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This research focuses on developing a uniquely miniaturized 4×4 Butler Matrix Network integrated with a 1×4 linear array antenna, generating four beams with exceptional isolation and transmission coefficients. Extensive analyses evaluate the antenna's radiation characteristics, including gain, directivity, and beam-forming capabilities. Innovative design techniques achieve significant Butler matrix miniaturization without compromising performance, resulting in a compact final design measuring 23mm × 20.5mm. The integrated multi-beam antenna array demonstrates favorable outcomes, ensuring impedance matching at 50Ω, high gain, and four beams directed at angles of ±8º and ±33º. These results highlight the design's superiority over traditional counterparts, with gains of up to 11 dB. Detailed radiation patterns for all ports are presented. The paper also provides insights into the manufacturing process, materials used, and challenges faced. The results conclusively confirm the system's compliance with performance criteria, effectively operating within the 28 GHz frequency band. This research significantly contributes to downsizing antenna systems, facilitating more compact and efficient communication devices in the future. [ABSTRACT FROM AUTHOR]

The 5G system-based cognitive radio network is promised to meet the requirements of huge data applications with spectrum. However, the M-ary effect on the detection has not been thoroughly investigated. In this paper, an M-ary of quadrature amplitude modulation detection system is studied. Many rates are used in this study 4, 16, 64, and 256 constellation points. The detection system is applied to cooperative spectrum sensing to enhance the performance of detection for various rates of M-ary with low signal-to-noise ratio (SNR). Further, three kinds of signals based 5G system are sensed: filtered-orthogonal frequency division multiplexing (F-OFDM), filter bank multi-carrier (FBMC), and universal filtered multi-carrier (UFMC). The best detection performance is obtained when the M-ary=4 and number of SUs=50 user, whereas the worst detection performance is obtained when the M-ary=256 and number of SUs=10 user, as revealed in the simulation results. In addition, the detection performance for the F-OFDM signal is better than that of UFMC and FBMC signals for SNR <0 dB. [ABSTRACT FROM AUTHOR]

According to several research circles, it is predicted that future wireless systems that employ smart antenna techniques would be more effective at using available spectrum and at building new networks at lower cost, while also improving service quality and allowing for cross-technology operation. These systems require constant monitoring in order to function properly, allowing users to apply machine learning algorithms to analyse large amounts of data from various antenna settings. Machine learning is a technique in which a machine learns and improves on its own, based on past data. These techniques enable the smart antenna target to be learned in an efficient, reliable, and adaptive manner. In this paper, the antenna array and antenna developed for the Internet of Things applications were highlighted. In this paper, we review how machine learning techniques can handle these applications effectively and what the concept of adaptive antenna is and when it can be used in this day and age characterized by the rapid development of information technology. [ABSTRACT FROM AUTHOR]

Summary: Reducing the losses of 3‐phase transformers is still considered a significant target by many transformer designers and manufacturers. Core joint design is one of the factors related to the losses. In previous studies, core losses and flux density distribution motivated researchers to design appropriate T‐joints. However, the variation of load and thermal profiles are the most important factors related to the losses in transformers. This study proposed a new T‐joint configuration for the core of the 3‐phase transformer. The proposed model was built after considering the variation of load and thermal profiles. Results were compared with those of conventional T‐joint designs, such as butt‐lap and 45° mitered designs, that are currently used. The no‐load losses of the proposed model were reduced by more than 6.8% and 10% compared with those of the butt‐lap and mitered T‐joint designs, respectively. Furthermore, the total losses, the hot spot temperature of the core, and the oil temperature decreased significantly. The proposed model contributes to the literature on new T‐joint designs for improving transformer performance. [ABSTRACT FROM AUTHOR]

ABSTRACT Basis of the microwave imaging is the contrast in dielectric properties of breast normal tissue and tumor. Confocal microwave imaging involves transmitting an ultrawideband signal through number of antennas and records the scattered signals. Then by synthetically focusing reflections from the breast, we can make image from breast. In this article, we demonstrate the feasibility of detecting 10- and 5-mm tumors in three dimensions with different antenna arrangements with different number of antennas. Two models of hemispherical array are presented. An image formation algorithm is presented for 3D image making. Successful detection of 10- and 5-mm tumors are achieved with the hemispherical arrangement. The influences of the different breast sizes for tumor detection are also explored. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2917-2929, 2015 [ABSTRACT FROM AUTHOR]

A double SAW resonator system was developed as a novel method for gas sensing applications. The proposed system was investigated for hydrogen sensing. Commercial Surface Acoustic Wave (SAW) resonators with resonance frequencies of 433.92 MHz and 433.42 MHz were employed in the double SAW resonator system configuration. The advantages of using this configuration include its ability for remote measurements, and insensitivity to vibrations and other external disturbances. The sensitive layer is composed of functionalized multiwalled carbon nanotubes and polyaniline nanofibers which were deposited on pre-patterned platinum metal electrodes fabricated on a piezoelectric substrate. This was mounted into the DSAWR circuit and connected in parallel. The sensor response was measured as the difference between the resonance frequencies of the SAW resonators, which is a measure of the gas concentration. The sensor showed good response towards hydrogen with a minimum detection limit of 1%. [ABSTRACT FROM AUTHOR]

A novel ultra-wideband (UWB) antenna is presented which has UWB characteristics in a medium same as breast. To optimise the antenna for its best operation, effect of variation in different parts of the antenna is analysed and presented. The antenna's characteristics are presented in simulation and experimental measurements. The results of the authors' study show that the antenna has excellent performance across 4 to more than 9 GHz. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the development and design of proximity coupled feed patch antenna as a bio-sensor. This sensor system consists of a two-layer Flame Retardant (FR-4) patch antenna coated with Multi Walled Carbon Nanotubes (MWCNTs) for absorbing bio-molecules. The best design of patch antenna is chosen based on simulation results using Computer Simulation Technology (CST) microwave studio software. After adding bio-material on the top of antenna and interaction with MWCNTs based on the changes in the effective dielectric constant, the resonant frequency of patch antenna is changed. Experimental results have shown 1 MHz change in resonant frequency of patch antenna upon exposure to ethanol. Based on operating frequency (5 GHz) this technique can be used in network sensor systems to measure bio-materials in future research. [Copyright &y& Elsevier]

In this study, the ability of the Capillary-attached conductive gas sensor (CGS) in real-time gas identification was investigated. The structure of the prototype fabricated CGS is presented. Portions were selected from the beginning of the CGS transient response including the first 11 samples to the first 100 samples. Different feature extraction and classification methods were applied on the selected portions. Validation of methods was evaluated to study the ability of an early portion of the CGS transient response in target gas (TG) identification. Experimental results proved that applying extracted features from an early part of the CGS transient response along with a classifier can distinguish short-chain alcohols from each other perfectly. Decreasing time of exposition in the interaction between target gas and sensing element improved the reliability of the sensor. Classification rate was also improved and time of identification was decreased. Moreover, the results indicated the optimum interval of the early transient response of the CGS for selecting portions to achieve the best classification rates. [ABSTRACT FROM AUTHOR]

Sliding mode control (SMC) is a nonlinear controller that is used to achieve desired performance in the presence of unstructured uncertainty as a result of carelessness of parameter specification of the system. The main aim for sliding control, or also called Variable Structure Control, is to control the nonlinear plant by introducing a sliding surface. The sliding surface should be reached by making the state of system approach this level. In this paper, an integral augmented sliding mode control (SMC+I) is proposed to improve the control performance of a plant with uncertainty giving the example of bench-top helicopter and the results are compared with the results obtained from conventional sliding mode control with and without a boundary layer. [ABSTRACT FROM AUTHOR]