PIER | PIER Journals

2026-06-30

PIER

Vol. 185, 125-135, 2026

doi:10.2528/PIER26031209

download: 152

Comprehensive Design Method of High-Performance Energy-Selective Structure Based on Stacked Slotline

Huan Jiang, Yanlin Xu, Tao Tian, Bowen Deng, Hao Ding and Peiguo Liu

This paper presents a high-performance energy-selective structure (ESS) design methodology based on a stacked slotline. By leveraging the unique characteristics of three-dimensional stacked structures, the method efficiently converts spatial waves into guided waves in slotline transmission lines, which can be tailored via lumped-circuit design to achieve precise energy-selective functionality. The proposed design approach systematically extends previous work by providing a clear theoretical foundation for decoupling and independently optimizing multiple ESS performance indicators. This allows the design of structures with flexibly selectable frequency bands and high shielding efficiency. Two prototypes were fabricated to validate the method. Prototype I targets bandwidth expansion, achieving an operational range from 2.2 to 8.2 GHz (115.4% relative bandwidth), with less than 1 dB insertion loss and over 10 dB shielding effectiveness across the band. Prototype II emphasizes shielding performance, reaching a shielding efficiency greater than 33 dB between 3.9 and 6.3 GHz, with a maximum of 40.3 dB. Both prototypes were fabricated and validated through experimental measurements, showing agreement with the simulation results. The performance of the two designed structures far exceeds other existing ESSs in terms of broadband or high shielding efficiency, indicating that the comprehensive design method has great potential to significantly improve the design of targeted technical specifications.

Comprehensive Design Method of High-Performance Energy-Selective Structure Based on Stacked Slotline

2026-06-27

PIER

Vol. 185, 118-124, 2026

doi:10.2528/PIER26020911

download: 155

Accelerating Field Decay Along Nonlocal Metasurfaces by Suppressing the Norton Wave

Alexander Zhuravlev, Dmitry Tatarnikov, Yury Kurenkov and Stanislav B. Glybovski

Investigations into the nature of electromagnetic fields produced by dipole sources over homogeneous flat ground or impedance surfaces date back many years. In general, at a long distance r from the source, the near-surface field is mostly contributed by the geometrical optics term (describing the radiation pattern), a guided wave, and the higher-order reactive contribution referred to as the Norton wave. In the special case of a perfect magnetic conductor interface, the first two terms vanish, so the residual Norton wave determines the steepest achievable field decay profile of r^-3/2 (for a two-dimensional horizontal magnetic dipole). In this letter, we reveal that in the presence of a nonlocal metasurface described by the second-order impedance boundary condition, the field decay can be further accelerated by suppressing the Norton wave (approaching the profiles r^-5/2 and r^-7/2 for electric and magnetic fields, respectively). In a proposed practical realization of a nonlocal metasurface, the effect is numerically verified and shown to reduce the edge diffraction effects by 10 dB for the shield diameter of only one wavelength, paving the way toward compact antenna systems.

Accelerating Field Decay Along Nonlocal Metasurfaces by Suppressing the Norton Wave

2026-05-14

PIER

Vol. 185, 97-109, 2026

doi:10.2528/PIER26021001

download: 330

Hybrid Genetic Optimization of Metasurfaces for Scattering Control: X-Band Design and Experimental Validation

Sandro Marzullo, Ilaria Marasco, Antonella D'Orazio and Giovanni Magno

The design of large-scale coding metasurfaces poses significant computational challenges, often limited by the prohibitive time required for full-wave simulations necessary for optimization. This paper proposes an efficient design strategy based on a Hybrid Genetic Algorithm, validated through the design, fabrication, and characterization of an X-band metasurface for Radar Cross Section reduction. The proposed design strategy relies on a two-stage optimization process: a fast pre-optimization phase, based on the analytical Huygens-Fresnel principle, generates a preliminary solution which is subsequently refined by a second optimization stage utilizing full-wave simulations. Specifically, the optimization targets a 1-bit coding scheme, where meta-atoms switch between two distinct states with a phase difference of 180 ± 37°. This hybrid approach demonstrates optimal convergence, reducing computational time by 25% compared to traditional full-wave-only techniques. Furthermore, a novel ``spiralling cross'' unit cell topology is introduced. Owing to its delay-line geometry, this structure provides additional degrees of freedom for spectral tuning and supports intermediate phase shifts, thus enabling encoding schemes beyond traditional 1-bit configurations. Experimental results confirm the validity of the proposed approach, demonstrating how the combination of versatile geometry and hybrid optimization effectively overcomes the trade-offs between numerical accuracy and computational efficiency.

Hybrid Genetic Optimization of Metasurfaces for Scattering Control: X-Band Design and Experimental Validation

2026-04-30

PIER

Vol. 185, 49-56, 2026

doi:10.2528/PIER26021102

download: 608

Fixed-Condition Spoof Plasmonic Parametric Amplifier for Multi-Carrier Signals

Wenyi Cui, Yue Cen and Jingjing Zhang

To achieve synchronous and uniform amplification of dense multi-carrier signals, this paper proposes a multi-frequency nondegenerate parametric amplifier (PA) based on a nonlinear spoof surface plasmon polariton (SSPP) waveguide. By engineering the dispersion characteristics of a varactor-diode-loaded waveguide, we realize an SSPP platform that exhibits minimized phase mismatch for three distinct signal-idler pairs under a constant pump frequency (13.348 GHz) and a fixed bias voltage. Experimental results show that the amplifier delivers highly uniform gains exceeding 20 dB for three closely spaced carriers at 6.363, 6.489, and 6.549 GHz, effectively emulating a three-frequency-shift keying (3FSK) signal. This work demonstrates a fixed-condition amplification scheme that requires no dynamic tuning, offering a promising solution for amplifying densely spaced carriers in integrated communication systems.

Fixed-Condition Spoof Plasmonic Parametric Amplifier for Multi-Carrier Signals

Fellow Article

2026-04-13

PIER

Vol. 185, 17-48, 2026

doi:10.2528/PIER26011404

download: 677

Microwave Wire Media: Theory and Main Physical Effects

Denis Sakhno, Constantin Simovski and Pavel A. Belov

We present a review of homogenization models of microwave wire media with different geometries. We begin with a simple (uniaxial) wire medium and then consider more complex types of wire media - double, triple, and interlaced wire media - which remain underexplored. We discuss boundary problems with wire media and the most important physical effects revealed using the reviewed homogenization models.

Microwave Wire Media: Theory and Main Physical Effects

Fellow Article

2026-07-28

PIER

Vol. 185, 136-144, 2026

doi:10.2528/PIER26032405

download: 21

Ionic-Ferroelectric Halide Perovskite Artificial Synapses with Dual-Mode Synaptic Plasticity (Invited Paper)

Dae-Han Kang, Kwan-Nyeong Kim, Hea-Lim Park, Joo Sung Kim, Jung-Min Heo, Huanyu Zhou, Dong-Hyeok Kim, Gyeong-Tak Go, Ju Yong Park, Antonio Facchetti, Min Hyuk Park, In-Hyeok Park and Tae-Woo Lee

Halide perovskites have demonstrated both short-term and long-term synaptic plasticity behaviors through various physical mechanisms, making them suitable neuromorphic electronics. However, most studies rely on distinct materials or device architectures optimized for one single mechanism, limiting the realization of both forms of synaptic plasticity within a unified material system. Here, we report ionic-ferroelectric halide perovskite (IFHP) artificial synapses that integrate two fundamentally different resistance switching processes within a single material. This functionality is enabled by the ferroelectric Dion-Jacobson perovskite (4-AMP)PbI₄ (4-AMP = 4-(aminomethyl)piperidinium), which exhibits ion-migration-dominated behavior below the coercive voltage (V_C ~ 3.5 V) and ferroelectric polarization switching above. Accordingly, the device exhibits volatile paired-pulse facilitation without stable non-volatile memory retention under sub-coercive stimulation, while exhibiting increasing non-volatile memory above V_C. The ferroelectric-polarization-driven long-term plasticity is further supported by extended retention over 2 × 10⁴ s, cycling operation, and device-to-device reproducibility. In addition, the IFHP artificial synapse emulates bio-inspired associative learning and nociceptive sensory functions, highlighting its potential as neuromorphic hardware. These results establish a single-material pathway for voltage-programmable mixed plasticity, addressing a key challenge in halide perovskite neuromorphic hardware.

Ionic-Ferroelectric Halide Perovskite Artificial Synapses with Dual-Mode Synaptic Plasticity (Invited paper)

2026-05-29

PIER

Vol. 185, 110-117, 2026

doi:10.2528/PIER26031208

download: 302

An Abbe-Hopkins Unified Formulation of Optical Imaging for Efficient Cross-Model Verification in Computational Lithography

Qi Sun, Ying Wang, Ziyin Ma, Shujie Liu, Degui Li, Zhonglei Mei and David H. Wei

Accurate simulation of partially coherent imaging is crucial for computational lithography, with Abbe and Hopkins as the two main formulations being used. Although the two methods are equivalent in theory, practical simulators making independent choices between Abbe and Hopkins could hardly produce consistent results that match the desired accuracy owing to the inherently different ways of numerically representing, discretizing, and truncating the illumination source and lens pupil function, etc. Moreover, classical Hopkins models require prior construction and/or eigen decomposition of the high-dimensional transmission cross coefficient (TCC), the prohibitive costs of which hinder timely model verification. To address these challenges, we developed a unified Abbe-Hopkins formulation in conjunction with a TCC-free Hopkins pointwise sampler for efficient cross-model validation. Our formulation supports both Abbe and Hopkins modeling in a single unified framework, with the two simulation modes using exactly the same numerical representations of the illumination source and projection lens. Cross-model verification for randomly sampled points is performed efficiently by evaluating the Hopkins quadratic form through a fast Fourier transform of an image and a few pointwise multiplications between images, without ever explicitly constructing a TCC and eigen-analyzing it. Numerical tests show that the Abbe and Hopkins results agree up to the machine precision level.

An Abbe-Hopkins Unified Formulation of Optical Imaging for Efficient Cross-Model Verification in Computational Lithography

Fellow Article

2026-01-05

PIER

Vol. 185, 1-16, 2026

doi:10.2528/PIER25110804

download: 1554

Progress in Structured Light with Nonlinear Optics

Sachleen Singh and Andrew Forbes

The control of all of light's degrees of freedom and its harnessing for applications is captured by the emergent field of structured light. The modern toolkit includes external modulation of light with devices such as metasurfaces and spatial light modulators, their intra-cavity insertion for structured light directly at the source, and their deployment to engineer quantum structured light at the single photon and entangled state regimes. Historically, this control has involved linear optical elements, with nonlinear optics only recently coming to the fore. This has opened unprecedented functionality while revealing new paradigms for nonlinear optics beyond plane waves. In this review we look at the recent progress in structured light with nonlinear optics, covering the fundamentals and the powerful applications they are facilitating in both the classical and quantum domains.

Progress in Structured Light with Nonlinear Optics

2026-05-01

PIER

Vol. 185, 87-96, 2026

doi:10.2528/PIER26031707

download: 501

Surface Wave Couplers for Terahertz Wireless Communication Receiver Front Ends

Yanfeng Zhao, Jiajun He, Cong Liu, Xiaoyuan Hao, Xizhi Li, Wei Wu, Quan Xu, Xueqian Zhang and Jiaguang Han

Free-space electromagnetic waves can be coupled into on-chip propagating surface waves (SWs), a process that holds great promise for receiver front-ends in wireless communication systems. However, it has traditionally faced challenges in coupling efficiency and in controlling the on-chip wavefront of SWs. To address these challenges, we design and experimentally demonstrate SW couplers operating in the terahertz regime based on metal-insulator-metal resonators. Our devices achieve not only broadband and highly efficient coupling, with an efficiency exceeding 60% over a 20 GHz bandwidth, but also enable directional steering of the excited SWs to designated on-chip ports. In this way, mode conversion and onchip routing functionalities are seamlessly integrated into a single compact component. Based on this design, we fabricated devices and implemented corresponding terahertz wireless communication links, successfully demonstrating 16-QAM data transmission in both single-link and dual-link configurations.

Surface Wave Couplers for Terahertz Wireless Communication Receiver Front Ends

2026-05-01

PIER

Vol. 185, 57-86, 2026

doi:10.2528/PIER25042501

download: 491

Acoustic Computation: From Effective Medium Theory to Biomedical Ultrasound Imaging (Invited Paper)

Erqian Dong, Sichao Qu, Xiaochuan Wu, Helios Y. Li and Nicholas Xuanlai Fang

This paper reviews recent advances in acoustic computation and modeling, specifically bridging effective medium theory (EMT) and biomedical ultrasound imaging. To achieve this, we examine how EMT provides the physical foundation for wave-based imaging through homogenized parameters, focusing on image reconstruction across diverse systems ranging from single pulse-receivers to multi-input and multi-output (MIMO) tomography. Furthermore, we highlight cross-disciplinary insights from computational optics, such as the transport of intensity equation and ptychography, while addressing acoustic-specific challenges like aberration correction and wave interference. In light of these challenges, emerging solutions are discussed, including ultrasound matrix imaging (UMI) via transfer matrix methods, inverse-designed matching layers, and hardware-accelerated approaches like the Krimholtz-Leedom-Matthaei (KLM) electro-acoustic model for ultrafast imaging. Ultimately, by integrating physical understanding of effective media with advanced computational algorithms, these developments provide a robust framework for the future of high-resolution 3D ultrasonography and acoustic holography.