Quad-Band Transmissive Metasurface with Linear to Dual-Circular Polarization Conversion Simultaneously

Simple design of a wideband and wide-angle reflective linear polarization converter based on crescent-shaped metamaterial for Ku-band applications

Design and analysis of a dual-band polarization converting metasurface is presented in this letter. The proposed converter, which consists of two square split ring resonators, exhibits peak resonances at frequencies of 5.6, 7.3, 8.8, 15.1, and 15.9 GHz. The surface behaves as a polarization converter for linearly polarized incident waves in two frequency ranges, i.e., 5.4–9.0 GHz with a polarization conversion ratio (PCR) $\geq$ 93 $\%$ , and 14.6–16.1 GHz with a PCR $\geq$ 99 $\%$ ). The size and thickness of the unit cell are, respectively, $0.126\lambda _{\mathrm{o}}$ and $0.057\lambda _{\mathrm{o}}$ , where $\lambda _{\mathrm{o}}$ is the largest wavelength (corresponding to the lower frequency). The mechanism of polarization conversion is studied by examining the surface currents for all the resonance frequencies. Both simulated and experimental results reveals that the polarization converter can be utilized in C-, X- and Ku-band applications.

Design and Experimental Analysis of Dual-Band Polarization Converting Metasurface

A simple design of a broadband multifunctional polarization converter using an anisotropic metasurface for X-band application is proposed. The proposed polarization converter consists of a periodic array of the two-corner-cut square patch resonators based on the FR-4 substrate that achieves both cross-polarization and linear-to-circular polarization conversions. The simulated results show that the polarization converter displays the linear cross-polarization conversion in the frequency range from 8 to 12 GHz with the polarization conversion efficiency above 90%. The efficiency is kept higher than 80% with wide incident angle up to 45°. Moreover, the proposed design achieves the linear-to-circular polarization conversion at two frequency bands of 7.42–7.6 GHz and 13–13.56 GHz. A prototype of the proposed polarization converter is fabricated and measured, showing a good agreement between the measured and simulated results. The proposed polarization converter exhibits excellent performances such as simple structure, multifunctional property, and large cost-efficient bandwidth and wide incident angle insensitivity in the linear cross polarization conversion, which can be useful for X-band applications. Furthermore, this structure can be extended to design broadband polarization converters in other frequency bands.

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Simple design of efficient broadband multifunctional polarization converter for X-band applications

Metasurfaces (MSs) offer us an efficient way to control electromagnetic wave polarization due to its capability of flexible wave manipulation and compact configurations. However, the design of dual-band polarization conversion MS with high angular stability is still a challenge, especially in transmission geometry. Here, we propose a dual-band linear-to-circular (LTC) polarization conversion MS with high angular stability by using an array of multi-resonance meta-atoms. The meta-atom consists of two outer double split-ring layers and a central bar layer with circle-slot and can realize circular polarization at two bands with high efficiency and angular stability. The MS can transform the x-polarized wave into right-hand circular polarization (RHCP) at lower band and left-hand circular polarization (LHCP) at higher band and an opposite role for the y-polarized wave. The results show that the MS operates with insertion loss less than 0.5 dB and 0.3 dB and axial ratio below 3 dB in the frequency range of 9.05-9.65 GHz and 12.55-13.1 GHz, respectively. Moreover, our MS is insensitive to the oblique incident waves and can operate at high performance with the incident angle less than 55°. The proposed MS provides a new avenue to design meta-devices with dual frequency property and also high angular stability.

Dual-band transmissive circular polarization generator with high angular stability

Ultra-wideband linear-to-circular polarization converter with ellipse-shaped metasurfaces

The rapid development of modern communication systems propels the demand of high performance and miniaturization of RF/microwave components. Power dividers and filters are indispensable circuit components in amplifiers and antenna feed-networks which occupy large footprint of circuit broads, particularly at low frequency. The purpose of this study is to initiate a new type of planar transmission line with unique dual signal-path characteristics and ultimately achieve circuit miniaturization. In this paper, a novel technique of consolidating microstrip lines (MLs) and coplanar waveguide (CPW) lines on a single dielectric substrate, designated as the composite microstrip/CPW line (CM/CPW line), is proposed. With reference to the average line length of ML and CPW, it warrants a physical length reduction of 48.3% and further achieves a reduction of 80.8% after zigzagging CM/CPW line. The proof-of-concept design example of a two-way Wilkinson power divider (WPD) has demonstrated the effectiveness of the miniaturization technique. The simulation, in combination with the experimental results, validates that a size reduction factor of 86.9% when compared to conventional one has been achieved while maintaining a fractional bandwidth of 57.7% for the WPD. 

Miniaturization of microwave planar circuits using composite microstrip/coplanar-waveguide transmission lines

In this letter, a novel compact frequency beam-scanning antenna (FBSA) using composite waveguide based on folded half-mode substrate integrated waveguide (FHMSIW) and spoof surface plasmon polaritons (SSPP) is proposed. The novel composite FHMSIW/SSPP waveguide with compact size and high field-confinement is initiated by embedding dual SSPP structures into the FHMSIW. Its transmission characteristic has flexible features from both the FHMSIW and SSPP. To excite the radiation mode from the composite slow-wave waveguide, a simple single-sided sinusoidal modulation method is designed and used. In this way, the common open stop-band problem around broadside is effectively eliminated, and the beam-scanning range of the antenna can be flexibly designed without changing the modulation structure. The presented scanning antenna owns a compact size and a simple feeding network. The experimental results indicate that the proposed FBSA can achieve continuous beam scanning from backward to forward in a wide scanning range of 60° within a bandwidth of 7.7–10.1 GHz. The stable unidirectional radiation patterns and appropriate gains are also realized in the entire operating frequency band.

Design and Analysis of a Compact Frequency Beam-Scanning Antenna Based on Composite FHMSIW/SSPP Waveguide

In this study, a triple-band microstrip antenna with compact size and simple structure is proposed for WLAN and 5G applications. The radiating element consists of a circular patch, a Y-shaped patch, and a monopole impedance converter. In order to obtain the desired operating bands, the monopole impedance converter is inserted between the circular patch and Y-shaped patch. The proposed antenna can work in the frequency range of 2.38∼2.53 GHz, 3.29∼4.11 GHz, and 4.72∼5.01 GHz, with the corresponding peak gains of 4.09 dBi (2.4 GHz), 2.95 dBi (3.5 GHz), and 4.01 dBi (4.9 GHz), respectively. The measures’ results are in approximate agreement with the simulated values, which shows that the proposed compact antenna can offer omnidirectional radiation, appropriate gains, and sufficient bandwidths.

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A Triple-Band Microstrip Antenna with a Monopole Impedance Converter for WLAN and 5G Applications

In this manuscript, we reconsider the amplitude and phase combination of the plane-wave generator (PWG) from an electromagnetic field inverse radiation perspective and further propose a new method based on the Gauss-Newton inversion (GNI) to perform the inverse design of PWG. Furthermore, the wideband antenna pattern is applied in the transfer function and makes the inversion results closer to the engineering implementation. Compared with the traditional least-squares method (LSM) and singular value decomposition (SVD) method, the proposed method owns the merits of less amplitude range of the input source and stronger robustness.

Shi-Bin Wang

Papers

Ultra-wideband linear-to-circular polarization converter with ellipse-shaped metasurfaces

Miniaturization of microwave planar circuits using composite microstrip/coplanar-waveguide transmission lines

Design and Analysis of a Compact Frequency Beam-Scanning Antenna Based on Composite FHMSIW/SSPP Waveguide

A Triple-Band Microstrip Antenna with a Monopole Impedance Converter for WLAN and 5G Applications

Design of Plane Wave Generator Based on Strong Robust Inverse Radiation Problem Solving Method