Novel Design of Band-Pass Waveguide Filter With HTS E-Plane Insert

In this paper, the idea of a band-pass filter (BPF) with HTS E-plane insert in the cross waveguide is implemented in Ka-band. The advantage of this approach is to solve the problem of mounting HTS insert into the body of the metal waveguide in order to ensure good electrical contact. A three-step method for the synthesis and design of such a filter is proposed and implemented. The method includes synthesis of the normalized prototype filter, sequentially iterative synthesis of filter geometry, and the final synthesis with optimization using numerical electrodynamic analysis of the entire geometry. It is shown that for the narrowband BPF, resonance windows in the E-plane insert should be performed with accuracy better than ±0.2 μm. The characteristics of such filters are expected better or not worse than their counterparts on the basis of rectangular waveguides, but at less stringent conditions of fastening HTS insert in the body of the waveguide. For fabricating the BPF, epitaxial HTS YBa
₂
Cu
₃
O
_7-δ
films sputtered on both sides of MgO single crystal dielectric substrate of 0.5 mm thickness were used. The difference between losses in the produced filter and its simulated sample is explained with insufficient accuracy of making resonance windows in the HTS insert.