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This paper describes the design of a hybrid coupler with a continuously variable output phase difference. This is achieved by using reconfigurable transmission lines with electrically tunable lengths controlled by two biasing voltages through varactor diodes placed across the coupler branches. The design of the coupler is based on the quadrature hybrid structure for the case where the output phase difference is 90° and on the asymmetric structure for the other cases. The proposed coupler can achieve a tunable output phase difference from 52° to 128°, while keeping a coupling coefficient of −3 dB (± 0.5 dB) over the entire desired frequency band. To validate the simulated results, a prototype working at 3.5 GHz was fabricated and tested. The measurement results show good correspondence with the simulation results, especially when the output phase difference is 90°, while a phase mismatch of less than 7° was observed for the other cases. The presented coupler would be a great asset for antenna feeding arrays, especially the Butler matrix.

This study introduces an approach to predicting cardiovascular diseases (CVDs) by leveraging neural networks and evaluates its performance against the widely recognized SCORE2 risk assessment tool. Given the significant global health impact of CVDs, our research aims to assess the effectiveness of deep learning-based models compared with traditional methods. Our methodology involves developing and deploying a neural network model capable of learning intricate patterns and relationships from a comprehensive dataset. Leveraging a large population cohort with extended follow-up enables precise and long-term risk estimation. We utilize the T-paired test to compare risk predictions between our neural network model and the SCORE2 tool. Our results indicate a notable accuracy of 0.77 for our neural network-based model in predicting CVDs, with the T-paired test revealing no significant variations in risk levels between the two methods. These findings underscore the effectiveness of neural networks as a robust tool for CVD risk prediction and advocate for further exploration and integration of these technologies to enhance cardiovascular risk assessment, thereby advancing predictive modeling in healthcare.

A new small high-gain wideband rectangular patch antenna is proposed in this paper. The antenna has a simple structure where the dimensions are about 11 mm by 7 mm by 1.58 mm leading to a good bandwidth. The antenna structure is optimized and simulated using electromagnetic commercial software, and the measured bandwidth defined by return loss

A new small circular patch antenna for ultra-wideband (UWB) applications is presented. By studying this structure, it is shown that the insertion of a slot with the desired length and width in the ground plane, can lead to a large bandwidth. Our antenna, whose dimensions are 18×12×1.58 mm3, was fed by an SMA female connector with characteristic impedance of 50Ω in order to measure the return loss and VSWR and to compare them with the simulation results. The bandwidth obtained from measurements ranges from 3.52 to 13.67 GHz for VSWR < 2 and from 3.26 GHzto14.23GHz for VSWR < 3. The radiation pattern is omnidirectional on most of the operating band. High Frequency Structure Simulator (HFSS) was used for simulation whose results are in good agreement with the measured parameters.

In this paper, a wide-band and high-gain microstrip antenna with mullti-layer microstrip patch and an aperture-coupled feeding is proposed. The antenna has a condensed structure where the dimension is about 8.5mm by 7.5mm by 4.662mm leading to good bandwidths covering 8.05 GHz to 12.01 GHz (39.48%), and the gain is up to 5.23dB. The low expenses of this profile and its simple configuration allows for an its easy fabrication, with appropriation with wireless and satellite communication.

In this paper, we propose the design of and provide an analysis of, a rectangular patch antenna and its integration in a 4 element linear array. A T form power divider feeds in parallel the array elements through microstrip lines. The basic antenna has a simple structure, with dimensions of about 16´18´1.6 mm3, leading to a good bandwidth. In addition, the patch element characteristics, such as the reflection coefficient and the voltage standing wave ratio (VSWR), are improved by the insertion of a slot in the structure. The main objective of the 4 element array structure is the enhancement of the gain, which is enhanced up to 12.6 dBi. A prototype of the antenna is fabricated and tested with network analyzer. The proposed antenna has 4 resonant frequencies that define 4 bandwidths, defined by a return loss of less than -10 dB, and are: (7.62 GHz, 1250 MHz), (9.20 GHz, 330 MHz), (11.07 GHz, 940 MHz) and (15.02 GHz, 920 MHz), respectively. The simple configuration of this profile permits an easy and low-expense fabrication process, with usability in many applications such as in radar, satellite, and wireless communications.