Substrate‐integrated waveguide filtering crossovers with improved selectivity

Abstract

Two substrate-integrated waveguide (SIW) filtering crossovers with high selectivity are presented. The orthogonal degenerate TE201 and TE102 modes in center square cavity are employed to realize the cross transmission and channel isolation. The offset coupling positions are then exploited for surrounding TE101-mode rectangular cavities to produce transmission zeros (TZs) above the passband in the first crossover design or for TE201-mode oversized rectangular cavities to generate one TZ on each side of the passband in the second crossover design. The footprint of first crossover has greatly been reduced, while the selectivity of both crossovers has been greatly improved. Two prototypes centered at 20 GHz are designed, fabricated, and tested for demonstration, showing good agreement between the simulated and measured results.