Passive Components for Ultra-Wide Band (UWB) Applications

UWB technology brings the convenience and mobility of wireless communications to very high-speed interconnects in the home and office due to the precision capabilities combined with the low power. This makes it ideal for certain radio frequency sensitive environments such as hospitals and healthcare as well as radars. UWB intrusion-detection radar is used for detecting through the wall and also used for security with fuse avoidance radar, precision locating and tracking (using distance measurements between radios), and precision time-of-arrival-based localization approaches. The FCC issued a ruling in 2002 that allowed intentional UWB emissions in the frequency range between 3.1 and 10.6 GHz, subject to certain restrictions for the emission power spectrum. Other definitions for ultra-wideband range of frequency are also used such as any device that has 500 MHz bandwidth or fractional bandwidth greater than 25% is considered an UWB enable high data rate to be transferred with a very low power that does not exceed −41.3 dBm

Non-Invasive Electromagnetic Biological Microwave Testing

Blood glucose monitoring is a primary tool for the care of diabetic patients. At present, there is no noninvasive monitoring technique of blood glucose concentration that is widely accepted in the medical industry. New noninvasive measurement techniques are being investigated. This work focuses on the possibility of a monitor that noninvasively measures blood glucose levels using electromagnetic waves. The technique is based on relating a monitoring antenna’s resonant frequency to the permittivity, and conductivity of skin, which in turn, is related to the glucose levels. This becomes a hot researched field in recent years. Different types of antennas (wideband and narrowband) have been designed, constructed, and tested in free space. An analytical model for the antenna has been developed, which has been validated with simulations. Microstrip antenna is one of the most common planar antenna structures used. Extensive research development aimed at exploiting its advantages such as lightweight, low cost, conformal configurations, and compatibility with integrated circuits have been carried out. Rectangular and circular patches are the basic shapes that are the most commonly used in microstrip antennas. Ideally, the dielectric constant εr, however, and other performance requirements may dictate the use of substrate whose dielectric constant can be greater. As in our prototype blood sensor, the miniaturized size is one of the main challenges

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Ultrawideband Vivaldi Antenna for DVB-T, WLAN, and WiMAX Applications

Compact Vivaldi patch antenna with a parasitic meander line is presented in this paper. A PIN diode switch is used to connect and disconnect ultrahigh frequency band (UHF) with ultrawide bandwidth (UWB). The operating frequencies can be switched among different services, depending on the switching states (ON/OFF) to add the lower band when required. This antenna is suitable for portable DVB-T which extended from 450 MHz to 850 MHz receiver applications and the WLAN (Wireless Local Area Network) IEEE 802.11b,g (5.1–5.8) GHz frequency bands and WiMAX band (3.3–3.8) GHz. The measured reflection coefficient of the proposed antenna is compared with the simulated one; good agreement is observed. Also, simulated radiation pattern of the antenna is presented. All simulations are carried out using the EM commercial simulator, high frequency structure simulator (HFSS) ver.13

Low SAR, compact and multiband antenna

This paper proposes a new mobile handset antenna structure to reduce the value of the specific absorption rate (SAR) and to cover most of the mobile operating bands and other wireless applications. The covered bands are the GSM 900, DCS 1800, PCS 1900, UMTS 2100, and most of the LTE bands. Furthermore, it covers the ISM, WiMAX and the WLAN bands. The electromagnetic radiation in the direction of the human head is reduced via the use of electromagnetic band gap structure (EBG). The antenna is constructed from a monopole and a meander line. The operating bands ranges from (850-1030 MHz) and (1.71-7.8 GHz). Moreover, the first band of the antenna can be tuned by using various meander line lengths or by adjusting the spacing between the monopole and the meander line, while the second band can be tuned by adjusting the monopole length or the meander line area. The antenna volume is 20×20×1:5mm (0.6 cm ), so the proposed antenna is suitable for many wireless handheld devices. The simulation results are compared to the experimental measurements and a good agreement is observed

Novel, compact and multiband antenna for mobile and wireless communication

In this paper, an open slot antenna fed by a U shaped monople is introduced. The slot antenna radiates in the range from 1.6 to 3.44 GHz and from 3.8 to 5.7 GHz. The slot is formed by an open ring of quarter wavelength at 900 MHz. Thus, the ring acts as a monopole at 900 MHz in addition to a wideband slot radiator in the high frequency range. In order to serve the LTE700 MHz band, another ringe monopole is added to the antenna. The proposed antenna has a -10dB bandwidth which extends from 674 to 750 MHz, from 872 to 976 MHz, from 1.6 to 3.44GHz, and from 3.8 to 5.7 GHz. The antenna size is 23 × 31 × 1.5 mm. A prototype of the antenna was fabricated using FR4 substrate (ε = 4.5) with 1.5mm thickness and loss tangent of 0.025. This paper proposes a new mobile handset antenna structure with low SAR values with compact size that cover most of the mobile operating bands and other wireless applications. The covered bands are the GSM900, DCS1800, PCS1900, UMTS2100, and most of the LTE bands including the LTE700 band. Furthermore, it covers the ISM, WIMAX and the WLAN bands. The SAR calculations are done using the CST 2012 commercial package and the voxel head modal. The SAR values are calculated at different operating bands, different distances, and different orientations. The effect of the human body on the performance of the antenna is tested by calculating the radiation pattern in the presence of the body. The simulation results are compared to the experimental measurements and a good agreement is observed