Active inductor design for reconfigurable bandpass microstrip filter applications

Herein, the design of an active inductor and its typical application for a reconfigurable band-pass filter circuit are presented. The Active Inductor design consists of a passive variable phase and amplitude compensating network and a highly linear inverting amplifier in order to form a gyrator-C design. The design allows a wide frequency range for tuning the equivalent inductance and resistance values that enable it to be used as a filter design where the inductor equivalent resistance increases and improves signal rejection for band-pass filter applications. As a typical application, first-order active band-pass filter had been designed and prototyped. The simulation and measurement results of the design are compared with the performance results of counterpart designs in literature. From the experimental results, it can be concluded that the proposed design is a suitable model for design of tunable band pass filter circuits. The design has an operation band of 0.7-2.1GHz with the equivalent inductance value of 2.6nH

UWB gain enhancement of horn antennas using miniaturized frequency selective surface

In this work, enhancement of the radiation performances of horn antennas are worked out within their operation bandwidth by placing the miniaturized Frequency Selective Surface (FSS)s perpendicularly into the inner part of their flares. Here each FSS consists of only a single miniaturized double-sided inverted Tshaped square unit cell designed on the low-cost FR4 with relative permittivity 4.4, loss tangent 0.0035 and thickness 1.58 mm in 3D CST environment so that it is able to focus the propagating electromagnetic waves to increase the directivity properties like a dielectric lens, while keeping the mismatching characteristics with less size and low manufacturing cost compared to its counter parts. Herein an exponentially tapered TEM horn with the operation bandwidth of 5-13 GHz is taken as an example horn antenna for measurements. From the measured results of the prototyped module, it can be observed that the proposed module keep mismatching characteristics of the horn antenna, meanwhile the gain and beam widths are enhanced to amplify the signal in the operation band without any increase in the total volume of the module or making the design bulky. Thus, it is expected that this methodology can be implemented to horn antennas effectively reducing volume and cost of communication system

Variable data structures and customized deep learning surrogates for computationally efficient and reliable characterization of buried objects

In this study, in order to characterize the buried object via deep-learning-based surrogate modeling approach, 3-D full-wave electromagnetic simulations of a GPR model have been used. The task is to independently predict characteristic parameters of a buried object of diverse radii allocated at different positions (depth and lateral position) in various dispersive subsurface media. This study has analyzed variable data structures (raw B-scans, extracted features, consecutive A-scans) with respect to computational cost and accuracy of surrogates. The usage of raw B-scan data and the applications for processing steps on B-scan profiles in the context of object characterization incur high computational cost so it can be a challenging issue. The proposed surrogate model referred to as the deep regression network (DRN) is utilized for time frequency spectrogram (TFS) of consecutive A-scans. DRN is developed with the main aim being computationally efficient (about 13 times acceleration) compared to conventional network models using B-scan images (2D data). DRN with TFS is favorably benchmarked to the state-of-the-art regression techniques. The experimental results obtained for the proposed model and second-best model, CNN-1D show mean absolute and relative error rates of 3.6 mm, 11.8 mm and 4.7%, 11.6% respectively. For the sake of supplementary verification under realistic scenarios, it is also applied for scenarios involving noisy data. Furthermore, the proposed surrogate modeling approach is validated using measurement data, which is indicative of suitability of the approach to handle physical measurements as data sources. © The Author(s) 2024

Modeling and realization of cavity-backed dual band SIW antenna

Herein, substrate integrated waveguide technology is applied in order to design high performance dual-band microstrip patch antennas. Two microstrip patch antenna designs were studied and modeled in 3D electromagnetic simulators. The obtained optimal models were then realized and measured. The measurement performance of the proposed antenna designs were then measured for 2.4 and 5.6 GHz. The results suggest that the proposed model consisting of a modified microstrip cavity-backed antenna and a defected ground structure is a high performance and low cost solution for 2.4 and 5.6 GHz applications

Design and implementation of doppler microwave motion sensor for indoor application

Ministry of Science, Industry & Technology - Turkey: 0230.STZ.2013-1 VIKO Electrical & Electronics Industry Inc. :0230.STZ.2013-1This paper presents a systematic integration and circuits design scheme of ISM-band Doppler radar for shortrange applications. The authors designed a complete CW Doppler radar transceiver and made a test for verification. Firstly, we establish a system model by conventional radar equation. Secondly, design the schematics of main modules including an oscillator, a mixer, and antennas. Finally, perform system integration using the designed circuits diagrams and parameters. The performance is found fairly satisfactory by test verificatio

Surrogate-Based Design Optimization of Multi-Band Antenna

In this work, design optimization process of a multi-band antenna via the use of artificial neural network (ANN) based surrogate model and meta-heuristic optimizers are studied. For this mean, first, by using Latin-Hyper cube sampling method, a data set based on 3D full wave electromagnetic (EM) simulator is generated to train an ANN-based model. By using the ANNbased surrogate model and a meta-heuristic optimizer invasive weed optimization (IWO), design optimization of a multi-band antenna for (1) 2.4-3.6 GHz for ISM, LTE, and 5G sub-frequencies, and (2) 9-10 GHz for X-band applications is aimed. The obtained results are compared with the measured and simulated results of 3D EM simulation tool. Results show that the proposed methodology provides a computationally efficient design optimization process for design optimization of multiband antennas. © 2022 Applied Computational Electromagnetics Society (ACES). All rights reserved

Application of artificial intelligence algorithms on modeling of reflection phase characteristics of a nonuniform reflectarray element

Reflectarray antennas (RAs) have the ability to combine the advantages of both traditional parabolic reflector and phased array antennas without the need for feed network designs. Microstrip reflectarrays (MRAs) have the advantages of being small size, light weighted, easy to prototyped, high gain, low side-lobe level, and a predetermined radiation pattern. These can be achieved by precise calculation of reflection phase at each RA unit independently with a phase compensation proportional to the distance from the feed. The challenging problem is to have a fast and high accurate unit element to be used in multidimension, multiobjective design optimization. Herein, artificial intelligence algorithms (AIAs) have been used for prediction of reflection phase characterization of an X band MRA unit element with respect to the geometrical design parameters. Firstly, a nonuniform unit RA has been designed in 3D electromagnetic (EM) simulation tool for creating the training validation data sets. Then, the data sets are given to the different types of AIA regression models such as multilayer perceptron, symbolic regression, and convolutional neural network. From the results of the validation data set, it can be concluded that the proposed models have sufficient accuracy that can be used in a computationally efficient design optimization process of a large-scale RA design. © 2019 John Wiley & Sons, Ltd

Design and realization of quasi Yagi antenna for indoor application with 3D printing technology

With the advances in the extrusion depositing base three-dimensional (3D) printing technology and decreases intheir costs, these technologies are being used in manyfields for fast and low cost prototyping means. One ofthese applications is manufacturing of microwave circuits.Herein, design and realization of quasi Yagi antenna forindoor application with 3D printing technology is pre-sented. First, design of a wide band microstrip quasi Yagiantenna consists of a dipole fed by a coplanar strip line, arectangular patch, and a ground reflector is studied. Thesize of the antenna is reduced by using a half bowtieshaped dipole and reflector. The studied microstrip quasiYagi antenna is aimed to operate within the operation fre-quency range of 670–3000 MHz. Then for experimentalresults, the designed antenna is fabricated by using a 3Dprinter with poly(lactide acid) material. From observingthe experiment results it can be concluded that 3D printedantenna has good performance, within the operation bandwith a good return loss characteristic performance of lessthan210 dB and a moderate gain of 3.5–4.6 dBi. As itcan be seen, the 3D printer technology is an efficientmethod for fast and accurate prototyping of antennadesignResearch Fund of the Artvin Coruh University: 2017.F14.02.0

Realization of Dielectric Sheets for Gain Improvement of Ultra-Wideband Horn Antennas Using 3D Printer Technology

WOS: 000476623500019In this work, 3D printing technology had been used to prototyped 10 dielectric sheets with relative dielectric constant of 2.5 for gain improvement of a TEM horn antenna. By loading the 3D printed dielectric sheets to the aperture of the horn antenna it is achieved to improve the radiation performance of the antenna over an ultra-wide operation band of 2-13 GHz. Here the Periodic dielectric sheets are designed to function similarly to a dielectric lens for focusing the incoming electromagnetic waves to increase directivity properties, while keeping their mismatching characteristics with less size and low manufacturing cost compared to its counterpart lens designs. The dielectric sheets had been prototyped via the use of 3D printing technology for experimental measurements. The measured performance of the proposed 3D printed dielectric loaded TEM horn antenna is compared with its counterpart ultra-wide band gain improvement methods for horn antennas in literature. From the measured results of the prototyped module, not only the proposed 3D printed dielectric sheets are smaller and have lower cost compared to their counterpart designs but also achieves to improve the gain characteristics of the antenna design over an ultra-wide band operation band without a distortion on antenna's S-11 characteristics

Realization of dielectric sheets for gain ımprovement of ultra-wideband horn antennas using 3d printer technology

In this work, 3D printing technology had been used to prototyped 10 dielectric sheets with relative dielectric constant of 2.5 for gain improvement of a TEM horn antenna. By loading the 3D printed dielectric sheets to the aperture of the horn antenna it is achieved to improve the radiation performance of the antenna over an ultra-wide operation band of 2-13 GHz. Here the Periodic dielectric sheets are designed to function similarly to a dielectric lens for focusing the incoming electromagnetic waves to increase directivity properties, while keeping their mismatching characteristics with less size and low manufacturing cost compared to its counterpart lens designs. The dielectric sheets had been prototyped via the use of 3D printing technology for experimental measurements. The measured performance of the proposed 3D printed dielectric loaded TEM horn antenna is compared with its counterpart ultra-wide band gain improvement methods for horn antennas in literature. From the measured results of the prototyped module, not only the proposed 3D printed dielectric sheets are smaller and have lower cost compared to their counterpart designs but also achieves to improve the gain characteristics of the antenna design over an ultra-wide band operation band without a distortion on antenna's S-11 characteristics