2, and that of the DGTDPO method is only 0.0971. That is, compared with the approximation methods, the hybrid method improves the accuracy by more than 64%.

Multiple slit interference: a hyperbola based analysis

Abstract: The textbook description of multiple slit interference employs a standard path difference formula that was originally calculated for the purpose of analyzing Young's double slit experiment. It was arrived at on the basis of a pair of assumptions that help simplify the geometry of the slit-barrier-screen arrangement and the ensuing formalism needed to estimate the positions of interference fringes on the detection screen. According to the conventional approach, convergent rays of light that emanate from different slits can be treated as effectively parallel in the far field limit. Such a parallel ray approximation-based analysis was shown by Thomas (2019; 2020) to be redundant, paradoxical and limited in precision. In this paper, the task of reformulation that began previously with the elementary 2-slit experiment is now extended to encompass the N-slit scenario, diffraction at a single-slit and the formation of circular fringes. In order to derive one of the key results (the generalized hyperbola theorem for N-point sources), a novel computational technique called Analytical Induction is introduced. The procedure involves a synthesis of concepts from Cartesian geometry and Discrete mathematics, namely coordinate transformation by Euclidean translation and a method of proof called the principle of mathematical induction, respectively. The final goal attained are two distribution functions that succinctly and precisely describe the variation of intensity of interference fringes on the distant screen, when it is oriented parallel and perpendicular relative to the line joining the sources. A comparison is then drawn between the predictions of the conventional and the new analyses by means of numerical-graphical simulation with MATLAB. The theoretical methods and results presented herein may have a significant bearing in areas of applied optics like interferometry, holography and spectroscopy. On the pedagogic front, it is suggested that the current geometrical program being visually more intuitive, be incorporated into the standard curriculum of an advanced undergraduate/graduate level course in physical optics, to complement the conventional approach.

Wave-optics simulation of dynamic speckle: I. In a pupil plane.

Abstract: This two-part paper demonstrates the use of wave-optics simulations to model the effects of dynamic speckle. In Part I, we formulate closed-form expressions for the analytical irradiance correlation coefficient, specifically in the pupil plane of an optical system. These expressions are for square, circular, and Gaussian scattering spots and four different modes of extended-object motion, including in-plane and out-of-plane translation and rotation. Using a phase-screen approach, we then simulate the equivalent scattering from an optically rough extended object, where we assume that the surface heights are uniformly distributed and delta correlated from grid point to grid point. For comparison to the analytical irradiance correlation coefficient, we also calculate the numerical irradiance correlation coefficient from the dynamic speckle after propagation from the simulated object plane to the simulated pupil plane. Overall, the analytical and numerical results definitely demonstrate that, relative to theory, the dynamic speckle in the simulated pupil plane is properly correlated from one frame to the next. Such validated wave-optics simulations provide the framework needed to model more sophisticated setups and obtain accurate results for system-level studies.

The Simons Observatory: modeling optical systematics in the Large Aperture Telescope.

Abstract: We present geometrical and physical optics simulation results for the Simons Observatory Large Aperture Telescope. This work was developed as part of the general design process for the telescope, allowing us to evaluate the impact of various design choices on performance metrics and potential systematic effects. The primary goal of the simulations was to evaluate the final design of the reflectors and the cold optics that are now being built. We describe nonsequential ray tracing used to inform the design of the cold optics, including absorbers internal to each optics tube. We discuss ray tracing simulations of the telescope structure that allow us to determine geometries that minimize detector loading and mitigate spurious near-field effects that have not been resolved by the internal baffling. We also describe physical optics simulations, performed over a range of frequencies and field locations, that produce estimates of monochromatic far-field beam patterns, which in turn are used to gauge general optical performance. Finally, we describe simulations that shed light on beam sidelobes from panel gap diffraction.

Mode expansion theory and application in step-index multimode fibers for astronomical spectroscopy

Abstract: In astronomical spectroscopy, optical fibers are abundantly used for multiplexing and decoupling the spectrograph from the telescope to provide stability in a controlled environment. However, fibers are less than perfect optical components and introduce complex effects that diminish the overall throughput, efficiency, and stability of the instrument. We present a novel numerical field propagation model that emulates the effects of modal noise, scrambling, and focal ratio degradation with a rigorous treatment of wave optics. We demonstrate that the simulation of the near- and far-field output of a fiber, injected into a ray-tracing model of the spectrograph, allows us to assess performance at the detector level.

Topological polarization singularities in metaphotonics

Abstract: Polarization singularities of vectorial electromagnetic fields locate at the positions (such as points, lines, or surfaces) where properties of polarization ellipses are not defined. They are manifested as circular and linear polarization, for which respectively the semi-major axes and normal vectors of polarization ellipses become indefinite. First observed in conical diffraction in the 1830s, the field of polarization singularities has been systematically reshaped and deepened by many pioneers of wave optics. Together with other exotic phenomena such as non-Hermiticity and topology, polarization singularities have been introduced into the vibrant field of nanophotonics, rendering unprecedented flexibilities for manipulations of light-matter interactions at the nanoscale. Here we review the recent results on the generation and observation of polarization singularities in metaphotonics. We start with the discussion of polarization singularities in the Mie theory, where both electric and magnetic multipoles are explored from perspectives of local and global polarization properties. We then proceed with the discussion of various photonic-crystal structures, for which both near- and far-field patterns manifest diverse polarization singularities characterized by the integer Poincare or more general half-integer Hopf indices (topological charges). Next, we review the most recent studies of conversions from polarization to phase singularities in scalar wave optics, demonstrating how bound states in the continuum can be exploited to generate directly optical vortices of various charges. Throughout our paper, we discuss and highlight several fundamental concepts and demonstrate their close connections and special links to metaphotonics. We believe polarization singularities can provide novel perspectives for light-matter manipulation for both fundamental studies and their practical applications.

High performance integral imaging 3D display using quarter-overlapped microlens arrays

Abstract: A scheme of quarter-overlapped microlens arrays (QOMLA) is proposed to improve the display performance of integral imaging (II). The theory and the design of QOMLA is presented by the combination of geometric optics and wave optics and is verified by the optical experiments. The angular sampling density of the II system can be doubled in each dimension to further increase the spatial resolution. Multiple central depth planes can be constructed by adjusting the spacing of the multilayers, so as to expand the depth of field (DoF). Furthermore, QOMLA is easier to process when compared with the single-layer microlens array, and it reduces processing costs.

Defocus-induced phase contrast enhancement in pattern illumination time-resolved phase microscopy

Abstract: Photo-excited charge carrier dynamics in photocatalytic materials with rough surfaces have been studied via measurements using pattern-illumination time-resolved phase microscopy. Optimal defocusing is necessary for the phase-contrast detection of the refractive index change due to the photo-excited charge carriers. The signal enhancement of the phase-change was explained theoretically and experimentally. The optical phase variation due to the transmission of a rough surface is coupled with the quadratic phase term in Fresnel diffraction, and a slight defocusing can convert the phase image to the corresponding amplitude image. The phase-contrast image due to the photo-excited charge carriers is also enhanced by the defocusing. The explanation was supported by wave optics calculation, and the enhancement was demonstrated for two types of TiO2 substrates with different roughnesses.

Scattering of Toroidal Waves by Semitransparent Reflectors of Revolution in Application to Omnidirectional Antennas

Abstract: Problems of radiation pattern synthesis, sidelobe suppression, or back radiation suppression appear when using antennas with reflectors or ground planes The use of a semitransparent surface allows the required shape of a radiation pattern to be synthesized efficiently through the variation of reflection and transmission coefficients Effective radiation pattern synthesis is possible when using analytical formulas designed for the radiation patterns of antennas with semitransparent reflectors In this article, we present a model for the scattering of a toroidal wave of a general form by means of a semitransparent reflector of revolution The model allowed us to simulate the radiation patterns of various kinds of axisymmetric antennas with semitransparent reflectors and ground planes Two asymptotic expansions of the radiation pattern of the model were found in the physical optics approximation The expansions allow the radiation pattern for the entire space to be determined As an example of its application, we used the model to calculate the radiation patterns of a plane with Archimedean two-wire spiral antenna and a loop antenna above concave and convex reflectors, as well as an Archimedean slot spiral antenna with a ground plane We synthesized the optimal profiles of perfectly conducting and semitransparent reflectors and ground planes to improve the front-to-back ratio of the antennas

A generic framework for physical light transport

Abstract: Physically accurate rendering often calls for taking the wave nature of light into consideration. In computer graphics, this is done almost exclusively locally, i.e. on a micrometre scale where the diffractive phenomena arise. However, the statistical properties of light, that dictate its coherence characteristics and its capacity to give rise to wave interference effects, evolve globally: these properties change on, e.g., interaction with a surface, diffusion by participating media and simply by propagation. In this paper, we derive the first global light transport framework that is able to account for these properties of light and, therefore, is fully consistent with Maxwell's electromagnetic theory. We show that our framework is a generalization of the classical, radiometry-based light transport---prominent in computer graphics---and retains some of its attractive properties. Finally, as a proof of concept, we apply the presented framework to a few practical problems in rendering and validate against well-studied methods in optics.

The UAPO Solution for the Plane Wave Diffraction by a Resistive Half-Plane in the Case of Skew Incidence

Abstract: The extension of the Uniform Asymptotic Physical Optics approach to the three-dimensional diffraction problem involving a resistive half-plane is presented in this work. The resistive boundary conditions in correspondence of the screen are used to determine the reflection and transmission coefficients for both the polarizations and then the Geometrical Optics field around the structure. This enables the formulation of the electric and magnetic equivalent surface currents to be considered as radiating sources in the approach for the evaluation of the diffracted field. The ability of this contribution to compensate the jumps of the Geometrical Optics field is proved by means of numerical tests.

Uniform Ray Description of Physical Optics Scattering by Finite Locally Periodic Metasurfaces

Abstract: This paper presents a uniform ray description of electromagnetic wave scattering by locally periodic metasurfaces of polygonal shape. The model is derived by asymptotically evaluating the critical-point contributions of a physical optics scattering integral. It is valid for metasurfaces whose bulk scattering coefficients are periodic functions of a phase parameter which, in turn, is a continuous and smooth function of surface coordinates. The scattered field is expressed in terms of reflected, transmitted and diffracted rays that do not generally obey conventional geometrical constraints (i.e., Snell’s law and the Keller cone). An iterative technique is presented to determine the locations of critical points on one or multiple interacting metasurfaces. Numerical results demonstrating the utility and accuracy of the asymptotic physical optics model are also provided.

Circular Mesh-Based Physical Optics for Scattered Field Prediction

Abstract: In this letter, a physical optics (PO)-based scattered field calculation method is introduced. The proposed method divides the object into circular meshes. This technique exploited the analytical solution of scattered fields from circular plates to make it compatible with the PO surface integral framework. Therefore, it has no need for triangular-based surface reconstruction. The proposed method is compared to that of the PO with triangular mesh in terms of scattered electric power from a square plate and a spherical object. Given the averaged resolution of surface point at 0.04 of the wavelength, the proposed method yielded almost identical scattered power to those from the PO using triangular mesh.

Propagation of nonuniformly correlated Bessel beams in the air–sea turbulent link

Abstract: Nonuniformly correlated Bessel beams (NUCBs) have arbitrarily designed coherence distribution in the radial direction, which, coupled with the intrinsic nondiffraction characteristic of the Bessel amplitude, is supposed to exhibit improved reception quality in turbulent links. In this paper, the performance of NUCBs propagating through a special type of turbulent link, namely, the air–sea link, is analyzed. By means of wave optics simulation, the calculation of propagation properties such as aperture-averaged scintillation and the mean SNR of the NUCBs is conducted. Moreover, a comparative study between the nonuniformly and uniformly correlated Bessel beams (UCBs) is carried out.

Performance Evaluation of Automotive Radar in The Presence of Bumper with Multiple Paint Layers Using Bidirectional Loss Model

Abstract: In this paper, we propose a mathematical model to compute the bi-directional loss of an automotive radar in the presence of a bumper with multi-layered paint. The proposed model uses a physical optics (PO) based approximation for the reflective and dielectric losses. The model takes into account the shape of the bumper and compares it with a proprietary algorithm. The model is applied on a six-element microstrip array antenna placed behind a curved bumper, with and without the presence of multiple paint layers. The bidirectional loss, in the broad-side direction, as obtained from the model is 4.6 dB due to the presence of the bumper with a single paint layer and 8.8 dB when the number of paint layers is five.