With the exponential growth of the data traffic in wireless communication systems, terahertz(THz) frequency band is envisioned as a promising candidate to support ultra-broadband for future beyond fifth generation(5G)...With the exponential growth of the data traffic in wireless communication systems, terahertz(THz) frequency band is envisioned as a promising candidate to support ultra-broadband for future beyond fifth generation(5G), bridging the gap between millimeter wave(mmWave) and optical frequency ranges. The purpose of this paper is to provide a comprehensive literature review on the development towards THz communications and presents some key technologies faced in THz wireless communication systems. Firstly, despite the substantial hardware problems that have to be developed in terms of the THz solid state superheterodyne receiver, high speed THz modulators and THz antennas, the practical THz channel model and the efficient THz beamforming are also described to compensate for the severe path attenuation. Moreover, two different kinds of lab-level THz communication systems are introduced minutely, named a solid state THz communication system and a spatial direct modulation THz communication system, respectively. The solid state THz system converts intermediate frequency(IF) modulated signal to THz frequency while the direct modulation THz system allows the high power THz sources to input for approving the relatively long distance communications. Finally, we discuss several potential application scenarios as well as some vital technical challenges that will be encountered in the future THz communications.展开更多
针对超外差接收机中前端预选宽频段、低损耗与高带外抑制度的需求,文中在电感耦合方式的LC电调滤波器基础上,增加了寄生通带抑制滤波器,设计了一款基于20～800 MHz调谐范围的电调滤波器。通过实际测试得到在调谐范围内,滤波器插入损耗&l...针对超外差接收机中前端预选宽频段、低损耗与高带外抑制度的需求,文中在电感耦合方式的LC电调滤波器基础上,增加了寄生通带抑制滤波器,设计了一款基于20～800 MHz调谐范围的电调滤波器。通过实际测试得到在调谐范围内,滤波器插入损耗<1. 5dB,1 d B相对带宽约20%～30%,输入输出端口驻波<1. 5,二倍频处抑制度> 40d Bc,寄生通带抑制滤波器能将二次谐波和三次谐波寄生通带的抑制度分别提高40 d Bc和30 d Bc以上,从而利于滤波器在预选部分实现中频、镜频和本振反向等抑制作用。展开更多
基金supported by the National High Technology Research and Development Program of China (863 program) of China under Grant No.2011AA010200 supported by the National Natural Science Foundation of China (NSFC) under Grant No.61771116 and No.91738102
文摘With the exponential growth of the data traffic in wireless communication systems, terahertz(THz) frequency band is envisioned as a promising candidate to support ultra-broadband for future beyond fifth generation(5G), bridging the gap between millimeter wave(mmWave) and optical frequency ranges. The purpose of this paper is to provide a comprehensive literature review on the development towards THz communications and presents some key technologies faced in THz wireless communication systems. Firstly, despite the substantial hardware problems that have to be developed in terms of the THz solid state superheterodyne receiver, high speed THz modulators and THz antennas, the practical THz channel model and the efficient THz beamforming are also described to compensate for the severe path attenuation. Moreover, two different kinds of lab-level THz communication systems are introduced minutely, named a solid state THz communication system and a spatial direct modulation THz communication system, respectively. The solid state THz system converts intermediate frequency(IF) modulated signal to THz frequency while the direct modulation THz system allows the high power THz sources to input for approving the relatively long distance communications. Finally, we discuss several potential application scenarios as well as some vital technical challenges that will be encountered in the future THz communications.
文摘针对超外差接收机中前端预选宽频段、低损耗与高带外抑制度的需求,文中在电感耦合方式的LC电调滤波器基础上,增加了寄生通带抑制滤波器,设计了一款基于20～800 MHz调谐范围的电调滤波器。通过实际测试得到在调谐范围内,滤波器插入损耗<1. 5dB,1 d B相对带宽约20%～30%,输入输出端口驻波<1. 5,二倍频处抑制度> 40d Bc,寄生通带抑制滤波器能将二次谐波和三次谐波寄生通带的抑制度分别提高40 d Bc和30 d Bc以上,从而利于滤波器在预选部分实现中频、镜频和本振反向等抑制作用。
