High-Power Low-Pass Harmonic Filters With Higher-Order ${rm TE}_{{rm n}0}$ and Non-${rm TE}_{{rm n}0}$ Mode Suppression: Design Method and Multipactor Characterization

摘要

In this paper, a method to design high-power low-pass harmonic filters in rectangular waveguide technology is proposed. The new filters consist of a collection of smooth E-plane bandstop elements along the propagation direction and a smooth variation of the filter width. This yields to a broad rejected band for the fundamental ${rm TE}_{10}$ mode, together with higher-order (${rm TE}_{{rm n}0}$ and non-${rm TE}_{{rm n}0}$) mode suppression. Two different examples with stringent requirements of the space industry are provided to demonstrate the capabilities of the new methodology. By means of high-power simulations and an extensive measurement campaign, it will be shown that the smoothness of the filter profile guarantees high-power operation even with small minimum mechanical gaps. Moreover, unlike classical techniques, our method is not restricted to filters with small gaps. Hence, filters with larger gaps (always fulfilling the demanding frequency specifications) are fabricated for even higher power-handling performance.