Design Of Slot Antenna Research Articles

A Compact Wideband Dual-Polarized Slot Antenna With Five Resonances

This letter presents the design and analysis of a compact dual-polarized slot antenna using a triple-mode stepped slot-line resonator and a dual-mode cross-shaped monopole. The orthogonal polarization is achieved by feeding the two ports symmetrically at the opposite positions of the slot. All the five resonance frequencies can be flexibly adjusted by tuning different dimension parameters, so by increasing the frequency difference between the five resonance modes, a very wide common operating band (1.63-2.93 GHz) is obtained and also with a high port isolation (<; -32 dB). Finally, by loading two grounded lumped capacitors on the cusp sections of the monopole, its second resonance frequency can be independently reconfigured.

Design and study of a microstrip slot antenna operating at 2.8/3.1/3.6/4.7/5.4 GHz

A novel design of a multi band microstrip antenna is presented in this work. The double modified U slots planar patch antenna is designed, simulated and fabricated to operate at 2.8 GHz (between 2.794 to 2.846 GHz), at 3.1 GHz (between 3.145 to 3.196 GHz), at 3.6 GHz (between 3.56 to 3.3.644 GHz), at 4.7 GHz (between 4.684 to 4.772 GHz) and at 5.4 GHz (between 5.423 to 5.526 GHz) for WiMAX/WLAN applications. One of the main challenges was keeping a low profile and low cost substrate (1.2mm and FR4 respectively) with penta-band frequency response without scarifying these characteristics. Each resonant frequency is accomplished by modifying each U slot and patch radiator itself. Simulations had been conducted using HFSS software and measured parameters such as reflection coefficient (S11 parameter) was performed with a vector network analyzer. Measured results confirm simulated results that the antenna could work within mentioned frequencies. Parametric study was conducted in order to study the effect of slots variation over the design.

Design of CPW-Fed Slot Antenna with Rhombus Patch for IoT Applications

A CPW-fed slot antenna with rhombus patch radiator is proposed for 1.2276/1.5754/1.8/2.4/2.45/5.0/5.2/5.8 GHz wireless communication applications. The pentagon and rectangular slots are etched on the metallic layer of a single sided printed circuit board and rhombus patch radiator with a tuning stub in the feeding structure is embedded to form the proposed slot antenna. The dimensions of pentagon slot and tuning stub are changed to design and fabricate the antenna which can be operated at 1.2276/1.5754/1.8/2.4/2.45/5.0/5.2/5.8 GHz successfully. IE3D software is used to design this CPW-fed slot antenna and choose the better parameters to manufacture the proposed antenna. The influences of slot and stub dimension parameters of the proposed antenna on resonant frequency, input reflection coefficient expressed in decibel and impedance bandwidth are described. The proposed antenna with the volume of 100mm×80mm×0.6mm has been fabricated. The measured result shows that the proposed antenna can be successfully operated at 1.2-2.8 GHz and 3.35-7.56 GHz bands. These bands are suitable for IoT-based applications.

Structure and EM‐driven design of novel compact UWB slot antenna

In this study, a structure and design optimisation procedure of a novel compact ultra-wideband (UWB) slot antenna has been presented. In order to achieve small size of the structure and maintain acceptable electrical performance, a sufficiently large number of geometry parameters have been introduced. These include a stepped-impedance feed line and a meandered slot with all of dimensions being parameterised and subject to optimisation. All parameters are simultaneously adjusted using automated electromagnetic (EM)-simulation-driven optimisation algorithm. The design process is oriented towards explicit size reduction of the antenna structure. Penalty function approach is utilised to control the reflection response. In order to reduce the computational cost of the optimisation process, variable-fidelity EM models are utilised. The footprint of the optimised antenna is only 8.93 × 17.9 mm (160 mm2) while maintaining reflection below the –10 dB threshold in the entire UWB frequency range. The antenna has been favourably compared with the state-of-the-art compact structures in terms of the size. The obtained numerical results are supported by measurements of the fabricated antenna prototype.

Bandwidth Enhancement of Small Slot Antenna with a Variable Band-Stop Function

In this paper, a novel and compact design of microstrip slot antenna with band-notched characteristic for UWB application is proposed. In the proposed design, an inverted T-shaped slot at the square radiating stub is used to create an additional resonance at the higher frequencies. By obtaining this resonance, the usable upper frequency of the antenna is extended from 10.3 to 17.6 GHz which provides more than 140 % fractional bandwidth. Additionally, by cutting a pair of step-shaped slits in the ground plane, a desired frequency band-stop performance has been obtained. Experimental results obtained for this antenna show that it exhibits good gain and radiation pattern characteristics within the UWB frequency range. The proposed antenna can operate from 2.9 to 17.1 GHz for VSWR <2 with a rejection band around of 5–6 GHz to suppress any interference from wireless local area network systems. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for UWB applications.

Frequency- and time-domain analysis of a novel reconfigurable microstrip antenna for UWB applications

A new design of ultra-wide band reconfigurable microstrip slot antenna with switchable single and dual band filtering functions is presented and its time- and frequency-domain results are discussed. Two filtering functions are added to the performance of the antenna by means of etching a meander slot on the radiating patch and introducing a pair of hook-shaped coupling parasitic elements on the ground plane. Embedding PIN diode switches into the antenna structure has added an additional merit to the antenna as a switchable single/dual band filtering operation. The designed antenna has a simple structure with a very small size of 20 × 20 mm2. Suitable agreement exists between its time- and frequency-domain results. The measured impedance bandwidth for VSWR < 2 extends in the frequency range of 3.1–10.6 GHz with fractional bandwidth of 109%, while filtering the interference with C-band and X-Band satellite communication systems at 3.7–4.35 and 7.7–8.9 GHz, respectively.

Analysis and Design of a Novel Circularly Polarized Antipodal Linearly Tapered Slot Antenna

This paper presents and characterizes a novel antipodal linearly tapered slot antenna for generating the circularly polarized (CP) field. By introducing two symmetrical slots on the top and bottom layers of a rectangular WR-15 waveguide, we could obtain circular polarization with an axial ratio bandwidth of 34.1%. The waveguide was used to feed the proposed antenna with very wideband impedance matching. The antenna can achieve impedance bandwidth of 40% for S(1,1) <−15 dB from 50 to 75 GHz. The simulation and measurement results show that the antenna can produce very good radiation patterns, with stable gain of 9.8 dBi ± 1.24 dBi, low back radiation, and narrow beamwidth over the operating frequency range. The working principle of this CP antenna is explained, using theoretical equations and explicit current distributions. The proposed antenna is easy to manufacture and is a compact candidate for high performance CP millimeter-wave antenna.

Design of clover slot antenna for biomedical applications

A new clover slot antenna operating at 2.45GHz Industrial, Scientific, and Medical (ISM) band for biomedical applications is presented and experimentally verified. By putting a single feed and truncating clover slots with extra perturbation, good performance of polarization can be achieved. Also, the miniaturized size of the proposed antenna is 14×12×0.8mm3 by utilizing the clover shaped slots. A broader bandwidth of 2.5GHz is obtained for reflection coefficient less than −10dB. In addition, the radiation pattern of proposed antenna exhibits the maximum gain of −6dBi.

Design of a dual slot antenna for small animal microwave ablation studies.

This study presents the development of a dual-slot antenna for small animal tumor ablation. By using a dual-slot design at 8 GHz, it was hypothesized that smaller and more spherical ablations can be produced. After computer-aided design optimization, antennas were fabricated and ablations performed at 5-20 W for 15-120 s with the objective of creating ablations with a diameter/length aspect ratio of at least 0.9. The new dual-slot design at 8 GHz created significantly more spherical ablations than a commercial antenna at 2.45 GHz in ex vivo liver tissue (Average Aspect Ratio 0.8081 vs. 0.4532, p <;<; 0.05). In vivo studies confirmed the highly spherical results ex vivo. Initial testing shows that the dual-slot antenna and 8 GHz generator can be used to ablate tumors in mice.

Design and simulation of a non-resonant antenna: waveguide slot antenna for 30 GHz

The main contribution of this article is the design and simulation of a non-resonant slot antenna based on wave guides to operate in the range of microwaves. The design is done using MATLAB and the Chebyshev synthesis to determine the distribution of current in each element. Based on this information, the size and distribution of the elements are calculated. Different design conditions are simulated, such as: changes in the level from main lobe to secondary and dierent number of slots at one frequency. The slots are interleaved with respect to the axis of the waveguide and separated by a distance (d). To determine its dimensions, it is necessary to deduce the conductances of the array. A particular design case is compared with simulations from the software CST Microwave Studio. It is observed that radiation diagrams are very similar in both number and amplitude of the lobes, validating the tool used.

Design of dual‐band cavity‐backed slot antenna loaded with spurline

A design of dual-band cavity-backed slot antenna loaded with a spurline is presented for GPS and S-band radar applications. In the design, a very thin cavity (0.017 in thickness at 1.575 GHz) is used to achieve unidirectional radiation. The dual-band responses of the antenna are excited by the slot resonance at 1.575 GHz and waveguide transition effect at 2.4 GHz. Reasonable impedance bandwidths are obtained as 1.6% (26 MHz) at 1.575 GHz and 8.4% (203 MHz) at 2.4 GHz. The proposed slot can also be loaded with a spurline to adjust the antenna centre frequency and the phase of the radiated field. A switch using a PIN diode is deployed with the spurline. It is found that the spurline and the corresponding bias circuit for the PIN diode have little effect on the antenna radiation. Two proposed slots are combined to form an antenna which is right-hand circularly-polarised at both 1.575 and 2.4 GHz. A phase delaying system consisting of delay line and the spurline is designed to achieve 90° phase difference at both frequencies. The measured axial-ratio bandwidths are 1.5% (24 MHz) at 1.575 GHz and 4.5% (110 MHz) at 2.4 GHz, which are sufficient for practical applications.

A High-gain and Low-scattering Waveguide Slot Antenna of Artificial Magnetic Conductor Octagonal Ring Arrangement

A novel design of high-gain and low-scattering waveguide slot antenna is proposed in this paper. Firstly the scattering pattern of artificial magnetic conductor (AMC) composite surface is estimated by array factor anal- ysis method. The comparison between octagonal ring arrangement and chessboard arrangement proves that the former arrangement has the characteristic of diffuse- ness-like and expands the bandwidth of radar cross section (RCS) reduction. Secondly, the metal surface of waveguide slot antenna (WSA) is replaced by the octagonal ring arrangement composite surface (ORACS). The gain is improved because of spurious radiation units which are around the slot. At the same time using the phase cancella- tion principle, a backscatter null achieves RCS reduction in the vertical direction. Experimental results show that for the novel antenna after loading with the ORACS, the gain is improved by 5 dB; the bandwidth of RCS reduction (re- duction greater than 10 dB) is 5.24-5.92 GHz.

On the matching characteristics of a rectangular slot located near the edge of a finite-size ground plane

We study the matching characteristics of a rectangular slot located in the farthest upper part of a ground plane. First, we investigate the effect of geometrical parameters including the length and width of the slot, the ground plane height, and feed point position on the input impedance. In turn, we consider the matching between the slot and a feed and examine impedance-matched frequencies and bandwidths. An approximate closed-form expression for the impedance-matched wavelength of the slot in terms of its length, width, and feed-point position is given. The results can aid in the design of application-specific slot antennas for handheld devices.

Circular slot antenna with capacitive loading technique for broad circularly polarized bandwidth

ABSTRACTA microstrip‐fed circular slot antenna design is proposed. To excite good CP (circularly polarized) radiation, the technique of loading a cross patch (with unequal arm lengths) into the circular slot is initially applied. Here, good impedance matching can be further attained by dividing the cross patch into two equal sections with a gap loaded in between them, in which this gap will induce a capacitive loading effects on the proposed antenna. The measured results shown that the proposed antenna has 10 dB impedance bandwidth of 36.4% (2116–3124 MHz), and its corresponding CP bandwidth (along 3 dB axial ratio, AR) was 12.3% (2345–2655 MHz). In addition to that, the proposed CP slot antenna has also yielded peak gains of more than 3.3 dBic across the CP bandwidth. Detailed process of designing the proposed CP slot antenna is explicitly shown, and vital parametric studies were also conducted by simulation. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:715–720, 2016

Design of a Novel Coaxial Feed Triple Frequency Patch Antenna with Slots and Shorting Pin

This paper presents a detailed explanation on the design of a novel triple frequency rectangular slot antenna for wireless local area network (WLAN) applications in IEEE 802.11b/g/a systems. This proposed antenna operates in ISM band at frequency of 2.4 Ghz and also in C band at 4.85 Ghz AND 6.1Ghz. The antenna has been designed and simulated on a foam substrate with dielectric constant of 1.06 and a thickness of 7mm. The design is analysed by Finite Element Method based HFSS Simulator Software (version 13.0) by which return loss, 3D polar plot and Gain of the antenna are computed. In addition, the measured results show good radiation characteristics at the three operating frequencies, proving the dual-band operation of the proposed antenna.

Design of a Compact Quad-Band Slot Antenna for Integrated Mobile Devices

In order to incorporate different communication standards into a single device, a compact quad-band slot antenna is proposed in this paper. The proposed antenna is composed of a dielectric substrate, T-shaped microstrip patch with a circle slot and an inverted L-slot, and a comb-shaped ground on the back of the substrate. By adopting these structures, it can produce four different bands, while maintaining a small size and a simple structure. Furthermore, a prototype of the quad-band antenna is designed and fabricated. The simulated and measured results show that the proposed antenna can operate over the 1.79–2.63 GHz, 3.46–3.97 GHz, 4.92–5.85 GHz, and 7.87–8.40 GHz, which can cover entire PCS (Personal Communications Service, 1.85–1.99 GHz), UMTS (Universal Mobile Telecommunications System, 1.92–2.17 GHz), WCDMA (wideband code-division multiple access, 2.1 GHz), Bluetooth (2.4–2.48 GHz), WiBro (Wireless Broad band access service, 2.3–3.39 GHz), WLAN (Wireless Local Area Networks, 2.4/5.2/5.8 GHz), WiMAX (Worldwide Interoperability for Microwave Access, 2.5/3.5/5.5 GHz), and X-band SATcom applications (7.9~8.4 GHz). The proposed antenna is particularly attractive for mobile devices integrating multiple communication systems.

Design of Compact and High Directive Slot Antennas Using Grounded Metamaterial Slab

In this letter, a simple and compact approach for directivity enhancement of slot antenna using a grounded metamaterial slab is proposed. This approach has been applied in two different configurations. In the first configuration, two dielectric layers are used for designing antenna and metamaterial slab. Despite the directivity enhancement, an improved bandwidth of about 10.74% is obtained for this configuration. It is also shown that, over the whole working band, a significant broadside directivity improvement is maintained compared to the unloaded slot. In the second configuration, only a single layer of dielectric is used for designing both antenna and metamaterial slab. Thus, in this case, the total thickness of the loaded antenna is noticeably reduced to 0.5 mm, or 0.014 λ0 at resonance.

Design of compact slot antenna based on split ring resonator for 2.45/5 GHz WLAN applications with circular polarization

In this article, compact slot antenna based on split ring resonator (SRR) with circular polarization (CP) for 2.4/5 GHz WLAN applications is noticed. Using metamaterial with both negative permittivity and permeability improves the antenna parameters. Thus, the prototype antenna is designed based on metamaterial SRRs to achieve CP and compact size. The final antenna has bi-directional pattern with CP and dual-band at 2.2–2.8 GHz for WLAN, Bluetooth application, and 5.2–7 GHz for IEEE WLAN protocol with gain 2.1 and 2.5 dBi, respectively. The size of prototype patch antenna is 40 × 40 mm. It is designed and fabricated on FR-4 low cost substrate with er = 4.4 and thickness of 1.6 mm. It is simulated by HFSS commercial full wave software. In addition, the experimental results are presented and compared here with simulation. The antenna efficiency is more than 90% for first band and more than 80% for second band and typically is more than 70% in 2–7 GHz. The antenna gain is simulated and compared with measurement and antenna gain is around 3–4.5 dBi. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:12–16, 2016

Annular ring slot antenna design with reconfigurable polarization

A microstrip-fed conventional annular ring slot (ARS) antenna with linear polarization (LP) is initially studied. To generate two orthogonal degenerate modes for circular polarization (CP) radiations, two identical meandering perturbation slots (MPS) are symmetrically loaded into the ARS. By further incorporating a PIN diode switch across each MPS, the proposed antenna can switch between left-hand CP (LHCP), right-hand CP (RHCP), and LP. All three polarizations have shown good impedance bandwidth and broad CP bandwidth that can satisfy the wireless local area network (WLAN) 2.4-GHz operating band (2400–2480 MHz). Furthermore, desirable gains of 1.8–2.0 dBi and 2.40–2.84 dBic are also exhibited at LP and LHCP/RHCP, respectively. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:110–120, 2016.

Design of a Concentric Array Radial Line Slot Antenna for High-Power Microwave Application

A compact concentric array radial line slot antenna (CA-RLSA) operating at $K_{u}$ -band for high-power microwave (HPM) application is proposed in this paper. The efficiency of HPM-RLSA becomes lower as the aperture size reduces due to rotational asymmetry of the illumination. The HPM-CA-RLSA was designed to overcome this difficulty with notable power handing capacity. It is fed by circularly polarized TE11 coaxial waveguide mode to generate a rotational symmetric cylindrical wave excitation. Furthermore, the reflection canceling structure of this HPM-CA-RLSA is not only simpler than the one in the HPM-RLSA but also improves the frequency response performance. An antenna prototype with length of 8 cm and aperture diameter of 40 cm is designed, which has a gain of 32.0 dBi, reaching an aperture efficiency of 62.7%, and an axial ratio less than 0.5 dB at 12 GHz. The simulated results show that this antenna has a power handing capacity of more than 500 MW.