No abstract

The combination of electric vehicle (EV) and carsharing is expected to provide social and environmental benefits, like encouraging sustainable travel behaviors (reducing car ownership and vehicle kilometres of travel) and improving the accessibility and flexibility of urban transport. Thus, electric carsharing is encouraged to be adopted for daily trips, and the operators propose the friend-invitation promotion scheme for the membership expansion. This study explores the effectiveness of this scheme and the characteristics of the scheme participants and their invited friends (e.g., age, friend-invitation pattern, and EV rental pattern). The analysis found that 28.4% of these invited friends would make at least one EV rental after registration, whereas 30.4% of the other members who registered in the same period would do so, indicating that these invited friends were less active. Therefore, suggestions are given based on the EV rental pattern of these invited friends (preferring a longer journey using a smaller but cheaper EV) to enhance the effectiveness of the friend-invitation promotion scheme.

In order to improve antenna radiation performances, a dipole antenna with 3D diamond‐structure electromagnetic band‐gap (EBG) substrate is analyzed and its transmission performances are investigated. The diamond‐structure EBG substrate was fabricated with aluminum oxide ceramic by 3D printing technique and sintering process, and its band‐gap measured by a transmission‐reflection method was between 9 and 11.5 GHz, with a maximal loss of −50 dB at 9.9 GHz. The radiation frequency of designed dipole antenna corresponded to the frequency of strongest reflection of the EBGs. Comparison of E‐plane radiation patterns of dipole antenna without substrate, dipole antenna with a common ceramic substrate and dipole antenna with EBGs showed that gain of dipole antenna with EBGs was 3 dB higher than that of dipole antenna with a common ceramic substrate and 5 dB higher than that of dipole antenna without substrate, thus the gain was improved by 3.2 times. Moreover, the radiation pattern of dipole antenna with EBGs was smoother, which showed that EBGs can effectively suppress propagation of surface waves. In addition, the main lobe width was reduced, thus antenna directivity was improved.