Communication in Terahertz (THz) band is envisioned as a promising technology to meet the ever-growing data rate demand, and to enable new applications in both nano-scale and macro-scale wireless paradigms. In this study, we propose the first system-level design that is suitable for THz communication in macro-scale range with 100+ Gbps data rate. The design is based on the proposed terahertz pulse-level beam-switching with energy control (TRPLE), and motivated by the rise in Graphene-based electronics, which include not only compact generator and detector for pulse communication, but also the capability of beam scanning aided with nano-antenna-arrays. The very high path loss seen in THz wireless channel requires the use of narrow beam to reach longer transmission ranges. On the other hand, impulse radio that emits femtosecond-long pulses allows the beam direction to steer at pulse-level, rather than at packet-level. For TRPLE, we mathematically analyze the data rate for an arbitrary wireless link under the THz channel characteristics and the energy modulation scheme. Then, a novel optimization model is formulated to solve the parameters of the inter-pulse separation and the inter-symbol separation, in order to maximize the data rate while meeting the interference requirement. With the optimization, the data rate of 167 Gbps is shown achievable for most users in 20-m range. A MAC protocol framework is then presented to harness the benefits of the pulse separation optimization.
The capability of motion is one of the important aspects for a micro-robot to fulfill its given tasks. Micro-autonomous systems usually require large force, large displacement and less power consumption. Among different actuation schemes, electromagnetic actuator shows the benefit in a combination of force, displacement and cost effective control. A bristle-based inchworm mobile robot using a short stroke electromagnetic linear actuator is described in the paper. The main body and movable unit of the robot are joined by using a sealed bellows and the bristle legs are designed so that it can operate both on plane surfaces and in liquid. The actuator designed for the robot is a tubular type linear machine with an overall size of Φ7 × 10 mm. The key dimensions of the actuator were determined through magnetic field analysis to achieve optimum force output and necessary travel stroke within the limited space. The predicted actuation force of the actuator is 20 mN and the stroke length is 1.2 mm. Two working prototypes of the actuator were constructed and the performance tests show the effectiveness of the design. A sensorless control scheme with a novel start-up strategy for the designed actuator was developed based on the robotic system modeling and the analyzed results show the satisfactory performance of the system. 相似文献
