Broadband Low-Loss Four-Way Power Divider Using Composite Cavity

A novel four-way power divider, which utilizes the axially symmetric oversized coaxial to transform input to multiway ridge waveguides directly, is presented in this letter. The broadband performance is achieved by means of changing the inner to outer radius ratio of the central oversized coaxial to introduce its higher order TE <tex-math notation="LaTeX">₄₀</tex-math> mode within the operating band. Moreover, two kinds of transition structure realize the impedance matching optimization. For demonstration, a power divider centered at 3.7 GHz is designed and fabricated. The measured results exhibit that the proposed power divider owns a wide fractional bandwidth (FBW) of 107.1%. The in-band insertion loss (IL) for the four paths is better than 0.2 dB; meanwhile, the amplitude and phase imbalances are less than <tex-math notation="LaTeX">±</tex-math> 0.1 dB and <tex-math notation="LaTeX">±</tex-math> 0.2 <tex-math notation="LaTeX">∘</tex-math> , respectively. Good agreement is observed between the simulated and measured results.