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A prototype of wireless power transmission (WPT) system has been designed in small scale which can be used to drive portable electronic devices. For power transmitting purpose RF/microwave has been used. A detail discussion on transmitting and receiving antenna of WPT system has been presented. The step by step design method has been used in designing the entire system. Then, a simple practical approach has been demonstrated. The detail performance on the practical implementation of wireless power transmission system has been analyzed. The 4GHz designed system provides 2W receiving power when the transmitter sends 20W from a distance of 52m. The difficulties and limitations for implementing the designed model in the laboratory have been featured. Then, the ideas for overcoming the limitations also have been proposed.

In this study, the design of a compact and novel millimeter wave cotton textile-based wearable antenna for body-centric communications in healthcare applications is presented. The free space and on-body antenna performance parameters for the proposed antenna at 60 GHz are investigated and analyzed. The antenna is based on a 1.5 mm thick cotton substrate and has an overall dimension of 7.0 × 4.5 × 1.5 mm3. In free space, the antenna is resonant at 60 GHz and achieves a wide impedance bandwidth. The maximum gain at this resonant frequency is 6.74 dBi, and the radiation efficiency is 93.30%. Parametric changes were carried out to study the changes in the resonant frequency, gain, and radiation efficiency. For body-centric communications, the antenna was simulated at 5 different distances from a three-layer human torso-equivalent phantom. The radiation efficiency dropped by 24% and gradually increased with the gap distance. The antenna design was also analyzed by using 10 different textile substrates for both free space and on-body scenarios. The major benefits of the antenna are discussed as follows. Compared to a previous work, the antenna is very efficient, compact, and has a wide bandwidth. In BCWCs for e-health applications, the antenna needs to be very compact due to the longer battery life, and it has to have a wide bandwidth for high data rate communication. Since the antenna will be wearable with a sensor system, the shape of the antenna needs to be planar, and it is better to design the antenna on a textile substrate for integration into clothes. The antenna also needs to show high gain and efficiency for power-efficient communication. This proposed antenna meets all these criteria, and hence, it will be a good candidate for BCWCs in e-health applications.

In order to survive in this modern world, electricity is an essential thing. Electricity allows us to power the technology we use every day. Without electricity, people can't imagine their lives. As a developing country, Bangladesh still lacks electricity every day. The electricity supply to the rural areas is very poor. It is known that energy can be converted from one form to another form. As noise is the energy, it can also be converted into various forms of energy. Noise can be represented as a sound that is loud or unpleasant and causes disturbances such as street traffic sounds, construction sounds, airports, etc. Using a suitable transducer, noise (sound) energy can be transferred into a viable source of electricity generation. This can be accomplished by employing a transducer and converting noise-induced vibrations into electrical energy. Our main goal is getting enough energy, reducing the pressure of the main grid of electricity and decreasing fossil fuel imports. This paper presents the design and investigation of an energy harvesting system from noise. In this paper, an application is designed to get energy from noise by using a speaker as a transducer. Voltage has been stepped up by using a transformer, a diode which gives DC value which can be tapped into a battery and provide energy from the battery when it is needed. The embedded device was initially tested by clapping hands and tested further by using car horns. The vibrations created by car horns and other noises have been converted into electrical energy through the principle of electromagnetic induction. In total, the application produced optimal results of 0.5 -1.0 volts which were stepped up using a transformer while maintaining the whole system being low cost and user-friendly.