Miniaturized Half-Mode T-Septum SIW Bandpass Filter With an Ultrawide Stopband
Kai Feng Chen, Xiao Yang, Liang Zhou, Junfa Mao
Abstract
In this letter, novel miniaturized bandpass filters with wide stopband performance are proposed on the basis of the half-mode T-septum substrate integrated waveguide (HMTSSIW) resonator. The resonant TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n00</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n0m</sub> modes of the HMTSSIW resonator are analyzed precisely using the Ritz-Galerkin method, and their resonant frequencies can be controlled flexibly by adjusting the sizes of resonator. A three-order HMTSSIW filter is fabricated using MEMS technology on the benzocyclobutene dielectric. Simulated and measured results show the advantages of compact size and wide stopband. Then, an electric coupling structure is introduced, which allows the further suppression of the spurious TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">300</sub> mode by the controllable mixed coupling. Finally, a miniaturized HMTSSIW filter with 20-dB suppression beyond 10.37f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is simulated and measured.