PIER B | PIER Journals

2025-07-15

PIER B

Vol. 113, 37-50, 2025

download: 11

Designing MIMO Antenna with High Isolation Decoupling Structure

Jyoti C. Kolte, Ashwini Kumar and Payal Bansal

This paper presents the design and development of a miniaturized Multiple-Input Multiple-Output (MIMO) antenna for sub-6 GHz 5G applications, featuring reduced cross polarization and enhanced isolation between antenna elements. Utilizing characteristics mode analysis, slots are introduced in the patch to achieve orthogonal mode separation, effectively minimizing cross polarization. Further bandwidth enhancement is achieved by incorporating slot loading in the ground plane. To improve isolation between antenna elements, spiral decoupling (SD) and aperture spiral decoupling (ASD) structures are employed. The proposed MIMO antenna, with dimensions 0.32λ_o*0.32λ_o*0.01λ_o where λ_o is the wavelength at the lower band frequency of 3.5 GHz, was fabricated and experimentally tested to validate its performance. Measurement results indicate significant compactness, low envelope correlation coefficient (ECC), high gain, minimal channel capacity loss, and very low mutual coupling between elements. The measured results are in good agreement with simulated results, confirming that the proposed antenna is a promising candidate for advanced MIMO applications in next-generation wireless communication systems.

Designing MIMO Antenna with High Isolation Decoupling Structure

2025-07-15

PIER B

Vol. 113, 23-36, 2025

doi:10.2528/PIERB25042201

download: 22

A Composite Sliding Mode Control for PMSM Drives Based on an Adaptive Reaching Law with Disturbance Compensation

Pengpeng Liu, Zhonggen Wang and Wenyan Nie

To address internal parameter ingress and external load perturbations in the speed loop of a permanent magnet synchronous motor (PMSM) and enhance the dynamic performance and robustness of its speed control system, this study proposes a novel adaptive sliding mode reaching law-based controller integrated with a global non-singular fast terminal sliding mode observer (GNFTSMO). The proposed reaching law incorporates system state variables as power functions, thereby minimizing steady-state errors and resolving the inherent trade-off between chatter suppression and rapid response. To further enhance the dynamic and steady-state performance of the PMSM control system, a GNFTSMO is designed. This observer reduces the switching gain of the convergence law while incorporating feed-forward compensation for perturbations, thereby improving the system's anti-disturbance capability. The feasibility and effectiveness of the proposed sliding mode control method are empirically validated through both simulation and experimental studies.

A Composite Sliding Mode Control for PMSM Drives Based on an Adaptive Reaching Law with Disturbance Compensation

2025-07-11

PIER B

Vol. 113, 13-22, 2025

doi:10.2528/PIERB25051401

download: 98

A Compact Parasitic Mushroom Patch Loaded Antenna for 5G mm -Wave Applications (28 GHz /38 GHz )

Tarik El-Arrouch, Abdelaaziz El Ansari, Najiba El Amrani El Idrissi, Mahadu Trimukhe, Shobhit Khandare, Zahriladha Zakaria and Ahmed Jamal Abdullah Al-Gburi

This study introduces and evaluates a smaller rectangular antenna featuring parasitic mushroom patches to achieve enhanced gain and wide impedance bandwidth (WIBW) for 5G millimeter-wave (mm-wave) applications (28 GHz/38 GHz). The antenna structure consists of a simple rectangular patch fed by an inset feed microstrip line operating at 50 Ω. To improve the antenna gain and impedance bandwidth, a parasitic mushroom structure is introduced around the edges of the main patch. Additionally, to further enhance operating bandwidth and matching, two rectangular Defected Ground Structures (DGSs) are incorporated in the bottom side. The antenna is fabricated on a low-cost substrate specifically FR4 (ε_r = 4.4 , tangδ = 0.02), with dimensions of (12 × 13 × 0.8) mm³. The results demonstrate a wide impedance bandwidth of 14.2 GHz (50.71% FBW) covering frequencies of 25.98 GHz to 40.18 GHz, and the antenna achieves a maximum gain of 7.20 dB at 28 GHz and maintains an efficiency more than 80% across the entire bandwidth. These outcomes make the antenna a good choice for 5G applications at 28 GHz and 38 GHz.

A Compact Parasitic Mushroom Patch Loaded Antenna for 5G MM-Wave Applications (28 GHz/38 GHz)

2025-07-08

PIER B

Vol. 113, 1-11, 2025

doi:10.2528/PIERB25051204

download: 11

Multi-Objective Optimization of an Asymmetric Segmented Less-Rare-Earth Permanent Magnet Motor

Lu Zhang, Jinbin Xu and Chen Qi

In order to reduce the use of rare-earth materials and solve the problem of rising manufacturing costs of permanent magnet motors due to higher rare-earth prices, this paper proposes an asymmetric segmented less-rare-earth permanent magnet motor (ASLREPMM), which combines NdFeB permanent magnets with ferrite permanent magnets to form a common excitation source. In order to efficiently design the parameters of this motor, an optimization strategy of sensitivity stratification and multi-objective optimization is proposed, with output torque, torque pulsation, cogging torque and peak air-gap magnet density as the optimization objectives, and multi-objective optimization is carried out on the optimization variables with high sensitivity. Compared with the V-type permanent magnet motor (V-type PMM), the cogging torque of the optimized ASLREPMM is decreased by 49.67%, torque pulsation decreased by 10.77%, peak air-gap magnetic density increased by 0.051 T, and the total amount of NdFeB material decreased by 2184 mm³. The reasonableness of the structural design and the effectiveness of the optimization of the ASLREPMM are verified through experiments.