Meandered coupled-line single-section directional coupler designed in multilayer LTCC technology

A quarter wave coupled-line single-section directional coupler was developed in multilayer Low Temperature Co-fired Ceramics (LTCC) technology. To achieve compact size of a coupler the coupled-line section has been appropriately meandered. Such an approach allows for achieving significant miniaturization of the structure desirable especially at lower frequency ranges. The overall length of the couplers section can be reduced to about 50 percent of a conventional quarter wave directional coupler. The presented approach has been verified by measurements of a 3-dB single section coupled-line directional coupler operating at f0 = 1.5 GHz.