Wideband Unequal Filtering Power Divider With Arbitrary Constant Power Ratio and Phase Difference
Xin Guo, Yuhua Liu, Wen Wu
Abstract
A novel kind of wideband unequal filtering power divider (FPD) with arbitrary constant power ratio ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k} ^{2}$ </tex-math></inline-formula> ) and phase difference ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\Delta } {{\varPhi}}$ </tex-math></inline-formula> ) is proposed. Two general wideband filtering branches based on theory of commensurate <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\lambda }$ </tex-math></inline-formula> /4 lines are used to construct the wideband FPD. To design in-band constant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k} ^{2}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${{\varDelta}} {{\varPhi}}$ </tex-math></inline-formula> all-in-one, each filtering branch is designed with its own impedance transforming ratio, FBW and RL. An isolating resistance is successfully added, as two leading <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\lambda }$ </tex-math></inline-formula> /4 lines are designed to be proportional. Furthermore, the deviation of power ratio within passband due to different filters is corrected. For validation, a wideband unequal power divider across 1.76–3.04 GHz (53.33%) is designed and measured with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$|{S} _{21}~|$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$|{S} _{31}~| < 6~{{\pm }}~0$ </tex-math></inline-formula> .84 dB, phase difference of 90° ± 5° and filtering implanted.