A dual‐band filtering crossover with large frequency ratio for microwave and millimeter‐wave applications

Abstract

AbstractModern wireless communication systems require components that can support microwave and millimeter‐wave bands simultaneously. However, it is difficult for the existing dual‐band crossover configurations to achieve a frequency ratio larger than 5. In this letter, a dual‐band filtering crossover with a frequency ratio larger than 10 is presented for the first time. To implement such a large frequency ratio, a microstrip filtering crossover operating at microwave band and a substrate integrated waveguide filtering crossover operating at millimeter‐wave band are combined through the aperture coupling mechanism. As the two elements almost have no influence on each other, a high degree of design freedom over two bands can be obtained. For demonstration, a dual‐band filtering crossover operating at 2.4 and 28 GHz was designed, fabricated, and measured. Measured results are in good agreement with simulated ones, which validates the proposed structure.