Complex Feeding Network Research Articles

Beam steerable MIMO antenna based on conformal passive reflective metasurface for 5G millimeter wave applications

A conformal reflective metasurface fed by a dual-band multiple-input multiple-output (MIMO) antenna is proposed for low-cost beam steering applications in 5G Millimeter-wave frequency bands. The beam steering is accomplished by selecting a specific port of MIMO antenna. Each MIMO port is associated with a beam that points in a different direction due to a conformal reflective metasurface. This novel conformal metasurface antenna design has the advantages of higher gain, lower cost, a simpler feeding source, and a lower profile when compared to traditional reflective metasurfaces using bulky horn antennas and phased arrays with complex feeding networks and phase shifters for beam steering. The proposed beam steering antenna consists of a compact five-element dual-band MIMO and a 32×32\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$32 \ imes 32$$\\end{document} unit-cell conformal dual-band reflective metasurface placed at the top of the MIMO antenna to obtain the beam steering capability as well as gain enhancement. The proposed reflective metasurface has a stable response under oblique incidence angles of up to 600\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$60^0$$\\end{document} at 24 GHz and 38 GHz and its symmetric, single-layer structure, ensures polarization insensitivity and stable response under conformal conditions. The presented MIMO antenna design is not only compact but also offers a wideband response effectively covering the desired 5G mm-wave frequency bands. The overall size of the MIMO antenna alone is 70 ×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document} 12 mm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {mm}^2$$\\end{document} with a maximum gain of 5.4 and 7.2 dB. It is further improved up to 13.1 and 14.2 dB at 24 and 38 GHz respectively, with a beam steering range of ś400\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$40^0$$\\end{document} by using a conformal reflective metasurface. Unlike the existing beam steering strategies, the suggested method is not only cost-effective but also increases the overall directivity and gain of the source MIMO antenna. The measured results agree with the simulated results, making it a potential candidate in the 5G and beyond beam steering applications.

A Compact All-Band Spacecraft Antenna with Stable Gain for Multi-Band GNSS Applications

This study presents a compact and stable gain spacecraft antenna that operates in all Global Navigation Satellite System (GNSS) bands from 1.164 GHz to 1.610 GHz. The proposed antenna structure based on the single-feed crossed bowtie antenna concept consists of four triangular patches excited with a 90° phase difference in between to generate right-hand circular polarization (RHCP), without needing complex feed networks. The radiator part of the antenna is covered by a radome and is also supported by a cylindrical dielectric cavity frame (DCF) to weaken the diffracted waves propagating along the ground plane while increasing vibration resistance. The fabricated antenna provides a return loss better than 10 dB with lower than 3 dB axial ratio and a stable gain around 7.2 ± 0.3 dBic over the entire GNSS bands, as well as a more compact and lightweight structural performance. It is also verified that the structural integrity and functional performance of the fabricated antenna remain consistent despite exposure to an equivalent vibration level in the launch process. The presented all-band spacecraft GNSS antenna is an innovative implementation with space industry insight for multi-band space applications that have application-specific limitations and provides consistent performance, as well as operational safety with the antenna design simplicity.

A reconfigurable ultra-wideband high-purity multimode terahertz OAM antenna array based on graphene and vanadium dioxide

A reconfigurable ultra-wideband multimode terahertz OAM antenna array based on graphene and vanadium dioxide (VO2) is presented in this paper. The uniform circular array (UCA) composed of circularly polarized (CP) antennas, which include a ring radiation patch, a parasitic patch, a perovskite substrate and an irregular VO2 ground plane. The radiation patch is covered with a layer of graphene, by changing the chemical potential of graphene, the working bandwidth and axial ratio bandwidth of the antenna can be changed. By changing the phase state of VO2 (metal state / insulation state) to control the working state of the antenna. The impedance bandwidth (IBW) of the CP antenna proposed is 115.09% (1.73–6.42 THz), the axial ratio bandwidth (ARBW) is 43.97% (2.36–3.69 THz). Using the CP antenna unit can simplify the complex feed network, and only feeding the equal amplitude and equal phase excitation can realize the vortex wave. Changing the number and rotation angle of the antenna unit can realize multimode vortex waves with the l= 0, ±1, ±2, ±3, the purity is approximately 1, respectively. The proposed UCA has excellent application prospect in the 6G communication.

A high-efficiency hybrid microwave power receiving metasurface array with dual matching of surface impedance and phase gradient

This paper proposes a hybrid microwave power receiving (MPR) metasurface array with efficient dual matching of surface impedance and phase gradient. The hybrid array comprises three components: a reflective phase gradient metasurface (R-PGM) array, a surface wave focusing array, and an energy harvesting port. The R-PGMs efficiently convert incident electromagnetic waves into surface waves. The surface wave focusing array then concentrates the energy onto the integrated harvesting port through dual matching of surface impedance and phase gradient. Connecting a rectifier circuit enables efficient microwave energy reception and RF-DC conversion, avoiding the need for multiple rectifiers or complex feeding networks in traditional MPR designs. Numerical analysis and experimental tests verify the superior performance of this hybrid array design in efficient microwave energy harvesting and RF-DC conversion, achieving 90.84% plane wave-to-surface wave conversion efficiency, 76.67% surface wave energy harvesting efficiency, and 49.28% overall RF-DC conversion efficiency. Across the wideband range of 5.6–6.0 GHz, the energy harvesting efficiency remains consistently high, demonstrating the superior characteristics and promising potential of this design in MPR device development.

Optimal design of transmitarray antennas via low-cost surrogate modelling

Over the recent years, reflectarrays and transmitarrays have been drawing a considerable attention due to their attractive features, including a possibility of realizing high gain and pencil-like radiation patterns without the employment of complex feeding networks. Among the two, transmitarrays seem to be superior over reflectarrays in terms of achieving high radiation efficiency without the feed blockage. Notwithstanding, the design process of transmitarrays is more intricate due to the necessity of manipulating both the transmission phase and magnitude of its unit elements. For reliability, the design process has to be conducted at the level of full-wave electromagnetic models, which makes direct optimization prohibitive. The most widely used workaround is to employ surrogate modeling techniques to construct fast representations of the unit elements, yet the initial model setup cost is typically high and includes acquisition of thousands of training data points. In this paper, we propose a novel approach to cost-efficient design of transmitarrays. It is based on artificial-intelligence-enabled data-driven surrogates, which can be constructed using only a few hundreds of training data samples, while exhibiting the predictive power sufficient for reliable design. Our methodology is demonstrated by re-using the presented surrogate for the design of high-performance transmitarrays operating at various frequency ranges of 8–14 GHz, 22–28 GHz, and 28–36 GHz.

Experimental Demonstration of Beam Scanning of Dual-Metasurface Antenna

Beam-scanning antennas are employed in a wide range of applications, such as in satellite communications and 5G networks. Current commercial solutions rely mostly on electronically reconfigurable phased arrays, which require complex feeding networks and are affected by high losses, high costs, and are often power-hungry. In this paper, a novel beam scanning architecture employing a pair of planar metasurfaces, for use in thin reconfigurable antennas, is presented and experimentally demonstrated. The structure consisted of a radiative passive (non-reconfigurable) modulated metasurface, and a second metasurface that controls beam pointing, operating as a variable-impedance ground plane. Unlike other existing approaches, surface impedance variation was obtained by on-plane varactor diodes, no vias and a single voltage bias. This paper presents a design procedure based on an approximate theoretical model and simulation verification; a prototype of the designed antenna was fabricated for operation in X band, and a good agreement between measured results and simulations was observed. In the presented simple embodiment of the concept, the angular scanning range was limited to 10°; this limitation is discussed in view of future applications.

A monopulse array antenna based on SIW with circular polarization for using in tracking systems

In this paper, a monopulse slot array antenna with substrate integrated waveguide (SIW) has been designed and fabricated for application in tracking systems. This antenna has circular polarization and has a very simple design. For increasing the efficiency of the antenna and maintaining its one-layer structure, this design utilizes two modes (TE120, TE210) to excite the slots rather than the complex feed network commonly used in monopulse antennas. The feeding ports are well-isolated due to the orthogonality of the two modes. The feeding cavity is operated in these two modes to obtain the difference and sum patterns. The proposed antenna at the center frequency of 10 GHz has an impedance bandwidth of 200 MHz, and the reflection coefficient in this bandwidth is less than −10 dB. The zero depth of the difference pattern is less than −24 dBi, while the obtained gain of the sum pattern is 13.6 dBi. The polarization axial ratio is less than 3 dB in the range of 9.98–10.02 GHz. Also, the antenna aperture efficiency is 50 % at the desired frequency.

High Gain Fan-Beam Pattern Antenna Based on the Utilization of Diffracted Fields From Dielectric Slabs Edges for IoT and Sensing Applications

A high gain, low-cost antenna structure is designed for a smart car parking system. The antenna uses Printed Ridge Gap Waveguide (PRGW) technology, which is fully shielded, and suppresses any parasitic radiation from the feed, and minimizes back-lobe radiation. The proposed antenna uses a single MSL feed point, which eliminates the need for any complex feeding network design, and allows the antenna to be integrated easily with PCB transceiver circuitry. A novel technique for the design procedure is proposed, the technique provides a generalization of using either electric or magnetic excitations with dielectric or magnetic rectangular slabs. A unique physical insight accompanied with a thorough analysis of the propagation mechanism is provided. The technique has a significant impact on reducing the complexity of the feeding network. The realized structure is compact, low profile, and low cost. The beam pattern of the antenna is a Fan-Beam (Elliptical) pattern which is well suited for various sensing and Internet of Things (IoT) applications.

A Colinearly Polarized Full-Duplex Antenna With Extremely High Tx–Rx Isolation

In this letter, we present a colinearly polarized in-band full-duplex (FD) microstrip antenna system with passive self-interference cancelation achieved from extremely high interport isolation. The proposed FD antenna achieves this isolation enhancement without the use of any circulator, hybrid or complex feed-network, by adopting a novel combination of: 1) field-confinement near individual antennas due to metallic vias, and 2) U-shaped slots etched from the ground plane. The proposed FD antenna demonstrates interport isolation values of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&gt;\!\!54$</tex-math></inline-formula> dB over the operating band of 5850–5945 MHz (IEEE 802.11p band for V2X-ITS) and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\approx \!\!90$</tex-math></inline-formula> dB at 5.9 GHz, along with broadside gain of 5.63 dBi and X-pol level less than 20 dB. The design procedure of the proposed planar FD antenna is explained and verified by CST-MWS full-wave simulations along with experimental results on fabricated antenna prototype.

Multiport Pixel Antenna Optimization Using Characteristic Mode Analysis and Sequential Feeding Port Search

An optimization approach for multiport pixel antenna design using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${N}$ </tex-math></inline-formula> -port characteristic mode analysis (CMA) and sequential feeding port selection is proposed. CMA is utilized to characterize the maximum number of independent or orthogonal resonant modes that can be formed in the limited space constrained by the size of the pixel antenna. Once the maximum number of orthogonal resonance modes is found sequential feeding port selection is proposed to find the optimum feed positions to independently excite each of the orthogonal resonance modes. The resulting design does not need additional complex feeding networks or impedance matching circuits, making the physical implementation of the design straightforward, compact and practical. Two examples are provided to verify the performance of the proposed approach, including a 3-port pixel antenna and a 4-port pixel antenna operating at 2.4 GHz. The performance of the optimized antennas is very good, and verifies the usefulness of the proposed approach.

A Novel SIW Leaky-Wave Antenna for Continuous Beam Scanning from Backward to Forward

A novel, periodic, leaky-wave array antenna using substrate-integrated waveguide (SIW) technology is proposed for continuous beam scanning applications. For this purpose, a periodic structure with the ability to radiate from backward to forward is proposed. The unit cell of this periodic structure includes a longitudinal slot and an H-plane discontinuity. The H-plane step discontinuity is suggested to suppress the open stopband (OSB) and enable continuous beam scanning from backward to forward through the broadside. The impedance matching technique is used to suppress the open stopband. In contrast to phased array antennas, this form of antenna is distinguished by its ability to scan without requiring a complex feeding network. These antennas are used for different factors such as scanning the beam, determining the direction of arrival, avoiding collisions, indoor communications, etc. A prototype of the proposed antenna was fabricated for experimental characterization. The overall physical dimensions of the fabricated antenna are 7.9 mm × 128 mm. The results demonstrate that an adequate level of agreement between measurement and simulation is satisfactory. The results indicate that the suggested antenna can scan continuously in the frequency range of 14.5 to 22.5 GHz between −60 and +57.5 degrees through broadside with a maximum gain of 16 dBi and radiation efficiency of 71%.

A Multibeam Ambient Electromagnetic Energy Harvester With Full Azimuthal Coverage

Confronting the challenge of replacing or recharging batteries for numerous low-power devices in IoT, the harvesting of ambient electromagnetic (EM) energy is considered a promising approach. Since EM energy is randomly distributed in the environment, omnidirectional antennas or multibeam antennas are better choices for their large coverages which enable them to collect as much energy as possible. However, omnidirectional antennas usually have low gains resulting in low receiving energy, and most multibeam antennas with high gains require complicated feeding networks. To address these issues, a six-beam antenna without a complex feeding network is proposed in this paper. It consists of a triangular patch array layer and a surface waveguide layer. A peak gain of 8.3 dBi, as well as a 3-dB beamwidth of 620 in H-plane and 560 in E-plane have been achieved, affording full azimuthal coverage within a certain elevation angle range. For demonstration, an EM energy harvester is constructed based on the proposed antenna. It can be observed that the implemented device can harvest almost the same amount of EM energy in different horizontal orientations, and acquire multi-fold DC power in the case of multiple EM transmitters.

Dual-Polarized Nonuniform Fabry–Pérot Cavity Antenna With Flat-Topped Radiation Pattern

A method to realize the flat-topped radiation pattern of Fabry&#x2013;P&#x00E9;rot cavity antenna is proposed based on the ray-tracing model. In the design, a nonuniform partially reflective surface of dielectric substrate is proposed to reduce the sidelobe level and get a fast roll-off in the operating frequency band. Besides, a dumb source array is added around the dual-polarized feed array to minimize the disparity of beamwidth between E- and H-plane. The antenna was calculated with the proposed method, simulated by the full-wave simulation, and validated by the experiment. Compared with the traditional array synthesis method, there is no need to design a complex feed network because each coaxial port is fed equally in phase and amplitude. In addition, based on the proposed method, the aperture size is small and the flat-topped beamwidth is flexible.

Bandwidth Enhancement and Size Reduction of a Low-Profile Polarization-Reconfigurable Antenna by Utilizing Multiple Resonances

A new design method to significantly expand the axial ratio (AR) bandwidth of a single-fed, low-profile circularly polarized (CP) antenna without relying on any complex feed network or occupying a large transverse dimension is presented. First, four small patches arranged in chessboard pattern are utilized as the main radiator, and meanwhile, a cross slot with unequal slot lengths is adopted to excite triple sequentially orthogonal modes, aiming to attain two CP modes (AR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> and AR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ). Second, in order to further considerably enhance the AR bandwidth and concurrently reduce the overall size, the feeding cross-slot resonance is favorably excited and effectively coupled by the chessboard patches to produce a new slotline-based CP mode (AR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) located before AR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> . Finally, an I-shaped top-loaded monopole fence, as a new degree of design freedom, is employed to collaboratively regulate these multiple resonances to form a wide AR bandwidth covering AR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> , AR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , and AR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . Results show that, on the premise of keeping the inherent compact-size and low-profile advantages of microstrip antenna, the 3 dB AR bandwidth is remarkably enhanced up to 30.1% by the combination of the three CP modes. Based on the design method, a wideband polarization-reconfigurable antenna with switchable linear polarization (LP), left-handed circular polarization (LHCP), and right-handed circular polarization (RHCP) states is further designed and experimentally validated. The measured results demonstrate that, with quite compact transverse size ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.16\lambda _{0}^{2}$ </tex-math></inline-formula> ) and low profile ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.04\lambda _{0}$ </tex-math></inline-formula> ), a wide overlapped bandwidth (27.6%) of the polarization-reconfigurable antenna is successfully accomplished.

Wide-Scanning Circularly Polarized Reflector-Based Modulated Metasurface Antenna Enabled by a Broadband Polarizer

A circularly polarized leaky-wave antenna capable of frequency scanning is proposed in this article. The main objective is to achieve high gain and polarization purity without the need for a complex feed network. The antenna consists of two independent modules: 1) anisotropic-modulated metasurface antenna (MoMetA) for generating vertically polarized radiation with an operational scanning range of 19°–47° in elevation and 2) wideband polarization converter with high angular stability and capable of converting vertically linear polarization into circular polarization (CP). The aperture field estimation (AFE) method is used to design the MoMetA with high accuracy in predicting far-field pattern without the need for full-wave simulations. The gain of antenna in the bandwidth of 16–21 GHz is obtained well than 18 dBic. Simulation results show that the axial ratio in the maximum gain direction is lower than 3 dB all over its operational frequency bandwidth, demonstrating the proper operation of polarizer. In order to verify the simulation results, one prototype of the antenna is fabricated and its radiation patterns are measured in an anechoic chamber.

A 60 GHz Rhombic Patch Array Antenna With High Gain, Low Sidelobe Level, and Reduced Array Area

This work designs a 60 GHz rhombic patch array antenna with high gain, low sidelobe level (SLL), and reduced array area. This antenna consists of eight linear serial arrays with varying number of patches. A slot-coupled center-fed structure of substrate-integrated waveguide (SIW) is designed to simplify the complex feed network required for direct excitation of planar arrays and reduce insertion loss. The rhombic configuration utilizes the quantity ratio of patches for equivalent taper excitation to reduce SLL, rather than the use of tapered width as in traditional designs, which can achieve high gain and avoid cumbersome resizing of patches and connecting lines. An array factor analysis method is proposed to predict the SLL of the antenna. To form a planar array and further reduce the H-plane SLL, a -25-dB Dolph-Chebyshev SIW feed network is constructed. The measured gain of the rhombic array antenna is 18.2 dBi, and the E-plane and H-plane SLLs are less than -20 dB and -25 dB, respectively. This work also simulates a reference uniformly excited high-gain 8&#x00D7;10 array antenna. Compared to this reference antenna, the proposed rhombic array antenna has similar simulated gain but much lower SLL and 23% smaller array area.

Shared-aperture antennas based on mode modulation of a patch antenna and spoof surface plasmon polaritons

Light-weight shared-aperture antennas require the integration of multiple functions in separate frequency bands within the same physical aperture, having great potential use in remote sensing, radiometers, telemetry and communication, etc. In this letter, a method for designing light-weight shared-aperture antennas based on engineering of spoof surface plasmon polaritons (SSPPs) is presented. The proposed antenna consists of a feeding patch and a SSPP structure. Even and odd modes can be excited in different bands to realize different radiation performances. The simulated and measured results both corroborate that the presented shared-aperture antenna can achieveomnidirectional radiation at around 3.1 GHz and end-fire radiation at around 10.65 GHz, with peak gains about 1.90 dB and 6.24 dB, respectively. Without using several radiators and complex feeding networks, the antenna can work in two bands with different radiation patterns. This work provides an effective alternative design for shared-aperture antennas in light-weight and multi-functional wireless communication systems.

Optimization of sparse randomly spaced linear antenna array using hybrid iteratively reweighted least squares

&#x0D; &#x0D; &#x0D; Uniformly Spaced Antenna Array (USAA) with large radiating elements is characterized with complex feed network as well as high sidelobes level (SLL) leading to interference and power wastage. To solve these problems, research works have been carried out using different methodologies, to synthesize sparse Randomly Spaced An- tenna Array (RSAA) to reconstruct the desired radiation pattern using fewer radiating elements and suppressed SLL. In this paper, a deterministic Iteratively Reweighted Least Squares (IRLS) algorithm based on the concept of compressed sensing was used to achieve better sparsity through thinning. The SLL was also suppressed using Convex Technique (CT). The performance of the synthesized array was evaluated in terms of sparsity and SLL. Simulation results showed that it has a higher sparsity of 12 elements with SLL of -39.44dB which are 14.29% and 28.72% improvements, respectively compared to previous research work with 14 elements and SLL of -30.64dB.&#x0D; &#x0D; &#x0D;

Using Antenna Arrays with Only One Active Element for Beam Reconfiguration and Sensitive Study in Dielectric Media.

Antenna array pattern reconfiguration is usually achieved by changing the relative amplitudes and/or phases of the excitation distribution present in the array, at the cost of complex feeding networks. In this work, the mechanical displacement of a parasitic array perpendicular to another array with a single driven element is proposed. Additionally, the antenna is optimized addressing the variation of its response led by changes of the environmental dielectric constant of a surrounding gaseous medium. In such a way, a novel multipurpose antenna of utmost simplicity is obtained. From the computation of the self and mutual impedances, a control of the antenna radiation pattern by means of the induced currents in the parasitic elements is modelled. To illustrate the procedure, the technique will be applied to the variation of the side lobe level of a pencil beam and to obtain a flat-topped broadside beam from the same pencil beam, something with high interest for satellite applications. The proposed methodology represents an advance on the development of multipurpose antennas which resounds in simplicity not only in the reconfiguration of antenna beams, but in applications for the detection of particulate matter and/or measurements of the atmospheric dielectric constant.

Design of Single-Layer Broadband Omnidirectional Metasurface Antenna Under Single Mode Resonance

A single-layer broadband vertically polarized (VP) omnidirectional metasurface antenna is proposed in this communication. To guide the optimization and design of the antenna, characteristic mode (CM) analysis (CMA) is performed to investigate the intrinsic modal behaviors of the metasurface. A mode with VP omnidirectional radiation is first identified by analyzing an array of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 \times 4$ </tex-math></inline-formula> squared patches. To excite this mode, a complex feeding network is required, which leads to gain loss and increased structural complexity. Furthermore, the mode currents change with the frequency. Consequently, this mode cannot be excited efficiently in a wide bandwidth using a fixed feeding structure. To solve these problems, the modal current is analyzed at different frequencies. The sizes of the four corner patches and the other four edge patches are adjusted to optimize the modal behaviors. After optimization, the mode becomes much more desirable and can be efficiently excited in a wide bandwidth using a single probe. Therefore, the proposed antenna can be designed on a single-layer substrate and excited by a simple feeding structure with broadband characteristics. To verify the design, the proposed metasurface antenna is simulated, fabricated, and evaluated. The results show that the proposed metasurface antenna can achieve a broad bandwidth of 64.2%.