PIER Letters | PIER Journals

2024-04-13

PIER Letters

Vol. 119, 51-57, 2024

download: 32

Application of Improved SROM Based on RBF Neural Network Model in EMC Worst Case Estimation

Bing Hu , Yingxin Wang , Shenghang Huo and Jinjun Bai

The Stochastic Reduced-Order Models (SROM) is a non-embedded uncertainty analysis method that has the advantages of high computational efficiency, easy implementation, and no dimensional disasters. Recently, it has been widely used in the field of EMC simulation. In the process of optimizing electromagnetic protection design, the worst-case estimation value is an extremely important uncertainty quantification simulation result. However, the SROM has a large error in providing this result, which limits its application in the field of EMC simulation prediction. An improved SROM based on the Radial Basis Function (RBF) neural network algorithm is proposed in this paper, which improves the fitness function in the genetic algorithm center clustering process and constructs an RBF neural network model to obtain accurate worst-case estimation results. The accuracy improvement effect of the algorithm proposed in this paper in worst-case estimation is quantitatively verified by using a parallel cable crosstalk prediction example from published literature.

Application of Improved SROM Based on RBF Neural Network Model in EMC Worst Case Estimation

2024-04-12

PIER Letters

Vol. 119, 43-50, 2024

doi:10.2528/PIERL23112703

download: 51

Frequency Reconfigurable Antenna Design and Analysis with White LED Lamp, Red and Infrared LEDs

Valsalam Reji and Chellappan Thangappan Manimegalai

This research presents a frequency reconfigurable antenna analysis for wireless applications using multiple light sources. The antenna is constructed on a Roger substrate with (44x28) mm² dimensions. The antenna comprises two parallel tuner arrangements in addition to a V-shaped radiating section. Two optical PIN photodiodes are connected to the two parallel monopole tuners, which serve as the antenna's switching component and are utilized to adjust the resonant frequency. These two PIN photodiode switches work in the 600-1050 nm wavelength range. To analyze the antenna performance, four different optical sources are used. They are white colour LED lamp, 650 nm optical fiber, red LEDs, and IR LEDs. In every case, the antenna performance analysis are carried out for all the four logic state of the switches (00, 01, 10, 11). Under white lamp test conditions, the antenna's maximum gain is 6 dBi, and when red LEDs are employed as the optical source, its maximum bandwidth is 21%. The antenna reconfigurable frequencies are 3.5 GHz and 5-5.8 GHz (5, 5.2, 5.5, 5.8 GHz).

Frequency Reconfigurable Antenna Design and Analysis with White LED Lamp, Red and Infrared LEDs

2024-04-11

PIER Letters

Vol. 119, 35-41, 2024

doi:10.2528/PIERL24030104

download: 48

SIW Filter Based on a CPW Resonator and a Hybrid Electromagnetic Coupling Structure

Xiaohei Yan , Minjie Guo , Wenjing Mu , Xiumei Huang and Haiyan Zeng

This paper proposes a hybrid cross-coupled filter that utilizes a coplanar waveguide (CPW) resonator and a hybrid electromagnetic coupling structure. The filter features a flexible and controllable position of the transmission zeros and a quasi-elliptical response. It is composed of two CPW structures etched within the upper metal surface of a second-order substrate-integrated waveguide (SIW) resonant cavity. By adjusting the dimensions of the two CPW structures between the SIW resonant cavities and the width of the inductive coupling window, the strengths of the electric and magnetic couplings can be easily controlled to achieve a controllable hybrid cross-coupling effect in order to adjust the position of the transmission zeros and ultimately to realize the third-order filter with quasi-elliptical response characteristics. Simulation and test results indicate that the filter has a center frequency of 4.55 GHz, a -3 dB bandwidth of 180 MHz, a relative bandwidth of 4%, an insertion loss of -0.9 dB in the passband, a return loss of over 15 dB, and two transmission zeros located at 4.4 GHz and 4.7 GHz, respectively. The filter has several advantages, including a simple structure, low insertion loss, small circuit size, good frequency selectivity, and flexible and controllable transmission zeros. These features make it suitable for use in 5G (sub-6 GHz) wireless communication systems.

SIW Filter Based on a CPW Resonator and a Hybrid Electromagnetic Coupling Structure

2024-04-05

PIER Letters

Vol. 119, 27-33, 2024

doi:10.2528/PIERL24030407

download: 89

A Compact MIMO Antenna with Wideband Charaecteristics for WiFi 6E/X-Band Applications

Janani Sasikumar and Kanmani Ruby Erode Dhanapal

A novel proposal for upcoming wireless applications introduces a dual-band, highly decoupled, and compact microstrip patch co-planar waveguide (CPW)-fed MIMO antenna. This low-profile antenna exhibits narrow wide-band performance across the frequency bands of 6.2 to 11.2 GHz, with dimensions of 20 × 20 mm³ on a standard FR4 substrate. Through integration onto a printed circuit board (PCB) measuring 20 × 20 mm², the antenna configuration is expanded to a 4 × 4 MIMO arrangement. Individual antennas within this setup maintain a significant isolation of around 20 dB in the absence of a decoupling mechanism. Fabrication of the designed four-port antenna allows for practical measurement of various antenna parameters. The measured results closely align with simulated outcomes, encompassing S parameters, far-field patterns, and MIMO characteristics such as envelope correlation coefficient, channel capacity loss, and total active reflection coefficient. These results suggest that the antenna design presented in this study holds promise for future wireless applications.

A Compact MIMO Antenna with Wideband Charaecteristics for WiFi 6E/X-band Applications

2024-04-03

PIER Letters

Vol. 119, 21-26, 2024

doi:10.2528/PIERL24010804

download: 91

Comparative Study of High-Resolution RCS Models of Motorcyclists in W-Band Extracted from Measurements

Sevda Abadpour , Mario Pauli , Jan Siska , Nils Pohl and Thomas Zwick

Reliably modeling vulnerable road users (VRUs) such as motorcyclists in the virtual environment is indispensable in developing over-the-air (OTA) validation test methods. However, there are still challenges arising from many possible variations of VRUs, which may participate in the traffic scenarios. Therefore, it is essential to model them precisely and demonstrate consistency between virtual evaluation and reality. To achieve this goal, the VRUs must be modeled based on their backscattering behavior which can be prepared based on high-resolution (HR) radar cross section (RCS) measurements. This work presents the backscattering behavior of motorcyclists as one of the critical VRUs in traffic scenarios. The extracted model of a motorcyclist is analyzed and compared based on HR-RCS measurements with different motorcycle variants. This evaluation is a prerequisite for developing a realistic model of VRUs and ensuring an adequate level of accuracy.

Comparative Study of High-resolution RCS Models of Motorcyclists in W-band Extracted from Measurements

2024-04-03

PIER Letters

Vol. 119, 15-19, 2024

doi:10.2528/PIERL24021403

download: 102

A Simplified Extended Multilayer SIW Supporting TE₀₁ Mode Integrated with a Feeding Structure

Tzichat M. Empliouk , Christos I. Kolitsidas and George Kyriacou

In this letter, a TE₀₁ operation of a multilayered Substrate Integrated Waveguide (SIW) is presented. To enable the propagation of this typically unsupported mode, the SIW is integrated with feeding layer and with an Electromagnetic Band Gap (EBG) structure, exciting and confining the field within the proposed waveguide structure. The EBG is simply stacked on top and bottom of the proposed structure, allowing for ease of manufacturing. The overall proposed structure is simulated and measured, and the results indicate very low insertion loss in the passband of the waveguide.

A Simplified Extended Multilayer SIW Supporting TE<sub>01</sub> Mode Integrated with a Feeding Structure

2024-03-30

PIER Letters

Vol. 119, 7-13, 2024

doi:10.2528/PIERL24021201

download: 131

A Novel Filter with Reconfigurable Bandwidth OR Transmission Zeros Based on a Multiple-Mode Stub-Loaded Resonator

Liangzu Cao and Shouzhan Li

This paper presents a novel bandpass filter with reconfigurable bandwidth or transmission zeros. The proposed filter is based on a multiple-mode stub-loaded resonator. Three PIN diodes are utilized as switching elements to achieve four switchable operating states. The measurement results indicate that the 3 dB fractional bandwidth (FBW) of the filter can be varied from 32.3% to 70% at the centre frequency of 2.2 GHz, and the stopband attenuation is higher than 35 dB. The filter size is only about 0.28λ_g×0.19λ_g.

A Novel Filter with Reconfigurable Bandwidth or Transmission Zeros Based on a Multiple-mode Stub-loaded Resonator

2024-03-26

PIER Letters

Vol. 119, 1-6, 2024

doi:10.2528/PIERL24020702

download: 142

Scanned Antenna Arrays with Random Deactivated Elements

Noor Waadullah Yaseen and Jafar Ramadhan Mohammed

Usually inactive or also known as thinned elements are used to simplify the array design complexity by turning off some of the active elements in uniformly filled arrays. Consequently, the far-field radiation characteristics such as sidelobe level, beamwidth, and directivity may be negatively changed if no optimizer is used. Further, these radiation characteristics may be unavoidably deteriorated when the main beam is scanned to new directions other than the referenced broadside direction. In this paper, an efficient optimization method based on the genetic algorithm and a dynamic deactivation method is proposed to randomly deactivate a number of array elements to minimize the peak sidelobe level and at the same time maintain the array directivity undistorted, while scanning the main beam. The deactivation method chooses optimally the suitable number of elements and their locations that need to be deactivated such that the resulting radiation characteristics positively change according to the specified cost function. Also, the proposed scanned array uses binary coefficients to activate and deactivate the array elements, thus, the feeding network of the proposed array is very simple, and it can be easily implemented in practice. Through extensive simulation results, we show that the proposed optimization method has good performance under wide range of scanned main beam directions. It is also found that the number of deactivation elements (i.e., the optimization variables) increases with larger scan angle.