U-slot Antenna Research Articles

Designing an ultra-wideband directional antipodal Vivaldi antenna with U-slots for biomedical applications using an optimized attention network

Abstract This research introduces a compact Ultra-Wideband (UWB) antipodal Vivaldi antenna with a U-slot tailored for biomedical applications. Utilizing an elliptical tapered patch variation on a 50*32 mm2 substrate achieves its compact design. Parameter optimization, employing the Multi-Layer Stacked Shallow Attention Neural Network (MLSSANN) with Adaptive Gannet Optimization Algorithm (AGOA), ensures accurate predictions and efficient exploration of the design space. Performance analysis includes metrics like gain, directivity, reflection coefficients, return loss and radiation efficiency. The U-slot variant exhibits higher gain peaking at 24.5 GHz (10 dB) compared to the standard variant peaking near 37 GHz (13.7 dB). The U-slot antenna also shows improved directivity and return loss, with a 13.89 % enhancement in return loss at 3.7 GHz. Moreover, the addition of the slot shifts the lower cut-off frequency from 1,580 MHz to 740 MHz, reducing the antenna size by 41 % while maintaining acceptable radiation characteristics.

A Novel Double U-Slot Microstrip Patch Antenna Design for Low-Profile and Broad Bandwidth Applications

A low-profile double U-slot microstrip patch antenna with a wide operating bandwidth has been developed in this article. This design produces the dual radiative resonant modes adjacent to each even at the thickness of the antenna of <inline-formula> <tex-math notation="LaTeX">$0.02 {\lambda _{0}}$ </tex-math></inline-formula>. An extremely stable radiation gain that varied from 6.2 to 6.8 dBi is achieved within the whole operating band. In addition, detailed parametric studies in this article provide antenna engineers with simple approximate rules that result in an excellent first-pass design with prescribed characteristics requiring only minimal tuning. Finally, the proposed antenna with the thickness of <inline-formula> <tex-math notation="LaTeX">$0.04 {\lambda _{0}}$ </tex-math></inline-formula> is fabricated and measured. Simulated and measured results are found in good agreement with each other. They have evidently illustrated that the bandwidth is increased by 50&#x0025; compared to the traditional U-slot antenna. With the help of these simple design procedures and examples in this article, antenna designers could easily develop a low-profile broadband antenna.

Single-Fed Triple-Mode Wideband Circularly Polarized Microstrip Antennas Using Characteristic Mode Analysis

A method of triple-mode operation by capacitive slot loading is proposed for bandwidth enhancement of single-fed circularly polarized (CP) patch antennas. Instead of using even-numbered linearly polarized (LP) modes with quadrature phase, three orthogonal LP modes are used for CP bandwidth enhancement, where the middle mode is shared by two cross-polarized modes with the same polarization. The advantages include reduced constraints, lower complexity, and a higher degree of freedom for antenna design. Guided by the method, a U-slot antenna and an E-shaped antenna are proposed and designed with characteristic mode analysis (CMA). Both antennas work with a TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> -like mode and a TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> -like mode. Differently, the U-slot antenna works with an additional slot mode and the E-shaped antenna works with an additional TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> -like mode. The operating modes are manipulated by the slot loadings for creating phase difference. As a result, wideband CP radiation is achieved with a single feeding. CMA-based empirical formulas are derived for fast design. The proposed method and antennas are experimentally validated. Both antennas measure a bandwidth exceeding 21% for 10 dB return loss and 3 dB axial-ratio (AR), a significant improvement compared with conventional corner-truncated U-slot patch antennas of similar thickness or volume.

Near-field Shaped Focusing with Planar U-slot Antenna Array of Amplitude and Phase Regulation

Near-field Shaped Focusing with Planar U-slot Antenna Array of Amplitude and Phase Regulation

Chameleon Swarm Algorithm Assisted Optimization of U-Slot Patch Antenna for Quad-Band Applications

Existing optimization algorithms are insufficient in the face of problems with difficult measurement functions as well as a large number of design parameters. Therefore, to achieve such challenging applications, the Chameleon swarm algorithm and its variants, which belong to the family of meta-heuristic algorithms that have not been used in any antenna optimization study before, are used together with 3 different objective functions fitted from mathematical models. Then, a U-slot antenna application with 12 different variable design parameters with resonance frequencies of 3.5 GHz, 3.7 GHz, 5.2 GHz and 5.8 GHz is considered as a multidimensional and single-objective optimization problem. In this study, first of all, the success of the algorithm is reinforced by comparing the performance with other commonly used single and multi-objective optimization algorithms. In addition, the results obtained with different population parameters, weight coefficients, objective functions and variant models were compared. All these processes are compared within themselves, and the antenna results of the most successful result are displayed as 3D electromagnetic simulation. The results show that the optimization processes proposed for an antenna designer are a safe, practical and efficient solution for multidimensional and single-objective antenna optimization applications. In addition, any optimization problem with a large number of variable design parameters can undoubtedly be adapted to the Chameleon swarm algorithm.

Design of a Linearly Polarized HMSIW U-Slot Antenna

Design of a Linearly Polarized HMSIW U-Slot Antenna

U-Slot Cut Rectangular Microstrip Antenna with a Large Ground Plane and a Thin Substrate

It is very well known that the Rectangular Microstrip Antennas (RMA) are narrowband, but it is possible to enhance its bandwidth by cutting slots inside the patch. Some slots variations have been used to improve this important feature in modern mobile radiocommunication systems. U-slot antennas are employed in broadband applications, but it is very important to consider the usage of a thick substrate with a low dielectric constant. In this paper, an U-slot RMA built in a The Printed Circuit Board (PCB) with a thin FR4 substrate for 800 MHz to 900 MHz is presented and analyzed. The PCB that is necessary to fabricate the antenna is very low cost and it is conformable in many mobile terminals. The antenna was simulated in HFSS and measured using return losses and its antenna patterns.

Design and Analysis of Coax-Fed U-Slot Antenna for Wireless Applications

In this paper a multi frequency U-slot patch antenna for wireless applications is presented. The proposed antenna operates at four frequencies of 1.4GHz, 5.3GHz, 6GHz and 6.9GHz with return loss of -19dB, -22.50dB, -21.05dB, -19.37dB respectively. The antenna is designed with Rogers R04232 substrate with dielectric constant of 3.2 and dielectric loss 0.043 with dimensions of 47 × 54 × 1.5 mm3. Coaxial feed technique is used as a feed to the antenna which is having characteristic impedance 50 ohm. The simulation studies were carried out using Ansys HFSS 15.0 Software.

Improving the Gain Performance of 2 × 2 U-Slot Air Substrate Patch Antenna Array Operated at 28 GHz Wideband Resonance for 5G Application

In this paper, a 28-GHz dual 2 × 2 U-slot air substrate patch antenna array for 5G application is proposed. The idea of the U-slot antenna was applied in the patch antenna design which intended to decrease the antenna size. The structure of the U-slot patch antenna comprises a patch, two slots of U-shape, a ground plane, and coaxial feed lines. The proposed configuration of 2 x 2 U-slot array shows a high gain. With an extra U-slot, the proposed antenna yielded a bandwidth of about 3.93 GHz, the maximum gain of 14.5 dBi in the yz-plane, and performance efficiency of 85.82 %

Dual-band antenna modification by using dual bad EBG structure for WLAN/WiMAX applications

In this paper, a U-slot antenna as represent of dual-band antenna is studied. This antenna covers the WLAN/WiMAX application with a moderate gain of 4.5 dBi. The antenna excites two modes of TM10 and TM20 and consequently with excitation of high order modes surface currents of antenna substrate increase. To overcome this drawback a dual-band electromagnetic bandgap (EBG) is offered and results of EBG unit cell is matched with the U-slot antenna operation bandwidth at two bands. Finally, arrange of unite cell array and antenna for two goals is investigated. As results prove, the combining antenna with EBG cells can solve the mutual coupling effect more than 20 dB and improve gain and bandwidth of antenna for about 3.5 dBi and 1% for each frequency band, respectively.

Wearable Textile Patch Antenna for Medical Applications

In recent years of electronics industrialization, antennas are more popular components; wearable antennas play an important role due to their properties such as wireless communication and miniaturization. The design of wearable antennas have distinction in the area of antenna design and development, in this paper a thorough study had been carried out wearable antennas blended with textile, which has significant dielectric constant. This work describes the design a textile antenna, namely, a rectangular microstrip patch antenna and then rectangular with U-slot antenna with slits. After designing two kinds of antennas, a comparison will be made between their results. Conductive textile, a copper-plated polyester fabric, will be used for fabricating antenna radiators and grounds. An insulating denim fabric with dielectric constant 1.7 with a thickness of 0.7 is used for preparing the substrates. The proposed antenna is designed and all the results will calculated using Ansoft HFSS Software. After evaluating the results of a rectangular microstrip antenna and U-slot Antenna on textile substrate, the rectangular patch resonate at 2.5 GHz with the return loss of -16.86dB and the U-slot Antenna resonated at 2.2 GHz with return loss of -41.68dB and 3.9 GHz return loss of -16.16dB.

Compact 2-D Multibeam Array Antenna Fed by Planar Cascaded Butler Matrix for Millimeter-Wave Communication

This letter presents a 28 GHz two-dimensional (2-D) multibeam array antenna fed by a planar 4 × 4 cascaded Butler matrix (CBM). Utilizing the proposed concept of 3-D-to-planar CBM topology transition, the 4 × 4 U-slot antenna array integrated with planar CBM can be implemented with a multilayer lamination without additional connectors or routing lines. Due to the simplified topology of the circular sub-BM, whose width is only 0.5 λ0 (free-space wavelength at 28 GHz), none of the crossovers is needed to assemble the radiation elements at the outputs of the CBM. The dimension of the proposed 2-D beam-steering system has been dramatically reduced to 3.3 λ0 × 5.9 λ0, which is, to the best of the authors' knowledge, the smallest in this application area. A prototype has been fabricated and measured. The measured results show a well-controlled input matching in the operation band from 26 to 29 GHz. Besides, 16 spatial orthogonal beams with maximal 15.22 dBi gain at 28 GHz scan a conical space with the maximal cone angle of 77.4° in the elevation plane and 136.8° in the azimuth plane by feeding at different inputs, which agree well with the simulated results.

10 Ghz Optical Modulator using CPS structure for communication and Sensing

The combination of of wireless millimeter-wave (MMW) bands and fiber optic cables is able to compensate the propagation loss of millimeter waves in broadband communications and high-resolution imaging. This paper discusses the design and the realization of optical modulator using coplanar stripline (CPS) structure completed with the u-slot antenna patch for RF signal input. The substrate used for CPS structure is Lithium Niobat (LiNbO3) due to its large electro optical coefficient. A 10 Ghz radio wave frequency is inputted via microstrip u-slot antenna patch array 2 x 1 with input impedance 50 Ω, and acceptable return loss -10 dB. The light waves for the carrier are generated from the laser diode. Several measurements have been completely done and reported. The design is carried out by means of varying physical variable value which results in specification of the operating frequency 10 GHz. This is a pure research since the obtained results are not directly applied to the radio-over-fiber (RoF) technology.

Design and Analysis of Alphabetical Slots of Patch Antenna for Mobile Optical Communication at 60 GHz

Abstract In the last decade, huge development has been seen in the field of wireless communication. The performance depends on the shape and size of the antenna. The future aim of wireless communication is to provide data with high speed data range even in harsh geographical areas. Here aim is to design and compare the E and H slot, T-slot, O-slot and U-slot antenna. The designed patch antenna operates at a frequency of 60 GHz with maximum antenna gain and minimum radiation loss using high frequency structure simulator (HFSS). We will use Rogers RT/duroid 5880 as substrate due to its suitable mechanical and insulating properties. Resonant frequency used will be 60 GHz and height will be 1.6 mm, 1.57 mm, 1.6 mm and 0.508 mm for E and H slot, T-slot, O-slot and U-slot, respectively.

Frequency reconfigurable lte antenna with u shaped open end for portable wireless devices

In this paper, a frequency tuning method for an U-shaped slot antenna for long term evaluation (LTE) wireless communication devices is presented and the performance of the antenna (return loss, total and radiation efficiencies…etc) is reported. The lower operating frequency of the antenna (700 - 960 MHz) is switched with different inductor loadings from 110 nH to 30 nH. The inductor component loads the U-slot antenna and thus enables to tune the frequency of low band (700 - 960 MHz). Higher bands (1710 - 2700 MHz) of the antenna remain unchanged with different inductor loadings. The impact of the inductor position is also investigated and the results are reported. The antenna presented in the paper is comparable with that of Cho-Kang Hsu’s publication. However, in Chos publication, only one low band is covered. In our design, all of existing commercial LTE frequency bands (Band 17 - Band 7) used in typical mobile devices are covered by the proposed antenna.

Analysis of Reactive Loading in a U-Slot Microstrip Patch Using the Theory of Characteristic Modes [Antenna Applications Corner

In this article, the effect of reactive loading on a probe-fed, single-layer, U-slot loaded microstrip antenna is investigated using the theory of characteristic modes (TCM). A detailed analysis of reactive loading due to feed location and arm-angle variation is presented. The eigenvalue behavior of the characteristic modes can be modified by varying reactive loading on the U-slot antenna. Thus, it is possible to control certain modes such that they resonate in the desired frequency band. These modes can then be effectively excited to achieve the desired antenna performance. In addition, reactive loading helps to move the impedance loop to the center of the Smith chart. Optimized reactive loading has been shown to produce a modified U-slot structure without any increased cost or complexity. The optimized loaded antenna is wide-band, with a relatively stable radiation pattern.

Investigation into Low SAR PIFA Antenna and Design a Very Low SAR U-slot Antenna using Frequency Selective Surface for cell-phones and Wearable Applications

There are very important questions. “Do Electromagnetic waves have irreparable effects on human or not?” “Are there any relation between cancer and waves?” and finally “what should we do to be safe?”. In the present article, these questions will be answered simply and professionally. First of all, Specific Absorption rate (SAR) is define then L-Slot and U-slot antenna is designed and simulated using cell-phones and wearable applications, operating at and consist of GSM900 and GSM1800. Standard frequency band width for the first and second band is and for uplink and downlink and in the present research these numbers are obtained. The SAR of each antenna is measured and is compared with each other. Thanks to design of antenna, The SAR of U-Slot antenna is very low and it is almost stimulated and this sentence means this antenna is anti-cancer. Finally, Some SRR unit-cells are designed and when they are used in structure, SAR will be more decrease. Last SAR value is and for each bands .In the last table, There are some comparison between different creditable references and present article SAR reduction is acceptable and it is near to percentage.

Printed ultra-wideband monopole U-slotted antenna for triple band-rejection

A low-profile microstrip-fed planar monopole ultra-wideband (UWB) antenna with triple band rejection characteristics is proposed. The proposed antenna configuration consists of a bevelled ground with multiple U-slots embedded on the radiation patch for realizing the band notch characteristics. The notched frequency bands can be controlled by adjusting the parameters of the slots. The measured results demonstrate that the fabricated antenna exhibits an impedance bandwidth from 3 to 11 GHz for a VSWR ˂ 2 with three rejection bands at 3.38‒3.73 GHz for WiMAX, 5.12‒5.84 GHz for WLAN and 7.23‒8.56 GHz for X-band satellite communication services. Band rejection function is confirmed by the three gain diminishes occurring at 3.7, 5.35, and 8 GHz and stable gain outside the rejection bands. Measured group delay ensures that the designed antenna has good transmission capability of UWB signal with minimum distortion.

Design and Performance Analysis of Asymmetrical U-Slot Circular Patch Antenna for Wimax and WLAN Applications

The dual U-slot and tri-U-slot patch antennas have been designed to operate in WiMAX and WLAN applications. The radiation parameters such as return loss, radiation patterns, VSWR, and gain of the antennas have been analyzed using CST microwave studio. The proposed antennas have simple structure, simple coaxial feed, inexpensive, ease of fabrication and light weight designed for realizing dual band characteristics. The dual U-slot antenna has the bandwidths of 0.27GHz and 0.47GHz ranging 3.37GHz to 3.64GHz and 5.15GHz to 5.62GHz respectively. The tri-U-slot antenna has the bandwidths of 0.14GHz and 0.66GHz ranging from 3.61GHz to 3.71GHz and 5.18GHz to 5.84GHz respectively. The gains of the dual U-slots antenna have 8.77dBi, 9.47dBi and 8.1dBi and tri-U-slot antenna have the gains of 8.71dBi, 8.66dBi and 9.09dBi at the operating frequencies of 3.67GHz, 5.2GHz and 5.8GHz respectively. The simulated and measured results show that the antennas have stable gains, good impedance matching and directional radiation patterns. The measured and simulated results are in good agreement.

A Double U-Slots Microstrip Antenna for Triple-bands Operation

this paper, a design of double U-slots microstrip antenna with triple bands operation is presented. The antenna geometry is fed with a coaxial line feed technique. The feed is connected between the two arms of U-slots. The two slots are created on patch which is placed on the dielectric substrate of FR4 material with the overall dimensions of 74 mm × 67 mm × 1.6 mm. The proposed antenna geometry's performance is investigated in the frequency range of 5 GHz to 10 GHz. This geometry exhibits three resonances at 6.64 GHz, 8.21 GHz, and 9.18 GHz. However, in this work we presented U-Slot antenna which excites dual band operation with improved performance. The bandwidth at second resonant frequency was obtained broad as compared to the conventional patch antennas (2~3%). The proposed geometry was fabricated and tested for its validation. Measured results fairly agree with the simulated values. KeywordsAntenna, Slot Antennas, U-Slot, Triple Bands Antenna.