In this article a novel feeding system for BST Multiband Antennas is presented. This system is based on a 4 × 4 Butler matrix that uses a novel triple band hybrid. This hybrid operates on GSM900, DCS1800 and UMTS2100 bands. The presented novel implementation technique in the triple band hybrid can also be used in other application. The Butler matrix network is fabricated on FR4 substrate and the simulated and measured results are presented.

Introduction: The most important diagnostic indicator of Acute Coronary Syndrome (ACS) is typical clinical symptoms, like chest pain, but many patients may experience nonspecific (atypical) symptoms. Understanding these symptoms and their associated factors results in early diagnosis and more appropriate treatments. Objective: We aimed to determine atypical clinical symptoms and their predictors in patients with Acute Coronary Syndrome. Materials and Methods: This cross-sectional study was conducted on 1167 patients with ACS hospitalized at a specialized hospital in Rasht City, Iran, between December 2019 and October 2020. The research samples were selected by a consecutive sampling method. Data were collected through a researcher-made questionnaire by interview, in which sociodemographic characteristics, risk factors, disease-related factors, and symptoms of patients with ACS were collected. Data analysis was done by descriptive statistics and multiple logistic regression by the backward LR (likelihood ratio) method. The significance level was set as P<0.05. Results: In this study, 56.3% of the patients were male. The Mean±SD age of the patients was 60.9±11.1 years. About 28.1% of the patients experienced atypical clinical symptoms. The most common atypical symptoms were shortness of breath (29.4%), back pain (18.3%), and left shoulder pain (12.7%). The predictors of atypical symptoms were age (OR=0.98, 95% CI; 0.975 - 0.999, P=0.047), alcohol use (OR=1.86, 95% CI; 1.047 - 3.303, P=0.034), brain diseases (OR=2.36, 95% CI; 1.463 - 3.811, P=0.001), blood diseases (OR=1.45, 95% CI; 1.059 - 2.002, P=0.021), and gastroesophageal reflux (OR=1.31, 95% CI; 1.006 - 1.719, P=0.045) Conclusion: Since more than a quarter of ACS patients have unusual symptoms, detecting these symptoms and related factors can help in early diagnosis and conduct more appropriate medical treatment.

This paper introduces a reconfigurable polarization MIMO (Multi-Input Multi-Output) dielectric resonator antenna at a millimeter-wave frequency band. The proposed antenna consists of four single dielectric resonator antennas that are placed in configuration to form a MIMO antenna, and also this design is based on using the pin diode switching concept to control the antenna polarization. To modify the antenna structure for different polarizations, two pin diodes are used in the ground place of the MIMO antenna. The designed antenna operates at 4.35 GHz for polarization diversity applications of the modern wireless MIMO systems. The proposed antenna covers a bandwidth of 11.26% at the central frequency and provides circular and linear polarizations with a high gain of around 6.4 dB. The antenna performance in terms of reflection coefficient, gain, and axial ratio bandwidth in different modes (ON-ON, ON-OFF, OFF-ON, and OFF-OFF) is measured. The advantages of the designed antenna are simple structure (using two pin diode switches to modify antenna polarization), high gain, low profile, and light weight. According to the measurement and simulation results, the designed antenna displays good return loss and radiation performance. Using plexiglass as an antenna material which is very cheap and available in different dimensions is another advantage of the proposed antenna which reduces the fabrication cost.