Aperture Coupled Microstrip Antenna Research Articles

Design of Dual-Polarized Aperture-Coupled Microstrip Antenna with High Isolation at 28GHz

In this paper, a dual-polarized antenna with high isolation working at millimeter wave(mmW) frequency band is attempted. The proposed antenna can provide two orthogonal ports fed by only one square radiation patch with more than 30 dB isolation. In addition, the antenna can obtain a peal gain level of around 8dB for two ports. A more simple structure, which consists of two substrates and one foam layer rather than traditional two substrates, a cover plate and two foam layers, makes it more suitable for arrays form and easier for fabrication.

Tri-band Dual Substrate Aperture Coupled Microstrip Antenna for C, X, and Ku Band Applications

The design work presents a triple Y-fed dual substrate aperture coupled microstrip antenna that operates in C, X, and Ku bands. The overall dimension of the antenna is 50*40*1.894 mm. The antenna has four layers with two dissimilar substrates. A unique triple Y-structured feed line connected to a quarter-wave transformer forms the first layer of the design and shows a greater impact on impedance matching. A superimposed modified defected ground structure is sandwiched between two dissimilar substrates, FR4 and RT5880. The FR4 substrate is placed above the triple Y feed structure over which superimposed DGS is placed to obtain enhanced bandwidth. The third layer is formed by placing the second substrate RT5880 above the ground plane. The dielectric constant of the lower substrate is considered higher than the upper substrate to avoid undesired radiations at unwanted frequencies. A patch with three rectangular slots is placed over the RT5880 substrate for having tri-band characteristics. The patch is excited effectively through the slots in the ground plane thereby enhancing the coupling between the patch and the feed resulting in maximum radiation of RF energy. With this, an enhanced bandwidth of 12.66%, 16.67%, and 7.19% in all three bands is attained. Besides, the proposed design has a gain of 3.265 dBi at the C band, 3.305 dBi at the X band, and 4.385 dBi at the Ku band. The fabricated antenna is tested and the results are compared for both simulated and measured values. The results emphasize that a tri-band antenna can be used effectively in operating frequencies including the 5G wireless application band.

A Numerical Procedure to Design a UWB Aperture-Coupled Microstrip Antenna Suitable for Space Applications

In this paper, we show a dual-polarized ultra-wideband aperture-coupled microstrip antennae (ACMA) to be used in space missions such as CubeSat Ka-band applications. We also report the specific developed design procedure, which is distinguished from other design procedures by minimizing the complexity of construction, since it utilizes a simple multilayer structure without interlayer interconnections or inclusions. This design procedure develops an architecture for ACMA with the main objective of minimizing costs in large-scale production. The design starts from assigned specifications in terms of fractional bandwidth constrained to be larger than 40%, return loss better than 10 dB, and polarization purity and polarization isolation better than 25 dB, using materials with adequate ohmic and dielectric losses. A frequency-scaled prototype has been also designed, realized, and measured. Good agreement between the simulation and measurement results has been obtained.

Design of a wideband Fabry–Perot resonator antenna with a double‐layer partially reflective surface

A novel Fabry–Perot resonator antenna using a double-layer partially reflective surface (PRS) to enhance the operating bandwidth is proposed. Two layers of double-sided printed substrate are employed as the PRSs. A higher-permittivity dielectric substrate is inserted between the two PRSs to produce a positive reflection phase gradient, which is essential to expand the bandwidth. A wideband aperture-coupled microstrip antenna is utilized as the feed antenna to further improve the working bandwidth. A prototype of the proposed antenna is fabricated and tested to validate the simulated results. The experimental results show that the designed antenna has a wide impedance bandwidth ( S 11 < − 10 dB $$ \left|{S}_{11}\right|<-10\ \mathrm{dB} $$ ) of 9.43–13.0 GHz (35.7%) with a 3-dB gain bandwidth ranging from 9.12 to 12.26 GHz (31.4%) and a peak gain of 15.4 dBi at 10 GHz.

Broadband Dual-Polarized Aperture-Coupled Patch Antenna for 5G Applications

Abstract: This paper presents the design of a dual-polarized aperture-coupled microstrip antenna array for Sub-6GHz 5G communication systems. The antenna operates at 3.5 GHz and consists of 4×4 square patches. The proposed 4×4 array antenna feds by aperture-coupled feed line provide broadband bandwidth to operate in the N78 sub-6GHz 5G frequency band. The dualpolarized is presented, which gives two communications channels. The antenna consists of three layers and is designed on Rogers RO4003C substrate with a dielectric constant of 3.55 and substrate thickness of 0.8 mm. The final design of the antenna array with an overall size of 269 mm × 269 mm × 12.5 mm, and the results show that the 4×4 array has a 10dB bandwidth between 3.3-3.8 GHz and a maximum gain of 14.9 dB at 3.5 GHz, and the isolation between the two ports was 30 dB. The proposed antenna's gain, radiation efficiency, and bandwidth satisfy the requirements of 5G base station systems.

A broadband Fabry–Perot resonator antenna using partially reflecting surface with positive reflection phase gradient

A novel Fabry–Perot resonator antenna with a wide impedance- and gain-bandwidth is proposed in this paper. A wideband aperture-coupled microstrip antenna is used as the primary source, and a single-layer frequency selective surface with a positive reflection phase gradient is designed as a partially reflective surface. To validate the proposed approach, a prototype antenna operating in the X-band is designed, fabricated, and measured. Both simulation and measured results indicate that the proposed antenna exhibits wideband characteristics. The measured impedance bandwidth (|S11| &amp;lt; −10 dB) is 64.4%, ranging from 8.68 to 15.12 GHz. The experiments demonstrate that a 3 dB gain bandwidth of 31.9% from 8.61 to 11.80 GHz with a peak gain of 14.0 dBi at 10 GHz is achieved. In addition, the proposed antenna reveals good directional radiation patterns, low side-lobe level, and low cross-polarization over the whole working band.

Wide-Angle Scanning Lens Fed by Small-Scale Antenna Array for 5G in Millimeter-Wave Band

This article aims at high-gain and wide-angle scanning lens antenna design in millimeter-wave (MMW) band. The proposed antenna consists of a novel gradient-index (GRIN) lens and a phased array antenna (PAA) feed with aperture-coupled microstrip antenna (ACMA) elements. A new design methodology of the GRIN lens antenna is proposed, which comprises a preliminary design for rough shapes of GRIN lenses and two successive optimization steps. In the first optimization step, parameters of the GRIN lens are determined to achieve high directivity and wide scanning angle based on particle swarm optimization (PSO) algorithm and a quasi-2-D model. In the second step, the excitation coefficients of all elements for beam-steering purpose are obtained by the PSO algorithm with the goal of maximum directivity. To validate the approach, an MMW lens antenna, operating at 28 GHz, is numerically demonstrated with high directivity and a wide scanning range up to ±58°. Finally, the proposed antenna is fabricated by 3-D printing techniques. The measured results are in acceptable agreement with simulations.

Breast tissue tumor detection using “S” parameter analysis with an UWB stacked aperture coupled microstrip patch antenna having a “ + ” shaped defected ground structure

AbstractMicrowave imaging is an efficient technique that can be used for the early detection of breast cancer. Therefore the current research article presents the microwave imaging of two spherical tumors (radius 4 and 5 mm) in the breast phantom by using the monostatic radar-based technique. This is carried out by using an ultra-wideband (4.9–10.9 GHz), three-layered stacked aperture coupled microstrip antenna (SACMPA) with a defected ground structure to scan the breast phantom and make near field S parameter measurements from a breast phantom. The S parameter data from different locations and at different time intervals are noted and then used in a beam-forming algorithm; Delay and Sum to process it and form a 2D image of the tumor location in the breast phantom using MATLAB.The proposed SACMPA is a three-layered structure with overall dimensions of 37 × 43 × 4.85 mm3 that shows an impedance bandwidth of 6 GHz (4.9–10.9 GHz) and a simulated peak gain of 6.32 dB at a frequency of 9.1 GHz. The validation of S parameters and gain results are done using a Vector Network Analyzer (VNA) and an anechoic chamber. The experimental validation of the proposed microwave imaging procedure is done by allowing the SACMPA to radiate parallel to the breast phantom made from polythene (skin), petroleum jelly (fat), and wheat flour (with water as tumor) and record the S parameters on the VNA. The proposed microwave method is safe for human exposure as the antenna also shows simulated specific absorption rates of 0.271 and 1.115 W/Kg (on the breast phantom) at frequencies of 5.7 and 6.5 GHz, respectively (for 1 g of body tissue).

Dual‐polarized high gain resonant cavity antenna for radio frequency energy harvesting

A Fabry pérot antenna with a multilayer superstrate having nonuniform unit cells has been investigated as a receiving antenna for radio frequency (RF) energy harvesting applications. Here, the primary radiator is selected as a dual-polarized aperture coupled microstrip antenna with a double-layer superstrate. This antenna excites orthogonal polarizations, vertical (V) and horizontal (H) in the frequency band of 6.2 and 5.8 GHz, respectively, due to the presence of two orthogonal H-shaped slots in its ground plane. The proposed antenna provides a gain enhancement of 9.8 and 10.1 dBi at the respective frequencies. The rectifying circuit is designed for a frequency of 5.8 GHz using a voltage doubler topology. The circuit provides a power conversion efficiency of 41% at 0 dBm input power.

An aperture coupled microstrip antenna array for high power microwave application.

A three-layer aperture coupled microstrip antenna array (ACMA) is designed and fabricated for wideband high-power microwave (HPM) application, which has not been reported in the field of HPM. In this paper, the proposed antenna array overcomes the disadvantage of low power capacity of traditional microstrip antenna arrays. Moreover, based on the H-shaped aperture coupled structure, it enhances the relative bandwidth up to more than 50%. Compared with traditional HPM antennas, it has advantages of being low-profile (less than 0.2λ), wideband, lightweight, and easy to manufacture. The proposed antenna array consists of 60 elements; each element has four aperture coupled patch antennas fed by a four-way microstrip line power divider. In order to realize the modular design, the antenna array is divided into 10 identical modules; benefiting from this design, machining and assembling become easier. Additionally, cold tests and high-power tests are carried out, and the experimental results show that the ACMA achieves a relative bandwidth of 51.2% for voltage standing-wave ratio < 2 from 1.52 to 2.57 GHz. Consistent with simulation results, the measured gain is more than 28.8 dB in the whole bandwidth and it reaches a maximum of 32.1 dB. Finally, the high-power tests show that the power capacity of the proposed ACMA is greater than 140 MW, which proves the feasibility of the design in wideband HPM application.

High gain transmitarray antenna based on ultra‐thin metasurface

This article presents a bandwidth enhanced transmitarray (TA) antenna based on ultra-thin metasurface (MS) for high gain operating at X-band. The antenna consists of a three layers continuous flat structure and an aperture coupled microstrip antenna as the feed source. The relative phase shift of 360° is achieved by the unit cell design based on ultra-thin MS, and the quasi-spherical wave could be focused as plane wave when the wave goes through TA. The aperture coupled microstrip feed is designed with a bandwidth of 20.6%, and the bandwidth enhanced property of feed source will reduce the negative effect of elements mutual coupling on TA and increase the bandwidth of the TA antenna. The TA antenna gain increases from 8.25 to 18.98 dB and with a side lobe level of −14.3 dB. Owing to the low-profile and easy configuration, this kind of TA antenna has great potential, wireless communication.

Low‐cost multi‐layer antenna sub‐array for 79 GHz short‐range radar applications

A new wideband cavity-backed aperture coupled microstrip antenna is presented for 79 GHz short-range multi-input multi-output radar applications. This design is based on a sub-array consisting of two single elements, and each element is founded on a cavity backed aperture coupled patch antenna. A microstrip to strip-line transition and a series feeding topology is used to feed the elements. The antennas are manufactured by using a new high-resolution multi-layer PCB technology. This technology is able to deliver high-resolution stacked micro-vias on very thin substrates. The performance of the designed antenna has been verified by both simulations and measurements. The bandwidth is 11.2%, and the maximum gain and efficiency are 6.05 dBi and 80% along 77–81 GHz.

A Broadband Impedance-Matching Method for Microstrip Patch Antennas Based on the Bode-Fano Theory

Abstract Considering the narrow bandwidth of microstrip antennas, but also their applicability in upcoming technologies, this paper addresses the problem of wide-band matching, the theoretical bounds on the matching bandwidth and low-cost and low-complexity matching strategies. In this context the Bode-Fano bounds of single mode, linearly polarized aperture-coupled microstrip antennas is evaluated, optimized and compared to the theoretical bounds on matching bandwidth of other common feeding technologies. A detailed study of the input impedance of aperture-coupled patch antennas shows how to widen the Fano bounds. Based on this, a straight-forward and effective method to optimize the Fano bound is given. After optimization of the antennas input impedance, basic matching techniques can be applied, to exploit the enlarged bandwidth potential. As an example a $\lambda/4$-transformer as matching element is proposed. Design equations and simulation and measurement results of X-band prototypes are given as verification.

Effect of Feed Substrate Thickness on the Bandwidth and Radiation Characteristics of an Aperture-Coupled Microstrip Antenna with a High Permittivity Feed Substrate

Effect of Feed Substrate Thickness on the Bandwidth and Radiation Characteristics of an Aperture-Coupled Microstrip Antenna with a High Permittivity Feed Substrate

Effect of the Aperture Ratio on the Impedance Bandwidth of an Aperture Coupled Microstrip Antenna

Effect of the Aperture Ratio on the Impedance Bandwidth of an Aperture Coupled Microstrip Antenna

A Novel Broadband and High-Isolation Dual-Polarized Microstrip Antenna Array Based on Quasi-Substrate Integrated Waveguide Technology

A $2 \times 2$ dual-polarized (DP) aperture-coupled microstrip antenna array with high isolation, broadband, and low cross polarization for Ku-band is proposed based on the quasi-substrate integrated waveguide (Q-SIW) technology. The proposed microstrip antenna array is excited by two orthogonal four-way corporate (parallel) feed networks, which not only has a multistage structure with broadband but also provides pairs of differential outputs. The Q-SIW structure, composed of several reflectors and substrate integrated metal pillars, is used to increase the bandwidth, improve the isolation, and reduce the influence of feed network. The measured and simulated results show that the DP array exhibits an impedance bandwidth of 26.37% for vertical port and 27.77% for horizontal port. The cross polarization level is better than −34 dB and −40 dB for two ports, and the isolation between the two ports is above 32 dB.

Circularly Polarized Antenna Array with Sequential Rotation for Nanosatellites

This paper presents the design and characterization of an aperture-coupled microstrip antenna array to be installed onto a nanosatellite. The proposed antenna array has been optimized to operate at 2.26 GHz (S-Band), which is the operating frequency of the downlink channel of the Brazilian System for Meteorological Data Acquisition. The electromagnetic analyses are done by using the HFSS electromagnetic simulator. For the design validation, prototypes of single elements and antenna array were manufactured. The comparison between simulations and measurements indicates good performance of the designed antennas.

High gain CP aperture-coupled antenna for X-band application

In this paper, we present a composite feed circularly polarised aperture-coupled microstrip antenna at X-band with improved characteristics. The feed element is intended to produce right-hand circular polarization (RHCP). Along the periphery of the circular patch, two notches are cut at diametrically opposite points. The dimension of these diametrically opposite notches determines the AR. A prototype antenna has been designed, built-up and experimentally measured which allows the analysis and discussion about different characteristics of the antenna. The simulated 2:1 VSWR bandwidth is about 2.33 GHz (c GHz). The measured 3-dB AR bandwidth is about 1.7 GHz (8.7–10.4 GHz) and the centre frequency of the impedance bandwidth is 9 GHz which agrees with the simulation result. It is revealed by experimental results that the designed antenna achieves about 19% axial ratio bandwidth as much as 8.7 dBi gain.

A Low-Profile Aperture-Coupled Microstrip Antenna With Enhanced Bandwidth Under Dual Resonance

A low-profile aperture-coupled microstrip patch antenna (MPA) using the TM10 and TM30 resonant modes to enhance the impedance bandwidth is proposed in this paper. Based on the cavity model for a square MPA, the TM10 and TM30 modes as well as both higher odd-order and even-order modes between them can be characterized. In order to combine the dual radiative resonant modes for a wide impedance bandwidth, a rectangular radiating patch with an aperture-coupled feeder is employed and theoretically investigated at first, aiming to demonstrate that all of the undesired modes between them can be removed effectively. After that, by loading the shorting pins properly underneath the patch, the resonant frequency of TM10 mode is shown to progressively turn up with slight effect on that of TM30 mode. As a result, these two radiative modes can be allocated in proximity to each other, resulting in a wide impedance bandwidth with a stable radiation pattern and the same far-field polarization. Moreover, the principal parameters of the MPA have been extensively studied in order to investigate the sensitivity in input impedance of the aperture-fed patch antenna. Finally, the proposed antenna is fabricated and measured. Simulated and measured results are found in good agreement with each other and illustrate that the antenna achieves a wide impedance bandwidth of about 15.2% in fraction or 2.32–2.70 GHz under $\vert \text{S}_{\mathrm {\mathbf {11}}}\vert dB, while keeping a low profile property with the height of 0.032 free-space wavelength. Besides, a stable gain varied from 3 to 6.8 dBi within the whole operating band is also obtained.

Design of Aperture-Coupled Microstrip Antenna with Step Slots for Dual ISM Band

Design of Aperture-Coupled Microstrip Antenna with Step Slots for Dual ISM Band