PIER Letters | PIER Journals

2024-06-18

PIER Letters

Vol. 121, 27-32, 2024

download: 106

Controlling the Polarization Conversion and Asymmetric Transmission Properties of a Metasurface by Controlling the Chirality of Its Unit Cell

Sayan Sarkar and Bhaskar Gupta

Chirality (mirror asymmetry) of the unit cell ensures the phenomenon of polarization conversion in a metamaterial/metasurface. In this communication, we control the polarization conversion and asymmetric transmission properties of a metasurface by controlling the chirality of its unit cells. Radio Frequency PIN diode switches are used to control the chirality. When the switches are turned OFF, the unit cells become chiral, and the metasurface successfully exhibits polarization conversion as well as asymmetric transmission for linearly polarized incident waves. When the switches are turned ON, the unit cells become achiral and lose both the above properties. The polarization conversion switching phenomenon is also observed for circularly polarized incident waves. A simple ultrathin metasurface is designed and fabricated to demonstrate these properties.

Controlling the Polarization Conversion and Asymmetric Transmission Properties of a Metasurface by Controlling the Chirality of Its Unit Cell

2024-06-16

PIER Letters

Vol. 121, 19-25, 2024

doi:10.2528/PIERL24050201

download: 102

Common-Mode Voltage Analyses for Space Vector PWM Based on Double Fourier Series

Jian Zheng , Cunxing Peng , Liangshuai Lin and Kaihui Zhao

Space vector pulse width modulation (SVPWM) is widely used in three-phase inverters. As the performance requirements of inverters increase, there is a demand to suppress common-mode voltages (CMVs) generated by SVPWM. In order to suppress the CMVs, it is necessary to mathematically analyze the CMVs. By using a mathematical analysis method based on double Fourier series, general expressions of CMV harmonic amplitudes and spectra are obtained for seven-segment SVPWM and five-segment SVPWM. Comparative analyses on the CMV general expressions are performed for the two SVPWMs, and the CMV harmonics characteristics for the two SVPWMs are summarized. Simulations are carried out in an inverter-driven permanent magnet motor system, and simulation results are in good agreement with calculation ones, which verifies the correctness and validity of the mathematical analysis. Based on these analyses, a more in-depth research can be conducted on the CMV suppression.

Common-mode Voltage Analyses for Space Vector PWM Based on Double Fourier Series

2024-06-15

PIER Letters

Vol. 121, 13-18, 2024

doi:10.2528/PIERL24042901

download: 92

Analysis and Optimization on Weight Accuracy of the Adaptive Interference Cancellation

Yunshuo Zhang , Songhu Ge , Huanding Qin , Hongbo Liu , Zhongpu Cui and Jin Meng

Weight and reference signal are utilized in adaptive interference cancellation (AIC) for vector weighting to generate the signal with equal amplitude and opposite phase to the interference signal. Weight accuracy becomes the core factor to determine the performance of the AIC. In this letter, we analyze the influence of the weight accuracy on interference suppression performance, propose the quantitative characterization method of the weight accuracy with weight noise as an indicator, study the performance and influencing factors of the weight accuracy, and propose the optimization design method. The characteristics of weight accuracy in interference cancellation are verified by theoretical simulation analysis. This work fills in the blank of weight accuracy analysis and has solid theoretical value for exploring the capability boundary of the AIC.

Analysis and Optimization on Weight Accuracy of the Adaptive Interference Cancellation

2024-06-15

PIER Letters

Vol. 121, 7-12, 2024

doi:10.2528/PIERL24041803

download: 84

Uncertainty Analysis Method for EMC Simulation Based on the Complex Number Method of Moments

Jinjun Bai , Bing Hu , Haichuan Cao and Jianshu Zhou

The Method of Moments (MoM) is a non-embedded uncertainty analysis method that has been widely used in Electromagnetic Compatibility (EMC) simulations in recent years due to its two major advantages of high computational efficiency and immunity from dimensional disaster. A random variable sensitivity calculation method based on the Complex Number Method of Moments (CN-MoM) is proposed in this paper to improve the accuracy of the MoM in standard deviation prediction and thereby enhance the credibility of EMC simulation uncertainty analysis results. In the parallel cable crosstalk prediction example in the literature, the result of the Monte Carlo Method (MCM) is used as the standard, and the accuracy of the new method proposed in this paper is quantitatively verified using the Feature Selective Validation (FSV) method. Compared with the MoM, the proposed method can significantly improve the calculation accuracy of the standard deviation results without sacrificing simulation efficiency.

Uncertainty Analysis Method for EMC Simulation Based on the Complex Number Method of Moments

2024-06-14

PIER Letters

Vol. 121, 1-6, 2024

doi:10.2528/PIERL24040901

download: 129

Design and Implementation of a Millimeter Wave Active Antenna for UAV Communications

Ning Liu , Guanfeng Cui , Guotao Shang , Ruiliang Song and Bo Zhang

The millimeter wave communication technology used for drones could combine the advantages of drones and millimeter waves, providing high-speed data transmission and wide area network coverage capabilities, and has broad application prospects in military and civilian communication systems. Millimeter wave active antennas have the advantages of miniaturization, high frequency band, and flexible shaping, which is of great significance for ensuring the high-speed dynamic communication ability of drone platforms. In this paper, a millimeter wave active antenna suitable for unmanned aerial vehicles (UAVs) is designed and verified, operating in 24.75-27.5 GHz and adopting Antenna in Package (AiP) design. Frequency band test and communication performance test is conducted. To open and close the RF channels, the antenna's operating frequency range can be shown in the vector network analyzer which meets the design frequency band 24.75-27.5 GHz requirements. By loading 5G millimeter wave standard signals, the antenna can achieve real-time demodulation of 100 MHz, 256 QAM signals. The test shows that the system can meet the requirements of beam tracking and real-time information transmission during high-speed dynamic flight of UAVs. It has broad application prospects in UAV communication systems.