A Millimeter-Wave Spoof-Surface-Plasmon-Polaritons-Fed Dual-Polarized Microstrip Patch Antenna Array

A novel Spoof Surface Plasmon Polaritons (SSPPs)–fed dual-polarized microstrip patch antenna for millimeter-wave application is proposed in this paper. Owing to the single-conductor features of SSPPs, the proposed antenna has a compact and low-profile geometry that can be integrated into a single-layered substrate conveniently. The antenna has a measured impedance bandwidth of 14%. An average gain of 3 dBi and stable radiation patterns are also obtained. Then, by combining a pair of SSPPs feed network with the patch elements, a 1 × 4 SSPPs fed dual-polarized microstrip patch antenna array with satisfied broadside radiation is designed in 5G millimeter-wave band.

A novel spoof surface plasmon polaritons (SSPPs)-fed microstrip patch antenna with a simple low-profile geometry is proposed. The method of inserting an open-ended planar single-conductor SSPPs section into the supporting substrate under the rectangular patch is investigated originally to excite the required TM10 mode and to achieve the promising impedance matching simultaneously. An impedance bandwidth of 8.2%, stable linearly polarized unidirectional radiation, and a gain of around 6 dBi are confirmed by a fabricated prototype. A planar single-conductor parallel feed network consisting of the SSPPs power dividers is then analyzed, which has a simulated insertion loss of around 8 dB. By combining the feed network with the patch elements, a $1\times 4$ SSPPs-fed microstrip patch antenna array is designed in the Ka -band. The measurement verifies the stable radiation with an enhanced gain of about 12 dBi across the operating band. Due to the planar configurations with low cost and promising performance, the presented SSPPs-fed patch antenna and array may find potential applications in future millimeter-wave wireless systems.

In this paper, the spoof surface plasmon polaritons (SSPPs) transmission line (TL) of periodical grooved bow-tie cells is proposed. The complex propagation constant and characteristic impedance of the SSPPs TLs and microstrip lines (MLs) are extracted using the analytical method of generalized lossy TL theory. The properties of the SSPPs TLs with different substrates and the same geometrical configuration are experimented. Then, for comparison, two ML counterparts are also experimented, which shows that the SSPPs TL is less sensitive to the thickness, dielectric constant and loss tangent of the chosen substrate below the cutoff frequency, compared with the ML ones. The single-conductor co-planar quasi-symmetry unequal power divider based on this SSPPs TL is presented in microwave frequencies. For experimental validation, the 0-dB, 2-dB, and 5-dB power dividers are designed, fabricated, and measured. Both simulated and measured results verify that the unequal power divider is a flexible option, which offers massive advantages including single-conductor co-planar quasi-symmetry structures, wide-band operation, and convenient implementations of different power-dividing ratios. Hence, it can be expected that the proposed unequal power dividers will inspire further researches on SSPPs for future design of novel planar passive and active microwave components, circuits and systems.

A microwave power divider based on spoof surface plasmon polaritons was presented here. The proposed divider was composed of two different sizes of periodic circular hole array metal strips on a substrate with relative dielectric constant of 3.3, loss angle of 0.003 and thickness of 0.76 mm. Compared to rectangular hole and rectangular groove, the dispersion curve of circular hole was more deviated from the light line and the cut-off frequency was lowest. The simulated results show the S21 and S31 of the power divider are equal and about 3dB with the cut-off frequency of 10.8 GHz which means the input power is divided into two outports equally. According to the planar structure, the proposed divider has some significant advantages such as high confinement, adjustability and easy integration which can play an important role in the microwave communication circuits and systems.

This paper presents the design of a dual-band, dual-polarization metamaterial-based antenna. It combines two functions; the Global Positioning System GPS function and the Distance Measure Equipment DME function on the same patch element. The metamaterial structure has a large bandwidth (1.05-1.57 GHz) covering the GPS and DME spectra. It consists of periodic sub-wavelength square metallic patches etched on a thin dielectric substrate (1/40 wavelength) backed by a metallic ground plane. The patch antenna is inserted in the middle of the dielectric substrate. The experimental results confirm the excellent frequency behavior of the ultra-thin metamaterial-based dual-function antenna.

In this paper, a novel kind of mode composite transmission line (MC-TL) is proposed, and a dual-band power divider with a large frequency ratio using this novel MC-TL for 5G communication systems was developed. The proposed MC-TL was developed using spoof surface plasmon polaritons (SSPPs) and a corrugated substrate-integrated waveguide (CSIW) transmission line, which supports both a surface plasmon mode and TE10 mode, independently. The surface plasmon mode operates in the grooves of the surface metal layer, while the TE10 mode works in the substrate between two metal layers. These two parts can transmit different modes at independent frequencies. This structure can be used in dual-band transmission lines with a high frequency ratio. The characteristics and design of the MC-TL (SSPPs and CSIW) are analyzed and illustrated. The MC-TL was fabricated and measured to demonstrate its performance. Moreover, based on the proposed MC-TL, a dual-band power divider with a large frequency ratio (operating at 3 GHz and 28 GHz simultaneously) was also designed and fabricated. It can cover the frequency of a fifth-generation communication system perfectly. The measured outcomes align closely with the simulated results, demonstrating robust agreement and showcasing excellent transmission capabilities.

A wideband and high-gain planar endfire antenna based on spoof surface plasmon polaritons (SSPPs) at millimeter-wave (MMW) band is presented. First, a unilaterally corrugated surface antenna is demonstrated to radiate endfire beam tilted up from the flat plane of the corrugated metal teeth due to the effect of finite ground plane. Then, a SSPPs endfire antenna is designed with two symmetrically corrugated surfaces on the double sides of a metal strip. To excite the desired beam, the feeding network is comprised of a power divider and two L-shaped slots, so as to simultaneously produce oppositely tangential electric fields and identically normal electric fields. Moreover, the two equivalent identically tangential magnetic current sources above the corrugated surfaces are excited by flared feeding slot transitions. As a result, a synthetic endfire beam with zero-tilted angle is achieved. In final, such an antenna, operating in a range from 30 to 50 GHz with 50% fractional bandwidth, is designed with maximum gain of 16 dBi, as well confirmed in the experiment. The proposed SSPPs endfire antenna holds a very low profile and it is promising for application in MMW communication systems.

A broadband ± 45° dual-polarized dipole antenna with stable radiation pattern is proposed. The antenna consists of four dipoles, a shaped reflector and a broadband feeding network. To realize ± 45° dual-polarize radiation pattern, the dipoles are formed as a square loop and fed by the feeding network. The feeding network is formed by four baluns and two 1-to-2 power dividers. The baluns and the power dividers are used to feed the dipoles for achieving better performance in impedance matching and bandwidth. The square reflector is employed to stabilize the radiation. With this method, the antenna obtains the impedance bandwidth for 58.5% (|S11|>15 dB within 2.3–4.2 GHz), and the 3-dB beamwidth of the proposed antenna is within 65° ± 5° in the horizontal plane.

A compact wideband dual-polarized omnidirectional antenna array for base-station applications is proposed. It consists of ten antenna units. To generate ±45° dual-polarized ominidirectional radiation with low gain variation for each unit, three close-in crossed-dipole elements are uniformly arranged in a regular triangle shape and excited by two 1-to-3 power dividers with equal magnitude and phase, acting as a dual-polarized loop antenna. To obtain wide impedance bandwidth for each unit, the dipole element and power divider are designed to operate in a wide and well-matched band. Moreover, the unit features steady structure, easy fabrication, and high scalability, which makes it convenient to form an antenna array. To achieve a high gain for base-station applications, a ten-unit antenna array is designed, fabricated, and measured. A wide impedance bandwidth of 52.3% (1.62–2.77 GHz) for standing-wave ratio (SWR) < 1.5 and a high port-to-port isolation of 26 dB are realized. It also features a high gain of 10.3 ± 0.9 dBi and a small gain variation of less than 2.5 dB in the horizontal plane. Additionally, the sidelobe suppression of 18 dB and null filling below the main vertical beam are obtained by the designed feeding networks. These results make the proposed design attractive in base-station applications.

A broadband dual-polarized planar antenna is proposed for 2G/3G/LTE base stations. The dual-polarized antenna is composed of two perpendicularly crossed bow-tie dipoles. Each bow-tie dipole is excited by a microstrip stub that is directly fed by a coaxial line, making the dual-polarized antenna full planar. Due to the coupling between two crossed bow-tie dipoles, a broad bandwidth is achieved. It is shown that the dual-polarized antenna has a bandwidth of 45% (1.7-2.7 GHz) for return loss >15 dB with an isolation of higher than 30 dB between two polarization input ports. The dual-polarized antenna has a half-power beam width (HPBW) of around 65 ° and an average gain of 8.5 dBi for slant ±45° polarizations. An 8-element dual-polarized planar antenna array is developed for base station applications. A bandwidth of 56% (1.63-2.9 GHz) is obtained for the antenna array. The antenna gain of the array is about 16 dBi and the HPBW is 65±8° for each polarization.

ABSTRACTThis article presents the design and performance analysis of a high gain dual-polarized two-element cylindrical dielectric resonator antenna (DRA) array excited by two orthogonally placed H-shaped apertures. The antenna is operated in dual linear polarized mode by exciting TM110 (HEM11) mode in two DRAs using aperture coupling. The proposed antenna has a −10 dB impedance bandwidth of 9.52% (6.0–6.6 GHz) with isolation more than 40 dB among the two ports. Realization of gain enhancement and high isolation are accomplished by simultaneously exciting two DR elements using a pair of wideband Wilkinson's power divider placed on the bottom side of the substrate. The measured gain of the proposed antenna for both the ports is found to be 12.5 dB with a front to back ratio of 16 dB. The antenna has an overall radiation efficiency of 94% and symmetrical radiation patterns with co-polarization levels 40 dB higher than the cross-polarization in both the principal planes (XY and XZ) of bore-sight direction.

A quarter-wave patch antenna (QWPA) suffers from the fundamental disadvantage of a high cross-polarization level (XPL) in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> -plane. In this letter, we present a new method to overcome this issue by integrating a gradient spoof surface plasmon polariton (SSPP) structure on the side edges of QWPAs. In the proposed scheme, the SSPP structure is gradient loaded from the open end to the short end to suppress the cross-polarization radiation from the side edges. Both the single-ended and differentially-driven QWPAs are investigated and compared based on the proposed method. Simulated results indicate that SSPP-loaded QWPAs exhibit remarkable miniaturization and XPL reduction as compared with the conventional ones. To validate the feasibility of the proposed method, a differential prototype is fabricated and measured. Experimental results show that the proposed antenna achieves a distinct cross-polarization reduction of over 20 dB and a compact size of 0.088 × 0.095 λ0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at the center operating frequency.

This letter presents a simple and compact dual-polarized linear antenna array characterizing high interport isolation for in-band full-duplex communications. By using the symmetrically shared-interface configuration integrated with a 180° hybrid, the self-interference resulting from the impedance mismatching between the antenna and feeding network and the coupling among the antenna elements can be well suppressed theoretically. Furthermore, to achieve the high isolation in practice among a wide frequency band, a slotline-based 180° hybrid is proposed and studied, which features a high isolation between the sum and differential ports. For further verification, a demonstrator of a 1 × 4 array centered at 5.0 GHz is developed and fabricated. The measurements denote that the shared −10 dB impedance bandwidth of the two ports is from 4.75 to 5.18 GHz, and the interport 50 dB isolation bandwidth is from 4.55 to 5.66 GHz (over 21.7%).

This work presents a novel dual-polarized antenna array tailored for Internet of Things (IoT) applications, specifically designed to operate in the millimeter-wave (mm-wave) spectrum within the frequency range of 30–60 GHz. Leveraging printed ridge gap waveguide (PRGW) technology, the antenna ensures robust performance by eliminating parasitic radiation from the feed network, thus significantly enhancing the reliability and efficiency required by IoT communication systems, particularly for smart cities, autonomous vehicles, and high-speed sensor networks. The proposed antenna achieves superior radiation characteristics through a cross-shaped magneto-electric (ME) dipole backed by an artificial magnetic conductor (AMC) cavity and electromagnetic bandgap (EBG) structures. These features suppress surface waves, reduce edge diffraction, and minimize back-lobe emissions, enabling stable, high-quality IoT connectivity. The antenna demonstrates a wide impedance bandwidth of 24% centered at 30 GHz and exceptional isolation exceeding 40 dB, ensuring interference-free dual-polarized operation crucial for densely populated IoT environments. Fabrication and testing validate the design, consistently achieving a gain of approximately 13.88 dBi across the operational bandwidth. The antenna’s performance effectively addresses the critical requirements of emerging IoT systems, including ultra-high data throughput, reduced latency, and robust wireless connectivity, essential for real-time applications such as healthcare monitoring, vehicular communication, and smart infrastructure.

In this article, a spoof surface plasmon (SSP) ring resonator to generate dynamically reconfigurable vortex beams is proposed. According to the phase constant control of the SSP and the harmonic radiation principle, the tunable cylindrical vector vortex beams (VVBs) with different topological charges can be obtained. The tunable system that operates by electronic control would utilize varactors to change the wavenumber of SPP on the ring resonator and realize the reconfigurable VVBs modes at a fixed frequency. All VVBs have excellent orbital angular momentum (OAM) purity (above 90%). Interestingly, the antenna also simultaneously radiates the scalar vortex beams with tunable OAM modes. Both numerical simulations and experimental characterizations confirm the theoretical predictions. Because the designed antenna has the advantages of simple feeding network, easy bias circuit, as well as miniaturization and integration compatibility, we anticipate that the antenna will enable a wide range of applications for future wireless communication and imaging technologies.