Dual Circular Polarization Research Articles

Dual band four port MIMO antenna with dual circular polarization for Wi-Fi/WiMAX applications

The planar compact four port circularly polarized printed MIMO antenna described in this article is small and intended to support Wi-Fi and WiMAX applications. Suggested four E-shaped monopole elements make up the dual circularly polarized (CP) MIMO antenna that has two left hand CP (LHCP) elements and two right hand CP (RHCP) elements. An I shaped strip is used to join separate ground planes of designed E shaped monopole antenna to have same voltage levels. A good diversity performance is achieved with an envelope correlation coefficient (ECC) of less than 0.15. The 60 mm × 60 mm antenna is designed from FR4 material, which is inexpensive and has a 1.6 mm thickness. Using a high-frequency structure simulator (HFSS), the suggested MIMO antenna is designed and optimized. The measured findings demonstrate the circular polarization, 3-dB axial ratio beamwidth, impedance bandwidth of 2.11 GHz −2.42 GHz and 3.40 GHz-3.51 GHz, adequate axial ratio bandwidth (ARBW) of the suggested MIMO antenna along with high isolation of −17 dB, gain of 3.43 and 2.09 dBic at 2.4 GHz and 3.5 GHz respectively, TARC (Total active reflection coefficient) of less than 0 dB, a CCL (Channel capacity loss) of lesser than 0.4 bits/sec/Hz, and an MEG (Mean effective gain) value of less than 3 dB.

AcpAS: An Advanced Circularly Polarized Antenna Structure for an Airborne Relay Communication System

The airborne relay system is an important support for improving the stability of communication systems in complex electromagnetic environments. As a key component of the airborne relay system, the antenna needs to have characteristics such as high gain, dual circular polarization, wide beam coverage, and miniaturization. Based on the septum circular polarizer, this paper proposes a high-performance circularly polarized antenna structure suitable for airborne relay systems, named AcpAS. The structure consists of a coaxial feed port, a coaxial-to-waveguide transition, a septum circular polarizer, and a parabolic metal housing. Based on this structure, two antennas operating at 19.6 GHz to 21.6 GHz and 29.2 GHz to 31.2 GHz are designed in this paper. Simulated and measured results show that the two antennas have dual circular polarization characteristics, with beam coverage range of more than ±55° for gains higher than 0 dBi, and the radiation patterns exhibit good symmetry and wide-beam coverage characteristics.

Design of Automotive Radar Antenna for Covering Middle- and Long-Range With Dual-Circular Polarization

Design of Automotive Radar Antenna for Covering Middle- and Long-Range With Dual-Circular Polarization

Dual Circularly Polarized Diplexer-Antenna Array With Low-Sidelobe Level Based on Gap Waveguide at Ka-Band

Dual Circularly Polarized Diplexer-Antenna Array With Low-Sidelobe Level Based on Gap Waveguide at Ka-Band

Mechanism of Circular Polarization in Giant Pulses and Fast Radio Bursts

Some giant pulses and fast radio bursts (FRBs) exhibit notable circular polarization, which remains unexplained and carries significant implications for their emission mechanisms. In this study, we identify multiple nanoshot pairs uniformly spaced by approximately 21 μs within a giant pulse emitted by the Crab pulsar. Among these pairs, a subset displays left-hand and right-hand circular polarization in two distinct nanoshots. We propose that the occurrence of such nanoshot pairs with dual circular polarizations arises from the fragmentation of a linearly polarized nanoshot along the magnetic field lines under the extreme Faraday effect, leveraging highly asymmetrical pair plasma and the ultra-intense field of nanoshots. The asymmetry in pair plasmas is likely linked to discharge activities in pulsars. Moreover, the intense field of nanoshots induces cyclotron resonance within the magnetosphere, effectively slowing down the propagation velocity of the circularly polarized mode. Our findings suggest that Crab giant pulses composing nanoshots originate in its polar cap region and escape the magnetosphere along the polar magnetic field. This mechanism can also elucidate the origin of circular polarization in some FRBs and thus lends support to their magnetospheric origin.

Four‐port dual CP MIMO antenna with enhanced isolation for 5G applications

SummaryIn this paper, a 4 × 4 MIMO (multiple‐input multiple‐output) antenna with metasurface (MS), which is composed of dual circularly polarized (CP) patch antennas, is proposed for 5G (sub‐6 GHz) applications. The MIMO antenna consists of four microstrip patch antennas. In order to improve the isolation of the MIMO antenna, parasitic elements are placed on the MS and layer of patch antennas. In addition, a substrate‐integrated waveguide (SIW) structure is used at the center of the MIMO antenna for this purpose. The proposed MIMO antenna is fabricated for validation tests. The antenna has overall dimensions of 115 mm × 115 mm × 3.2 mm (1.219 × 1.219 × 0.033 , where is the free space wavelength at the lowest operating frequency in 10‐dB impedance bandwidth). The MIMO antenna has 10‐dB impedance bandwidth (IBW) from 3.3 to 3.8 GHz (14.08%), 3‐dB axial ratio bandwidth (ARBW) from 3.42 to 3.69 GHz (7.59%), and 6.36‐dBi peak gain. The isolation is greater than 28.14 dB in the n78 frequency band (3.3–3.8 GHz).

Wideband Dual Circularly Polarized Substrate-Integrated Cavity Antenna Array for Millimeter-Wave Applications

Wideband Dual Circularly Polarized Substrate-Integrated Cavity Antenna Array for Millimeter-Wave Applications

Wideband Dual Circularly Polarized Helical Antenna Array for Satellite Applications

Wideband Dual Circularly Polarized Helical Antenna Array for Satellite Applications

Optically Ambidextrous Reflection Circularly Polarized Luminescence Film with High Dissymmetry Factor and On‐Demand Handedness

AbstractThe self‐assembled cellulose nanocrystal (CNC) film has a left‐handed layered structure, which makes the reflection of right‐handed circularly polarized (CP) light a challenge. Herein, a nematic phase layer is designed and inserted into the chiral organization, to work as a half‐wave retarder and make the ambidextrous CP light reflection. The maximum reflectivity exceeds 80%, which breaks the 50% limitations of single‐direction light reflection and is the current maximum in all the reported CNC‐based films. This “sandwich‐like” structure displays different optical properties on both sides, displayed as the chromatism and the inversion of the circular dichroism signals. The dual CP light reflection and direction‐dependent optical phenomena are reserved in the synthesized circularly polarized luminescence (CPL) film, with the dissymmetry factor (glum) of −0.4245. However, this luminescent intensity and single‐direction emission are not enough in advanced optical systems. This work designs a triple CPL amplification path and develops the handedness inversion strategy, with the glum of −1.0551 and 0.4082. Then, the dual‐directional CPL emission films are designed, where the chiral optics can be switched on‐demand. Finally, the photonic crystal films are applied in the anti‐counterfeit and chiral superstructure induction.

A planar-structured circularly polarized single-layer MIMO antenna for wideband millimetre-wave applications

This paper presents a planar multiple-input-multiple-output (MIMO) antenna with dual circular polarization (CP) and a simple geometry for millimetre-wave band. The proposed design is featuring a fully grounded coplanar waveguide (CPW) and a systematically perturbed feedline radiator. The symmetry of the electric field is disrupted using varying stub sizes and offsets between the stubs, resulting in wideband operation and circularly polarized waves. Following full optimization of the physical parameters, the numerical design is validate experimentally. The results indicate that the proposed antenna design achieves a −10 dB impedance bandwidth from 24.6 GHz to 32.1 GHz, with an axial ratio (AR) of 3 dB or less from 26 GHz to 31.8 GHz. The peak realized gain is 10.3 dBic, with steady broadside radiation. The envelope correlation coefficient (ECC) is 0.01, and the diversity gain is 10 dB across the operating band. The planar structure and the wideband performance of the proposed design makes it suitable for application necessitating fix beam applications in the mm-wave band.

Compact dual-band dual sense circularly polarized flexible antenna with polarization rotation metasurface for off-body communications

ABSTRACT A dual-band dual circularly polarised flexible antenna, operating at 3.5 GHz for WiMAX and 5.8 GHz for industrial, scientific, and medical (ISM) bands, is proposed for wearable applications. The antenna design integrates a wideband comb-shaped slotted monopole antenna with a polarisation rotation metasurface (PRMF). The PRMF unit cell consists of a nested split square ring in the corner and a square ring in the centre, where the split square rings facilitate polarisation conversion and the centre square ring enhances the axial ratio. The PRMF integration helps achieve dual circular polarisation (CP) radiation, with left-handed CP in the WiMAX band and right-handed CP in the ISM band. The proposed monopole antenna and PRMF are printed on a conformal polyimide substrate, with a total footprint of 48 × 48 mm2 (0.31λo2). The proposed antenna has a 10 dB impedance bandwidth of 24.9% (3.2 to 4.2 GHz) and 18.9% (5.3 to 6.43 GHz), a 3-dB axial ratio bandwidth of 11.1% and 21.4%, and a peak gain of 6.4 and 6.7 dBic in both bands. Numerical and measured results demonstrate that the antenna performs well in the presence of human body and structural deformations. These attributes make the proposed design highly suitable for off-body wearable applications.

A Stable-Gain Millimeter-Wave Fabry-Perot Antenna Based on Circular Polarizer-Integrated PRS with Positive Reflective Phase Gradient

In this paper, we present a millimeter-wave Fabry-Perot antenna with dual resonances, circular polarization, and stable gain. To achieve circularly polarized radiation, we integrate a receiver-transmitter circular polarizer into the partially reflective surface (PRS) of the antenna. The PRS is specifically designed with a positive reflective phase gradient, which contributes to a stable gain in the dual-resonance frequency band. For the radiation source, we adopt a linearly-polarized substrate-integrated waveguide cavity-backed slot fed by a printed ridge gap waveguide. Experimental measurements conducted on a fabricated prototype of the proposed antenna demonstrate its impedance and axial ratio bandwidths of 28.6–30.0 GHz and 28.6–29.6 GHz, respectively. Furthermore, the antenna exhibits a peak gain of 12.1 dBi and a gain fluctuation lower than 0.6 dB within the operational frequency band.

A miniaturized dual wide‐band polarization reconfigurable antenna integrated with artificial magnetic conductor for next‐generation wireless applications

SummaryIn today's intricate wireless communication environment, ensuring system quality demands the use of a reliable and versatile antenna system. This research article introduces a polarization reconfigurable antenna integrated with a 4 × 4 Artificial Magnetic Conductor (AMC) surface. The AMC unit cell exhibits a triple‐band reflection phase response at 1.8GHz, 4.5GHz, and 5.5GHz, demonstrating double negative metamaterial behavior. The antenna features two distinct C‐shaped metal strips connected to two PIN diodes, enabling dynamic current distribution adjustment. Consequently, the proposed antenna offers three reconfigurable states, facilitating seamless switching between dual circular polarization (left and right‐hand circular polarization) and linear polarization. With a frequency coverage ranging from 1.29 to 2.52GHz and 3.59 to 6.15GHz, the antenna boasts a maximum axial ratio (AR) bandwidth of 31.96%. Additionally, it achieves a maximum peak gain of 5.5 dB and maintains front‐to‐back ratio (FBR) values exceeding 25 dB, while recording a minimum specific absorption rate (SAR) value of 0.1059 W/kg. The integration of the AMC surface ensures enhanced performance of the antenna. Experimental results from constructed prototypes closely align with simulation outcomes, validating the effectiveness of the proposed antenna. Consequently, this antenna holds significant promise for next‐generation wireless applications.

A novel dual-band elliptical ring slot MIMO antenna with orthogonal circular polarization for 5G applications

This paper presents a dual-band 4-element multiple-input-multiple-output (MIMO) antenna featuring orthogonal circular polarization (CP) for Sub-6 GHz 5G applications. The single antenna combines a non-uniform width elliptical ring slot and a feed network, utilizing two L-shaped secondary feed lines to generate CP within the targeted frequency bands (3.55−3.80 GHz and 4.60−4.80 GHz). Using the single antenna as a unit antenna, a 4-element MIMO configuration is devised, employing a mirror technique for element placement to achieve orthogonal CP. This placement method effectively enhances coverage area and enlarges the 3-dB axial ratio bandwidth in the lower band (3.40–3.80 GHz). The common ground connections among elements are established via four strip lines. The antenna shows a good diversity performance considering the envelope correlation coefficient (ECC) result of less than 0.04 and isolation greater than 15 dB. The simulated gains of the MIMO antenna are 4 and 5 dBic in the respective bands. The single and MIMO antennas are fabricated, and the antennas’ performances are evaluated. A good agreement is observed between the measured and simulated results. The dual CP and diversity performances of the MIMO antenna make it more efficient for 5G wireless applications.

Switchable Dual Circularly Polarized Luminescence in Through-Space Conjugated Chiral Foldamers.

Organic materials with switchable dual circularly polarized luminescence (CPL) are highly desired because they can not only directly radiate tunable circularly polarized light themselves but also induce CPL for guests by providing a chiral environment in self-assembled structures or serving as the hosts for energy transfer systems. However, most organic molecules only exhibit single CPL and it remains challenging to develop organic molecules with dual CPL. Herein, novel through-space conjugated chiral foldamers are constructed by attaching two biphenyl arms to the 9,10-positions of phenanthrene, and switchable dual CPL with opposite signs at different emission wavelengths are successfully realized in the foldamers containing high-polarizability substitutes (cyano, methylthiol and methylsulfonyl). The combined experimental and computational results demonstrate that the intramolecular through-space conjugation has significant contributions to stabilizing the folded conformations. Upon photoexcitation in high-polar solvents, strong interactions between the biphenyl arms substituted with cyano, methylthio or methylsulfonyl and the polar environment induce conformation transformation for the foldamers, resulting in two transformable secondary structures of opposite chirality, accounting for the dual CPL with opposite signs. These findings highlight the important influence of the secondary structures on the chiroptical property of the foldamers and pave a new avenue towards efficient and tunable dual CPL materials.

Ka-Band Wide-Angle Scanning Phased Array with Dual Circular Polarization

A wide-angle scanning phased array with dual circular polarization in the Ka-band is presented in this paper. To improve the scanning capability of the phased array, the microstrip element is modified by loading many metal posts at its center and periphery. In addition, a stripline coupler is designed to achieve dual circularly polarized (CP) radiation, and the inner conductor of the subminiature micro-push-on (SSMP) connectors for feeding the coupler is extended to the top layer of the multilayer element by introducing an open stub, which simplifies the assembly process between the SSMP connector and multilayer printed circuit board (PCB) due to through-hole soldering instead of blind-hole soldering. The proposed element can cover a frequency range from 28 GHz to 30.5 GHz with a relative bandwidth of 8.5% in the Ka-band. An 8 × 8 phased array is constructed based on this proposed element, and a wide-angle scanning range from −65° to +65° is obtained for the dual circular polarization. The proposed array has a gain fluctuation of 5.1 dB and an axial ratio (AR) of less than 3.3 dB during beam-steering. The prototype is fabricated and measured, with a good agreement between the measured and simulated results. The proposed phased array can be applied in a Ka-band millimeter-wave (MMW) communication system.

C-Slot Circular Polarized Antenna for Hybrid Energy Harvesting and Wireless Sensing

This paper presents a new hybrid energy harvesting on electromagnetic solar for wireless energy harvesting of ambient from sensors of low-power devices. The axial ratio (AR) requirements produce Left-Hand Circular Polarization (LHCP) and Right-Hand Circular Polarization (RHCP) and simultaneously produce a 90-degree phase difference during energy harvesting, adopting a new design in designing a dual-feed broadband circular polarized (CP) antenna. To get the frequency band 2.3–2.4 GHz, we propose a C-Slot antenna with a circular patch dual feed. To estimate the diversity of the phase and magnitude output of the feed configuration under AR value, we used a 50 Ohm feed network output of the characteristic analysis for a dual feed CP antenna. An Axial ratio frequency range of less than 3 dB is achieved using polarization analysis with different branch channel couplers. To produce a DC output voltage, a high-frequency rectifier circuit embedded with a thin-film solar cell on the antenna is then connected to two T-junction power divider rectifiers, resulting in a high-efficiency design. A complete system-level analysis will include multiple signal classification methods of powered ambient RF energy using a wireless energy harvesting array that proposes a compact structure and demonstrates optimal configuration. Reliable operation in typical indoor environments indicates a self-contained sensor Node. Therefore, it has significant implications for powering small electronics and wireless sensor applications independently of the IoT Network or real implementation telecommunications industry.

Shared Aperture Dual-Band Dual Circularly Polarized Multibeam Antenna for Satellite-Assisted Internet of Vehicles

Shared Aperture Dual-Band Dual Circularly Polarized Multibeam Antenna for Satellite-Assisted Internet of Vehicles

Wideband Dual Circularly Polarized Helical Antenna With Reduced Mutual Coupling for MIMO Applications

Wideband Dual Circularly Polarized Helical Antenna With Reduced Mutual Coupling for MIMO Applications

Wideband Simultaneous Dual Circularly Polarized Phased Array Subarray with Scalable Characteristics for Satellite Communications

This paper proposes a budget-friendly, highly integrated, and low-profile wideband simultaneous dual circularly polarized phased array subarray with scalable characteristics for satellite communications. In order to achieve wideband, the antenna unit is not only fed by double-fed point probe contact, but also by electromagnetic coupling. Moreover, the dual circularly polarized radiation of the antenna unit is realized by a miniaturized 3 dB bridge-type phase-shift network. In addition, the phased array subarray uses metalized vias to reduce inter-element crosstalk, which effectively improves the active voltage standing wave ratio (VSWR) and beam steering characteristics. Also, the subarray has interchangeability and versatility, enabling convenient two-dimensional expansion to form a tile-type phased array antenna. Besides, the phased array subarray can be used to achieve two-dimensional ±40∘ beam scanning in both the azimuth and elevation planes. Within ±40∘ beam scanning, the active VSWR of the subarray is less than 2.5 in 9.55 - 14.35 GHz (40.17%). At 12.1 GHz, the two-dimensional gain decreases by less than 2.1 dB and 1.95 dB, respectively. The proposed antenna exhibits good performance in terms of matching and beam steering characteristics, which make it suitable for use in future 5G/6G phased array antenna systems.