Multilayer Antenna Research Articles

Multilayered and Low-Volume Cavity Resonator Antenna Using Metasurface Reflector and Superstrate for Airborne Application

This work explains an efficient combination of the artificial magnetic conductor (AMC) based metasurface (MS) and metamaterial (MTM) based superstrate inserting between the two sides of a radiating monopole antenna applicable for C-band airborne application. The antenna is based on low volume and multilayer configuration on which a compact AMC-MS reflector is placed below the radiator antenna and reflective type MTM superstrate placed above the radiating antenna forming a resonant cavity for obtaining enhanced impedance bandwidth (IBW), miniaturized antenna dimensions with lower antenna volume compared with existing multilayer antenna designs. The final MTM superstrate-loaded antenna provides a total size of 32 mm × 32 mm × 16.8 mm. Due to MTM superstrate loading, the final antenna provides an extended IBW of 15.64%, an improved gain of 7.26 dBi, and higher gain-to-area ratio of 16.42 by maintaining the compactness. Moreover, the final antenna provides positive gain values better than 2.18 dBi for theta = ± 45° and phi = 0°–360° for the complete working band. Hence, the proposed cavity resonator antenna can be easily fitted inside the airborne devices and provide an excellent broadside radiation performance.

Using the zeroth order resonance of an inter‐digital capacitive unit‐cell to design antennas for passive UHF RFID tags

Meander-line and multi-layer antennas have been used extensively to design compact UHF radio-frequency identification (RFID) tags; however the overall size reduction of meander-line antennas is limited by the amount of parasitic inductance that can be introduced by each meander-line segment and multi-layer antennas can be too costly. In this paper, a new compact antenna topology for passive UHF RFID tags based on zeroth order resonant (ZOR) design techniques is presented. The antenna consists of lossy coplanar conductors and inter-connected inter-digital capacitor (IDC) unit-cells with a ZOR frequency near the operating frequency, which is a key component in the design process because the unit-cells chosen for the design are inductive at the operating frequency. This makes the unit-cells very useful for antenna miniaturization. The new design in this work has several benefits; namely the coplanar layout can be printed on a single layer, matching inductive loops that reduce antenna efficiency are not required and ZOR analysis can be used for the design. Finally, for validation, a prototype antenna was designed with a unit-cell ZOR resonant frequency of 900 MHz, fabricated and characterized. A maximum read-range of 7.6 m was determined.

60 GHz Broadband LTCC Antenna for 5G Mobile Communication Systems

This paper provides a numerical investigation in designing wideband circularly polarized 60 GHz antenna using Low-Temperature Co-fired Ceramic technology (LTCC). The LTCC provides high-density multilayer integration, low dielectric loss, and low costs. The use of LTCC technology is advantageous for easy and flexible 3D integration and freer vias distribution in the substrate. The designed antenna focuses on obtaining a better trade-off in terms of size, gain, circular polarization (CP), and large bandwidth. The circular polarization was chosen in order to minimize the transmission errors caused by polarization inconsistency between the transmitter and the receiver. The antenna geometry is developed taking into consideration the design rules of the LTCC with a layer thickness of 100 µm after firing and a metal layer thickness of 9 µm. A bandwidth of more than 33% centered at 60 GHz was obtained for this designed multilayer antenna. The results are obtained by using the High-Frequency Structure Simulator (HFSS). The proposed integrated antenna can be used in future 5G wireless communication systems and other 60 GHz spectrum applications.

X-Band Multilayer Stacked Microstrip Antenna Using Novel Electromagnetic Band-Gap Structures

In this work, a multi-layered rectangular microstrip antenna, with an inset feeding technique, is designed. It consists of a 10 GHz resonating conventional microstrip patch and a novel 9 × 9 electromagnetic bandgap (EBG) array printed on a 0.5 mm thin FR-4 epoxy as superstrate; an air-spacer separated both. The top radiating patch is magnetically coupled with the bottom radiator such that it also radiates. The bottom dielectric layer’s other side is finished with the perfect ground for minimizing the back-lobe radiation. The dimensional parameters are optimized for both patch and the EBG surface in the Finite Element Method (FEM)-based EM solver ANSYS HFSS. The superimposition of the top EBG surface improves the gain without degrading the performance of the lower patch. This antenna has a −10 dB reflection bandwidth of 1.2 GHz with −30.57 dB minimum reflectivity at 9.9 GHz (better VSWR). The proposed prototype offers a gain of 9.45 dBi in both E and H planes. Finally, the device is fabricated using the conventional PCB technology. The performances of the device, like gain and radiation pattern, are measured in the anechoic chamber. It is found that the simulation and measured results are in near agreement. The physical dimensions of the proposed antenna are 55 mm × 55 mm × 17.67 mm.

A single-layer metallo-dielectric superstructure for enhancing the performances of EBG cavity antenna

Abstract A novel single-layer metallo-dielectric superstructure is proposed in this paper. It is constructed by two asymmetric unit- cells optimally arranged on the same layer to construct a partially reflective surface to be placed over a multilayer microstrip slot antenna named feed antenna for enhancing its performances. The radiation is expected to be maximum at the center of the formed layer. Thus, to maintain a high-gain performance, the unit-cells placed at the center are designed to provide a quasi-optimal reflection phase with high reflectivity at the frequency band of interest. A prototype of the proposed antenna operating at 10 GHz with overall size of 2.133λ0 ×2.133λ0 ×0.56λ0 is successfully designed and fabricated. The calculated and measured antenna gain results indicate that the proposed antenna exhibits a wider radiation bandwidth performance of about 41.15% and 36.15%, respectively.

A Compact Multilayer Triple-Band Circularly Polarized Antenna Using Anisotropic Polarization Converter

A compact multilayer antenna enabled with anisotropic linear-to-circular (LTC) polarization converter (PC) is investigated in this letter for triple-band circularly polarized (CP) operation. The intended circularly polarized antenna provides a miniaturized size of 0.27 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.27 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.10 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> at 2.38 GHz. The fabricated CP antenna provides extended impedance bandwidths of 13.0%, 18.2%, and 14.7% at the center frequencies of 2.38, 3.44, and 5.5 GHz, respectively. The antenna provides an axial ratio (AR) bandwidths of 3.53%, 1.73%, and 13.62%, higher gain-to-area ratio of 28.91, 39.10, and 30.28 for the three bands. Moreover, the antenna provides positive gain values and AR <; 3 dB for theta = ±45°, ±46°, and ±32° and phi = 0° to 360° at 2.45, 3.52, and 5.65 GHz, respectively. Hence, the antenna is well suitable for small satellite applications.

An X-Band Substrate Integrated Waveguide Fed Patch Array Antenna: Overcoming low efficiency, narrow impedance bandwidth, and cross-polarization radiation challenges

In this article, the efficient development of a new class of multilayer microstrip patch antenna (MPA) fed by a substrate integrated waveguide (SIW) for X-band applications is presented. It consists of performing the feed network in the SIW and the radiating structure in the microstrip technology. The proposed structure demonstrates that the best alternative to a costly, heavy, and bulky rectangular waveguide feeder is an SIW, which provides miniaturization, performance enhancements, cost reductions, and ease of integration with MPAs. The proposed patch array is composed of three stacked layers from top to bottom, including two SIW layers as a feeding network and one layer as the antenna layer. To verify the concept of the proposed antenna, a prototype of a 2 × 2 SIW patch array with a 39 × 41 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> physical aperture was fabricated and measured with an impedance bandwidth of 9.18% for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\left|{{S}_{11}}\right|{&lt;}{-}{10}\hspace{0.33em}{\text{dB}}$</tex-math></inline-formula> and a radiation efficiency above 78% in the whole operating frequency bandwidth. The maximum measured gain of the proposed array at 10 GHz is 11.1 dB, which is equivalent to 57.7% of the aperture efficiency. The proposed array can be easily developed to be used in larger arrays, and it is a good candidate for generating a symmetrical unidirectional pattern with a low cross-polarization level.

Dual-Polarized High-Isolation Antenna Design and Beam Steering Array Enabling Full-Duplex Communications for Operation Over a Wide Frequency Range

A new dual-polarized antenna and array are presented for In-Band Full-Duplex (IBFD) applications, offering high inter-port isolation. The single-element antenna system consists of four H-shape slots, stacked patches for wide bandwidth, and two external hybrid couplers. The multilayer antenna is well matched from about 2.1 to 2.4 GHz and provides high isolation in this frequency range in excess of 60 dB. Two different prototypes are simulated and measured to highlight the design process. In addition, a new and compact hybrid coupler with excellent phase and magnitude stability is also presented for improved antenna radiation and IBFD performances. When compared to other similar types of hybrid coupler and antenna systems, the proposed configurations are simple to manufacture, provide a higher isolation bandwidth (10%), and higher gain of 7.3 dBi with cross-polarization levels of 30 dB or lower. The single-element design was also extended to a 2×2 array and studied for different beam steering and feeding scenarios. The operating bandwidths and isolation values offered by these S-band antenna and array systems can support new data link possibilities for beam steering and future low-cost IBFD wireless networks by simple antenna fabrication.

Design of a Cylindrical Crossed Dipole Phased Array Antenna for Weather Surveillance Radars

We present a cylindrical dual-polarization phased array antenna for weather surveillance radars that features high isolation, matched copolar beams, low sidelobe levels, and adaptive null steering. We present a crossed dipole antenna element to replace the patch antenna on the currently deployed cylindrical polarimetric phased array radar (CPPAR). The crossed dipole element offers suppressed surface wave and lower coupling between adjacent elements of an array. As a result, we achieved lower backlobe and sidelobe levels, and a higher match between copolar beams of CPPAR compared to the currently deployed multi-layer patch antenna. Further reduction of the sidelobe level and adaptive null steering are obtained using a modified particle swarm optimization. The proposed null steering mitigates the interference among the four concurrent beams of a cylindrical phased array radar. The improvement in CPPAR radiation characteristics has been verified by comparing the presented crossed dipole antenna’s radiation patterns and the existing aperture coupled patch antenna. The proposed crossed dipole phased array can benefit national weather radar networks to provide accurate multiparameter measurements enabling reliable observation of severe weather phenomena.

High-Gain Multi-Layer Antenna Using Metasurface for Application in Terahertz Communication Systems

In this paper, a novel high-gain multi-layer antenna is designed for use in terahertz communication systems. The frequency range covered by this antenna is 8-13 THz. To improve the antenna's gain, a proposed rectangular metasurface structure environment has been used. To strengthen and connect the layers, several plastic bases have been used, which do not have a destructive effect on the antenna's radiation pattern. The use of the proposed rectangular metasurface structure medium has increased the gain by more than 10.5 dB compared to the conventional antenna.

3D Printed Wideband Multilayered Dual-Polarized Stacked Patch Antenna With Integrated MMIC Switch

Capability of 3D printing for developing wideband multilayered antenna systems packaged with active RF circuit components remains relatively unexplored. To address this gap, this manuscript demonstrates wideband patch antenna that is integrated with a polarization selection switch. Antenna bandwidth is enhanced with customized substrate thicknesses and stacked patch layers. Switch is integrated with 3D vertical transitions to achieve wide bandwidth, smaller packaging, and low-loss. To enable future antenna array applications, a detailed investigation is also presented to maximize the performance of the microstrip feed lines by adjusting the substrate thickness and deposition process. The antenna consists of 13 dielectric and conductive layers. Specifically, the manuscript demonstrates the lowest attenuation in the literature for a fully printed microstrip line with 0.25 dB/cm measured loss at 18 GHz. The antenna operates with more than 80% radiation efficiency and 45% bandwidth. The polarization switch is embedded within the antenna structure. The antenna retains a high cross-polarization ratio of ~20 dB due to 3D feed line transitions and symmetric location of the switch with respect to the antenna feeds.

Study of effective permittivity for a multilayer substrate dipole antenna

AbstractThe design of integrated systems requires the knowledge of the values of the effective permittivity of the substrate. Designing antenna using computer-aided design tools is a long process that necessitates doing iterative steps to find the correct dimensions that meet specific requirements at a certain operating frequency. The objective of this work is to propose an analytic model to reduce the time required for the design. By using electromagnetic simulation, the effect of the relative permittivity and the height of the substrate on the final effective permittivity have been studied. An analytic model that helps the designer in estimating the value of the effective permittivity has been proposed.

A compact folded SIW multibeam antenna array for 5G millimeter wave applications

AbstractA novel compact multilayer multibeam antenna array based on substrate integrated waveguide (SIW) is proposed in this letter for 5G millimeter wave (mm‐wave) applications. A multimode beam forming network (BFN) cascaded by phase compensation and coupling structures is folded to make the antenna array more compact. The phase difference between the output ports of traditional multimode beamforming network is very unstable, which would seriously affect the multibeam performance of antenna array. Therefore, the compensating phase shifter adopts the SIW transmission line structure with unequal length and width, which enables the multimode BFN achieving better performance in the bandwidth of 27–29 GHz. Four slot arrays are employed as the radiation structure. The overall structure of the proposed antenna consists of three parts, including a multimode beamforming network, a compensated phase shifter, and an SIW slot array. If these components are cascaded directly, the size of the antenna would be very large and the aperture efficiency will be low. So the proposed antenna is folded into three layers, one part for each layer. The overall antenna size is 66.7 mm × 47.5 mm (6.23λ × 4.44λ at 28 GHz). The antenna array is designed, fabricated, and measured. The measured results show that four deflected beams are realized in the band of 27–29 GHz. The radiation beams demonstrate a wide azimuthal coverage of ±48 deg, and a peak gain of 16.8 dBi for Port 1 excitation and 17.3 dBi for Port 2 excitation. The simulated radiation efficiency is better than –2 dB from 27 to 29 GHz. The proposed antenna features a compact size, low profile, good radiation performance, which is well suited for applications in the 5G mm‐wave communication systems.

Reconfigurable log‐periodic dipole array on textile

A microwave planar log-periodic dipole array (LPDA) antenna embroidered on textiles is presented for the first time. This antenna gives a 3.33:1 impedance bandwidth with 5 dBi average gain across the 0.9–3GHz band. This multi-layer textile antenna employs a new denim stack-up for repeatable measurements. The presented LPDA is tested under conformal conditions, with a demonstrated ability of frequency-dependent beam-steering through physical manipulation. Further, the antenna is considered for body-worn applications due to its conformal and low profile. A 2cm thick ground beef slab was used to emulate the human tissue for measurements. Overall, the presented LPDA brings forward new opportunities for several long-distance wideband and wearable applications.

Wideband Frequency Selective Surface Based Transmitarray Antenna at X-Band

In this paper, a wideband multilayer transmitarray antenna is designed for Ku frequency band. The unit cell is designed at 12GHz using frequency selective surface structure. Double square ring with center patch based multilayer unit cell is simulated. The effect of substrate thickness variation on transmission coefficient magnitude and phase range is discussed. The horn antenna designed at X-band will be used as feed source for transmitarray antenna. Transmitarray simulation results show wide impedance bandwidth from 10 to 13GHz. Wide gain bandwidth of 1.975GHz with peak gain of 18.96dB is achieved. The proposed transmitarray design will find applications in high gain, directional, low profile antennas for X-band communication systems.

Giant magneto-refractive effect in mid-infrared second-harmonic generation from plasmonic antennas.

Active modulation of nonlinear-optical response from metallic nanostructures can be realized with an external magnetic field. We report a resonant 20% magneto-refractive modulation in second-harmonic generation (SHG) from spintronic multilayer antennas in the mid-infrared. We discuss mechanisms of this modulation and show that it cannot be explained by an unequal enhancement of the electromagnetic field. Instead, we propose a novel, to the best of our knowledge, contribution to the nonlinear susceptibility, which relies on the spin-dependent electron mean free path. In contrast to magneto-optics in ferromagnets, our approach allows simultaneous observation of the enhanced SHG and its large modulation.

Novel optimizing algorithm of superdirective multi-layered cylindric antenna

We propose the design of a superdirective antenna based on a multi-layered dielectric cylinder. A novel optimization goal is proposed based on the physical characteristics of the Dirac delta function. The side-lobe properties of superdirective antenna is discussed and treated as the optimization goal for antenna design for the first time. A multi-stage genetic algorithm and trust region reflective algorithm are utilized to shorten the time duration for optimization. The optimizing efficiency is higher and the cost of time is significantly reduced compared with proposed designs. The effect of weight of different algorithms is discussed. Both the dielectric loss and metallic loss are also discussed for practical cases. The optimization is of low computing cost and can be accomplished by personal computers.

Effects of LBSCA glass addition on the sintering characteristic and microwave dielectric properties of ZnTiNb2O8 ceramics

In this study, ZnTiNb2O8-xLBSCA (x = 0, 0.2, 0.4, 0.6, 0.8, and 1 wt%) ceramics were synthesized via solid-phase reaction. Effects of different contents of LBSCA glass on the sintering characteristic, phase composition, microstructure, and microwave dielectric properties of ZnTiNb2O8-xLBSCA ceramics were investigated in detail via X-ray diffraction, scanning electron microscopy, and Rietveld refinement analysis. Rietveld refinement result confirmed the existence of main phase ZnTiNb2O8 and secondary phase ZnNb2O6 in all samples, and the content of secondary phase decreased with increasing x. LBSCA glass obviously promoted grain growth, densification, and ordered arrangement of grains, which was conducive to good microwave dielectric properties. In general, the addition of LBSCA glass contributed to a decrease in sintering temperature to 950 °C, as well as improvement in microwave dielectric properties of ZnTiNb2O8 ceramics. ZnTiNb2O8-0.4wt%.LBSCA ceramics sintered at 950 °C showed excellent optimal properties of $${\varepsilon }_{r}$$ = 33.826, $$Q\times f$$ = 49,143 GHz, and $${\tau }_{f}$$ = $$-57.59 {\rm ppm}/^\circ{\rm C }$$ . Therefore, this ceramic can act as potential candidate for low-temperature fired material and promisingly be applied to multilayer filters and antennas.

Design of Wideband Differentially Fed Multilayer Stacked Patch Antennas Based on Bat Algorithm

A new approach for the design of wideband multilayer stacked patch antennas is proposed based on the bat algorithm. Differential topology is described for multilayer stacked patch antennas to achieve the stable and symmetry radiation patterns as well as the high cross-polarization (XP) suppression within the design band. The fabricated antenna prototypes show 25.5% and 34.9% impedance bandwidth for the two-layer and three-layer designs, respectively. The measured results validated the design.

High Port-to-Port Isolation Dual-Polarized Antenna Array Dedicated for Full-Duplex Base Stations

This letter discusses the design of a dual-polarized four-element linear antenna array with increased port-to-port isolation, intended for base stations of single-channel full-duplex systems. The antenna is designed for the U-NII 5.15-5.925 GHz frequency band and is characterized by port-to-port isolation higher than 57 dB and cross polarization better than -27 dB within the mainlobe. An electromagnetically coupled microstrip antenna is used as a single element of the antenna array. Enhanced isolation is obtained owing to the multilayer antenna structure and special feeding network utilizing the pairwise antiphased feeding technique combined with a careful selection of phase-shifters and power dividers. The antenna parameters are optimized with the use of full-wave simulations, while the scattering parameters and radiation characteristics are verified by measurements.