Communication equipment and filter thereof

Abstract

The invention discloses communication equipment and a filter thereof. The filter comprises: a shell having a first direction and a second direction perpendicular to each other; a common cavity arranged on the shell; a first filtering branch coupled with the common cavity and composed of six filtering cavities which are sequentially coupled along a main first coupling path, wherein the six filtering cavities of the first filtering branch further form a capacitive cross coupling zero point; and a second filtering branch coupled with the common cavity and composed of seven filtering cavities which are sequentially coupled along a main second coupling path, wherein the seven filtering cavities of the first filtering branch further form two inductive cross coupling zero points. Through the above mode, the isolation degree between the two filtering branches is high, the product complexity can be reduced, and the stability of the filter is improved.

Description

technical field [0001] The present application relates to the technical field of communication, in particular to a communication device and a filter thereof. 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 upper limit frequency and lower limit frequency. And if the transmit channel and the receive channel exist at the same time, it should also be considered to maintain high isolatio...

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Problems solved by technology

[0003] The inventor of the present application has found in the long-term research and development work that in order to reduce the size of the filter, the filter usually includes two or more than two groups of filtering branches with different frequencies, but the passband bandwidth is between (1426Mhz-2201Mhz) and ( 2299Mhz-2691Mhz) the out-of-band suppression performance of the two groups of filter wave branches is poor, it is difficult to achieve a high degree of isolation between the received signal and the transmitted signal; and the number of cavity discharges is large, the structure is complex, and the filter volume is large, which is not easy conducive to miniaturization

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