Rectangle Patch Research Articles

Enhancing MIMO Antenna Isolation with Novel Electromagnetic Band Gap (EBG) Structure and Genetic Algorithm Optimization

ABSTRACT A novel Electromagnetic Band Gap (EBG) structure is proposed to minimize common connector between closely spaced rectangular patch antennas. The 2D EBG architecture is placed on the horizontal plane of a 1/2 rectangle patch antenna array, reducing mutual coupling by over 20 dB without compromising far-field performance, gain, or bandwidth. By optimizing the EBG structure using a genetic algorithm, noise is reduced by −60 dB compared to −25 dB without it, improving the isolation of the antenna array. Inserting 3 EBG modules between the two patches decreases the 2.45 GHz mutual coupling to −60 dB, showcasing the significant enhancement in isolation. This MIMO antenna design with an EBG structure is suitable for wireless LAN communication systems, offering improved signal separation and performance. The proposed method integrates square patch antennas operating at 24 GHz with a metamaterial EBG structure on a Rogers R04350B substrate, using a genetic algorithm for optimization. Experimental results demonstrate over 22 dB improvement in isolation between antenna elements, maintaining consistent radiation patterns across frequencies.

Frequency-multiplexed multifunctional coding metasurface based on transmission and reflection modes

In this work, a frequency-multiplexed multifunctional coding metasurface is proposed, which can realize focusing lens at the lower frequency and multiple scattering beams at the higher frequency. The two functions can be manipulated independently. The proposed metasurface is composed of the top metal patch with a circular ring, two fan rings and two rectangle patches (CFRP), the bottom metal patch with C-shaped and rectangular metal slots (CRS) and a dielectric substrate. By changing the opening direction and size of CRS and the tilt direction and fan ring size of CFRP, the amplitude and phase of transmission and reflection can be modulated, respectively. The transmission mode works at 7 GHz, which can form focal points in different focal planes. The reflection mode works at 17.5 GHz, which can form multiple scattered beams in different directions in the far field. To further verify its practical feasibility, the proposed metasurface is fabricated and measured, the experimental results are in good agreement with the numerical simulation results. The proposed metasurface provides new possibilities to develop multifunctional devices.

A Low-Profile Dual-Polarized Patch Antenna With Simple Feed and Multiple Decoupling Techniques

A low-profile dual-polarized patch antenna with simple feed and multiple decoupling techniques is proposed. The proposed antenna consists of two substrates separated by 5 mm. At the top and bottom of Sub 1 are a microstrip balun (Port 2), and a rectangle patch etched with two symmetrical small rectangular slots. A rectangular slot, etched on the metal reflector of Sub 2, is excited by a microstrip line (Port 1). Multiple decoupling techniques are synthesized to achieve high port-to-port isolation, including physical isolation, the shorting pins grounding, orthogonal polarization, and different radiation modes. In particular, the designed antenna has a low profile without any complex feed structure, and the simulated isolation achieves better than 52 dB. Furthermore, its profile is only 0.08 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free-space wavelength at 3.55 GHz, and the measured isolation achieves 45 dB in the working bandwidth of 3.3 <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">–</b> 3.8 GHz <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">.</b> The fabricated prototype is a promising candidate for the 5G New Radio band n78 communication systems.

Design of Microstrip Antenna for Satellite Applications at K-Band

The Abstract-Satellite application's five-band microstrip patch antenna is suggested, and it is modelled using the HFSS studio software. The suggested microstrip patch antenna is constructed using templates that are square and rectangular in shape. The most crucial component of virtually every wireless advanced communication system is the microstrip patch antenna, which is crucial in transforming electrical signals into EM wave signals for electromagnetic transmission. This work develops an antenna that can function in the Ku/k/ku bands at frequencies between 10 GHz and 40 GHz. The majority of antennas for satellite applications are designed to have good wide bandwidth, high gain, and small size characteristics. Adjust and perfect the length using a rectangle and square patch of 4.3-4.4 dielectric constant substrate. Resize and improve the field's length; The microstrip patch antenna is made to operate in several frequency bands, including the ku, k, and ka bands.

A Compact Dual-Polarized Patch Antenna With L-Shaped Short Pins

A compact dual-polarized patch antenna with L-shaped short pins is proposed. The proposed antenna is configured with two substrates of 1.524 and 1.5 mm thickness, stacked by two prepregs of 2 × 95 µm thickness. The top layer is a rectangle patch with a T-shaped slot, two T-shaped branches, and two L-shaped short pins, which are shorted to the bottom layer of the metallic ground with the same size pins, and is fed by two vertical coaxial probes. In total, two L-shaped short pins achieve high isolation between the two ports by introducing three rectangular slots etched on the ground, two L-shaped strips in the middle layer connected with the short pins, and two T-shaped branches. Moreover, a wider bandwidth is realized by two L-shaped strips. A prototype of 0.16 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.16 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.04 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> has been fabricated, where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free-space wavelength at the center frequency. The measured isolation of better than 35 dB is obtained over the operating bandwidth of 3.46–3.58 GHz. The experimental results agree well with the simulation results, making it a competitive candidate for 5G applications in the indoor and terminal scene.

Antenna Array Performance in Microwave Imaging Technique for Brain Tumor Detection

Recent advancements in microwave tomography (MT) imaging studies have stimulated interest in antenna array development for medical imaging. An antenna and a model of the human head are required for the medical MT system, particularly in detecting brain tumors. Previous studies have shown that antenna arrays are more reliable as compared to a single element of patch antenna in detecting brain tumors. In this study, a single patch antenna is first designed to work at 3.2GHz using CST Studio software. To evaluate the effectiveness of antenna arrays in microwave imaging systems, the patch antenna is then improved into a 2x1 and 4x1 array. The gain, directivity, return loss (S11), Voltage Standing Wave Ratio (VSWR), and bandwidth are compared between single and arrays of antenna models. It has been proved that 2x1 and 4x1 antenna arrays resulted in higher performance. With a maximum gain of 7.11 dB, the 4x1 rectangle patch antenna has 11.3 dBi directivity, -13.88 dB return loss, and 91.1 MHz bandwidth, meanwhile single patch antenna has a gain of 3.34 dB, 5.68 dBi directivity, - 17.33 dB return loss, and 132 MHz bandwidth. Overall, a 4x1 patch antenna is made reliable and sensitive to be used in detecting brain tumors as higher gain and directivity may be useful to penetrate multilayer human head.

SEMICIRCULAR SLOT BASED UWB MICROSTRIP PATCH ANTENNA FOR VARIABLE BAND NOTCHED APPLICATIONS

The patch antenna with Ultra-Wide Band (UWB) characteristics is a promising candidate for wireless communication. It is a major research problem to mitigate electromagnetic interference (EMI) with narrowband technologies such as 5G lower band, Wi-MAX, WLAN and satellite band, which are all in the UWB region. This study describes a UWB antenna with variable band rejection that can be used to avoid interference with Wi-MAX and 5G lower band applications. The UWB characteristics of a simple rectangle patch antenna with a faulty ground structure has been designed for operational bandwidth (2.7–13) GHz. A novel method semicircular slot (SCS) at the radiation patch creates a band notched from (3.25–3.80) GHz and (3.4–4) GHz. Variable band rejection between (2.95–4.40) GHz can be achieved by adjusting the “Wa” values. When measured over the band rejection frequency, the return loss (S11) and VSWR values are very close to 0 dB and larger than 2. The simulated and measured results such as return loss, VSWR, 2-D polar pattern and gain have almost similar agreement. The design of the suggested antenna is simple, compact and efficient for Wi-MAX application, this is an ideal UWB antenna with the band notch characteristics.

Design of a Novel Circularly Polarized MIMO Antenna with Enhanced Isolation for Ultra-wideband Communication

In this paper, we propose a circularly polarized (CP) ultra-wideband (UWB) MIMO antenna. Compared with common linearly polarized (LP) UWB antenna, the proposed antenna can excite circular polarization (CP) mode for WLAN communication and its impedance bandwidth can also fully cover UWB spectrum. It consists of identical circularly polarized antennas. Each unit adopts circular monopole with extended orthogonal rectangle patch to realize broadband and symmetrical rectangular ground with slot in the diagonal of each antenna unit to achieve circular polarization for WLAN band. It has a very compact size and the dimension is 25 × 51 × 0.8 mm3. The impedance bandwidth of the proposed antenna is from 3.1 GHz to 13.5 GHz, with average gain of 4 dBi, fully covering UWB bandwidth and enhanced by 38%. At the same time, circular polarization is achieved by embedding two symmetrical rectangular slot structures in the two opposite corners of every antenna unit. The extended orthogonal rectangle patch is introduced to enhance impedance bandwidth and broaden axial ratio (AR) bandwidth. The measured 3 dB axial ratio (AR) bandwidth is 1.8 GHz (4.7-6.5 GHz), fully covering WLAN band. Meanwhile, the slit slot between antenna units and rectangular openings are introduced to achieve high isolation. The proposed antenna keeps ECC (envelope correlation coefficient) below 0.01, which showing good isolation and diversity characteristics. The proposed antenna can simultaneously operate in the UWB spectrum and exhibit circularly polarized (CP) radiation characteristic in WLAN.

An enhanced gain of frequency and polarization reconfigurable graphene antenna in terahertz regime

In this paper, a patch antenna with a unique shape and feeding at terahertz frequency is presented. The shape of the patch can change between three shapes of triangle, rectangle, circle and slotted patches by using the properties of graphene. In this way, by changing the shape of the patch, it is possible to simultaneously take advantage of the features of patches with different shapes in one antenna structure. In addition to the ability of changing the resonance frequency of the antenna in the range of 3.8 to 5.3 THz, the polarization is also changeable between linear and circular polarization, so, we have a frequency and polarization reconfigurable antenna. Besides, by using a metasurface and proximity coupled feed, the gain of the antenna has been improved and the maximum gain of 3.7 dBi has been achieved. The provided antenna having a suitable impedance bandwidth in all states, and the maximum bandwidth 28.5%, can be used for wideband applications.

Design of triple‐band dual‐sense shared aperture circular polarized antenna for multimode BeiDou communication and navigation integration

In the article, a triple-band dual-sense shared aperture circular polarized (CP) antenna is proposed for multimode BeiDou communication and navigation applications. By integrating the stub-loaded rectangle patch with the shorting-pin-loaded ring patch, the coverage of GPS L2, GPS L5, BDS-2 B2, BDS-2 B3, and BDS-1 L/S bands is realized. Besides, wideband filtering orthogonal feed network is adopted for feeding the ring patch to reduce the mutual coupling interference between the two patches. The slot-loaded ground plane is also employed for further decoupling. For validation, a prototype is designed, fabricated, and measured. The results indicate that the polarization of right-handed circular polarization (RHCP) is obtained at 1.2 GHz with a peak gain of 5.4 dBic for navigation service. While left-handed circular polarization (LHCP) and RHCP are realized at 1.615 GHz and 2.49 GHz, respectively, with the peak gains of 6.7 dBic and 7.4 dBic for communication service.

Corner Defected Multi-Resonance Ultra-Wideband Rectangular Patch Antenna

Objectives: The main objective of this article is to present a novel corner defected ultra wideband (UWB-3.1 to 10.6 GHz) rectangular patch with a partial ground plane to enhance the bandwidth with multi-resonance characteristics. By defecting the corners, the original rectangle patch will be converted into defected shape of proposed one to satisfy the objective. Methods: A FR-4 substrate with height (h) of 1.6 mm, dielectric constant (e r) of 4.3 and the loss tangent of 0.025 was used to develop the required antenna. The antenna was excited by a 50 Ohm microstrip line. This antenna was designed, simulated and analyzed by using MS–CST (Microwave Studio – Computer Simulation Technology) to attain the outcomes such as return loss (S11< -10 dB), voltage standing wave ratio (VSWR < 2), improved gain, Omni-directional radiation patterns, and enhanced bandwidth. Findings: It exhibits a fractional bandwidth (FBW) of 152.9 % between 2 GHz and 15 GHz. The antenna resonates at multiple frequencies owing to truncation of corners and produces resonant frequencies of 3.87 GHz and 11.36 GHz with the corresponding return losses of -26.03 dB and -34.87 dB respectively in the simulation point of view. The antenna was fabricated and tested. The measured and simulated results of the desired antenna were compared, and they show good agreement. Applications: The proposed antenna is suitable for UWB, WiMAX (Worldwide Interoperability for Microwave Access), C and X – band communications. Keywords: Ultrawideband; Rectangular patch; Bandwidth; Return loss; VSWR; Gain

Realizing of cross-polarization conversion for linearly polarized waves in multiband by orthotropic metasurface

A multiband reflective linear-polarization (LP) converter based on an anisotropic metasurface is proposed. The unit cell of the metasurface is composed of a hollow oval sheet and a rectangle patch. Simulation results show that the converter can convert LP wave to its orthogonal state and the polarization conversion ratio (PCR) is above 90% in four frequency bands (4.60–12.27 GHz, 13.79–13.90 GHz, 14.61–14.69 GHz, 15.44–15.52 GHz). Interestingly, the relative bandwidth of first band reaches up to 90.9%, which is even broader than most single-band polarization conversion metasurfaces. Furthermore, we analyze the physical mechanism of polarization conversion of the metasurface, and simplify the derived formulas to make approximate calculations for co- and cross-polarization coefficients. The proposed formulas have better applicability than the equations in previous work. The laboratory sample is fabricated, and we have experimentally characterized our idea in microwave region. This design can advance applications in microwave sensors and mm-wave systems.

A novel planar wide‐angle scanning phased array under operation of TM10 and TM20 modes

AbstractA low‐profile planar phased array based on the hybrid‐mode patch technique is presented to achieve the goal of increasing the scanning angle. The array element antenna simultaneously operates at TM10 and TM20 modes of two rectangle patches. By adjusting the length of a slot etched on one patch, the far field of the two modes can be combined by a certain proportion, and thus the complementary beams realize wide‐beam radiation. Besides, in order to improve the array active reflection performance in a wide‐scan range, the slot technique is adopted to achieve the element miniaturization, and a grounded isolator is introduced to reduce the mutual coupling between the array elements. The proposed phased array shows a measured main‐beam coverage from −68° to +66° with its gain fluctuation and sidelobe levels lower than 1.5 and − 10 dB, respectively.

Multiple-band absorber enabled by new type of metamaterial resonator formed by metallic split ring embedded with rectangle patch

Multiple-band perfect light absorber using new type of metamaterial resonator consisted of a metallic split ring embedded with a rectangle patch is designed in this paper. Four terahertz absorption peaks with narrow line-widths, large absorption coefficients, and discrete resonance frequencies are realized. The combined effect of multiple localized modes of the designed metamaterial resonator results in the quad-band near-unity absorption. Further results reveal that parameter changes of the metamaterial resonator provide the ability to tune the number of absorption peaks. Both the device design and its physical mechanism are different from the traditional design strategies of the multiple-band absorption devices, and thus the suggested scheme can offer an alternative design idea for multiple-band light absorbers and could have large application prospects, including the selective thermal radiation, thermal detection, imaging, spectrum enhancement, stealth technology, solar energy, sensing, etc.

Design of Low Profile and Wideband End-Fire Antenna Using Metasurface

In this paper, a metasurfing (MS) concept is demonstrated and applied in the design of the low profile and wideband endfire antenna on metallic surface environments. The MS comprises an array of varying patch printed on homogeneous host medium, and fed by a surface wave launcher (SWL). Each row patch is designed according to the operating wavelength and by altering the surface reactance of the MS the surface-wave mode can be manipulated into the free-space wave mode. Meanwhile, two row of rectangle patches with same size are located on between the surface wave launcher (SWL) and non-uniform MS, which is regarded as an impedance modulation to obtain a good impedance matching. The VSWR of the proposed antenna is below 2.5 from 3.8 GHz to 16.7 GHz in the measured results, which are in good agreement with the simulated results and the thickness of proposed antenna is only 5 mm ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.065\lambda _{L}$ </tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{L}$ </tex-math></inline-formula> is the free-space wavelength at the lowest operating frequency). Moreover, a stable end-fire beam and low side lobe level (SLL) is obtained in a wide frequency band, and the group delay and the time-domain result also are shown to prove the good wideband transmission.

A Wide Stopband Filtering Patch Antenna and its Application in MIMO System

This communication presents a wide stopband filtering antenna element and its application in multi-input multi-output (MIMO) system. Microstrip terminated coupled lines and a rectangle patch are utilized to generate the filtering function. By varying the length of the parallel coupled lines and open-circuited stubs, multiple transmission zeros can be introduced in the spurious band. Appropriate positioning the location of these transmission zeros enables a wide harmonic suppression. To demonstrate the proposed method, a wide stopband filtering antenna is designed and further applied in a four-element MIMO array. The measured and simulated results agree well. The proposed MIMO antenna obtains an attenuation of 12.6 dB up to $6.6\times $ the center frequency.

Design and characteristic mode analysis of a low-profile wideband patch antenna using metasurface

ABSTRACTA low-profile linearly polarized patch antenna using metasurface is proposed for wideband operation at 5-GHz Wi-Fi bands. The antenna is comprised of a rectangle patch sandwiched between a lattice of 3 × 3 periodic metasurface and the ground plane. The adopted coaxial probe feed is easy to fabricate and match. Characteristic mode analysis (CMA) is utilized to explain and understand the working mechanism of the proposed antenna. It is found that two dominant characteristic modes are well excited, leading to the broadband operation and linearly polarized radiation. The proposed dielectric-filled antenna with a low profile of 0.057λ0 (λ0 is the operating wavelength at 5.7 GHz in free space) attains about 30% measured −10 dB impedance bandwidth (4.89–6.62 GHz) with 7.28 dBi average gain. Across the bandwidth, the antenna efficiency is greater than 90%, and cross-polarization levels are less than 18 dB.

A Broadband Dual-Polarized Base Station Antenna With Anti-Interference Capability

A broadband dual-polarized antenna with antiinterference capability is presented in this letter for base station applications. The proposed antenna contains three parts: main radiator, feed structures, and reflector. Specifically, the main radiator has two crossed dipoles to realize ±45° polarizations; two vertical substrates, which have Γ-shaped feeding lines on the front side and rectangle patches on the back side, are placed between the main radiator and reflector for feeding; the reflector placed below is used to get high gain and unidirectional radiation. In addition, C-shaped stubs are arranged next to the feeding lines in order to filter the unwanted frequency band. A prototype of the antenna was fabricated and tested. The measured results show that it has a bandwidth of 52.6% ( $\rm{VSWR ) along with a sharp notch band from 2.27 to 2.53 GHz. Measured isolation of higher than 25.4 dB, half-power beamwidth of around 60° and average gain of 7.57 dBi across the operating band are also obtained. Having the advantages of anti-interference capability, dual polarization, wide bandwidth, high isolation, and good radiation performance, the proposed antenna can find its application in the next-generation wireless communication systems.

Anomalous diffraction in super-wavelength plasmonic metasurfaces

We demonstrate that super-wavelength sandwich plasmonic metasurfaces, with the top metal layer consisting of a periodic arrangement of differently sized rectangle patches, can support anomalous diffraction – one first-order diffraction is boosted greatly in a broad bandwidth while another first-order and zero-order diffractions are suppressed. More importantly, by adding and subtracting the patches in a unit cell and adjusting the geometric parameters, high efficiency and broadband first-order diffraction can be easily tuned from visible to near-, mid- and even far-infrared spectral regions. The metasurfaces can be applied as high-performance light dispersive components in beam splitters, thin-film solar cells and spectrometers.

Planar triple‐band antenna for LTE/GSM/UMTS and WLAN/WiMAX mobile device applications

ABSTRACTA planar triple‐band antenna with size 40 × 18 × 0.8 mm3 for LTE/GSM/UMTS and WLAN/WiMAX is developed in this article. The antenna is constructed in four steps. The first step is named Ant1. In one side of the substrate, a nonfolded strip is connected with a ground plane and a rectangle patch at both end of the nonfolded strip, respectively. Ant1 is fed by a T‐strip, which is in the other side of the substrate. Ant1 generates two modes at 2.8 and 1.97 GHz and is responsible for the operation band 1.25–3.65 GHz. The second step is named Ant2. On the basis of Ant1, the nonfolded strip is changed into folded strip. Two new resonant modes at 680 MHz and 5.8 GHz are introduced. Ant2 is responsible for the operation band (660–1120 MH) and (1.71–3.85 GHz). The third step is named Ant3. On the basis of Ant2, two branches (Br‐1, Br‐2) are introduced. Br‐1 and Br‐2 are in the same side of Ant1 and connected with the ground plane. Then the operation band (5.15–6.17 GHz) is added on the basis of Ant3. The fourth step is named Ant4. A slot is etched from the rectangular patch, and the impedance is greatly improved in the three operation bands. As a result, a triple‐band antenna covering the LTE 700/2300/2500 (1710 −2690 MHz)/GSM 850/900/(690–960 MHz)/GSM 1800/1900/UMTS (1710–2170 MHz)/WiMAX 3.5 GHz (3400–3650 MHz)/5.4 GHz (5250–5850 MHz) is formed. The gain for the proposed antenna is 1.2–4.2 dBi, and the radiation efficiency is about 67–95%. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2277–2281, 2015