Multiband Circular Polarization Research Articles

Multiband Circularly Polarized Apex Etched Hybrid Rectangular Dielectric Resonator for Wireless Applications

Multiband Circularly Polarized Apex Etched Hybrid Rectangular Dielectric Resonator for Wireless Applications

A multiband circular polarization selective metasurface for microwave applications

In this research article, a multiband circular polarization selective (CPS) metasurface is presented. A reciprocal bi-layered metasurface is designed by introducing the chirality in the structure. The top layer of the proposed metasurface is composed of circular split-ring resonator with a cross shape structure inside it. The same structure is printed on the bottom side of the proposed metasurface by rotating it at an angle of 90° to achieve chirality in the structure. The proposed metasurface is able to add CPS surface capability between 5.18 and 5.23 GHz for y-polarized incident wave. For the frequency band of 5.18–5.23 GHz, the transmission goes up to − 4 dB, while the polarization extinction ratio (PER) reaches up to − 27.4 dB at 5.2 GHz. Similarly, for x-polarized incident wave, three strategic CPS operating bands are achieved within the frequency ranges of 10.64–10.82 GHz, 12.25–12.47 GHz, and 14.42–14.67 GHz. The maximum PER of 47.16 dB has been achieved for the 14.42–14.67 GHz frequency band at 14.53 GHz. Furthermore, the response of the metasurface does not vary against oblique incidences up to 45°. The simple structure, angular stability, multiband and miniaturized size make this metasurface an outstanding applicant for polarization conversion and biomedical applications.

Design of Multi-band Circularly Polarized Microstrip Antenna

Design a multi-band circularly polarized microstrip antenna for ISM (2.4GHz, 5.8GHz) and WiMAX (3.3GHz-3.6GHz).Using Ansoft HFSS15.0 for the simulation analysis, The size of the resonance point and the resonance bandwidth are adjusted by opening four triangular grooves on four sides of the radiation patch. The simulation results show that the frequency band of the antenna’s return loss below -10dB is 2.38GHz-2.52GHz,3.37GHz-3.45GHz, and 5.6GHz-5.9GHz. The antenna meets the design requirements of multi-frequency and miniaturization.

Circular Dichroism: Intrinsic Chirality and Multispectral Spin‐Selective Transmission in Folded Eta‐Shaped Metamaterials (Advanced Optical Materials 4/2020)

Controlling the polarization states of light is of fundamental importance in modern photonic applications. In article number 1901448, Shengyan Yang, Changzhi Gu and co-workers have developed a novel folded metamaterial that possesses gigantic intrinsic 3D chirality and simultaneously supports multispectral spin-dependent transmission. A remarkable circular dichroism approaching unity is experimentally achieved, with >93% of the selected circularly polarized light being transmitted. The folded metamaterials provide an appealing platform for versatile photonic applications in multiband circular polarizers, polarization transformers, chiral imaging, and optical information processing.

A Multiple L-Shaped Slot Loaded Antenna with Multiband Circularly Polarized for WLAN & WiMAX Applications

In this paper, a compact four asymmetric Lshaped slots loaded antenna has been designed for the wireless network & WiMAX applications. The antenna consists of four asymmetrical L-shaped slots with an area of 94 mm2 , 66 mm2 , 44 mm2 & 28 mm2 respectively & probe fed provides for the excitation to the antenna. The antenna can be operated between 2.6 GHz to 5.4 GHz frequency range. The proposed antenna resonant at three different frequencies as 2.95 GHz, 4.85 GHz & 5.23 GHz & the return loss are -16.5 dB, -13.6 dB & -14.6 dB respectively. It produces one linear polarization at 2.95 GHz frequency & two circular polarizations at frequencies 4.84 GHz & 5.21 GHz. The proposed antenna finds its application in WLAN (2.94-3.05) GHz, WiMAX (4.81-4.92) GHz & IEEE 802.11a (5.15-5.35) GHz. The proposed antenna simulation results show that good radiation pattern with multi frequency band in comparison of reported designs.

Multi-band Circularly Polarized Microstrip Antenna for Wireless Communication

Multi-band Circularly Polarized Microstrip Antenna for Wireless Communication

ULTRA-COMPACT MULTI-BAND CHIRAL METAMATERIAL CIRCULAR POLARIZER BASED ON TRIPLE TWISTED SPLIT-RING RESONATOR

An ultra-compact chiral metamaterial (CMM) using triple-layer twisted split-ring resonators (TSRRs) structure was proposed, which can function as a multi-band circular polarizer. This ultra-compact structure CMM can convert an incident linearly y-polarized (x-polarized) wave propagating along thez(+z) direction to the transmitted left circularly polarized (LCP) waves at 7.28 GHz, 13.22 GHz and 15.49 GHz while the right circularly polarized (RCP) waves are at 9.48 GHz simultaneously. In addition, the large polarization extinction ratio (PER) of more than 20 dB across four resonance frequencies can be achieved. The experiment results are in good agreement with the numerical simulation results. The surface current distributions of the structure are analyzed to illustrate this linear to circular polarization conversion. The unit cell structure is extremely small both in longitudinal and transverse directions. Good performances and compact design of this CMM suggest promising applications in circular polarizers that need to be integrated with other compact devices.

Multiband Circular Polarizer Based on Fission Transmission of Linearly Polarized Wave forX-Band Applications

A multiband circular polarizer based on fission transmission of linearly polarized wave forx-band application is proposed, which is constructed of 2 × 2 metallic strips array. The linear-to-circular polarization conversion is obtained by decomposing the linearly incidentx-polarized wave into two orthogonal vector components of equal amplitude and 90° phase difference between them. The innovative approach of “fission transmission of linear-to-circular polarized wave” is firstly introduced to obtain giant circular dichroism based on decomposition of orthogonal vector components through the structure. It means that the incident linearly polarized wave is converted into two orthogonal components through lower printed metallic strips layer and two transmitted waves impinge on the upper printed strips layer to convert into four orthogonal vector components at the end of structure. This projection and transmission sequence of orthogonal components sustain the chain transmission of electromagnetic wave and can achieve giant circular dichroism. Theoretical analysis and microwave experiments are presented to validate the performance of the structure. The measured results are in good agreement with simulation results. In addition, the proposed circular polarizer exhibits the optimal performance with respect to the normal incidence. The right handed circularly polarized wave is emitted ranging from 10.08 GHz to 10.53 GHz and 10.78 GHz to 11.12 GHz, while the left handed circular polarized wave is excited at 10.54 GHz–10.70 GHz and 11.13 GHz–11.14 GHz, respectively.

Multiband Circularly Polarized Cavity-Backed Crossed Dipole Antenna

In this paper, novel designs of miniaturized and multiband circularly polarized (CP) cavity-backed crossed dipole antennas are proposed. Single-band and dual-band LC resonators are placed along both the arms of double-sided printed dipoles to realize dual-band and tri-band operations, respectively. Identical pairs of loaded dipoles are placed in crossed configuration to achieve dual-band and tri-band CP operations using vacant printed ring. Cavity-backed reflector is further employed to get enhancement in the 10-dB impedance bandwidth (IBW) and 3-dB axial ratio bandwidth (ARBW) along with unidirectional radiation pattern and wide 3-dB axial ratio beamwidth in the operating bands. Measured results confirm that the proposed dual-band cavity-backed crossed dipole antenna exhibits CP operation bandwidths ( $\text {AR} and ${{\text S}_{{11}}} ) of 7.50% and 26.15%, with center frequencies at 1.87 and 2.83 GHz, respectively. The corresponding CP operating bandwidths for the tri-band cavity-backed crossed dipole antenna are 1.24%, 9.55%, and 14.95% centered at 1.61, 2.20, and 2.81 GHz, respectively. The proposed dual-band and tri-band antennas can be used in DCS/PCS/Global Star/UMTS/WLAN applications.

MULTIBAND CIRCULARLY POLARIZED STACKED MICROSTRIP ANTENNA

In this paper, a multiband circularly polarized capacitive coupled stacked microstrip antenna is proposed. The multiband circular polarization (CP) is achieved by corner truncation, embedding slits and inclined slots on a three layered antenna structure. The proposed antenna also shows wideband behavior with an impedance bandwidth of 52.13% in the frequency range of 4.85 GHz to 8.27 GHz, while 3 dB axial ratio bandwidths in five CP bands are 0.51%, 4.54%, 0.33%, 0.83% and 1.29% in the frequency range of 5.12 GHz to 5.15 GHz, 5.45 GHz to 5.70 GHz, 5.90 GHz to 5.92 GHz, 6.25 GHz to 6.31 GHz and 7.68 GHz to 7.78 GHz, respectively. The antenna prototype is fabricated, and simulated results as axial ratio, radiation pattern and the reflection coefficient are validated with measured result.

Multi-band circular polarizer based on a twisted triple split-ring resonator

A multi-band circular polarizer using a twisted triple split-ring resonator (TSRR) is presented and studied numerically and experimentally. At four distinct resonant frequencies, the incident linearly polarized wave can be transformed into left/right-handed circularly polarized waves. Numerical simulation results show that a y-polarized wave can be converted into a right-handed circularly polarized wave at 5.738 GHz and 9.218 GHz, while a left-handed circularly polarized wave is produced at 7.292 GHz and 10.118 GHz. The experimental results are in agreement with the numerical results. The surface current distributions are investigated to illustrate the polarization transformation mechanism. Furthermore, the influences of the structure parameters of the circular polarizer on transmission spectra are discussed as well.

ASYMMETRIC CHIRAL METAMATERIAL MULTI-BAND CIRCULAR POLARIZER BASED ON COMBINED TWISTED DOUBLE-GAP SPLIT-RING RESONATORS

In this paper, an ultrathin asymmetric chiral metamaterial multi-band circular polarizer using combined twisted double-gap split-ring resonators (DGSRRs) is proposed and investigated. Experiment and numerical simulations are in good agreement, indicating that when a y-polarized wave is incident on this chiral metamaterial propagating along iz direction, the right circularly polarized (RCP) wave is emitted at 5.58GHz and 9.34GHz, while left circularly polarized (LCP) wave is excited at 6.41GHz and 7.65GHz, in addition to large polarization extinction ratio of more than 18dB at the four resonant frequencies. The surface current distributions are studied to illustrate the transformation behavior for both circular polarizations.

Design for Triple Band Patch Array Antenna with High Detection Ability

This paper proposes a theoretical analysis of hidden device detection and a design of multiband circular polarization patch array antenna for non-linear junction detector system application. A good axial ratio of circular polarization patch antenna is realized by a new approach that employs inclined slots, two rectangular grooves and a truncated ground for the conventional antenna. A good axial ratio of the 1.5 dB lower is measured by having an asymmetric gap distance between the ground planes of the coplanar waveguide feeding structure. The common ground plane of the linear array has an optimum trapezoidal slot array to reduce the mutual coupling without increasing the distance between the radiators. The higher gain of about 1 dBi is realized by using the novel common ground structure. The measured return loss, gain, and axial ratio of the proposed single radiator, as well as the proposed array antennas, showed a good agreement with the simulated results.

Compact dual-band circular polarizer using twisted Hilbert-shaped chiral metamaterial

We propose a kind of chiral metamaterial inspired from the fractal concept. The Hilbert fractal perturbation in the twisted split ring resonator element results in compact metamaterial and breaking mirror symmetry, which readily forms chirality over triple bands. The discrepancy between co-polarization conversion and cross-polarization conversion over multiple bands can be explored for multifunctional devices. A multiband circular polarizer is then numerically and experimentally studied in the X band based on the bilayered twisted Hilbert resonator with mutual 90° rotation. The ability of transforming linearly polarized incident waves to circularly polarized waves is unambiguously demonstrated with high conversion efficiency and large polarization extinction ratio of more than 20 dB across dual bands. Moreover, exceptionally strong optical activity and circular dichroism are also observed.

MULTI-BAND CIRCULAR POLARIZER USING ARCHIMEDEAN SPIRAL STRUCTURE CHIRAL METAMATERIAL WITH ZERO AND NEGATIVE REFRACTIVE INDEX

A novel multi-band circular polarizer is proposed by using a bilayered chiral metamaterial (CMM). The unit cell of the CMM is composed of four Archimedean spiral structures, which are twisted 90 - to each other in the upper and bottom layers. When a linearly polarized wave incidents on this circular polarizer, the simulation result shows that the transmission of right circularly polarized (RCP) wave can be obtained at 14.28GHz and 15.96GHz, while the transmission of left circularly polarized (LCP) wave is emitted at 15.3GHz and 16.88GHz. The retrieval results reveal that the efiective refractive index of the CMM closes to zero or negative at the vicinity of four resonances. The experimental results are in good agreement with the numerical results.

Multi-band circular polarizer using planar spiral metamaterial structure

A multi-band circular polarizer is proposed by using multi layered planar spiral metamaterial structure in analogy with classic spiral antenna. At three distinct resonant frequencies, the incident linearly polarized wave with electric field paralleling to one specific direction is transformed into left/right-handed circularly polarized waves through electric field coupling. Measured and simulated results show that right-handed circularly polarized wave is produced at 13.33 GHz and 16.75 GHz while left-handed circularly polarized wave is obtained at 15.56 GHz. The surface current distributions are studied to investigate the transformation behavior for both circular polarizations. The relationship between the resonant positions and the structure parameters is discussed as well.

Research and design of multimode GNSS antenna technology

With the merits of wide coverage, huge capacity of communications, good transmission quality, etc., Global Satellite Navigation System (GNSS) plays a vital role in the fields, such as the aviation, marine, mapping, timing and information services. As the essential part of satellite navigation system, Antenna’s overall performance is good or bad which have a significant impact on Navigation and Positioning System. In this paper, a multi-mode circular polarization GNSS antenna with single-feed stacked patch combined stub technology is presented. By inserting different cross shape stubs, the top square patch performs GNSS high frequency multi-band circular polarization, and the right-hand circular polarization mode in the GNSS low frequency is achieved through inserting different cross shape stubs in the center of the lower square patch. Theoretical analysis and simulation results show that the proposed multi-mode circular polarization antenna can meet multi-system positioning needs of the terminal users of satellite navigation.