Filter with multilayered structure

Abstract

The invention provides a filter with multilayered structure. The filter with multilayered structure comprises a ceramic base plate composed of six layers of LTCC, the top layer of the ceramic base plate is the microstrip line layer provided with a first resonator and a fourth resonator; the bottom layer of the ceramic base plate is the microstrip line layer provided with a second resonator and a third resonator; the middle layer of the ceramic base plate is the ground layer. According to the filter with multilayered structure, the gamma / 4 transmission line and open-loop resonator are formed on the upper layer and lower layer and the size of each part is designed reasonably, the size of the filter is smaller while the performance is not changed.

Description

technical field [0001] The invention relates to the field of filters, in particular to a filter with a multi-layer structure. Background technique [0002] Traditionally, half-wavelength microstrip resonators are often used to design microwave filters. However, due to the periodic resonance principle of the half-wavelength transmission line, the filter with this structure has an inherent disadvantage that its parasitic passband is usually located at twice the frequency of its operating frequency. In order to overcome this defect, a planar structure filter composed of a λ / 4 transmission line and an open-loop resonator is usually used. Since the secondary parasitic passbands of the λ / 4 transmission line resonator and the open-loop half-wavelength resonator are respectively located at the third and second multiplications of their operating frequency, the spurious passband of the filter frequency response extends to its The triple frequency doubling of the working frequency br...

AI Technical Summary

Problems solved by technology

However, due to the planar structure of this filter, its size is relatively large, which cannot meet the actual needs