Abstract: An IoT wireless power transfer sensor is provided, which includes a sensor circuit, a group of retrodirective searching antennas, a group of energy harvesting antennas and a communication antenna. The sensor circuit includes a switching unit, an energy converting unit, a power management unit and an energy converting and storage unit. The searching antennas are connected to the switching unit. When the switching unit is on, the searching antennas don't harvest the energy of an external device's scanning signal; they reflect the incident energy to the external device. The energy harvesting antenna is connected to the energy converting unit and receives the incident energy to charge the energy converting and storage unit. When the power storage level of the energy converting and storage unit reaches a first threshold value, the switching unit is consecutively switched between on and off to transmit a device information in back-scattered way to the external device.

Abstract: A smart hub is provided, which includes a control circuit and an antenna array (the functions thereof include transmitting/receiving scanning signals and transmitting wireless power transfer signals). The antenna array is connected to the control circuit and transmits a scanning signal to scan within an effective scanning range thereof. When the antenna array receives the reflected signal of the scanning signal, the control circuit controls the antenna array to keep transmitting a wireless power transfer signal, within a predetermined time interval, in the direction of receiving the reflected signal, and simultaneously receives the device information from a sensor which may exist via the antenna array within the predetermined time interval. The device information is generated by the sensor by backscattering.

Abstract: A smart hub is provided, which includes a control circuit and an antenna array (the functions thereof include transmitting/receiving scanning signals and transmitting wireless power transfer signals). The antenna array is connected to the control circuit and transmits a scanning signal to scan within an effective scanning range thereof. When the antenna array receives the reflected signal of the scanning signal, the control circuit controls the antenna array to keep transmitting a wireless power transfer signal, within a predetermined time interval, in the direction of receiving the reflected signal, and simultaneously receives the device information from a sensor which may exist via the antenna array within the predetermined time interval. The device information is generated by the sensor by backscattering.

Abstract: An IoT wireless power transfer sensor is provided, which includes a sensor circuit, a group of retrodirective searching antennas, a group of energy harvesting antennas and a communication antenna. The sensor circuit includes a switching unit, an energy converting unit, a power management unit and an energy converting and storage unit. The searching antennas are connected to the switching unit. When the switching unit is on, the searching antennas don't harvest the energy of an external device's scanning signal; they reflect the incident energy to the external device. The energy harvesting antenna is connected to the energy converting unit and receives the incident energy to charge the energy converting and storage unit. When the power storage level of the energy converting and storage unit reaches a first threshold value, the switching unit is consecutively switched between on and off to transmit a device information in back-scattered way to the external device.

Abstract: A manually operated brushless DC motor is disclosed herein, which is an educational electric motor and can overcome the shortcoming hard to visualize the movement of a motor due to the high-speed rotation of the motor. The manually operated brushless DC motor according to the present invention provides two switches to replace the brushes used in a conventional motor. Users/learners have to alternatively press the switches to complete a closed circuit and drive the motor to rotate. Only when the rotor rotates in synchronism with the pressing rate of the switches, the rotor accelerates. Otherwise the rotation speed of the rotor decreases. The manually operated brushless DC motor provides the users/learners with the opportunity of viewing the rotor rotating in a slow motion, and the experience of manually operating the motor.

Abstract: A manually operated brushless DC motor is disclosed herein, which is an educational electric motor and can overcome the shortcoming hard to visualize the movement of a motor due to the high-speed rotation of the motor. The manually operated brushless DC motor according to the present invention provides two switches to replace the brushes used in a conventional motor. Users/learners have to alternatively press the switches to complete a closed circuit and drive the motor to rotate. Only when the rotor rotates in synchronism with the pressing rate of the switches, the rotor accelerates. Otherwise the rotation speed of the rotor decreases. The manually operated brushless DC motor provides the users/learners with the opportunity of viewing the rotor rotating in a slow motion, and the experience of manually operating the motor.

Abstract: A miniature antenna for various wireless communication applications in the ISM band around 2.45 GHz is provided. The miniature antenna mainly contains a bended planar notch antenna with a metallic stub as a capacitive load. A microstrip feed line is also appropriately bended so as to achieve a significant reduction of the antenna's dimension. The miniature antenna could be implemented using simple manufacturing processes on a common circuit board without mechanical work or advanced processes such as low temperature co-fired ceramics. The antenna has a comparable performance to those antennas having much larger dimensions.

Abstract: A miniature antenna for various wireless communication applications in the ISM band around 2.45 GHz is provided. The miniature antenna mainly contains a bended planar notch antenna with a metallic stub as a capacitive load. A microstrip feed line is also appropriately bended so as to achieve a significant reduction of the antenna's dimension. The miniature antenna could be implemented using simple manufacturing processes on a common circuit board without mechanical work or advanced processes such as low temperature co-fired ceramics. The antenna has a comparable performance to those antennas having much larger dimensions.