Miniaturized substrate integrated waveguide filtering crossover

A miniaturized substrate integrated waveguide (SIW) filtering crossover is presented. The design concept is to fully exploit the orthogonal degenerate TE
₂₀₁
and TE
₁₀₂
modes in a SIW square cavity to realize the cross transmission, then four TE101-mode cavities are coupled to this square oversized cavity to implement the third-order response and more flexibly controlled bandwidth. Benefitting from the employment of the fundamental mode cavities, the footprint of the circuit has been reduced about 35% compared to our previous work. A prototype operating at 20 GHz is designed, fabricated, and measured for demonstration, showing excellent agreements between the simulated and measured results.