A Study Of Key Techniques For Antenna Arraying For Deep Space Communication At High Data Rate

Today, with in-depth studies of the propagation of electromagnetic waves andcontinuous exploration of deep space，antenna arraying techniques has been extensivelyconcerned and provide a good prospect of future application in deep spacecommunication at high data rate for its advantages such as low cost, high performance,high reliability and high flexibility. Based on the discussions of the present researchstatus, the author provides some analysis of key difficulties of applying antennaarraying in deep space communication at high data rate; carries out some research ontechniques for sub-band analysis and receiving signal reconfiguration according to thephase property of communication band; proposes a high performance adaptivecorrelation algorithm after providing some improvements for the classic correlationalgorithm system; presents a design of the simulation platform of antenna arraying fordeep space communication at high data rate; meanwhile, conducts a study of the powerdivider and impedance transformer for the prototype system for antenna arraying. Theauthor’s major contributions are outlined as follows:1. Key techniques and difficulties in applying antenna arraying into deep spacecommunication at high data rate have been systematically summarized. Major issuesneeded to be solved in this work include: getting the phase values effectively andaccurately in a low signal-to-noise ratio (SNR) condition, avoiding the fake delaycaused by the2π ambiguity error, and reducing the phase shift across the passband dueto the error in delay compensation.2. The application of sub-band analysis and receiving signal reconfiguration inantenna arraying has been studied. In order to avoid2π ambiguity error and phase shiftduring signal combination，the application of sub-band analyzing in antenna arrayinghas been studied. By theoretical analyses and derivations, both the amount of sub-bandthat meet the requirements of signal combination in different conditions and the rangeof delay that can be achieved have been derived. Then, polyphase filter bankchannelizer has been applied to the operation of analysis and synthesis. By selectingappropriate parameters, a512-channelizer has been designed，which realizes effectiveanalysis and synthesis for wideband signal. The reconfiguration error of quadraturephase-shift keying modulated signals in different amount of sub-band has beencompared and the calibration capability of the system with different amount of sub-bandhas been proved through simulation. 3. The improvements of the theory system of classical correlation algorithms havebeen realized. Firstly, the combining degradation for Matrix-Free algorithm has beenderived and it also has been compared with that for SUMPLE algorithm. It has beenproved that the combining degradation for Matrix-Free is lower than that for SUMPLEin the same condition. Then, the determination of the convergence rate of SUMPLE hasbeen derived by introducing the receivable covariance matrix. This indicates that theconvergence rate of SUMPLE algorithm is higher than that of Matrix-Free in the samecondition.4. A high performance correlation algorithm has been studied. Firstly, the methodto calculate the trend of the variance of weight updating values from every iteration hasbeen acquired through the analysis to Matrix-Free and SUMPLE. Secondly, a highperformance adaptive correlation algorithm is presented by introducing Sigmoidfunction for the low SNR condition in deep space communication at high data rate. Itshows that the proposed SVS-MF algorithm has a combining degradation close to thatof Matrix-Free and convergence rate approaches SUMPLE’s without increasing thecomputational complexity. This proves that SVS-MF algorithm has the best overallperformance.5. The simulation tool for antenna arraying for deep space communication at highdata rate has been studied. And based on SVS-MF correlation algorithm as well asreconfigurable channelizer, a simulation platform with flexible parameters has beendesigned. Simulation results show that, by setting an appropriate correlation averaginginterval, the system can realize a very high combining performance for differentarrangements of arrays under a very low SNR condition.6. The studies of multiband power divider and impedance transformer for theprototype system for antenna arraying have been carried out. Firstly, a compactdual-band power divider using a non-uniform transmission line is presented. Secondly, acompact quad-frequency impedance transformer that is composed of a two-sectioncoupled line to achieve ideal impedance matching at three arbitrary frequencies and arelated frequency.