Ultra-wideband Slot Antenna Research Articles

Wireless Passive Ceramic Sensor for Far-Field Temperature Measurement at High Temperatures.

A passive wireless high-temperature sensor for far-field applications was developed for stable temperature sensing up to 1000 °C. The goal is to leverage the properties of electroceramic materials, including adequate electrical conductivity, high-temperature resilience, and chemical stability in harsh environments. Initial sensors were fabricated using Ag for operation to 600 °C to achieve a baseline understanding of temperature sensing principles using patch antenna designs. Fabrication then followed with higher temperature sensors made from (In, Sn) O2 (ITO) for evaluation up to 1000 °C. A patch antenna was modeled in ANSYS HFSS to operate in a high-frequency region (2.5-3.5 GHz) within a 50 × 50 mm2 confined geometric area using characteristic material properties. The sensor was fabricated on Al2O3 using screen printing methods and then sintered at 700 °C for Ag and 1200 °C for ITO in an ambient atmosphere. Sensors were evaluated at 600 °C for Ag and 1000 °C for ITO and analyzed at set interrogating distances up to 0.75 m using ultra-wideband slot antennas to collect scattering parameters. The sensitivity (average change in resonant frequency with respect to temperature) from 50 to 1000 °C was between 22 and 62 kHz/°C which decreased as interrogating distances reached 0.75 m.

Miniaturized T and Inverted T Slotted Ultra Wide Band Antenna with Defected Ground (DG) System for 5G Communication

Miniaturized T and Inverted T Slotted Ultra Wide Band Antenna with Defected Ground (DG) System for 5G Communication

An Additive 3D-Printed Hemispherical Lens With Flower-Shaped Stub Slot Ultra-Wideband Antenna for High-Gain Radiation

An Additive 3D-Printed Hemispherical Lens With Flower-Shaped Stub Slot Ultra-Wideband Antenna for High-Gain Radiation

Norman window slot antenna with sectoral feed backed by linear phase reflector for ultra wideband applications

An ultra wideband (UWB) slot antenna is proposed, developed, and experimentally validated in this article. The Norman window-shaped UWB slot antenna demonstrates stable radiation characteristics in both directions—zenith (θ = 0°) and nadir (θ = 180°) over the entire UWB frequency range (3.1–10.6 GHz) as observed in both simulations and experiments. A linear phase reflecting UWB frequency selective surface (FSS) is proposed by printing two orthogonal layers of pair of double rectangular loops on the same side of dielectric substrate as a merged frequency selective surface (MFSS). The UWB MFSS is then loaded with the slot antenna and the impact of MFSS on the impedance and radiation characteristics in different configurations of antenna and MFSS together is studied. One configuration with optimum solution is developed for experimental validations followed by the analysis of its radiation characteristics. The proposed antenna demonstrates a directional radiation pattern due to suppression of back lobe radiation when integrated with the UWB MFSS. The proposed antenna demonstrates maximum gain of 7.86 dB with a gain enhancement of 3.6 dB in boresight (θ = 0°) direction when MFSS is applied as a reflector to opposite side of the antenna slot.

Hyperparameters optimization of neural network using improved particle swarm optimization for modeling of electromagnetic inverse problems

AbstractOptimization of hyperparameters of artificial neural network (ANN) usually involves a trial and error approach which is not only computationally expensive but also fails to predict a near-optimal solution most of the time. To design a better optimized ANN model, evolutionary algorithms are widely utilized to determine hyperparameters. This work proposes hyperparameters optimization of the ANN model using an improved particle swarm optimization (IPSO) algorithm. The different ANN hyperparameters considered are a number of hidden layers, neurons in each hidden layer, activation function, and training function. The proposed technique is validated using inverse modeling of two meander line electromagnetic bandgap unit cells and a slotted ultra-wideband antenna loaded with EBG structures. Three other evolutionary algorithms viz. hybrid PSO, conventional PSO, and genetic algorithm are also adopted for the hyperparameter optimization of the ANN models for comparative analysis. Performances of all the models are evaluated using quantitative assessment parameters viz. mean square error, mean absolute percentage deviation, and coefficient of determination (R2). The comparative investigation establishes the accurate and efficient prediction capability of the ANN models tuned using IPSO compared to other evolutionary algorithms.

Ultra-wideband Antenna with Slotted Ground Structure for Wireless Application

This paper presents a software-based design of an ultra-wideband slot antenna that is applicable for wireless applications. Due to introduction of polygonal wide slot in the ground plane, the ultra-wideband has been achieved. The battery slot and rectangular shapes are implemented to improve S11, operating bandwidth range and radiation pattern of antenna. The optimal dimensions of the presented antenna are 45mm × 45mm × 1.565mm and is simulated on FR-4 substrate with relative permittivity of 4.3 and loss tangent of 0.025. The proposed antenna shows wide impedance bandwidth of 4.56GHz (104%) ranging0 from 2.08GHz to 6.64GHz that covers WLAN and WIMAX application.

An Elliptical CPW Fed UWB Slot Antenna

A new CPW fed elliptical antenna for ultra-wideband (UWB) is proposed. The novelty of this antenna are very small size and uniplanar structure, which results in easy and low cost fabrication. This antenna has elliptical slot configuration which is fed by the CPW. This elliptical slot UWB antenna is enclosed in the extended surface of ground for decreasing the chip surface area. This antenna is designed with the optimal design parameters for the UWB spectrum. The designed antenna is printed on FR4 substrate and Vector Network Analyser is used for measuring return loss. The results of measurement results are similar to simulation results. The complete chip volume of antenna is 18.3 × 23 × 1.6 mm3.

Influence of FR4 material substrate on diamond slotted ultra wideband antenna in 1.71 GHz to 12 GHz

The presented manuscript describes the influence of FR4 material substrate on diamond slotted ultra wideband antenna in 1.71 GHz to 12 GHz. It also gives the brief review of various substrate materials on the performance of patch antennas. This design is printed on FR4 material substrate of size 44 × 34 × 1.6 mm3. The antenna shows an impedance bandwidth from 1.70 GHz to 12.83 GHz. It observes highest radiation efficiency as 97% at 2.1 GHz and maximum peak gain as 7.25dBi at 10.1 GHz. The description of modified grounds with different types of slots in the ground and patch are also shown. This patch antenna is simulated by using ANSYS HFSS. The comparison plot of measured and simulated return loss (S11) is also shown in the paper.

Multi‐adaptive neuro‐fuzzy inference system modelling for prediction of band‐notched behaviour of slotted‐UWB antennas optimised using evolutionary algorithms

This study introduces modelling of multi-adaptive neuro-fuzzy inference system (MANFIS) for predicting the bandwidth and notch frequencies of slotted ultra-wideband (UWB) antennas. Rectangular-shaped printed monopole antennas embedded with U-shaped slots are designed to realise triple band-notch characteristics. A MANFIS model is then developed to predict five output parameters (two cut-off frequency points and three notched frequency points) considering 15 geometrical variables of the designed antennas as the inputs of MANFIS model. Extensive simulation has been performed using HFSS software to generate training and testing data patterns. Two optimisation algorithms, genetic algorithm (GA) and particle swarm optimisation (PSO), are implemented to optimally determine the appropriate values of the fuzzy inference system parameters. For GA-optimised MANFIS model, the percentage error is observed between 1 and 2%, whereas, in PSO-trained MANFIS model, it is observed <1%. The comparative analysis establishes that the PSO-trained MANFIS model precisely predicts the antenna performances. For validating the proposed modelling technique, an optimised configuration of the slotted UWB antenna prototype has been fabricated and characterised.

Compact ultra‐wideband slot antenna with three notched‐band characteristics

A very compact ultra-wideband (UWB) slot antenna with three L-shaped slots for notched-band characteristics is presented in this article. The antenna is designed and fabricated using a new stepped slot with different size, integrated in the ground plane, and excited by a 50 Ω microstrip transmission line. The stepped slot is used to minimize the dimensions of the antenna and to achieve an impedance bandwidth between 2.65 and 11.05 GHz with voltage standing wave ratio (VSWR) less than 2. The length of the stepped slot is equal to a quarter wavelength to create a resonance in the desired frequency. Three L-shaped slots with various sizes are etched in the ground plane to reject three frequency bands in C-band (3.7-4.2 GHz), WLAN (5.15-5.825 GHz), and X-band (7.25-7.75 GHz), respectively. The notched-band frequency can be controlled by changing the length of the L-shaped slot. The proposed antenna has a very small size (20.25 × 8 × 1.27 mm3) compared with previous works. The measured and simulated results show a good agreement in terms of radiation pattern and impedance matching.

Ultra-Wideband Antennas for Wireless Communication Applications

A review paper concerning wide-band and ultra-wideband (UWB) antennas used for wireless communication purposes in terms of the materials as well as a numerical analysis is presented. These antennas which are taken into account are listed as wide-band microstrip antenna, wide-band monopole antenna over a plate, wide-slot UWB antenna, stacked patch UWB antenna, taper slot (TSA) UWB antenna, metamaterial (MTM) structure UWB antennas, elliptical printed monopole UWB antenna, and flexible wearable UWB antenna. The antennas’ performance is compared based on their size and how they can be applicable for portable communication device applications. This review paper furnishes a proper direction to select varieties of figures in terms of impedance bandwidth, gain, directivity, dimensions, time domain characteristics, and materials affecting these antenna’s characteristics.

Fork‐shaped patch printed ultra‐wideband slot antenna with dual band‐notched characteristics using metamaterial unit cells

In this article, a miniaturized fork-shaped patch ultra-wideband (UWB) planar wide-slot antenna with dual band-notched characteristics is proposed. With fork-shaped patch, ultra-wideband impedance matching from 3.1 to 13.2 GHz is easily achieved. Then, two novel and simple methods are applied to solve the difficulty for UWB slot antennas with fork-shaped patch to realize band-notched characteristics. By etching one pair of I-shaped resonators on both branches of the fork-shaped structure and adding a rectangular single split-ring resonator in the rectangular openings of fork-shaped patch, the wireless local area network (WLAN) band from 5.5 to 6.1 GHz and the International Telecommunication Union (ITU) 8 GHz band from 7.9 to 8.7 GHz are rejected, respectively. The coplanar waveguide-fed UWB antenna is successfully designed, fabricated, and measured. The measured and simulated results show a good agreement. The antenna provides nearly stable radiation patterns, high gains and high radiation efficiency.

A novel reconfigurable band-notched ultra-wideband slot antenna for cognitive radio systems

A novel reconfigurable band-notched ultra-wideband slot antenna for cognitive radio systems

Design and analysis of a compact omnidirectional UWB slot antenna

AbstractA slot antenna for ultra‐wide band (UWB) application with a compact size, enhanced bandwidth, low profile, flat gain characteristic and omnidirectional radiation pattern is presented in this article. This antenna fed by microstrip to slot line is designed and fabricated on an FR4 substrate with a half‐wavelength rectangular patch as a radiator at low frequency and a pair of quarter‐wavelength long symmetrical slots enhancing the bandwidth at high frequency. This proposed antenna with an overall size of 33 × 10 × 0.8 mm3 (0.33λ0 × 0.1λ0 × 0.008λ0 at 3 GHz) has a |S11| &lt; −10‐dB bandwidth of 3.08‐12.14 GHz (119%), a 1‐dB gain bandwidth of 3.04‐10.5 (110%), and a peak gain of 3.08 dBi at 5.45 GHz in Z direction.

Compact Ultra-Wideband Slot Antenna with Dual Band Rejection by Using H-Shape Notch

The main objective is to design a dual band rejection micro strip patch antenna. In this antenna, H-shaped slots are made in the patch to achieve notched characteristics at two licensed band employed for Wimax and WLAN band. The above mentioned frequency ranges are licensed for WLAN and satellite communication applications. These antennas maintain the Omni-directional radiation patterns and are mostly suited for ultra wide band applications. For wide band operation, the shape of patch has been altered to octagonal just by chamfering the corners of the rectangular patch. The antenna parameters like radiation patterns, VSWR, reflection loss have been described clearly in this section. Radar applications, terrestrial networking and communication, space communications are some of the applications in this ultra wide band frequency range.

Conceptual design of a compact four‐element UWB MIMO slot antenna array

In this study, an effective methodology to design a compact four-element multiple-input-multiple-output (MIMO) antenna with high performance over ultra-wide bandwidth (BW) is presented and discussed. Taking the advantages of symmetry of most planar ultra-wideband (UWB) antennas, an asymmetric feeding scheme technique is utilised to chop a previously developed UWB slot antenna with overall dimensions of 30 mm × 30 mm into two halves to yield a more compact structure while retaining its overall frequency- and time-domain performances. Benefiting from orthogonal orientation, a compact UWB MIMO antenna system is arranged using four half-sized elements. The proposed MIMO antenna has an overall size of 40 mm × 40 mm and exhibits impedance BW from 2.94 to more than 14 GHz (10 dB return loss) with port isolation better than 17 dB over the entire operating band without using any decoupling structures. This is achieved via the inherent directional radiation properties of slot antenna elements and their asymmetrical placements. Envelope correlation coefficient is computed, and it is within the acceptable limit, which validates the design concept for building a compact MIMO antenna system with good performance.

Compact UWB Slot Antenna Utilizing Traveling-Wave Mode Based on Slotline Transitions

A compact ultra-wideband (UWB) slot antenna using narrow slots is proposed. Different from the traditional wideband slot antennas with multiple resonant modes, the proposed design of this paper utilizes the traveling-wave mode. By using a slotline–CPW transition as the convertor, which connects a slotline and four open slots, the forward wave in the slot has small reflection. The working mode keeps stable at different frequencies, i.e., operating in the traveling-wave mode. As a result, both wide bandwidth and stable radiation patterns are achieved with inherent characteristic of traveling-wave mode. The proposed antenna occupies a small area and the slot width is narrow, which make it suitable to be mounted on the edge of metallic surface for wireless devices. Given an instance for validation, a prototype is fabricated, with a slit width of 0.2 mm and a total size of $25\times 30\times 0.762 $ mm3 ( $0.24\times 0.29\times 0.007 \lambda _{L0}^{3} $ , $\lambda _{L0} $ is the wavelength in free space at the lowest operating frequency). Measured results show that a relative bandwidth (VSWR < 2) of about 121% is achieved, covering the entire UWB. Besides, stable gains and radiation patterns are obtained in the operating band. The time-domain characteristic is also investigated, and a small-signal distortion is achieved.

Compact CoPlanar Waveguide-fed Ultra Wide Band and Band Switchable Slot Antenna for Cognitive Radio Front-end System

A compact coplanar waveguide (CPW)-fed ultra-wideband (UWB) slot antenna with four narrowband switchable states is presented in this paper. Cognitive Radio (CR) portable devices demand a compact antenna. In planar monopole antennas where a large space around the patch is getting wasted that can effectively be used in UWB slot antennas. The proposed antenna consists of a half-elliptical slot radiator fed through a half-elliptical shaped tuning stub to operate in the UWB mode for CR sensing. However narrowband antenna is required to operate in CR communication purpose. To operate in the narrowband mode the UWB slot antenna is fed through a defected ground structure (DGS) integrated CPW line. Frequency re-configurability is achieved by changing the DGS slot length using eight PIN diode switches. The proposed compact antenna can cover UWB frequency range from 3.14 GHz to 12 GHz. It has omnidirectional radiation pattern and also has high realized gain which is especially suited for CR front-end applications.

Design of Cross-Shaped CPW-Fed Ultrawideband Slot Antenna

A new design of ultrawideband (UWB) antenna of coplanar waveguide (CPW)-fed is proposed. The antenna is composed of a cross-shaped patch and house-shaped slot with the minimum dimension of 21mm × 20mm × 1.6mm. The analysis of S11, VSWR, radiation pattern and surface current is discussed with HFSS simulation software, and also the effect of parameters is presented. Experimental results show that the bandwidth of the antenna covers 110.67% (3.3—11.6GHz) of UWB range with return loss better than 10 dB. And the good impedance matching in frequency band confirms the antenna is a good candidate for the application of wireless system.

CPW-fed ultra-wideband slot antenna with broadband dual circular polarization

A novel coplanar waveguide (CPW) fed ultra-wideband slot antenna with broadband dual circular polarization is proposed, fabricated and measured. The antenna structure is simple and consists of two CPW-fed ports to achieve both right-hand circular polarization and left-hand circular polarization at the same frequency band with the overall size of 48 × 48 × 1 mm3. The design process of the proposed antenna is given and the circular polarization mechanism is analyzed from the surface current distribution. The variation of return loss, port isolation and axial ratio (AR) with antenna parameters is simulated. By optimizing the radiation patch and improving the ground plane, the ultra wide impedance bandwidth and broad axial ratio bandwidth are achieved. The measured impedance bandwidth is 153.1% (1.9–14.3 GHz) with return loss better than 10 dB, and the measured 3 dB axial ratio bandwidth is 102.6% (1.9–5.9 GHz). The gain and port isolation are better than 3 dB and 15 dB, respectively, within the AR band.