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2023-12-08
PIER C
Vol. 139, 87-94, 2024
download: 11
Performance Enhancement of High-Gain STDA Antennas with Reflector for 4G LTE and Sub-6 GHz 5G Applications: Design, Measurement, and Analysis
Mohd Wasim , Shelej Khera , Tanvir Islam , Praveen Kumar Malik , Sivaji Asha and Sudipta Das
The paper focuses on the design, measurement, and performance analysis of a high-gain cross-orthogonal series fed two dipole antenna (STDA) arrays with side-wall reflectors. The antenna is specifically designed for 4G Long Term Evolution (LTE) and sub-6 GHz 5G band applications. The designed antenna is capable of operating at multiple frequencies aiming to support 4G LTE and the sub-6 GHz 5G application bands. To improve the radiation characteristics and prevent coupling effects in the presence of side-wall reflectors, parasitic strip pair directors are included in the antenna design. Furthermore, the performance of the designed STDA is evaluated by forming different array configurations, such as 2×1, 2×2, and 2×3 arrays. The various array configurations are proposed to investigate the effect of the projected array arrangements on the radiation pattern, impedance bandwidth, and gain characteristics. The results of the measurements show that the radiation characteristics of the antenna has improved significantly. The proposed antenna operates at six distinct frequencies for S11≤-10 dB. The operating frequencies at 1.8, 2.35, and 2.6 GHz can be utilized for LTE and 3.2, 4.2, and 5.2 GHz can support sub-6 GHz 5G bands. The antenna is characterized by its compact size, measuring around 89 mm × 71 mm, while still achieving high gain of 12.3 dB for single STDA element with parasites and with reflector. These results emphasize the importance of the proposed design, which incorporates parasitic strip pair directors and side-wall reflectors. This design methodology plays a crucial role in enhancing the performance of the prescribed STDA array for both 4G LTE and sub-6 GHz 5G applications.
Performance Enhancement of High-gain STDA Antennas with Reflector for 4G LTE and Sub-6 GHz 5G Applications: Design, Measurement, and Analysis
2023-12-07
PIER C
Vol. 139, 79-86, 2024
download: 15
A Low-Profile, Size-Reduced, High Gain, Circularly Polarized Anti-Jam Global Positioning System Antenna Array
Grant Evans , Jack Nemec , Victor Obi and Sungkyun Lim
A high gain, circularly polarized array antenna is proposed with low profile and compact size using T-shaped top loading, t-matching, and a reflector. Composed of 4 individual elements, the array has a -3-dB impedance bandwidth of 1.39% (1.564-1.586 GHz) and a 3-dB axial ratio beamwidth of 79° (-42°-37°) in measurement. The front-to-side ratio of the total realized gain pattern is 27.1 dB and the front-to-back ratio is 25.5 dB. The peak realized gain is 11.0 dBi in the forward (+z) direction. The proposed antenna is a good candidate for functioning as an anti-jam antenna in global positioning system, helping to block out jamming signals coming from the horizontal (90° and 270°) planes.
A Low-profile, Size-reduced, High Gain, Circularly Polarized Anti-jam Global Positioning System Antenna Array
2023-12-03
PIER C
Vol. 139, 67-77, 2024
download: 31
PMSWG Parameter Identification Method Based on Improved Operator Genetic Algorithm
Zhun Cheng , Chao Zhang and Yang Zhang
Permanent Magnet Synchronous Wind Generator (PMSWG) parameter identification method with improved operator genetic algorithm is proposed for the influence of perturbations caused by mechanical parameter changes on the dynamic performance of motor speed control system. Firstly, current with id=0 and id≠0 are injected into axis d respectively to design the fitness function. Through quantum coding, the genetic algorithm can obtain better population and fitness in the early stage, and find better solutions in the search space. At the same time, the cross method of two random numbers is used to make the cross variable not restricted in a range, which enhances the global search ability. Finally, the update strategy of hybrid mutation composed of Gaussian mutation and Cauchy mutation is introduced to ensure the global search ability of the algorithm, and the accuracy of the optimization results is improved. Experiments show that the proposed method avoids local optimization and achieves global optimization, which can further improve the convergence speed and identification accuracy of the algorithm.
PMSWG Parameter Identification Method Based on Improved Operator Genetic Algorithm
2023-12-03
PIER C
Vol. 139, 59-66, 2024
download: 25
Frequency Diversity Arc Array with Angular Broadening Null Steering for Sidelobe Suppression
Ying Tian , Wei Xu , Pingping Huang , Weixian Tan and Yaolong Qi
The structure of the frequency diversity arc array (FDAA) is a circular arc, which can achieve fast scanning in all directions and large viewing angles. By selecting the appropriate array elements for FDAA to form an effective working array and designing the symmetrical logarithmic frequency offset, a more aggregated point-like beam pattern is obtained. However, due to the structural characteristics of FDAA, the anti-density weighting phenomenon is generated, which limits the application of FDAA in radar system for target recognition and tracking. In order to solve the problem of high sidelobe of FDAA caused by inverse density weighting, a method of FDAA with angle widening null guidance for sidelobe suppression is proposed in this paper. The linear constraint minimum variance (LCMV) criterion is used to set zero points at a fixed position in the direction of interference, so that the interference is in a null with a certain width. Through Matlab simulation, it is verified that this method has a certain effect on suppressing FDAA sidelobe interference.
Frequency Diversity Arc Array with Angular Broadening Null Steering for Sidelobe Suppression
2023-12-02
PIER C
Vol. 139, 45-57, 2024
download: 48
A Combinatorial Approach to Quantitative Microwave Imaging for Breast Tumour Profiling Using SVBIM and SpaRSA
Ria Benny , Thathamkulam A. Anjit , Philip Cherian and Palayyan Mythili
A combinatorial quantitative reconstruction method employing Subspace-based Virtual Born Iteration Method (SVBIM) along with a greedy compressive sensing algorithm, Sparse Reconstruction by Separable Approximation (SpaRSA) to solve the ill-posed inverse problem in microwave imaging is proposed in this paper. SVBIM makes use of the contribution of the variational induced current to arrive at a better estimate of the permittivity profile in each iteration. SpaRSA operates in the sparse domain and reduces the computational overload, thereby guiding the inverse problem towards a faster global optimum solution. The merger of these two algorithms helps to reconstruct breast profiles having high-permittivity tumour inclusions (ε = 60) with reduced error. The proposed reconstruction method is capable of extracting the salient information regarding tissue differentiation (permittivity and conductivity) and dielectric distribution of various tumour and fibroglandular inclusions within the object, dimensions, resolution, size, shape and coordinate localization of inclusions. In comparison to various methods reported in literature, the results obtained using the proposed method are highly encouraging. In the presence of 30 dB noise, the above-said imaging technique produces a significantly reduced permittivity error value of 0.47 in the reconstruction of tumour inclusions as against 0.85 and 0.71 in the case of TV norm and Re-weighted Basis Pursuit methods respectively. The experimental validation is carried out using a phantom having three inclusions of sizes 10 mm, 6 mm, and 3 mm. The inclusions have been localized successfully with errors of 0.089, 0.133, and 0.21, respectively.
A Combinatorial Approach to Quantitative Microwave Imaging for Breast Tumour Profiling Using SVBIM and SpaRSA
2023-12-01
PIER C
Vol. 139, 31-43, 2024
download: 72
A Small Size Wideband m -Shaped Polygonal Slot Antenna for X-Band Satellite Applications
Mostafa Mahmoud Rabie , Mohamed S. El-Gendy , Angie Reda El Damak , Fawzy Ibrahim and Hadia El-Hennawy
This paper presents a small size M-shaped polygonal slot antenna for X-band satellite telemetry and Synthetic Aperture Radar (SAR) applications. The proposed antenna has been designed on a Roger RT-Duroid 5880 substrate. The reflection coefficient |S11| of the proposed antenna covers the whole X-band from 6.63 GHz to 12.566 GHz. The proposed antenna is circularly polarized with axial ratio (AR) bandwidth that extends from 7.76 GHz to 8.58 GHz. The proposed antenna provides a simultaneous dual circular polarizations (RHCP and LHCP). The gain of the proposed antenna varies between 6.6 dBi and 9.4 dBi. The proposed antenna realizes an efficiency of 92%. The overall size of the proposed antenna is 17 x 16 x 0.508 mm3 (0.56λ0 x 0.53λ0 x 0.016λ0). Therefore, it is suitable to be employed in satellite telemetry application from 7.9 GHz to 8.4 GHz especially for CubeSats that have limited surface area. Apart from that, this antenna finds its applications in SAR on small satellites from 9 GHz to 10 GHz, military, and RFID tag (tracking-equipment). It has been observed that the measurement results match the simulated ones. The proposed antenna design can be practically employed for the previously mentioned applications.
A Small Size Wideband M-shaped Polygonal Slot Antenna for X-band Satellite Applications
2023-11-24
PIER C
Vol. 139, 21-29, 2024
download: 50
The Direct Torque Control of Brushless DC Motor Based on Sliding Mode Variable Structure
Gai Liu , Yiran Wu and Qingbo Shao
Aiming at the problem of slow response speed and poor anti-interference ability using the traditional PI control in the direct torque control strategy of brushless DC motor (BLDCM), the direct torque control (DTC) of the BLDCM based on the sliding mode change (SMC) structure is proposed. In the BLDCM DTC system under the new flux linkage set mode, the traditional PI control is replaced by the improved SMC control to realize the new torque given mode and realize the DTC of the BLDCM. Firstly, the integral sliding mode surface is used instead of the traditional linear sliding mode surface to optimize the continuity of the SMC structure and reduce the high-frequency perturbation caused by the differential phase, thus reducing the smooth torque and system steady-state error. Secondly, the system is simulated by MATLAB/SIMULINK; the given torque of the improved SMC is the most stable; and the speed response curve is smoother. Finally, the construction of the BLDCM test platform is completed. The experimental results show that in the BLDCM DTC control system of the new flux linkage set mode, based on the improved SMC, the system has faster response speed and stronger anti-interference, and shows stronger dynamic and static performance.
The Direct Torque Control of Brushless DC Motor Based on Sliding Mode Variable Structure
2023-11-23
PIER C
Vol. 139, 11-20, 2024
download: 107
Design of Permanent Magnet Synchronous Wind Power Control System
Huajun Ran , Wenjin Wei and Yue Gao
To tackle the slow response and insufficient interference resistance exhibited by permanent magnet synchronous motors (PMSMs) under traditional field-oriented control (FOC). This paper proposes an integral sliding mode controller (SMC) to improve the speed loop, and adaptive law is also developed using a nonlinear smooth function to eliminate the chattering phenomenon of the sliding mode control. Meanwhile, an extended state observer is designed to estimate and compensate for the disturbances caused by wind speed uncertainty and the system's internal disturbances. Then, model predictive control (MPC) is employed for the current loop to eliminate the overshoot and achieve fast tracking. Finally, a step-by-step model reference adaptive scheme (MRAS) is proposed to identify the parameters and eliminate the internal disturbances in addressing parameter perturbation in the motor during operation. The simulation results demonstrate that the enhanced system exhibits almost no overshoot, superior steady-state performance, quick dynamic response, and resistance to both internal and external disturbances, ultimately validating the efficacy of the approach.
Design of Permanent Magnet Synchronous Wind Power Control System
2023-11-19
PIER C
Vol. 139, 1-10, 2024
download: 94
Design of True Time Delay Line Based Octal Transmit Receive Module for Wideband Phased Arrays
Kilari Sreenivasulu , Kamla Prasan Ray , Alagarswami Vengadarajan and Dharmavarapu Srinivasa Rao
Wideband phased arrays for Electronic Warfare (EW) applications utilize narrowband phase shifters in a switched configuration to cover a multi-octave bandwidth in split bands. Wideband True Time Delay (TTD) line circuits are the best candidates to replace narrowband phase shifters in such systems, covering the complete operating bandwidth in a single step. The Transmit Receive Module (TRM) is a critical component of any phased array system. A novel design of a TTD line-based Octal Transmit Receive Module (OTRM) for a 32-element EW phased array over a frequency range of 1-6 GHz is presented in this paper. The OTRM is designed on a single multi-layer PCB by integrating eight transmit-receive (TR) channels, associated controllers, and power conditioning circuitry in a compact size and weight of 800 grams. The paper addresses challenges associated in design of TR channels to fit within the inter-element spacing of 14 mm and to achieve isolation of ≥40 dB between channels. The designed OTRM tunes time delay up to 508 ps maximum with a step of 2 ps by using a single TTD line circuit for ±45° scan coverage. The OTRM has demonstrated its potential capability for use in wideband Radar, EW, and Communication system applications. Efficient thermal management of the OTRM is achieved by introducing Copper coins below the final power amplifiers and a liquid cold plate to dissipate a heat load of 32 watts per TR channel. The proposed OTRM delivers transmit power of 8 watts (CW), receive gain of 25 dB, and a noise figure of 6 dB per TR channel with an overall efficiency of 19% (min) over a 5 GHz bandwidth. RF path analysis of the TR channel in transmit and receive paths is carried out using the Systemvue software tool. To verify the design of the OTRM over different time delay and attenuator states, measurements are conducted using a Vector Network Analyzer (VNA).
Design of True Time Delay Line Based Octal Transmit Receive Module for Wideband Phased Arrays