This paper presents a low profile dual polarized directional antenna composed of loop and dipole arrays mounted on a ground plane with each loops and dipoles being fed independently. Each loop antenna is paired with a...This paper presents a low profile dual polarized directional antenna composed of loop and dipole arrays mounted on a ground plane with each loops and dipoles being fed independently. Each loop antenna is paired with a reflector while each dipole antenna is paired with a director and a reflector. The proposed antenna is intended for an indoor base station (BS) with resonance frequency of 2.4 GHz and capable of producing four orthogonal directional pattern with downward elevation angle equals to 30°;and half power bandwidth (HPBW) less than 80°;in both vertical and horizontal polarization. The reflection characteristics of the loop and dipole arrays are less than -10 dB and the mutual coupling between the vertical and horizontal polarization elements is nearly less than -20 dB. In later progress, the dipole antenna was substituted with printed dipole antenna to achieve a better performance. Both the calculated and measured results demonstrated that the desired radiation patterns were achieved, and the measured results agreed well with the calculated ones. Consequently, a low profile antenna with a thickness of 0.16 λ (20 mm) having the expected radiation pattern is successfully designed.展开更多
The threat of biological and chemical terror acts remains a growing worldwide concern.There is therefore a need to develop appropriate technology for the detection of chemical and biological warfare agents,with early ...The threat of biological and chemical terror acts remains a growing worldwide concern.There is therefore a need to develop appropriate technology for the detection of chemical and biological warfare agents,with early identification intended for use by first responders.Here,we disclose the developed autonomous air sampling and detection system for evaluation of the presence of chemical and biological warfare agents that can be harmful to the population.The current device utilizes the designed mist generator-assisted air collection system(338 l min^(−1))and biosensing chip technologies,such as electrochemical measurement,Au nanoparticle-based localized surface plasmon resonance,and rapid microfluidic chip PCR for detection of minute concentrations lower than the mean lethal dose(LD_(50))of nerve gases(sarin and VX),toxic proteins(BTX/A/Hc and ricin),and pathogens(anthrax simulant).An operation time of only 5–15 min is needed for the collection and detection;sample preparation is already integrated into the system without the need for direct human intervention.In addition to the system’s sensitivity and ease of use,its portability makes it highly beneficial for first responders,which could aid in immediate risk assessment and mitigation of on-site events.展开更多
文摘This paper presents a low profile dual polarized directional antenna composed of loop and dipole arrays mounted on a ground plane with each loops and dipoles being fed independently. Each loop antenna is paired with a reflector while each dipole antenna is paired with a director and a reflector. The proposed antenna is intended for an indoor base station (BS) with resonance frequency of 2.4 GHz and capable of producing four orthogonal directional pattern with downward elevation angle equals to 30°;and half power bandwidth (HPBW) less than 80°;in both vertical and horizontal polarization. The reflection characteristics of the loop and dipole arrays are less than -10 dB and the mutual coupling between the vertical and horizontal polarization elements is nearly less than -20 dB. In later progress, the dipole antenna was substituted with printed dipole antenna to achieve a better performance. Both the calculated and measured results demonstrated that the desired radiation patterns were achieved, and the measured results agreed well with the calculated ones. Consequently, a low profile antenna with a thickness of 0.16 λ (20 mm) having the expected radiation pattern is successfully designed.
基金This work was financially supported by‘a R&D Program for Implementation of Anti-Crime and Anti-Terrorism Technologies for a Safe and Secure Society,’Funds for Integrated Promotion of Social System Reform and Research and Development of the Ministry of Education,Culture,Sports,Science and Technology(MEXT)of Japan,and a Grant-in-Aid for Scientific Research from MEXT.
文摘The threat of biological and chemical terror acts remains a growing worldwide concern.There is therefore a need to develop appropriate technology for the detection of chemical and biological warfare agents,with early identification intended for use by first responders.Here,we disclose the developed autonomous air sampling and detection system for evaluation of the presence of chemical and biological warfare agents that can be harmful to the population.The current device utilizes the designed mist generator-assisted air collection system(338 l min^(−1))and biosensing chip technologies,such as electrochemical measurement,Au nanoparticle-based localized surface plasmon resonance,and rapid microfluidic chip PCR for detection of minute concentrations lower than the mean lethal dose(LD_(50))of nerve gases(sarin and VX),toxic proteins(BTX/A/Hc and ricin),and pathogens(anthrax simulant).An operation time of only 5–15 min is needed for the collection and detection;sample preparation is already integrated into the system without the need for direct human intervention.In addition to the system’s sensitivity and ease of use,its portability makes it highly beneficial for first responders,which could aid in immediate risk assessment and mitigation of on-site events.
