A Vertically Distributed Triangular Patch Resonator-Based Bandpass Filter With MISL Technology

This letter aims to design a third-order bandpass filter (BPF) based on the metal integrated suspended line (MISL) platform. To achieve a compact filter design, a triangular patch resonator (TPR) is used, effectively reducing the overall size. At the same time, the available 3-D space is efficiently utilized by employing a vertically stacked resonator arrangement. By implementing a separate electric and magnetic coupling path (SEMCP), a flexible arrangement of transmission zeros (TZs) is introduced, and the influence of different resonator configurations on the dominance of electric and magnetic couplings is discussed. In order to validate the proposed design method and theory, we have developed a prototype. The measurement results show good agreement with the simulation ones, confirming the compact size and low-loss characteristics of the proposed design.