网络分析仪中反射计的双定向耦合器的设计和优化

摘要

Put forward a kind of double directional coupler can be used in the reflectometer.The coupler is cascaded by two microstrip directional coupler.And though making the odd mode capacitance equal to the even mode capacitance by putting a dielectric slice up the middle band of the microstrip line the directionality of the coupler is successfully improved.At last the double directional coupler is successfully simulated that the coupling degree is 10 dB the standing-wave ratio is greater than 15 dB and the isolation degree is greater than 28 dB and the frequency band is between 2 G and 3 G that can be applied to the reflectometer.%提出一种可以应用于反射计的双定向耦合器的设计,此耦合器由两个微带定向耦合器级联而实现,并且通过理论推导在微带线中心导带上方加入介质片增加奇模电容来实现奇偶模相速度相等,从而提高双定向耦合器的定向性.利用HFSS电磁仿真软件成功仿真耦合度为-10 dB,驻波大于-15 dB,2～3G的宽频带,隔离度大于-28 dB能够应用于网络分析仪中反射计的双定向耦合器.