Methods for reducing and directly controlling the speed of DNA through a nanopore are needed to enhance sensing performance for direct strand sequencing and detection/mapping of sequence‐specific features. A method is created for reducing and controlling the speed of DNA that uses two independently controllable nanopores operated with an active control logic. The pores are positioned sufficiently close to permit cocapture of a single DNA by both pores. Once cocapture occurs, control logic turns on constant competing voltages at the pores leading to a “tug‐of‐war” whereby opposing forces are applied to regions of the molecules threading through the pores. These forces exert both conformational and speed control over the cocaptured molecule, removing folds and reducing the translocation rate. When the voltages are tuned so that the electrophoretic force applied to both pores comes into balance, the life time of the tug‐of‐war state is limited purely by diffusive sliding of the DNA between the pores. A tug‐of‐war state is produced on 76.8% of molecules that are captured with a maximum two‐order of magnitude increase in average pore translocation time relative to the average time for single‐pore translocation. Moreover, the translocation slow‐down is quantified as a function of voltage tuning and it is shown that the slow‐down is well described by a first passage analysis for a 1D subdiffusive process. The ionic current of each nanopore provides an independent sensor that synchronously measures a different region of the same molecule, enabling sequential detection of physical labels, such as monostreptavidin tags. With advances in devices and control logic, future dual‐pore applications include genome mapping and enzyme‐free sequencing.

In this paper, the RF energy harvesting system and RF-based wireless power transfer system are proposed and designed for battery-less self-sustaining application. For energy harvesting, the designed antenna array improves the received RF power effectively and also can harvest RF energy in multi-frequency bands. For wireless power transfer, the proposed helical antenna realizes the system design in miniaturization. Subsequently, the T shape LC matching network are designed between the antenna and the rectifying circuit to obtain more power transmission. The measured results show that the proposed Wi-Fi rectifier and 433 MHz rectifier offer a maximum conversion efficiency of 66.8% and 76% in case of the input power is −3 dBm and 0 dBm, respectively. Finally, the performance of the RF-based wireless power transfer system and RF energy harvesting system are attested by experimentally measurement, the measured results indicate that these systems can be used to power electronic. K E Y W O R D S antenna array, low-power electronic devices, rectifier, RF energy harvesting, RFbased wireless power transfer 1 | INTRODUCTIONWith the explosive and rapid development of electronic technologies, various low-power integrated electronic devices, and miniaturized wireless systems have become ubiquitous throughout our daily lives. Meanwhile, numerous studies have been focused on the feasibility of powering these devices and systems through the harvesting of ambient radio frequency (RF) electromagnetic energy from some power sources such as mobile signal base station and Wi-Fi routers. 1-3 Besides, the idea of using wireless power transfer (WPT) technique for powering low-power and energy-constrained electronic devices has also become an upsurge of research. 4 It is significant that RF energy harvesting (EH) technique and WPT technique are the potential alternatives in generating clean and renewable power source, which definitely presents a promising scheme in battery-less self-sustaining applications for future.For RF EH technique, a rectenna (receiving antenna and rectifying circuit) is one of the most popular system components. Various designs have been investigated, such as multiband rectennas, 5-7 broadband rectennas, 8,9 and rectenna arrays. 10,11 The overall performance of a rectenna is normally determined by the performance of the designed receiving antenna and the RF-to-DC conversion efficiency of the rectifying circuit. Since the ambient RF sources are weak, a receiving antenna with high gain is required to improve input power levels, simultaneously, broadband means more RF energy can be accumulated from different frequency bands. Hence, antennas with high gain and broadband are greatly preferred. At present, the main challenge is how to improve the power conversion efficiency for such a nonlinear rectifying circuit at low-input power levels. This is because the nonlinear characteristics of rectifying diodes, the input impedance of a rectifying circuit varies with frequency and input power levels. Here

In this article, a new 2 × 2 circular microstrip antenna array with air dielectric layer for ambient RF energy harvesting has been proposed. Two pairs of arc-shaped slots located close to the boundary of the circular microstrip patch have been designed for achieving dual-band response and extending the frequency bandwidth. The antenna has a frequency bandwidth from 1.85 to 1.93 GHz and from 2.0 to 2.1 GHz which can cover GSM-1800 and UMTS-2100 bands. At the frequency of 1.89 and 2.05 GHz, the measured gain is 5.3 and 6.6 dBi, respectively, and high gain of 3.8-9.3 dBi has been achieved over the whole band. Also, a broadband rectifier that can cover all the bandwidths of the antenna array is designed for the rectenna, which has the maximum rectifying efficiency of 53.6%. Finally, a cube device formed of four antenna and four rectifiers is designed to harvest RF energy, whose maximum output DC voltage is 2.3 V and the maximum output power is 4 mW that can drive four LEDs and an electronic watch. K E Y W O R D Santenna arrays, dual-band, energy harvesting, rectifier, RF

No abstract