PIER C | PIER Journals

2026-02-14

PIER C

Vol. 166, 113-125, 2026

doi:10.2528/PIERC26011203

download: 17

Sensorless Control of PMSM Based on a Novel Nonlinear Sliding Mode Observer with Phase-Locked Loop

Kun Wang, Zhonggen Wang and Wenyan Nie

To improve the position detection accuracy of sensorless control for permanent magnet synchronous motors (PMSM) and address issues such as significant chattering amplitude in traditional Sliding Mode Observers (SMOs), a Novel Adaptive Nonlinear Super-Twisting Sliding Mode Observer (NANSTSMO) combined with a Higher-order Gain Compensation Phase-Locked Loop (HGCPLL) is designed in this study. First, a multimodal nonlinear function is designed to replace the sign switching function, and this multimodal nonlinear function is then integrated with both the NANSTSMO and the HGCPLL. Second, a compensation mechanism is introduced to precisely estimate the rotor position. Finally, simulations are conducted using MATLAB/Simulink, and a motor test platform is constructed. Compared with the traditional sliding mode control and referenced sliding mode control strategies, the proposed method demonstrates superior effectiveness.

Sensorless Control of PMSM Based on a Novel Nonlinear Sliding Mode Observer with Phase-Locked Loop

2026-02-13

PIER C

Vol. 166, 106-112, 2026

doi:10.2528/PIERC25123002

download: 18

Design and Analysis of a Symmetric CPW-Fed Slot Ring Antenna with Uniform Gaps for Multi-Band ISM, WiMAX, Satellite Applications

Ravi Kumar Maddumala, Kollipara Radha, Udara Yedukondalu, Vasudha Vijayasri Bolisetty and Kottapadikal Vinodan Vineetha

In this study, we describe a circular ring slot antenna with three circular holes, which is supplied by a CPW-fed split ring resonator metamaterial. This proposed antenna covers sophisticated satellite communication applications for wireless devices, including 5G, military, and aerial radar, and resonates between 2.4 GHz and 10.4 GHz, with a center frequency of 3.542 GHz and an S₁₁ of -37.7 dB, and a center frequency of 7.5 GHz and an S₁₁ of -30.4 dB, respectively. The produced antenna satisfactorily validates the specified antenna metrics. The suggested antenna is built on an affordable FR4 substrate and has physical dimensions of 38 × 38 × 1.6 mm³. The proposed simulated design antenna is validated by the measured data. The results show a good correlation between the measured data and the simulation. The operational impedance range of the proposed antenna is less than -10 dB. The circular ring slot antenna has proven to be remarkably capable of reaching multiband frequencies of 3.54 GHz and 7.5 GHz. The proposed antenna may have an effect on radiation characteristics and gain, resulting in a good contender. Each component of the circle-shaped ring slot antenna design is essential to achieving the important and encouraging results.

Design and Analysis of a Symmetric CPW-Fed Slot Ring Antenna with Uniform Gaps for Multi-Band ISM, WiMAX, Satellite Applications

2026-02-13

PIER C

Vol. 166, 97-105, 2026

doi:10.2528/PIERC25123102

download: 29

A Miniaturized Wideband PIFA Antenna for Medical Implant Systems

Amina Abbas, Farid Bouttout, Asma Djellid, Youcef Braham Chaouche, Ismail Ben Mabrouk and Amjad Iqbal

This article presents a miniaturized wideband planar inverted-F antenna (PIFA) for deep biomedical implant applications at 915 MHz. Compactness and wide impedance bandwidth are achieved using a shorting pin, a circular radiating patch, and open-ended slots etched in the ground plane. The antenna occupies an ultra-small volume of 63.5 mm³ and is designed and analyzed inside a four-layer cylindrical human tissue phantom. Simulated and measured results show stable impedance matching over the ISM band, with a measured -10 dB bandwidth of 481 MHz (44.02%) and a peak realized gain of -28 dBi. Specific absorption rate (SAR) analysis confirms compliance with IEEE safety limits. In-vitro measurements using minced pork exhibit close agreement with simulations, validating the antenna's performance and suitability for reliable deep biomedical implant communication systems.

A Miniaturized Wideband PIFA Antenna for Medical Implant Systems

2026-02-12

PIER C

Vol. 166, 89-96, 2026

doi:10.2528/PIERC25120405

download: 34

A Low Sidelobe Dual-Beam Sparse Reflectarray Antenna with Combination of Transmissive and Reflective Elements

Wei Luo, Mingli Xie, Liu Luo and Yuqi Yang

A low sidelobe dual-beam reflectarray antenna is proposed based on the sparse array principle. The reflected dual beams achieve high gain through optimized phase compensation, in which the transmissive elements act as dummy elements to suppress sidelobes. A global search optimization technique based on genetic algorithm (GA) is adopted to improve the arrangement of transmissive and reflection elements. Since all the reflective and transmissive elements operating in the same wide frequency band are non-uniformly distributed on the aperture, both the backward radiation and cross polarization levels are effectively suppressed. The measurement results show that the sidelobe level of the dual-beams is less than -19 dB. The peak gain and peak aperture efficiency of the designed antenna are 26.0 dBi and 38.9%, respectively. The 3-dB gain bandwidth is 13.8%. The front to back ratio at 30 GHz is 27 dB. This dual-beam antenna has the advantages of high gain, low sidelobes, and wide beam radiation range, which make it suitable for millimeter-wave multi-target radar detection systems.

A Low Sidelobe Dual-Beam Sparse Reflectarray Antenna with Combination of Transmissive and Reflective Elements

2026-02-11

PIER C

Vol. 166, 76-88, 2026

doi:10.2528/PIERC25111803

download: 68

An Experimental Validation of Amplitude Only Genetic Algorithm Techniques for Side Lobe Level Optimization and Beam Shaping in 6G Massive MIMO Systems

Neev B. Patel, Rizwan Habibbhai Alad, Kosha Shah, Yashvi Mojidra and Purvang D. Dalal

Traditional side-lobe suppression techniques such as Chebyshev and Taylor tapering provide limited adaptability to hardware constraints and fixed array geometries. Existing Genetic Algorithm applications predominantly focus on planar arrays with variable spacing, leaving linear arrays with fixed element spacing underexplored. This work presents a genetic algorithm-based amplitude tapering framework for optimizing side-lobe levels in 8element linear phased arrays with fixed 0.48λ spacing. The approach incorporates hardware quantization constraints and validates performance through experimental implementation. Experimental validation uses the Analog Devices CN0566 Phaser kit operating at 10.25 GHz (centre frequency) with 0.5 dB gain resolution and 2.8125˚ phase quantization. Genetic algorithm parameters including population size, mutation rate, and fitness function were held constant while the convergence rate and side-lobe suppression are evaluated. This research work demonstrates practical genetic algorithm implementation for linear phased array optimization under real-world hardware constraints, providing design guidelines for X-band radar and communication systems.

An Experimental Validation of Amplitude Only Genetic Algorithm Techniques for Side Lobe Level Optimization and Beam Shaping in 6G Massive MIMO Systems

2026-02-11

PIER C

Vol. 166, 68-75, 2026

doi:10.2528/PIERC25122405

download: 29

Wideband GCPW-Fed Coplanar Vivaldi Antenna with Low Cross-Polarization

Yiqing Gao, Zhao Bai, Hongcheng Zhou, Changhai Hu, Zhongming Yan and Yu Wang

The traditional microstrip-fed Vivaldi antenna has the disadvantage of a high cross-polarization level owing to the nonparallelism between the electric field and the antenna plane. Based on the balanced E-field distribution property of the grounded coplanar waveguide (GCPW) structure, this paper proposes a planar ultrawideband Vivaldi antenna with low cross-polarization. The measured results confirm that an enhanced impedance bandwidth of 159.54% is achieved in the range of 2.01-17.86 GHz (|S₁₁| < -10 dB) with a 4-6 dB improvement in cross-polarization over traditional Vivaldi antenna. In addition, the proposed antenna has a maximum gain of 9.9 dBi within the size of 88.2 mm × 107.3 mm × 1 mm. Owing to the advantages of ultra-wideband, low cross-polarization ratio, stable radiation patterns and high gain, the proposed method can be widely applied in UWB communication and multifunctional integrated RF systems.

Wideband GCPW-Fed Coplanar Vivaldi Antenna with Low Cross-Polarization

2026-02-11

PIER C

Vol. 166, 57-67, 2026

doi:10.2528/PIERC25123004

download: 49

Lower Cost Variable-Leakage-Flux Reverse-Salient-Pole Permanent Magnet Motor by Reducing Rare-Earth Permanent Magnet Usage

Xiping Liu, Hongzhan Hu, Qianli Jia, Zhangqi Liu and Zhiguo Zhu

This paper proposes a novel less-rare-earth variable-leakage-flux reverse-salient-pole motor (LRE-VLF-RSPM). The proposed motor achieves the reverse-salient-pole and variable-leakage-flux characteristics by reasonably arranging three layers of arc-shaped flux barriers between adjacent magnetic poles. Furthermore, it incorporates ferrite magnets to reduce the usage of rare-earth permanent magnets by one-third while maintaining torque output, thereby fulfilling the less-rare-earth objective. First, the paper introduces the rotor topology and operational principle. Subsequently, it employs two-dimensional finite element analysis (FEA) to compare the electromagnetic performance - including torque, flux-weakening capability, constant power speed range (CPSR), and high-efficiency region proportion - among a conventional V-type synchronous motor (CTVSM), a variable-leakage-flux reverse-salient-pole motor (VLF-RSPM), and the LRE-VLF-RSPM. The final results demonstrate that the proposed motor reduces rare-earth usage by one-third compared to the benchmark motor and exhibits superior flux-weakening capability, a wide constant power speed range, and a large high-efficiency region. These findings verify the effectiveness and feasibility of the proposed motor.

Lower Cost Variable-Leakage-Flux Reverse-Salient-Pole Permanent Magnet Motor by Reducing Rare-Earth Permanent Magnet Usage

2026-02-10

PIER C

Vol. 166, 52-56, 2026

doi:10.2528/PIERC25110505

download: 49

Wide-Passband Miniaturized Filter with Higher-Order Mode Suppression Using QMSIW and Microstrip Resonators

Jingyv Wang, Haiyan Zeng, Mengling Su, Xuan'an Chen, Lishan Huang, Jinming Ou and Xiaohei Yan

This paper presents a wide-passband, miniaturized filter based on quarter-mode substrate-integrated waveguide (QMSIW) resonant cavities and microstrip resonators. The filter employs two QMSIW resonant cavities, which effectively reduce its size. Moreover, the higher-order modes TE₁₂₀, TE₂₁₀, and TE₂₂₀ cannot propagate within these cavities. The addition of two microstrip resonators at the coupling iris between the QMSIW cavities enables a fourth-order filter response using only two resonant cavities. High selectivity is achieved through cross-coupling, which introduces two transmission zeros (TZs). The filter was fabricated and measured, showing good agreement with the simulation results. Compared with other substrate-integrated waveguide (SIW) filters, the proposed filter offers advantages in compactness, passband bandwidth, and higher-order mode suppression.

Wide-Passband Miniaturized Filter with Higher-Order Mode Suppression Using QMSIW and Microstrip Resonators

2026-02-10

PIER C

Vol. 166, 41-51, 2026

doi:10.2528/PIERC25120901

download: 29

High-Gain Dual Band MIMO Antenna Using Metamaterial Surface for Bluetooth, Wi-Fi and 5G Applications

Nilesh Lakade, Shankar D. Nawale, Anjali Rochkari, Mahadu Trimukhe and Rajiv Kumar Gupta

In this paper, an elliptical monopole antenna is operated in fundamental mode by reducing the electromagnetic coupling (EMC) between higher-order modes. The electromagnetic coupling is decreased by decreasing the width of the radiating element and ground-plane dimensions, and increasing the gap between the radiating element and ground plane. The ellipse is sliced from the top, as there is little surface current on the top portion of a monopole. The symmetrical portion of this sliced elliptical monopole is selectively etched with little effect on impedance variation. Dual-band characteristics are obtained over 2.3-2.7 GHz (Wi-Fi and Bluetooth bands) and 5.4-5.9 GHz (WLAN band), as well as over 2.3-2.7 GHz (Wi-Fi and Bluetooth bands) and 5.13-5.71 GHz (WLAN band), depending on the etching amount. A rectangular strip is added to the etched monopole to operate over 2.3-2.7 GHz (Wi-Fi, Bluetooth bands) and 3.3-3.9 GHz (5G band). To enhance the gain of a compact dual-band antenna, a reflecting metamaterial surface consisting of an array of square patches is designed and placed below the structure. A high-gain dual-band MIMO antenna is designed by placing four elements orthogonally above the centre of four edges of the metamaterial surface. S₁₁ < -10 dB, isolation > 18 dB and 22 dB, and antenna gain of 7.5 dBi and 7.4 dBi are obtained over 2.35-2.7 GHz and 3.3-3.6 GHz, respectively. The structure is fabricated. The measurement results validate the simulation ones.

High-gain Dual Band MIMO Antenna Using Metamaterial Surface for Bluetooth, Wi-Fi and 5G Applications

2026-02-09

PIER C

Vol. 166, 27-40, 2026

doi:10.2528/PIERC25122407

download: 108

Photovoltaic Power Prediction Model Based on Fuzzy Entropy Clustering and Self-Attention Mechanism Combined with ICEEMDAN-WOA-CNN-BiLSTM

Zhongan Yu, Faneng Wu, Zhiwei Huang, Zihao Deng and Feng Zhang

To address the randomness and nonlinearity of photovoltaic (PV) power caused by meteorological factors, this paper proposes an ICEEMDAN-WOA-CNN-BiLSTM prediction model integrated with fuzzy entropy clustering and a self-attention mechanism. First, the original PV power sequence is decomposed into multiple multi-scale intrinsic mode function (IMF) components and residuals via the Improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (ICEEMDAN). Subsequently, components with similar complexity are merged using fuzzy entropy clustering to simplify the calculations. Then, the Whale Optimization Algorithm (WOA) is adopted to optimize the hyperparameters of the CNN-BiLSTM model, and the self-attention mechanism is integrated into the model to enhance the weights of key features. Comparative experiments demonstrate that the proposed model significantly outperforms single and traditional hybrid models in terms of Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Coefficient of Determination (R2). This can effectively improve the accuracy of short-term PV power prediction and provide support for power station dispatching and power grid stability.

Photovoltaic Power Prediction Model Based on Fuzzy Entropy Clustering and Self-Attention Mechanism Combined with ICEEMDAN-WOA-CNN-BiLSTM

2026-02-09

PIER C

Vol. 166, 19-26, 2026

doi:10.2528/PIERC25121605

download: 43

A Miniaturized Highly Isolated Quad-Port Penta-Band-Notched UWB MIMO Antenna Based on EBG Structures

Koritala Nagavardhani, Pullagura Rajesh Kumar and Veera Malleswara Rao

This paper presents a miniaturized quad-port ultrawideband (UWB) MIMO antenna that integrates band-notch functionality and exhibits high isolation. The design employed four circular monopole radiators positioned on a modified defected ground structure (DGS), and periodic electromagnetic bandgap (EBG). These EBG components are an advanced variation of traditional mushroom-type structures that incorporate grid-shaped top patches, a metallic ground plane, and multiple vias connecting both layers. Located at the center of the substrate, the EBG network effectively reduces the electromagnetic coupling between adjacent radiating elements. To achieve multi-band rejection, five inverted U-shaped slots are etched into each monopole, enabling selective suppression of unwanted frequencies at 3.36-3.56 GHz, 3.72-3.92 GHz, 4.11-4.32 GHz, 4.59-4.83 GHz, and 5.22-5.50 GHz, corresponding to WiMAX, C-band, Wi-Fi, INSAT, and WLAN systems. Experimental validation confirms that the antenna attains -10 dB impedance bandwidth extending from 3.0 to 14.0 GHz, with inter-element isolation above -22.5 dB, gain of 6.2 dB, and radiation efficiency reaching 79.2%.

A Miniaturized Highly Isolated Quad-Port Penta-Band-Notched UWB MIMO Antenna Based on EBG Structures

2026-02-09

PIER C

Vol. 166, 9-18, 2026

doi:10.2528/PIERC25122502

download: 37

Broadband Array Aperture Fill Time Correction Algorithm Based on Low-Complexity Variable Fractional Delay Filter

Yufan Wang, Mingwei Shen, Zixuan Wang and Guodong Han

To address the aperture fill time problem in broadband arrays, this paper proposes an efficient delay compensation algorithm based on a variable fractional delay (VFD) filter with high numerical stability. A low-complexity Newton structure is introduced into the VFD Lagrange interpolation algorithm; in addition, the numerical stability is significantly enhanced by centrally offsetting the element delay parameters and avoiding the explicit inversion of the transformation matrix. Subsequently, the robust Newton-VFD is applied to the implementation of the broadband array aperture fill time correction algorithm. The algorithm utilizes a cascaded architecture consisting of coarse integer-delay compensation and fine fractional-delay correction via the Newton-VFD. Simulation results demonstrate that the proposed low-complexity Newton-VFD significantly reduces hardware complexity while maintaining excellent magnitude-frequency characteristics, which enables efficient and high-precision correction of broadband array aperture fill time.

Broadband Array Aperture Fill Time Correction Algorithm Based on Low-Complexity Variable Fractional Delay Filter

2026-02-09

PIER C

Vol. 166, 1-8, 2026

doi:10.2528/PIERC25122409

download: 49

A Design Approach of High-Efficiency Filtering Power Amplifiers Using Harmonic-Tuned Network and Terminated Coupled-Line Structures

Lang Ran, Bin Wang, Yongxin Wang and Shihao Chen

A design approach using a harmonic-tuned network (HTN) and terminated coupled-line structures (TCLSs) for high-efficiency filtering power amplifiers (FPA) is proposed in this paper, effectively addressing the efficiency degradation caused by the integration of filtering structures in conventional FPA designs. The proposed approach enables compact circuitry while providing bandpass filtering characteristics. Bandpass filtering is realized through the cascaded TCLSs, while the incorporation of open-circuit and short-circuit branches introduces additional transmission zeros and poles, significantly improving frequency selectivity. In addition, HTN enables precise control of the harmonic impedance, effectively improving the efficiency of the power amplifier (PA). Based on this approach, an FPA operating in the 2.3-2.6 GHz band is designed and implemented. Experimental results show that the FPA achieves a output power (Pout) of 40.8-41.3 dBm, a drain efficiency (DE) of 67.2-72.2%, a gain of 12.8-13.3 dB, and stopband suppression greater than 39 dB on both sides of the passband. These results verify the effectiveness of the proposed design in enhancing PA efficiency and enabling circuit miniaturization, while also providing a feasible design approach for FPA development.