Artificial lighting is responsible for a large portion of total energy consumption and has great potential for energy saving. This paper designs an LED light control algorithm based on users' localization using multiple battery-less binary human detection sensors. The proposed lighting control system focuses on reducing office lighting energy consumption and satisfying users' illumination requirement. Most current lighting control systems use infrared human detection sensors, but the poor detection probability, especially for a static user, makes it difficult to realize comfortable and effective lighting control. To improve the detection probability of each sensor, we proposed to locate sensors as close to each user as possible by using a battery-less wireless sensor network, in which all sensors can be placed freely in the space with high energy stability. We also proposed to use a multi-sensor-based user localization algorithm to capture user's position more accurately and realize fine lighting control which works even with static users. The system is actually implemented in an indoor office environment in a pilot project. A verification experiment is conducted by measuring the practical illumination and power consumption. The performance agrees with design expectations. It shows that the proposed LED lighting control system reduces the energy consumption significantly, 57% compared to the batch control scheme, and satisfies user's illumination requirement with 100% probability.

We propose a proof-of-concept of a switchable multi-frequency MMIC (monolithic microwave integrated circuit) oscillator device, operating in the 60 GHz millimeter wave band, which is implemented in GaAs p-HEMT transistor technology. Oscillators that can switch between two frequencies have been designed, fabricated and evaluated. The oscillator uses a cross-coupled FET topology, combined with a bent asymmetric coplanar stripline for the resonator, and a switched-capacitor for the frequency switching components. The oscillator generates two oscillations at f/2 and f where f is the target frequency of around 60 GHz. The switchable oscillator has been demonstrated for the range of frequency from 44 GHz to 68.9 GHz. Moreover, the designed oscillator exhibits a wide-band negative resistance property that allows fabricating switchable oscillators covering the 50 to 75 GHz V-band. An evaluated switchable oscillator delivers -17.09 dBm and -13.72 dBm output power at 62.45 GHz and 64.78 GHz, for a supplied power of 40.6 mW and 39.1 mW, respectively.