Abstract-As important fundamental equipment, high voltage switchgears are widely used in electric power systems and directly relative to the power reliability and quality. Partial discharge (PD) online monitoring is one of the most effective methods used for insulation testing and diagnosis in high voltage switchgears and power systems. This paper proposes a unique ultra-wide-band (UWB) antenna with high performance for PD ultra-high-frequency (UHF) detection in high voltage switchgears. Actual PD experiments were carried out, and the designed antenna was used for PD measurements. The measured results demonstrate that the proposed antenna has wide work frequency band, good omnidirectional radiation patterns and appreciable gain, which indicate that the proposed antenna is suitable for UHF online monitoring of PDs in high voltage switchgears.

The mechanism is described by which a passive UHF RFID tag coupled with a tuning circuit is integrated with a current transformer for sensing ac current in an electrical wire for smart power monitoring of individual appliances. A capacitance change in the tuning circuit results from a reverse bias voltage from the current transformer. The tuning circuit reactance is detected by a capacitance sensing RFID tag and the value is transmitted as a 5-bit sensor code which is directly related to the ac current drawn by an electrical load. The passive tag harvests energy and offers an innovative solution for energy management in future smart homes and for industry 4.0. As well as indicating current level, the technique can also be used to detect the ON and OFF state of an electrical device and is demonstrated to work for a rapidly switching load. The sensor is tuned for EPC Class 1 Generation 2 UHF RFID readers at 868 MHz.

Recently, myriad stretchable flex sensors have been developed based on the principle of changing piezo resistance, capacitance and impedance. However, these approaches suffer from cyclic stability, poor hysteresis, relatively lower...

While research in passive flexible circuits for 1 Wireless Power Transfer (WPT) such as coils and res-2 onators continues to advance, limitations in their power 3 handling and low efficiency have hindered the realization 4 of efficient all-printed high-power wearable WPT receivers. 5 Here, we propose a screen-printed textile-based 6.78 MHz 6 resonant inductive WPT system using planar inductors with 7 concealed metal-insulator-metal (MIM) tuning capacitors. A 8 printed voltage doubler rectifier based on Silicon Carbide 9 (SiC) diodes is designed and integrated with the coils, 10 showing a power conversion efficiency of 80-90% for 2-11 40 W inputs over a wide load range. Compared to prior 12 wearable WPT receivers, it offers an order of magnitude im-13 provement in power handling along with higher efficiency 14 (approaching 60%), while using all-printed passives and 15 a compact rectifier. The coils exhibit a simulated Specific 16 Absorption Rate (SAR) under 0.4 W/kg for 25 W received 17 power, and under 21 • C increase in the coils' temperature 18 for a 15 W DC output. Additional fabric shielding is in-19 vestigated, reducing harmonics emissions by up to 17 dB. 20 We finally demonstrate a wirelessly-powered textile-based 21 carbon-silver Joule heater, capable of reaching up to 60 • C 22 at 2 cm separation from the transmitter, as a wearable 23 application which can only be wireless-powered using the 24 proposed system.25

An ultra-thin, electromagnetic bandgap (EBG) backed antenna is presented for 24 GHz ISM band wearable applications. The antenna is a slotted bow-tie, with an overall dimension of 0.91𝝀 𝟎 × 0.84𝝀 𝟎 × 0.01𝝀 𝟎 , backed by a 𝟓 × 𝟓 element 0.01𝝀 𝟎 thick EBG structure; it is manufactured on a flexible substrate (𝜺 𝒓 = 2.2). The performance of the EBG-backed antenna in terms of reflection coefficient and free-space radiation patterns is investigated in scenarios with and without structural bending. It is shown that the integration of the EBG enhances the antenna's front-lobe gain by 2.63 dBi, decreases back-lobe radiation by 12.2 dB, and decreases the specific absorption rate (SAR (1 g)) from > 28 W/kg to <1.93 W/kg, significantly reducing potential harm to the human body. Furthermore, the results show the performance of the EBG-backed antenna is highly insensitive to body proximity, and that its performance is preserved when bent along the either axis.