Symmetric Design Research Articles

Long-Range Proton Channels Constructed via Hierarchical Peptide Self-Assembly.

The quest to understand and mimic proton translocation mechanisms in natural channels has driven the development of peptide-based artificial channels facilitating efficient proton transport across nanometric membranes. It is demonstrated here that hierarchical peptide self-assembly can form micrometers-long proton nanochannels. The fourfold symmetrical peptide design leverages intermolecular aromatic interactions to align self-assembled cyclic peptide nanotubes, creating hydrophilic nanochannels between them. Titratable amino acid sidechains are positioned adjacent to each other within the channels, enabling the formation of hydrogen-bonded chains upon hydration, and facilitating efficient proton transport. Moreover, these chains are enriched with protons and water molecules by interacting with immobile counter ions introduced into the channels, increasing proton flow density and rate. This system maintains proton transfer rates closely resembling those in natural protein channels over micrometer distances. The functional behavior of these inherently recyclable and biocompatible systems opens the door for their exploitation in diverse applications in energy storage and conversion, biomedicine, and bioelectronics.

Enhanced edge - intrude triangle metamaterial absorber with polarization insensitivity for S, C, X and Ku band applications

This paper presents a novel metamaterial absorber designed to function effectively across the S, C, X, and Ku frequency bands (2–18 GHz). The unit cell of the metamaterial absorber is derived from an edge-intruded triangular structure, exhibiting multiple resonances. It is thoughtfully designed to achieve fourfold symmetry, ensuring polarization insensitivity. The proposed structure, fabricated on an FR4 substrate with a metallic ground plane, demonstrates exceptional absorption peaks at 2.5 GHz (97%), 3.4 GHz (96.5%), 5.2 GHz (99%), 9.07 GHz (98.8%), 12 GHz (98.1%), 13.66 GHz (89.1%), and 16 GHz (98.9%). The absorber’s four-fold symmetric design ensures polarization insensitivity, while its ultra-thin profile (0.013λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\lambda$$\\end{document}) offers several practical benefits. By harnessing the unique properties of near-zero refractive index (NZRI) metamaterials, this absorber has the capability for precise control over electromagnetic waves. Its outstanding performance and versatility position it as a strong candidate for applications such as wavefront shaping, beam steering, sensing, and electromagnetic cloaking.

Generating Bent Functions and Dynamic Filters: A Novel Equivalence-Based Approach

Boolean functions are fundamental building blocks in both discrete mathematics and computer science, with applications spanning from cryptography to coding theory. Bent functions, a subset of Boolean functions with maximal nonlinearity, are particularly valuable in cryptographic applications. This study introduces a novel equivalence relation among all Boolean functions and presents an algorithm to generate bent functions based on this relation. We systematically generated a collection of 10,000 bent functions over eight variables, all originating from the same equivalence class, and analyzed their structural complexity through rank determination. Our findings revealed the presence of at least five distinct affine classes of bent functions within this collection. By employing this construction, we devised an algorithm to generate a filter function capable of combining Boolean functions. This filter function can be dynamically adjusted based on a key, offering potential applications in symmetric cipher design, such as enhancing security or improving efficiency.

Ultra-broadband absorber and perfect thermal emitter for high-efficiency solar energy absorption and conversion

This study proposes a pyramid-shaped solar absorber designed with multi-layered Ti-SiO2 ring stacked. The structure achieves an average absorption efficiency of 98.03 % over the range of 280–4000 nm, and under AM1.5 spectral conditions, the weighted average absorption efficiency reaches 97.66 %, the bandwidth with an absorption efficiency greater than 90 % reaches 3750 nm. To explore the reason for achieving ultra-broadband absorption with this structure, the electromagnetic field distribution at three absorption peaks was calculated. The results revealed that the resonance between the polarization direction of the three-layer circular ring stacked structure and the plasmon resonance at the junction of Ti and SiO2 contribute to the model's capability for ultra-broadband high-efficiency absorption. At the same time, the thermal emissivity of the structure was calculated at high temperatures of 1000 K and 2000 K, both exceeding 97 %. Furthermore, due to the fully symmetrical design, the absorber is polarization-independent. It was found through calculations that whether in TM mode or TE mode, as the incident angle varies from 0° to 60°, the average absorption efficiency of the absorber changes only by 11.16 %, thereby verifying the structure's excellent insensitivity to incident light angles. In summary, all these characteristics indicate that the model has excellent application prospects in fields such as solar energy collection and photothermal conversion.

Semantic segmentation of optical satellite images for the illegal construction detection using transfer learning

As urban populations grow, the demand for new infrastructure intensifies. However, some builders often neglect to obtain necessary permits, resulting in unstable structures that endanger public safety and disrupt city planning. Illegal construction poses significant challenges to economic development and social harmony. To tackle this issue, there is an urgent need for an automated illegal building monitoring system that can accurately identify and notify authorities about unlawful constructions. Current methods are often inefficient due to limited data access, inadequate analysis, and lack of automation.Recent technological advancements suggest that using satellite imagery alongside semantic segmentation is a highly effective approach for detecting illegal buildings. This process not only ensures the safety and compliance of structures but also enhances overall regulatory enforcement. This research distinguishes itself from previous studies by primarily focusing on illegal construction. It employs a diverse range of machine learning models, including the U-Shaped Network and Visual Geometry Group, and incorporates customized evaluation metrics that are not typically found in earlier research. Additionally, it utilizes real-world data, enhancing its practical relevance, and features IoT integration for real-time monitoring capabilities.We chose U-Net as our architecture due to its symmetrical design, which facilitates effective feature extraction. Its skip connections play a crucial role in preserving important features during the segmentation process. U-Net is known for its high accuracy and adaptability across various domains, making it versatile for our needs. Additionally, it performs well even with limited data, demonstrating robustness in diverse conditions. Furthermore, its compatibility with transfer learning enhances its applicability. For all these reasons, U-Net was selected as our model.Our experiments revealed that the Unet_mini model outperformed all others, demonstrating its effectiveness in addressing illegal construction challenges in urban areas. Qualitative results further illustrate the model's robustness, showing a significant reduction in false positives and improved accuracy in identifying illegal structures. This comprehensive approach not only improves detection rates but also contributes to more efficient regulatory enforcement, thereby promoting safer urban environments.This research distinguishes itself from previous studies by primarily focusing on illegal construction detection rather than general segmentation tasks. It employs a diverse range of machine learning models, including the U-Shaped Network and Visual Geometry Group, and integrates customized evaluation metrics that are not typically found in earlier research. Furthermore, it utilizes real-world data, enhancing its practical relevance, and incorporates IoT integration for real-time monitoring capabilities, setting it apart from existing studies.

Revisiting the shuffle of generalized Feistel structure

The Generalized Feistel Structure (GFS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{GFS}$$\\end{document}) is one of the most widely used frameworks in symmetric cipher design. In FES 2010, Suzaki and Minematsu strengthened the cryptanalysis security of GFS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{GFS}$$\\end{document} by searching for shuffles with the best diffusion property. In ASIACRYPT 2018, Shi et al. suggested a set of shuffles, which makes GFS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{GFS}$$\\end{document} a better resistance against Demirci–Selcuk meet-in-the-middle cryptanalysis. Since these shuffles are different from the currently known good ones and also different from the shuffles used in TWINE\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{TWINE}$$\\end{document} and LBlock\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{LBlock}$$\\end{document}, our research focuses on a more comprehensive evaluation of GFS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{GFS}$$\\end{document} with different shuffles, including diffusion property of shuffle, differential, linear, impossible differential, zero-correlation linear, integral and Demirci–Selcuk meet-in-the-middle cryptanalysis, to find the best one. Such evaluations entail significant time consumption. Thus, we utilize Mixed Integral Linear Programming models and introduce an evaluate-and-filter strategy to achieve it efficiently. Our results verify that the shuffles discovered by Suzaki and Minematsu and those used in TWINE\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{TWINE}$$\\end{document} and LBlock\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{LBlock}$$\\end{document} are the best so far. We also find that the cryptanalysis resistances of GFS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ exttt{GFS}$$\\end{document} are not necessarily consistent. It is this finding that makes the necessity of our more comprehensive evaluation self-evident.

Tunable Graphene‐Based Absorber Using Nanoscale Grooved Metal Film at Telecommunication Wavelengths

Graphene‐based absorbers have various modern applications across industries due to their exceptional properties. Some common applications include: thermal management and energy storage. Herein, the design and simulation of a broadband tunable absorber based on graphene with perfect absorption spectra in the near‐infrared region are reported. The proposed structure consists of an MgF2 layer and golden disc surrounded by L‐shaped golden arms placed on single layer of graphene. The structure guarantees polarization‐insensitive (PI) performance under normal incident due to the symmetrical design. The investigation of the PI of the structure reveals almost similar absorption for oblique incident angles up to 55° for TM and up to 60° for TE polarization. The desirable resonance wavelength is achievable by tuning the geometrical parameters. By changing the chemical potential of graphene, the absorption and bandwidth of absorber are controllable. A full width at half maximum of 330 nm is another superiority of this absorber. These considerable aspects of the proposed structure make it practical for varieties of applications such as cloaking, sensing, switching, and so on.

Study the variation of the pitching frequency of sounding rockets

Sounding rockets typically feature an axially symmetric design and are launched vertically to facilitate research and high-altitude atmospheric data collection. Manufacturing errors can cause axial asymmetry, leading to undesirable rocket trajectory dispersion. Sounding rockets are often designed to spin around their axis to mitigate these effects. However, axial spinning motion can resonate with short-period oscillations, creating large normal loads that may damage the rocket’s structures. This paper focuses on analyzing the variations in the pitching frequency, which may help predict the roll resonance phenomenon. In this study, the authors constructed a six-degree-of-freedom dynamic model for a sounding rocket, considering all aerodynamic problems and the variation of inertial characteristics. To determine the pitching frequency, an impulse is applied to the rocket to generate short-period oscillation. The Fourier transform is then used to analyze and obtain the frequency of the rocket while oscillating in space. The results demonstrate agreement with the theoretical model, thereby substantiating the validity of the current method. The findings of this research provide valuable recommendations for the design and manufacturing process of sounding rockets, which may help mitigate the adverse effects of motion resonance during flight.

Deep neural network-enabled dual-functional wideband absorbers

The increasing interest in switchable and tunable wideband perfect absorbers for applications such as modulation, energy harvesting, and spectroscopy has significantly driven research efforts. In this study, we present a dual-function terahertz (THz) metamaterial absorber supported by deep neural networks (DNN). This absorber achieves dual-wideband perfect absorption through the use of graphene and vanadium dioxide (VO₂), enabling both switching and tuning functionalities. Simulation results show that, in the insulating phase of VO₂, a high-frequency wideband absorption ranging from 9.31 to 9.77 THz is achieved, with an absorption rate exceeding 90%. In contrast, in the metallic phase of VO₂, a full-band wideband absorption above 90% is observed from 8.44 to 9.75 THz. The corresponding fractional bandwidths are 61.3% and 174.6%, respectively. Additionally, electrical tuning of graphene’s Fermi level from 0.01 to 1 eV enables continuous modulation of absorption intensity between 48 and 100%. The absorber also exhibits polarization insensitivity to TE and TM waves due to its symmetric design and broad incidence angle. This design holds significant potential for various THz applications, including switching, electromagnetic shielding, stealth technology, filtering, and sensing.

Bandgap formation mechanism in tacticity inspired elastic mechanical metastructures

Tacticity is long known as a significant contributor in changing the chemical and mechanical properties of the polymers drastically. This study explores mechanism of bandgap formation in elastic mechanical metastructures designed with a focus on tacticity. We introduce metabeams, comprising a primary slender beam embedded with short secondary beams featuring end masses at their tips. The investigation delves into the numerically simulated vibration characteristics of metabeams using finite element analysis, with a subsequent comparison to experimental results for fabricated metabeams. Employing a unit-cell design approach that manipulates spatial and physical parameters, we explore a wide range of uniform and non-uniform metabeam configurations based on the distance between secondary beams and distribution of local resonators as per tacticity. Hence, drawing inspiration from tacticity, we extend our investigation to isotactic and syndiotactic metabeams, altering physical parameters (mass) within the unit cell for both configurations. The strategic distribution of end masses on attached secondary beams introduces unique characteristics to isotactic and syndiotactic metabeams, allowing for the modulation of bandgaps without altering the natural frequencies of the resonators in symmetric and anti-symmetric metabeam designs. Our research demonstrates, incorporating tacticity in metabeam design offers a novel and unconventional approach to modulate the bandgap formation mechanism.

Flag-transitive point-primitive symmetric 2-designs of prime square order

Flag-transitive point-primitive symmetric 2-designs of prime square order

Far field ring beam generation based on 3-bit encoded metasurface

Abstract The encoding metasurface establishes a bridge between the physical and digital worlds, ushering in a new era of manipulating electromagnetic waves and realizing programmable metamaterials through digital coding sequences. This "digital metasurface," relying on binary logic, significantly simplifies the design process, thereby enhancing the flexibility and efficiency of controlling electromagnetic waves. While most encoding metasurfaces control beamforming for pencil-shaped beams, we propose a 3-bit encoding metasurface with a "well structure" in the microwave band.The 3-bit encoding metasurface features a more extensive encoding sequence, offering increased degrees of freedom and flexibility in manipulating the direction of electromagnetic wave propagation. Its symmetric design features polarization-insensitive characteristics, suitable for generating annular beams by varying gradient-encoded numbers radially. This approach enables the production of linearly polarized omnidirectional radiation within the desired elevation angle range. Additionally, adjustments in quantity and orientation of the produced annular beams are achieved through Fourier convolution theorem. This type of annular beams holds promise for applications in various fields, including wireless radio broadcasting and wireless local area networks.

Design of Docking Interfaces for On-Orbit Assembly of Large Structures in Space

Considering the complexity of on-orbit assembly during space missions and the super-large size of space structures, this paper presents the design for a new type of docking interface with an androgynous body that exhibits a number of advantages, including high connection strength and a compact structure. The androgynous body has a conical guided symmetric design with a symmetry of 90°. The geometric design of the docking surface is described in detail in order to prove its advantages. Structural design was carried out using UG modeling as well as dynamic simulation using Recur Dyn to obtain the displacement coordinate curves of the docking port. The geometry of the docking port’s high docking misalignment tolerance was verified, and misalignment tolerance and lens splicing experiments were also performed. The docking port’s ability to be quickly connected or disconnected within a translation tolerance of 23.5 mm and a tilt tolerance of 24° was verified. This article provides a useful reference for space missions in terms of module docking and on-orbit assembly.

A Six‐Axis Asymmetric Parallel Manipulator Co‐Driven by Direct‐Drive and Geared Motors for Enhanced Force‐Sensing Capability

This article introduces a novel six‐axis parallel manipulator co‐driven by motors with and without geared reducers. The design leverages the high stiffness provided by the geared motors and the high force‐sensing capability of the direct drives. When the geared motors move synchronously with their direct‐drive counterparts, the manipulator mimics a Delta robot's spatial translation, while the direct drives double as high‐performance force sensors. An asymmetric design of the manipulator is proposed to allocate a larger portion of torque to the geared motors, raising the overall stiffness of the mechanism. Relations between the external force to the driving torque are derived and the torque redistribution effect of the asymmetric design is illustrated numerically. Experimental results on prototypes of both the symmetric design and the asymmetric design show that direct drives consistently exhibit much higher linearity in the force‐to‐torque relationship compared to the geared drives, and also confirm that asymmetric design alleviates the torque burden on the direct drives. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Symmetric and asymmetric ceramic-supported polyelectrolyte multilayer nanofiltration membranes

Polyelectrolyte multilayer based nanofiltration membranes can remove organic micropollutants from water. Such polyelectrolyte multilayer membranes (PEMMs) are often assembled on polymeric supports, but less research focuses on inorganic (ceramic) supports. In this work, we assembled symmetric and asymmetric, coatings of poly(allylamine (PAH) and poly(styrene sulfonate) (PSS) on ceramic supports. Symmetric membranes are assembled with the same salt concentration in the coating solution for each layer. Asymmetric membranes use very permeable layers (high salt concentration in coating solution) as base layers and dense top layers with lower permeability (low salt concentration in coating solution) as filtration layers. By reversing the coating order – first salt-free and after that high salt concentration, we obtained reverse asymmetric membranes. They consistently outperformed the symmetric and standard asymmetric design in removing organic micropollutants, reaching an average retention of 85 ± 13 % compared to 77 ± 14 % for the standard asymmetric membranes. We attribute this higher retention to a more efficient pore overcoating for the reverse asymmetric membranes. This work demonstrates that ceramic supports combined with reverse asymmetric PEMMs can be efficiently used for micropollutant removal from water.

Metasurface‐based circularly polarised antenna: Enhanced bandwidth with characteristic mode analysis and symmetric branch design

AbstractA low‐profile circularly polarised (CP) metasurface antenna is proposed, utilising characteristic mode analysis (CMA). The antenna design features a two‐layer laminated substrate, a 4×4 Butterfly‐shaped metasurface, a rectangular slot, an irregular transmission line, and a ground plane. The metasurface is analysed using mode significance (MS), characteristic angle (CA), and characteristic current to determine the resonance bandwidth and CA resonance points, which exhibit a near 90° difference. At the intersection of the two MS modes, their CAs differ by nearly 90°, and their far‐field radiation directions align, indicating the potential for achieving circular polarisation at the desired frequency. The integration of the metasurface with the slot antenna is simulated to validate the CMA findings. Additionally, the CP bandwidth is enhanced by modifying the transmission line branches. Measurement of the fabricated antenna reveals an impedance bandwidth (IBW) of 27.4%, a 3‐dB axial ratio bandwidth (ARBW) of 10.1%, and a peak gain of 6.9 dBic at 4.4 GHz. Compared to the design without branches, IBW and ARBW have increased by 10% and 7.3%, respectively.

Symmetrical Transformer Design for Suppressing Even-Order Components in CM Noise Applied to Converter With Fixed-Frequency PWM Strategy

Symmetrical Transformer Design for Suppressing Even-Order Components in CM Noise Applied to Converter With Fixed-Frequency PWM Strategy

DOES CRUCIATE LIGAMENT SUBSTITUTION AND IMPLANT ASYMMETRY MAKE A DIFFERENCE FOR TOTAL KNEE ARTHROPLASTY KINEMATICS? A MULTI-IMPLANT EVALUATION

The non-implanted knee differs in comparison to total knee arthroplasty (TKA) designs, with regard to asymmetry and functionality of the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). While surgeons may choose to implant either posterior stabilized (PS) or bi-cruciate stabilized (BCS) TKAs, substituting for one or both cruciate ligaments, the effects of symmetry versus asymmetry in substituting TKA designs have not been widely analyzed to determine possible benefits. Therefore, the objective of this research study was to determine if either TKA asymmetry and/or anterior ligament stabilization can lead to more normal-like kinematics and clinical benefit for patients. In vivo, femoro-tibial kinematics for 64 subjects were evaluated in this retrospective study. Overall, ten subjects had a normal, non-implanted knee, 20 had a BCS TKA, and 34 had one of two different PS TKAs. All three TKAs had varying degrees of symmetry incorporated into the design, and all were implanted by the same surgeon and were analyzed using fluoroscopy during a deep knee bend. At full extension, the BCS TKA subjects demonstrated a statistically more anterior position of both condyles compared to both PS TKAs. The BCS TKA subjects also experienced more posterior femoral rollback and axial rotation in early flexion and from full extension to maximum knee flexion. Additionally, the TKAs in this study having asymmetry experienced greater amounts of posterior femoral rollback and weight-bearing knee flexion. The results from this study indicated that in early flexion, the anterior cam/post mechanism does pull the femoral component more anterior, and all TKAs experienced posterior femoral rollback when the posterior cam engaged the post. The asymmetric designs also achieved greater rollback and axial rotation compared to the symmetric designs.

Enhancing safety in narrow-band transformerless PLC couplers with a passive symmetrical filter

As the demand for efficient data transmission over existing power infrastructure grows, power-line communication (PLC) systems have become increasingly vital. However, integrating communication signals with high-voltage power lines poses significant safety challenges, emphasizing the need for reliable, safe, and high-performance components. To address cost and safety concerns, this article introduces a symmetrical third-order band-pass filter design that employs a transformerless coupler, avoiding the expense and bulk of traditional transformers while enhancing both equipment and human safety in narrow-band PLC systems. The design, functionality, and safety considerations are discussed, with a focus on implementing a passive analog Butterworth filter, chosen for its flat frequency response in the passband. Additionally, we address the safety aspects of transformerless couplers in PLC applications, emphasizing their reliability and efficiency in maintaining signal integrity while minimizing the risks associated with high-voltage environments. Simulations validated the proposed design, confirming its effectiveness in achieving the desired frequency response. The design is cost-effective due to the elimination of the transformer and ensures safety through the strategic rearrangement of the coupler components, which isolates the power line from the communication side.

Designs in finite classical polar spaces

AbstractCombinatorial designs have been studied for nearly 200 years. 50 years ago, Cameron, Delsarte, and Ray-Chaudhury started investigating their q-analogs, also known as subspace designs or designs over finite fields. Designs can be defined analogously in finite classical polar spaces, too. The definition includes the m-regular systems from projective geometry as the special case where the blocks are generators of the polar space. The first nontrivial such designs for $$t > 1$$ t > 1 were found by De Bruyn and Vanhove in 2012, and some more designs appeared recently in the PhD thesis of Lansdown. In this article, we investigate the theory of classical and subspace designs for applicability to designs in polar spaces, explicitly allowing arbitrary block dimensions. In this way, we obtain divisibility conditions on the parameters, derived and residual designs, intersection numbers and an analog of Fisher’s inequality. We classify the parameters of symmetric designs. Furthermore, we conduct a computer search to construct designs of strength $$t=2$$ t = 2 , resulting in designs for more than 140 previously unknown parameter sets in various classical polar spaces over $$\mathbb {F}_2$$ F 2 and $$\mathbb {F}_3$$ F 3 .