Filtering device

Abstract

An embodiment of the invention discloses a filtering device, and relates to the technical field of mobile communication. The filtering device solves problems of high insertion loss and poor far-end suppression performance of an existing filter. The filtering device in the embodiment is characterized in that a pass band of a primary unit consisting of at leas three coaxial filters covers a pass band of a secondary unit consisting of at least three dielectric filters, the bandwidth of the primary unit is twice of that of the secondary unit, so that when the coaxial filters are coupled to the dielectric filters, insertion loss of the coaxial filters is reduced, and total insertion loss of the filtering device is lowered. The transmission zero of the primary unit is positioned at second harmonic frequency point of the secondary unit, so that the filtering device has high suppression degree to secondary harmonic waves, and a good far-end suppression performance is realized. The filtering device in the embodiment is mainly used as a duplexer of a transceiver module of a base station.

Description

technical field [0001] The invention relates to the technical field of mobile communication, in particular to a filtering device. Background technique [0002] Filters are widely used in mobile communication systems. For example, the duplexer of the transceiver module of the base station is composed of an RF (Radio Frequency, referred to as: radio frequency) cavity filter, which is located on the back of the transceiver board. On the hardware, it is used for the transmission of single-channel high-power radio frequency signals. Among them, the cavity filter usually adopts a coaxial filter with a coaxial cavity. [0003] With the development of mobile communication technology in the direction of multi-band, coaxial filters are increasingly unable to meet the low insertion loss requirements of mobile communication systems, and the emergence of TE (transverse wave) 01 mode dielectric filters with dielectric cavities solves the problem. this problem. The TE01-mode dielectric ...

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Problems solved by technology

[0005] In order to overcome the above-mentioned defects of the TE01 mode dielectric filter, two solutions have been proposed in the prior art: one is to add a metal resonator at the port of the TE01 mode dielectric filter, which can make the higher harmonic frequency and the passband The distance becomes farther, but the suppression of high-order harmonics still does not meet the requirements, and the insertion loss is relatively large; the other is to add a low-pass filter in the front stage of the TE01 mode dielectric filter, which can improve the higher However, since the stop band of the low-pass filter is flat and not steep, it is impossible to obtain a high degree of suppression for the high-order harmonics that are about 200 to 400 MHz away from the pass band, and the insertion loss is relatively large.

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