关键词: 短波信道, 窄波束, 功率比值增益, 相干带宽

Abstract: The authors propose a method of using transmit narrow-beam to spatially concentrate the radiation energy on dominant path and suppress undesired paths in the shortwave communication. Based on the time-variant double layers & plane valley electron density profile, the theoretical analysis of narrow-beam channel characteristics is conducted. Under the mid-latitude mid-range communication, the calculations of channel parameters are taken for different number of transmit antennas at different time and the serving region size is calculated for certain narrow beam. Both the theoretical study and the calculation results show that the gain of the power ratio of dominant path to the others and the coherence bandwidth can be dramatically increased in the shortwave communication with narrow-beam.

Key words: shortwave channel, narrow-beam, gain of power ratio, coherence bandwidth