Microwave Segment OAM Occurrence And Transmission Simulation

With the transfer of wired access to wireless access, how to efficiently use the radio spectrum has become a research hot spot. In order to improve the spectrum utilization efficiency, IEEE has established the standards working groups of802.22,802.16h and1900which were all for dynamic spectrum access in2004and2005, respectively. In2008, Garcia-Escartin studied the Quantum multiplexing based on Orbital angular momentum(OAM) of photons, and two methods for quantum channel Integrating, i.e., the qubit combiner and the OAM multiplexer are analyzed. In2012, Thide’confirmed that microwave OAM spiral beams can achieve multiple independent wireless transmission at the same frequency in the2.4GHz band through using lots of experiments. Meanwhile, Wang used8OAM channel to realize the data transmission in free space, especially, the spectral efficiency increased to95.7bits·s-1·Hz-1. In2013, the5G white paper of Datang Telecom has made OAM multiplexing technology as one of the criteria that will be used in the next generation communication system. Different from other Multiplexing methods, such as Frequency Division Multiplexing, Time Division Multiplexing, Code Division Multiplexing and Space Division Multiplexing etc., OAM multiplexed uses different carrier to transmit different signals under different multiplex modes. Even though the carrier frequency, time, space, and the polarization state are under the same situation, theoretically, it also may produce infinite number of OAM channels.In order to develop OAM multiplexing, we need to study the generation, transmission and detection of OAM carrier. However, at the radio band, only parabolic antenna and phased array antenna are used to generate OAM beam. Within this context, the main work of this thesis is as follows,(a) Taking Laguerre-Gaussian (LG) mode as an example, basic theory of OAM is introduced; the corresponding OAM beam characteristics of each mode is simulated and analyzed; then, we extend to Radio frequency band and the OAM generator based on parabolic antenna and antenna array are presented. (b) The OAM generation models based on dipole array and microstrip patch array are established, respectively. Numerical results of the corresponding electric field distribution, phase distribution and mode patterns are give, and the transmission produce is simulated.(c) An OAM generator with a rotating parabolic reflector as the reflector, and a patch arrays as the feeder is designed, and verified by numerical simulation.(d) The characteristics and the application fields of the metamaterial are introduced and then the research progress of the metamaterial OAM generator is discussed.