Ultra-wideband, wide angle, asymmetric transmission based chiral metasurface for C and X band applications.

A multi-layered chiral device manifesting asymmetric transmission (AT) facilitating one-way channeling of electromagnetic (EM) waves, based on the inherent polarization is presented. The designed metasurface depicts a high transmission contrast with an efficiency above 80% for an ultra-wide operational range of 6.3-12.3 GHz, constituting a fractional bandwidth of 64%. As an additional feature, the reported metasurface yields robustness against oblique incidences up to 45[Formula: see text] while maintaining high transmission efficiency. This report also introduces a unique analogy of the AT based communication system with logic-gates by formulating its truth-table and logic circuit. Furthermore, new insights of AT magnitude's dependence to oblique incidences are presented on the account of surface impedance mismatch due to TE and TM polarization with varying incidence angle. Moreover, avoidance of grating lobes and the associated transmission deterioration through utilization of electrically small periodic metasurface is presented. The results have been numerically and practically validated yielding state-of-the-art features. Operating within C and X band, the reported work is an ideal candidate for practical AT applications.

A wearable sensor based multi-criteria-decision-system for real-time seizure detection.

This paper presents a wireless, low power and low cost two part wearable for real-time epileptic seizure detection. Using parameters of Electro-cardiograph (ECG), Electro-dermal Activity (EDA), body motion and breathing rate (BR), a novel multi-criteria-decision-system (MCDS) is proposed that reduces false alarms and true negatives. The combination of a chest and hand worn wearable continuously senses these parameters transmitting the data to a smart phone application via BLE 4.0 where long-short-term-memory (LSTM) based anomaly detection algorithms and logistic classifiers decide on the occurrence of the seizure in real time. A 96% precision and 90% recall is achieved through testing on synthetic data.

Disposable, Paper-Based, Inkjet-Printed Humidity and H2S Gas Sensor for Passive Sensing Applications.

An inkjet-printed, fully passive sensor capable of either humidity or gas sensing is presented herein. The sensor is composed of an interdigitated electrode, a customized printable gas sensitive ink and a specialized dipole antenna for wireless sensing. The interdigitated electrode printed on a paper substrate provides the base conductivity that varies during the sensing process. Aided by the porous nature of the substrate, a change in relative humidity from 18% to 88% decreases the electrode resistance from a few Mega-ohms to the kilo-ohm range. For gas sensing, an additional copper acetate-based customized ink is printed on top of the electrode, which, upon reaction with hydrogen sulphide gas (H2S) changes, both the optical and the electrical properties of the electrode. A fast response time of 3 min is achieved at room temperature for a H2S concentration of 10 ppm at a relative humidity (RH) of 45%. The passive wireless sensing is enabled through an antenna in which the inner loop takes care of conductivity changes in the 4-5 GHz band, whereas the outer-dipole arm is used for chipless identification in the 2-3 GHz band.