COMPACT DUAL-BAND SUBSTRATE INTEGRATED WAVEGUIDE CROSSOVER WITH HIGH ISOLATION

A compact dual-band substrate integrated waveguide (SIW) crossover with high isolation is proposed. Two identical slots are etched on the ground plane to achieve dual-band response and compact size. The passbands are generated below the cutoff frequency of the SIW due to the electric dipole behaviour of the slots. In-line ports are also employed to obtain good transmission and high isolation. To validate the concept, a dual-band crossover operating at 2.4 GHz and 5.4 GHz is designed, fabricated, and measured. The crossover size including in-line ports is 43.2 * 43.2 [mm.sup.2], equivalent to 0.43[[lambda].sub.g] * 0.43[[lambda].sub.g], here [[lambda].sub.g] is the guided wavelength at the first operating frequency. The tested insertion loss and isolation at the two operating frequencies are smaller than 0.27 dB and greater than 40 dB, respectively.