This letter proposes a wideband filtering differential phase shifter with enhanced harmonic suppression. Through the original transmission line model, the numerical relationship between the prescribed amplitude/phase response and the initial design parameters can be readily established. Then the simple transformation from the transmission line to its T-type lowpass network is utilized to suppress the harmonics efficiently with almost the same in-band phase shift response. For demonstration, a prototype is designed and fabricated, the proposed filtering phase shifter features enhanced harmonic suppression up to $3.5f_{0}$ and an enhanced suppression level of 33.5 dB.

中文翻译：

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具有增强谐波抑制功能的宽带滤波差分移相器

这封信提出了一种具有增强谐波抑制功能的宽带滤波差分移相器。通过原始传输线模型，可以轻松地建立规定的幅度/相位响应与初始设计参数之间的数值关系。然后，利用从传输线到其T型低通网络的简单转换，以几乎相同的带内相移响应有效地抑制谐波。为演示起见，设计并制造了一个原型，所提出的滤波移相器具有增强的谐波抑制能力，最高可达到 $ 3.5f_ {0} $ 以及33.5 dB的增强抑制水平。