Triple-Band Single-Layer Rectenna for Outdoor RF Energy Harvesting Applications.

A triple-band single-layer rectenna for outdoor RF energy applications is introduced in this paper. The proposed rectenna operates in the frequency bands of LoRa, GSM-1800, and UMTS-2100 networks. To obtain a triple-band operation, a modified E-shaped patch antenna is used. The receiving module (antenna) of the rectenna system is optimized in terms of its reflection coefficient to match the RF-to-DC rectifier. The final geometry of the proposed antenna is derived by the application of the Moth Search Algorithm and a commercial electromagnetic solver. The impedance matching network of the proposed system is obtained based on a three-step process, including the minimization of the reflection coefficient versus frequency, as well as the minimization of the reflection coefficient variations and the maximization of the DC output voltage versus RF input power. The proposed RF-to-DC rectifier is designed based on the Greinacher topology. The designed rectenna is fabricated on a single layer of FR-4 substrate. Measured results show that our proposed rectenna can harvest RF energy from outdoor (ambient and dedicated) sources with an efficiency of greater than 52%.

Dual patch antenna sensor for pneumothorax diagnosis: sensitivity and performance study.

Pneumothorax may cause serious health problems and often death if medical and surgical treatment is delayed. The absence of reliable, safe, portable and easy-to-use equipment in the ambulance is the primary clinical motivation of this work. We investigate pneumothorax diagnostic performance and sensitivity of a dual patch antenna system (sensor). The operation frequency range is set to 1-4 GHz. Parametric study is conducted using simplified rectangular tissue numerical models. Variation of S12 parameter, related to frequency, is compared in order to distinguish healthy and pneumothorax cases, reaching a difference of 20.1 dB, at 1.87 GHz. MRI-based anatomic models are also modified in order to simulate pneumothorax incident, in realistic clinical case. The best performance configuration scenario is applied onto the modified anatomic models, revealing satisfactory sensor performance (7.1 dB, at 2.3 GHz). Sensor diagnostic ability reaches 1 cm of air thickness. The paper concludes with proposed design specifications for thorax experimental phantom.