Broadband and miniaturised LTCC quadrature hybrid using stacked multi-section structure

A broadband low-temperature co-fired ceramic (LTCC) quadrature hybrid using a stacked multi-section structure is proposed. The idea of placing multi-sections vertically on each LTCC layer is implemented to achieve broadband characteristics and miniaturised area. The overall dimensions of the proposed hybrid are only 9.5 × 8 × 0.9×mm and it achieves a size reduction of 80×. Measured S₁₁, S₂₁, S₃₁, S₄₁ and phase error from 90° are better than -12, -3.5, -3.5, -15 dB and 0.8° from 4 to 6 GHz, respectively.