8mm波射频前端调频源的研究与设计

Research and Design of FM Source of 8mm Wave RF Front-end

调频连续波引信系统要求调频源具有较高的线性度,可实现较高的测距精度。并需用Ka波段功分器将调频源分为两路,一路作为发射信号,一路与回波信号混频。介绍了一种毫米波高线性度、宽频带的小型化调频频率源设计和Ka波段高隔离度的一分二威尔金森功分器设计。利用MACOM公司的压控振荡器MAOC-009267输出频率范围为11.23~11.91GHz,利用UMS公司的三倍频器CHX1191-QDG将压控振荡器输出频率进行倍频。功分器是在普通Wilkinson功分器的基础上进行改进,将输出支路距离增大以减小输出支路的耦合。测试结果表明,频率源调谐电压为3~6.4V时,调频频率范围为33.68~35.91GHz,对基波和二次谐波的抑制都在15dB以上,频率在35GHz时的输出功率为-7.25dBm,频带内输出功率较为平坦。功分器输出支路耦合度降低,频率在35GHz时,反射系数都在-20dB以下,插损大约为-3.9 dB,隔离度达到-30dB。

The system of continuous wave linear frequency-modulation(CW-LFM) fuze requires that the FM source has high linearity, it can achieve higher ranging accuracy. The Ka band power divider is needed to divide the FM source into two channels, one channel is used as transmit signal, the other is mixed with the echo. Here presents a design of a millimeter wave fuze FM source with high linearity and broadband and a design of Wilkinson power divider with high isolation in the Ka band. MAOC-009267 is a VCO of MACOM. The output frequency of theVCO is varied from 11.23 GHz to 11.91 GHz, the three multiplier uses CHX1191-QDG of UMS. The output frequency of VCO will be multiplied. The structure of the power divider is changed on the basis of the ordinary Wilkinson power divider, and the distance of the output end is increased, and coupling of the two output end will decrease. Test results show that when the tuning voltage is 3V^6.4V, the FM frequency range is 33.68GHz^35.91 GHz, and the suppression of the fundamental and second harmonics is above 15 dB, the output power at 35 GHz is -7.25 dBm, and the output power in the frequency band is relatively flat. The output coupling of the power divider is reduced. When the frequency is at 35 GHz, the reflection coefficients are below -20 dB, and the insertion loss is about -3.9 dB, and the isolation degree is -30 dB.