PIER C | PIER Journals

2026-05-29

PIER C

Vol. 171, 59-66, 2026

doi:10.2528/PIERC26041505

download: 31

A Compact SRR Metamaterial and DGS-Based Dual-Bandpass Filter for Sub-6 GHz Wireless and IoT Applications

Youssef Khardioui, Younes Siraj, Kaoutar El Bakkar, Ali El Alami, Mohammed El Ghzaoui and Youssef Mejdoub

In modern wireless communication systems, it is essential to use a bandpass filter at the front end of the radio receiver to limit the bandwidth of the signal before it is passed to the rest of the receiver. This study presents the design, fabrication, and analysis of a compact dual-band metamaterial bandpass filter (BPF) for modern wireless communication systems. The proposed structure evolves from an initial open-loop resonator design and integrates metamaterial unit cells to significantly enhance frequency selectivity, reduce inser-tion loss, and improve impedance matching. To further enhance the performance, defected ground structures were incorporated, resulting in refined bandwidth control and supe-rior return-loss characteristics. The final filter operates at center frequencies of 2.4 and 3.95 GHz, achieving low insertion losses of 0.6 and 0.9 dB, along with return losses of 27.6 and 32.9 dB, respectively. Its compact size of 20 × 18.46 mm² corresponds to an electrical size of (0.33 × 0.25)λ_g². Owing to its excellent electrical performance and miniaturized form, the proposed filter is suitable for wireless communication applications, including GPS, Blue-tooth, Wi-Fi, WiMAX, 5G, and sub-6 GHz bands, making it ideal for modern systems, such as the Internet of Things (IoT).

A Compact SRR Metamaterial and DGS-Based Dual-Bandpass Filter for Sub-6 GHz Wireless and IoT Applications

2026-05-29

PIER C

Vol. 171, 49-58, 2026

doi:10.2528/PIERC26042202

download: 11

Electromagnetic Scattering Characteristics of Dielectric-Coated Targets Using the Characteristic Mode Basis Function Method

Jiayu Yan, Zhonggen Wang, Wenyan Nie and Han Lin

Analyzing the electromagnetic scattering of electrically large targets with complex coatings presents significant computational challenges. This paper proposes a highly efficient hybrid acceleration method within the Electric Field Integral Equation (EFIE) framework, combining the Thin Dielectric Sheet (TDS) approximation, Characteristic Mode Analysis (CMA), and Adaptive Cross Approximation (ACA). First, a generalized TDS formulation maps dual-layer equivalent currents onto a single-surface model, substantially reducing the initial unknowns while preserving physical consistency. Next, domain decomposition and CMA are utilized to construct a reduced-order matrix, enabling a direct, non-iterative solution that fundamentally bypasses traditional convergence bottlenecks. Finally, the ACA algorithm compresses well-separated far-field interactions to further minimize computational and memory costs. Comprehensive numerical experiments calculating the Radar Cross Section (RCS) of electrically large coated targets demonstrate that the proposed hybrid scheme offers superior accuracy and drastically reduces matrix storage and computation time compared to conventional full-wave direct solvers and traditional TDS-EFIE (electric and magnetic) formulations.

Electromagnetic Scattering Characteristics of Dielectric-Coated Targets Using the Characteristic Mode Basis Function Method

2026-05-29

PIER C

Vol. 171, 44-48, 2026

doi:10.2528/PIERC26041802

download: 26

Compact Reflection-Type Phase Shifter Using an Impedance-Transforming Transdirectional Coupler Based on Double-Shielded Coupled Lines

Aleksandr N. Sychev, Sergey A. Artishchev, Natalia S. Ragimova and Evgeniy V. Shesterikov

This letter presents a novel tunable reflection-type phase shifter (RTPS) employing an impedance-transforming transdirectional (IT TRD) coupler terminated by varactor-based reflective loads. The coupler is based on double-shielded coupled lines (DSCLs) and is implemented as a distributed surface-mount component, providing inherent impedance transformation for increasing the relative phase shift for given varactors. Fabricated using standard PCB technology, the prototype features intrinsic DC isolation between the RF path and control circuits, requiring only a single control voltage. Measured results show that the RTPS operates over a wide frequency band from 2.2 to 2.8 GHz (24%), achieving a tunable phase shift of up to 180˚ with an insertion loss of 1.3±0.7 dB and a return loss better than 11 dB. The proposed design is characterized by compact physical dimensions of 0.1 × 0.21λ at the center frequency.

Compact Reflection-Type Phase Shifter Using an Impedance-Transforming Transdirectional Coupler Based on Double-Shielded Coupled Lines

2026-05-28

PIER C

Vol. 171, 34-43, 2026

doi:10.2528/PIERC26042201

download: 27

Discrete Space Vector Modulation Model Predictive Flux Control with Reformulated Incremental Cost Function and Efficient Search Strategy for SPMSM

Yang Zhang, Jiahao Zhang, Ping Yang, Wancheng Xie and Shaoziyi Wu

Conventional model predictive flux control (C-MPFC) generates large steady-state ripples, and the system reference values are heavily dependent on the permanent magnet (PM) flux This paper proposes a discrete space vector modulation model predictive flux control with a reformulated incremental cost function and efficient search strategy (RDSVM-MPFC) for surface-mounted permanent magnet synchronous motors (SPMSMs). First, a unified cost function based on flux increments is reconstructed by redefining the d-axis reference flux. Second, the candidate set is expanded via discrete space vector modulation (DSVM) in the spatial flux increment plane to generate a set of virtual flux increment vectors (VFIVs), thereby significantly suppressing steady-state errors. Furthermore, to manage the heavy computation burden associated with the expanded VFIVs, a three-stage hierarchical optimization strategy is designed. This approach achieves rapid identification of the optimal control vector, which preserves the high steady-state precision while largely reducing the computational complexity of the system. Finally, experimental studies demonstrate that the proposed RDSVM-MPFC strategy eliminates sensitivity to PM flux variations and markedly suppresses steady-state pulsations.

Discrete Space Vector Modulation Model Predictive Flux Control with Reformulated Incremental Cost Function and Efficient Search Strategy for SPMSM

2026-05-27

PIER C

Vol. 171, 25-33, 2026

doi:10.2528/PIERC26040103

download: 29

Structural Optimization of Short Primary Single-Sided Linear Induction Motor

Cheng Wen, Zilei Duan, Mingye Li and Aosai Li

This study focuses on a Short-Primary Single-Sided Linear Induction Motor (SSLIM), which is widely used in the rail transit sector due to its low operating noise and small turning radius. Therefore, designing linear induction motors with better performance is of great significance. This study aims to enhance electromagnetic thrust and reduce fluctuations in electromagnetic force by optimizing the motor's structural design. First, a motor model is established based on its operating principles, and a brief analysis of its electromagnetic characteristics is conducted. Second, two design schemes were selected for both the primary and secondary components. For the primary components, one scheme employs a chamfered structure to suppress fluctuations in electromagnetic force, while the other modifies the tooth tip shape from rectangle to trapezoid to increase thrust. For the secondary components, one scheme involves incorporating a material with higher electrical conductivity into specific areas of the aluminum plate, and the other involves slotting to optimize the magnetic field distribution and increase thrust. Finally, the performance of the optimized model was compared with that of the initial model. The results showed that the average thrust increased by 5.3%, while the fluctuations in thrust and normal force decreased by 13.6% and 30%, respectively, validating the effectiveness of the optimization approach.

Structural Optimization of Short Primary Single-Sided Linear Induction Motor

2026-05-27

PIER C

Vol. 171, 14-24, 2026

doi:10.2528/PIERC26040302

download: 54

Design and Analysis of a Novel Miniaturized Multiband Flowerpot-Shaped Patch-Based Dielectric Resonator Antenna for 5GNSS, UMTS, PCS, Wi-Fi5, WiMAX, and NR Sub-6 GHz 5G Applications

Kaushal Patel and Falgun Thakkar

In this study, a novel miniaturized multiband flowerpot-shaped patch-based cylindrical dielectric resonator antenna (FPSDRA) is proposed for 5G-enabled GNSS (GPS), UMTS, PCS, Wi-Fi5, WiMAX, and NR 77/78 sub-6 GHz 5G applications. The proposed antenna prototype operates at 1.54 GHz, 2.01 GHz, 3.23 GHz, 3.95 GHz, and 5.54 GHz for the mentioned applications. It employs a novel low-cost flowerpot-shaped radiating patch underneath a cylindrical dielectric resonator (CDR) made of alumina ceramic (Al₂O₃, ∈_DR = 9.8) material and is fed by a combined microstrip-line-tapered trapezoidal feedline. Later, a reduced ground plane is used as a reflector on the rear side of the substrate to reduce antenna size. It is made up of a low cost 1.6 mm FR4 laminate sheet (∈_r = 4.4, tanδ = 0.02) and miniaturized to a physical size of 65 × 45 mm². The parametric analysis was carried out for reflection coefficients (S₁₁-dB) by changing the ground plane width, CDRA radius, and flower petal radius to achieve adequate results. Likewise, this prototype has measured reflection coefficient of < -20 dB for 1.54 GHz (L1-band), < -25 dB for 2.01/3.23 GHz (S-band), < -20 dB for 3.95 GHz (S-band), and 5.54 GHz (C-band), peak gains of 2.01 dBi, 2.05 dBi, 3.02 dBi, 4.85 dBi, and 2.24 dBi for the respective bands along with adequate -10 dB impedance matching bandwidths and stable radiation features in a convincing agreement compared to earlier designs. The proposed prototype is simulated in CST software, assembled, and tested by VNA and an anechoic chamber setup for L1/S/C band applications.

Design and Analysis of a Novel Miniaturized Multiband Flowerpot-Shaped Patch-Based Dielectric Resonator Antenna for 5GNSS, UMTS, PCS, Wi-Fi5, WiMAX, and NR Sub-6 GHz 5G Applications

2026-05-26

PIER C

Vol. 171, 1-13, 2026

doi:10.2528/PIERC26033003

download: 67

CMA-Based Flexible Four-Element SWB MIMO Antenna with Enhanced Isolation for Wearable Applications

Xiaoyan Wei, Zhonggen Wang, Wenyan Nie, Chenlu Li and Zhengting Zhang

This paper proposes a flexible four-element super-wideband (SWB) multiple-input multiple-output (MIMO) antenna based on characteristic mode analysis (CMA) for wearable wireless communication, broadband sensing, and wireless body area network (WBAN) applications. The antenna employs a spiral mesh radiator combined with a defected ground plane incorporating triangular and T-shaped slots to form a multi-slot-coupled current path, enabling the cooperative excitation of multiple characteristic modes. The proposed antenna achieves an impedance bandwidth of 3.23-44.68 GHz, satisfying the SWB criterion. A four-port MIMO configuration is adopted to enhance diversity and isolation performance. Measured results agree well with simulations, with port isolation better than 20 dB across the operating band. In addition, the envelope correlation coefficient (ECC) is below 0.0015; the diversity gain (DG) is close to 10 dB; the total active reflection coefficient (TARC) is below -10 dB; and the channel capacity loss (CCL) is less than 0.12 bit/s/Hz. The antenna also maintains stable SWB impedance matching and radiation performance under bending conditions, making it suitable for flexible SWB wearable and WBAN systems.