一种宽带矢量调制器的设计及其应用

矢量调制器是一种可以同时控制微波信号幅度和相位的器件。本文介绍了一种基于新型微带定向耦合器的宽带矢量调制器。新的耦合器结构克服了传统微带耦合器耦合度低、方向性差的问题,也不需要Lange耦合器复杂的加工工艺,在平衡放大器、移相器和衰减器等场合具有广泛的应用。其次,研究了用串联电感对衰减器中PIN二极管的寄生参数进行补偿的一种简单方法,以改善衰减器衰减量变化时的相位性能。该方法原理简单,可在一定带宽内替代复杂的平衡结构,并给出相近的性能。最后给出了矢量调制器的测试结果和它在自适应天线阵等实际系统中的应用情况,并讨论了用于提高载波和边带抑制、满足高精度要求的校准方法。

A Wideband Vector Modulator and Its Applications

A vector modulator has the ability to control both the amplitude and phase simultaneously.The analysis and design of a vector modulator based on the novel microstrip directional coupler are presented.The new coupling structure has superior performances than traditional microstrip coupler for its good directivity and tight coupling by introducing a coupling capacitor.It is also easier to fabricate than Lange coupler.The coupler has many applications such as balanced amplifier,phase shifter and attenuator.A simple method using series inductor to compensate the parasitic components of the PIN diodes in an attenuator is also proposed.The method can decrease phase variation for high attenuation.It has comparative performances but much simpler than balanced devices.The performance of the vector modulator is proved by experimental results.In addition,applications of the vector modulator in practical systems such as adaptive antenna array are presented,with its calibration method to improve carrier and sideband suppression.