Cavity medium filter

Abstract

The invention discloses a cavity medium filter comprising a cavity provided with a plurality of resonant cavities. Each resonant cavity is provided with a resonator, parts of resonant cavities form cross coupling, and a coupling window is arranged between at least one pair of resonant cavities; in addition, at least one coupling window is provided with a tuning device which is used for matching and adjusting the coupling amount of belonged adjacent two resonant cavities on at least two places of the coupling window; one of the resonant cavities serves as a zero cavity and generates reflectionwith the other resonant cavity to generate transmission zero on the side of a frequency band; and a cross coupling device for generating transmission zero on the other side of the frequency band is arranged between two resonant cavities used for cross coupling. The invention ensures that the cavity medium filter can accurately tune and improve the out-of-band inhibition capability thereof, so that the integral performance of the filter is comprehensively improved.

Description

【Technical field】 [0001] The invention relates to the field of mobile communication equipment, in particular to a cavity dielectric filter. 【technical background】 [0002] In modern mobile communication technology, microwave radio frequency devices have become an indispensable and important part. As a basic radio frequency device, the filter has a series of indicators such as insertion loss, out-of-band rejection, passive intermodulation and power capacity, which have an important impact on the performance of the whole machine. Due to its own loss, the traditional metal coaxial cavity filter cannot obtain a high quality factor (Q value) when the cavity size is limited, resulting in certain restrictions on indicators such as out-of-band rejection and insertion loss. , and the metal surface silver plating treatment and other links will also have a certain impact on the passive intermodulation index. [0003] As for the existing cavity dielectric filter, since there is no sui...

AI Technical Summary

Problems solved by technology

Due to its own loss, the traditional metal coaxial cavity filter cannot obtain a high quality factor (Q value) when the cavity size is limited, resulting in certain restrictions on indicators such as out-of-band rejection and insertion loss. , and the metal surface silver plating treatment and other links will also have a certain impact on the passive intermodulation index

[0003] As for the existing cavity dielectric filter, since there is no suitable and convenient tuning method at present, it is difficult to debug the device during the manufacturing process, and the RF performance index of the device is also difficult to achieve.

[0004] In the known cavity dielectric filter, two methods are mainly used for tuning, one is to tune by setting a plurality of vertical tuning rods deep inside the cavity on the filter cover plate, and the other is to tune by setting a plurality of vertical tuning rods on the filter side Multiple tuning rods are inserted horizontally on the wall for tuning. The tuning effects of these two methods are very limited, and the filter is basically used as an overall unit for overall tuning.

[0005] In addition, most of the existing cavity dielectric filters suppress out-of-band signals through the natural attenuation of the coaxial dielectric resonator itself, and this method achieves higher out-of-band suppression by increasing the number of coaxial dielectric resonators , will lead to an increase in volume and cost, and is not conducive to the performance optimization of the device

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