A Dual-Band Antenna Enabled Using a Complimentory Split Ring Resonator (CSRR) Placed in the Ground Plane

The microstrip patch antenna is regarded as one of the key components for compact, low cost RF communications and wireless power techniques. In some instances, there are requirements that a system communicate on a different band than the wireless power harvesting band. To address these multi-frequency, a novel dual-band patch antenna enabled with complementary split ring resonators (CSRRs) is designed and fabricated. This antenna operates at 2.4Ghz and 915 MHz, and the antenna miniaturization is achieved by etching the complementary split ring resonators (CSRRs) in the ground plane. A prototype antenna is fabricated and tested, and measured results are in good agreement with simulations. Furthermore, the influence of the CSRR on the behavior of the antenna is also explored and discussed

Effect of Rubber Compound Treatment and PTFE Extension Beam on Piezoelectric Energy Harvester Power Density / Mohd Sofwan Mohd Resali and Hanim Salleh

Due to a number of advantages for small power applications (milliwatts), many researchers have begun to focus on usable energy harvesting from ambience. Over the years, to further expand the applications of vibration energy harvesting technology, many researchers have focused on how to improve the reliability and efficiency of the harvester. This paper presents work on improving piezoelectric energy harvesters based on structural modifications. Two different strategies of structural modification are proposed for optimization by using additional beam structure and additional rubber compound layer on the origin of the piezoelectric beam. This work summarizes the optimum performance of the strategies at a resonance frequency of 50±2 Hz at 0.25g ms-2 of acceleration. The parameters compared among the strategies are resonance frequency, voltage and power output. In general, the structural modification PZT-MER by clamped PTFE cantilever beam at the free end of piezoelectric and rubber compound gives the best power output of 2.87mW compared to PZT-ME (0.72 mW) and PZT-M (22μW)

Improved Approach to Enforcement of Road Weight Restrictions

This project focused on the enhancement and evaluation of a battery-less wireless weigh-in-motion (WIM) sensor for improved enforcement of road weight restrictions. The WIM sensor is based on a previously developed vibration energy harvesting system, in which energy is harvested from the vibrations induced by each passing vehicle to power the sensor. The sensor was re-designed in this project so as to reduce its height, allow it to be installed and grouted in an asphalt pavement, and to protect the piezo stacks and other components from heavy shock loads. Two types of software interfaces were developed in the project: a) An interface from which the signals could be read on the MnDOT intranet b) An interface through a wireless handheld display Tests were conducted at MnRoad with a number of test vehicles, including a semi tractor-trailer at a number of speeds from 10 to 50 mph. The sensor had a monotonically increasing response with vehicle weight. There was significant variability in sensor response from one test to another, especially at the higher vehicle speeds. This variability could be attributed to truck suspension vibrations, since accelerometer measurements on the truck showed significant vibrations, especially at higher vehicle speeds. MnDOT decided that the final size of the sensor was too big and could pose a hazard to the traveling public if it got dislodged from the road. Hence the task on evaluation of the sensor at a real-world traffic location was abandoned and the budget for the project correspondingly reduced.Minnesota Local Road Research Board and Minnesota Department of Transportatio

Optimization and Learning in Energy Efficient Cognitive Radio System

Energy efficiency and spectrum efficiency are two biggest concerns for wireless communication. The constrained power supply is always a bottleneck to the modern mobility communication system. Meanwhile, spectrum resource is extremely limited but seriously underutilized. Cognitive radio (CR) as a promising approach could alleviate the spectrum underutilization and increase the quality of service. In contrast to traditional wireless communication systems, a distinguishing feature of cognitive radio systems is that the cognitive radios, which are typically equipped with powerful computation machinery, are capable of sensing the spectrum environment and making intelligent decisions. Moreover, the cognitive radio systems differ from traditional wireless systems that they can adapt their operating parameters, i.e. transmission power, channel, modulation according to the surrounding radio environment to explore the opportunity. In this dissertation, the study is focused on the optimization and learning of energy efficiency in the cognitive radio system, which can be considered to better utilize both the energy and spectrum resources. Firstly, drowsy transmission, which produces optimized idle period patterns and selects the best sleep mode for each idle period between two packet transmissions through joint power management and transmission power control/rate selection, is introduced to cognitive radio transmitter. Both the optimal solution by dynamic programming and flexible solution by reinforcement learning are provided. Secondly, when cognitive radio system is benefited from the theoretically infinite but unsteady harvested energy, an innovative and flexible control framework mainly based on model predictive control is designed. The solution to combat the problems, such as the inaccurate model and myopic control policy introduced by MPC, is given. Last, after study the optimization problem for point-to-point communication, multi-objective reinforcement learning is applied to the cognitive radio network, an adaptable routing algorithm is proposed and implemented. Epidemic propagation is studied to further understand the learning process in the cognitive radio network