To understand people's judgement of the naturalness of object colours and preference for the lit environment, lighting booth experiments were conducted. Seven different LED spectral power distributions, all at correlated colour temperatures of 2700 K, 4000 K and 6500 K, were simulated for high CIE colour rendering index (Ra), high colour quality scale (CQS) colour preference scale (Qp) keeping Ra ¼ 80, high feeling of contrast index (FCI) keeping Ra ¼ 80, high CQS relative gamut area scale (Qg) keeping Ra ¼ 80, low FCI keeping Ra ¼ 80, low Qp keeping Ra ¼ 80, and for a mimic of a fluorescent lamp (FL) in terms of the closest possible value of the Ra, FCI and Qp to the reference FL. Other metrics such as the gamut area index (GAI), memory CRI, and nCRI were also considered in the analysis. Sixty observers evaluated 24 lighting situations. This paper deals with a comparison evaluation, where LED lighting was compared to FL lighting. It was found that Ra does not explain the subjective naturalness of objects and the subjective preference of the lit environment for the different light sources. The results also indicate that people's judgement of naturalness and overall preference were explained better when a reference-based metric (such as Qp) and an area or volume-based metric (such as Qg or GAI) were both considered while maintaining the light source chromaticity difference (Duv) value within the limit AE 0.0054.
This paper presents a new implementation of the beam-steerable two-dimensional phased antenna array for the forthcoming 5G networks. The antenna enables easy integration of phase shifters and other active electronics on a single PCB, low-loss feed network, low profile, and beam steering in both azimuth and elevation plane. In addition, the antenna is scalable in the number of elements and it can be made compatible with low-cost mass production in plastic injection molding with a metal coating. The antenna consists of a rectangular waveguide feed network, waveguide-to-PCB transitions, phase shifters on a PCB, and horn antenna radiating elements. The parts have been first designed and simulated individually and the operation of the whole structure is then verified by electromagnetic simulations. The phase shifter used in this work is a meandered microstrip line section, but the structure also enables the implementation of active phase shifters. A four-by-four antenna array prototype was manufactured. The beam-steering properties of the phased antenna array have been tested with radiation pattern measurements at 72.5 GHz, and the measured gains are compared with the simulated ones. The measured gains are 15.2 and 11.2 dBi for the boresight beam, and the beam was steered to 40°.
Abstract-An approach that can be used for exploiting the sensing capabilities of radio-frequency identification (RFID) is presented and formulated. In this approach, sensor information is carried through the modulation frequency of RFID . The aim of this work is to investigate the sensor concept and to characterize the sensor performance both theoretically and experimentally. Furthermore, the operation of the sensor radio-frequency (RF) parts and oscillator are described analytically, and the equations are verified by simulations and measurements. The concept is experimentally demonstrated at a single carrier frequency to test its suitability for ultra-high frequency (UHF) RFID applications, and shown to be feasible for implementing sensors that can be read across distances up to 14 meters.
Wireless capsule endoscopy (WCE) systems are used to capture images of the human digestive tract for medical applications. The antenna is one of the most important components in a WCE system. In this paper, we propose a compact capsule antenna operating at the 433-MHz ISM band. The antenna conforms to the outer-wall of a small capsule module with dimensions of 19.5 mm × 10 mm. A colon-equivalent tissue phantom and CST Gustav voxel human body model were used to numerically verify the operation of the capsule antenna. The simulation results in the colon-tissue phantom were then validated through in-vitro measurements using a liquid phantom. According to the phantom simulations, the capsule antenna has −10 dB impedance matching from 288 to 2200 MHz. The ultrawideband characteristic enables the capsule antenna to tolerate the detuning effects due to electronic modules in the capsule and due to the proximity of various different tissues in gastrointestinal tracts. While providing ultrawide operational bandwidth and sufficient radiation performance, the small size makes the antenna suitable especially for pediatric patients in addition to adults.
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