Chen Wang

Bio: Chen Wang is an academic researcher from Anhui Normal University. The author has contributed to research in topics: Antenna (radio) & Polarization (waves). The author has an hindex of 1, co-authored 4 publications receiving 1 citations.

A Broadband Ultra-Thin Polarization Rotator Using Periodically Loaded Parallel Strip-Lines

Abstract: A polarization rotator based on loaded parallel strip-lines is theoretically and experimentally investigated. The unit cells are short-stub loaded parallel strip-lines. The arrays on the front and back layers are rotated by 90° to each other. By loading the stubs, good coupling between the two layers is obtained. Such a structural rotation along with the loading stubs allow the $y$ -polarized wave to be converted to $x$ -polarized wave through field coupling. A broad transmission bandwidth of 30% (86-116 GHz) by using the proposed structure has been reached. In addition, the PTFE substrate is only 0.25 mm thick, which is less than $0.1\lambda $ at 86 GHz. Such a thickness allows the polarization rotator to be easily mounted on antenna radomes. The fabricated prototype demonstrates good agreement between simulation and measurement results.

A Dual-band Non-destructive Dielectric Measurement Sensor Based on Complementary Split-ring Resonator

Abstract: A dual-band non-destructive dielectric constant sensor based on the complementary split ring 14 resonators is presented. The resonators for both bands use the complementary split ring structure of 15 different sizes. Numerical simulation demonstrates that the resonating frequency and quality factor is 16 dependent on the variation of dielectric constant and loss tangent, making it a potential structure for 17 dielectric measurement. To search for the optimal thickness for measurement, parametric study is 18 conducted and the retrieval expressions are obtained for both bands. The measured results indicate an 19 accuracy of 1.5% in comparison with the data in the literature. In addition, the effect of air gap has 20 been analyzed, showing that it is an important error source and eliminating such effect can improve 21 the measurement accuracy.

Reflection type dual-band dual-rotation-direction microwave band linear-circular polarization converter

Abstract: The invention discloses a reflection type dual-band dual-rotation-direction microwave band linear-circular polarization converter. The polarization converter is formed by periodically arranging unit structures. Each unit structure is of a three-layer structure, the lower layer is a whole metal layer, the middle layer is a dielectric layer, and the upper layer is a metal pattern layer composed of asquare metal layer and a chamfered square ring. The reflection type linear-circular polarization converter efficiently converts x (y) polarized waves into right (left) circular polarized waves in a frequency band of 10.6 GHz to 14.0 GHz in two frequency bands, and converts the x (y) polarized waves into left (right) circular polarized waves in a frequency band of 17.8 GHz to 21.1 GHz. The converter is simple in structure and convenient to machine. The reflection type dual-band and dual-rotation linear-circular polarization converter can be applied to the fields of satellite communication, electronic investigation, radio and television and the like.

Broadband Reflective Polarization Rotator Built on Single Substrate

Abstract: A broadband polarization rotator built on single substrate is presented in this work. The device is designed for operation in the K and Ka bands. A slant array is used to achieve polarization rotation by 90° in a reflective manner. Broadband has been obtained, with the operation frequency range covering 15–45 GHz for 3 dB criteria, which is almost 100% fractional bandwidth. In addition, the insertion loss is less than 0.3 dB over a moderate broad incident angle from 0°–20°. Furthermore, the polarization conversion ratio can be as high as 0.95. By using a bi-static method, the fabricated prototype is measured, and the measured results demonstrate satisfactory agreement with the simulation ones. In comparison with other reflective designs in the literature, this design provides good bandwidth as well as polarization conversion ratio. Miniaturization can be investigated to increase the angular stability.

Modified ground and slotted MIMO antennas for 5G sub-6 GHz frequency bands

Abstract: Multiple input multiple output (MIMO) systems, which use multiple antennas to deliver faster data rates, are one of the promising methods in 5G services. 5G is a popular issue among the world's main telecom firms currently. The sub-6 GHz band for 5G applications in various countries lies between 3 and 5 GHz. The sub-6 GHz 5G bands are 3.4–3.8 GHz in Europe, 3.1–3.55 GHz in the USA, and 3.3–3.6 GHz and 4.8–4.99 GHz in China. This paper presents a two-element slotted octagon-shaped antenna operating in the sub-6 GHz band (3.1–4.5 GHz) for 5G applications. A T-formed isolation structure is placed at a ground plane to minimize mutual coupling between MIMO antennas. The proposed MIMO antenna has physical dimensions of 55 × 38 mm2 and an envelope correlation coefficient or correlation of 0.0004 over the entire operating band. The antenna operates at 3.6 GHz, with a return loss of 40.8 dB at the resonance. An antenna prototype has been investigated and proven to be of excellent quality in terms of performance like isolation >20 dB, efficiency >80%, and mean effective gain <−3 dB over the full operating band.

Extraction of the Complex Relative Permittivity from the Characteristic Impedance of Transmission Line by Resolving Discontinuities

Abstract: This paper describes a material complex permittivity extraction technique based on four measurements of two identical coaxial (circular and rectangular) lines, distinguished by their lengths. The paper presents a combination of propagation parameters through mixing the eigenvalue principle and the lines’ characteristic impedance to improve the extraction techniques of intrinsic material parameters. However, the accuracy of some material parameters is insufficient, as the discontinuities at the feedline–ideal line interface are not adequately solved. In these cases, a new formulation of the complex effective permittivity is suggested, associating the propagation constant and the characteristic impedance for a homogeneous structure. Next, uncertain errors that can negatively impact the method are removed from the mathematical expression. Then, a characteristic impedance expression is developed in the second stage to improve the mathematical formulation. Finally, a correction coefficient in tune with reality and a polynomial function to amend the behavior of some of the curves are provided. The approach’s novelty lies in its ability to extract and correct the characteristic impedances despite discontinuity impedances at the ideal line–feedline interface. Several materials are tested with circular and/or rectangular coaxial fixtures to confirm the performance of the suggested method. The test cells are homogeneous, full, and long, at 80 mm and 100 mm (50 mm for the circular one). Determining the propagation constant from the eigenvalue of the wave cascading matrix (WCM) is a fundamental step in this method. Knowing the propagation constant helps to automatically compute a correction coefficient that depends on the fixture and the material being tested. Experimental validation is performed in the frequency range from some MHz to 10 GHz, 13.5 GHz, and 20 GHz, according to the tested material. Both test fixtures are filled with the sample material, with a vacuum considered as a reference parameter. The method’s accuracy is better than 5% on the relative permittivity parameter throughout the frequency range. All the tested samples are compared with the results using the filled two-transmission-line technique (FTTL), using only the eigenvalue determination principle. The trapper cells are coaxially circular and rectangular.

Dual-band polarization conversions and optical diode based on bilayer T-shaped metamaterial

Abstract: • The work achieved x- to -y / y- to -x conversions at 106 / 163 THzfor +z propagation. • The incident waves are blocked for – z propagation. • The T xy and T yx are increased to 0.74 and 0.75 with the PCR s reach up to nearly 100%. In this work, we propose a dual-band optical diode based on a bilayer T -shaped metamaterial. This optical diode can conveniently convert the x -polarized wave to y -polarized one at about 106 THz and convert the y -polarized to x -polarized wave at around 163 THz when linearly polarized waves impinge on the sample under a forward normal incidence (+z direction). The dual-band polarization conversion ratios can reach up to 99.9 % and 99.6 % at 106 and 163 THz, respectively. In addition, the bi-layer metamaterial works as an optical diode located around the frequencies 106 and 163 THz, i.e. the x - and y -polarized plane waves can pass through the metamaterial in the forward direction, however, they are prevented from backward. The maximum asymmetric transmission parameters are 0.46 and 0.50. At last, both the ratios and bandwidth of dual-band cross-polarization conversion can be conveniently manipulated by the rotation angle θ . This proposed dual-band polarization conversions and optical diode may have promising applications in optical nano-devices, such as optical switches and polarization converters.