Filter and communication equipment

Abstract

The invention discloses a filter and communication equipment. The filter comprises a shell provided with a first direction and a second direction perpendicular to the first direction; a first common cavity arranged on the first side of the shell; and a first filtering branch and a second filtering branch which are adjacently arranged on the first side of the shell, are respectively coupled with the first common cavity, and are respectively composed of ten filtering cavities and eight filtering cavities which are sequentially coupled, wherein four first cross coupling zero points and three second cross coupling zero points are respectively formed, the distance between the nth filtering cavity of the first filtering branch and the (n+1)th filtering cavity and the distance between the mth filtering cavity of the second filtering branch and the (m+1)th filtering cavity are equal to the distance between the (n+1)th filtering cavity of the first filtering branch and the (n+2)th filtering cavity and the distance between the (m+1)th filtering cavity of the second filtering branch and the (m+2)th filtering cavity respectively, n is an integer larger than 0 and smaller than 9, and m is an integer larger than 0 and smaller than 7. In this way, the out-of-band rejection performance of the filter can be improved, and the size of the filter can be reduced.

Description

technical field [0001] The present application relates to the technical field of communication, in particular to a filter and a communication device. Background technique [0002] In the mobile communication system, the required signal is modulated to form a modulated signal, which is carried on a high-frequency carrier signal, transmitted to the air through the transmitting antenna, and the signal in the air is received through the receiving antenna. Among the signals received by the receiving antenna, not only Include the desired signal, but also include other frequency harmonics, noise signals. For the signal received by the receiving antenna, it is necessary to use a filter to filter out unnecessary harmonics and noise signals. Therefore, the designed filter must precisely control its bandwidth. And if there are multiple channels, you should also consider maintaining high isolation between the passbands of each channel. [0003] The inventors of the present applicatio...

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Problems solved by technology

[0003] The inventors of the present application have found in the long-term research and development work that the filters in the prior art usually include two or more groups of filtering branches with different frequencies, but the arrangement of different filtering branches is not tight, and the filtering The arrangement of adjacent cavities in the branch is not equidistant and there is no common cavity setting, which causes the problem that the current filter volume is too large, especially when more filtering branches are involved. Especially serious; and, when there are multiple filtering branches at the same time, the out-of-band rejection performance of the filter is poor, and it is difficult to achieve a high degree of isolation between channel signals of different filtering branches

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