Research On Programmable S-band Integrated RF Components

With the development of modern communication technology,microwave communication has become the mainstream of modern communicaton due to its characteristics of large band capacity,short wavelength and strong directivity.Based on the S-band microwave communication band,the programmable and integrated design of S-band transceiver system is completed in this paper.Firstly,the development of microwave communication system is investigated and analyzed in this paper.The structure of transceiver and the main technical indexes of microwave communication are introduced.According to the engineering application background and application requirements,the index of the system is specified in detail.According to the requirements of the index,the system function and circuit is designed programmable,so that the system output frequency and function selection can be controlled by external programming.Secondly,the group delay equalization circuit and comb spectrum frequency doubling circuit are designed respectively for the group delay and phase noise indexes with high performance.The designed group delay equalization circuit contains three different types of group delay equalization and the equivalent capacitance of the varicolor diode can be controlled by the external DA chip to achieve the design of electrically adjustable group delay equalization,which is convenient for debugging and meets the application in multiple occasions.For the comb spectrum frequency doubling circuit of the source signal,the deterioration of the phase noise of the source signal and the efficiency of the step recovery diode are investigated.Through the designed step recovery diode comb spectrum circuit,the 100 MHz source signal output by the usual constant temperature crystal oscillator is doubled to the 1GHz signal required for the DDS chip.By improving the efficiency of the comb spectrum circuit and the additional phase noise,the output signal of the comb spectrum circuit can meet the requirements of the signal power and phase noise of the input frequency synthesizer module.The designed group delay equalization circuit and comb spectrum frequency doubling circuit first reach the system index requirements through ADS software simulation,and then debug and improve the produced object,and finally the actual measurement reaches the theoretical level of simulation,ensuring the system performance index requirements.Finally,the structure and PCB of the whole receiving and transmitting system is designed.The single module of the system structure meets the design of 3U4 HP CPCI standard board card,which makes the system can be flexibly applied in various occasions.Through the physical test,the group delay fluctuation index of the whole system is better than 1ns for jitter while the phase noise index is better than-85 d Bc/Hz@100Hz,-95 d Bc/Hz@1k Hz,-104 dBc/Hz@10k Hz,-111 dBc/Hz@100k Hz,-133 dBc/Hz@1MHz.