High-isolation duplexer and implementation method thereof

Abstract

The invention discloses a high-isolation duplexer and an implementation method thereof, the duplexer is provided with a transmitting filter arranged between an antenna port and a transmitting port and a receiving filter arranged between the antenna port and a receiving port, the transmitting filter is provided with a plurality of first series resonators and a plurality of first parallel resonators, and the receiving filter is provided with a plurality of second series resonators and a plurality of second parallel resonators. The plurality of first series resonators are sequentially connected in series between the transmitting port and the antenna port to form a first series path, one end of each first parallel resonator is connected to the first series path, and the other end of each first parallel resonator is grounded; and one end of the suppression resonator is connected with the transmitting port, the other end of the suppression resonator is grounded, and the resonant frequency of the suppression resonator is within the passband frequency of the receiving filter. According to the high-isolation duplexer and the implementation method thereof, through ingenious circuit structure design, the high-isolation characteristic of the duplexer can be well achieved, meanwhile, the miniaturization design requirement can be well met, and the high practical application value is achieved.

Description

technical field [0001] The present invention relates to a duplexer suitable for mobile communication terminals, in particular to a high isolation duplexer and a realization method thereof. Background technique [0002] At present, with the popularization of 5G communication technology, terminal products need to support more and more frequency bands, and the indicators are becoming more and more demanding. The function of the duplexer is to isolate the transmitting and receiving signals to ensure that both receiving and transmitting can work normally at the same time. For a duplexer, isolation is an important indicator, and the isolation at the transceiver end of the duplexer determines the degree of interference between signals. Compared with the weak signal received from the air, the signal leaked from the transmitter to the receiver will have a great impact on the sensitivity of the receiver. In order to achieve higher isolation, high-Q acoustic resonators are used in so...

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Problems solved by technology

In order to achieve higher isolation, high-Q acoustic wave resonators are used in some existing technologies, such as temperature-compensated surface acoustic wave (TC-SAW) and multilayer film surface acoustic wave (TF-SAW) technology. The resonator has a higher impedance ratio, which can provide higher suppression, but this method also has a relatively complicated manufacturing process

As another existing way to improve the isolation of duplexers, it can also be achieved by improving the circuit structure. However, there are still ways to improve the isolation of duplexers through circuit structure design. The design structure is relatively complex and the isolation The improvement effect is not ideal, and to a certain extent, it will also have an adverse effect on other performance parameters of the filter while improving the isolation

[0003] In addition, realizing miniaturization design is also a common demand for duplexers at present. In the current duplexer design, there is a conflict between miniaturization and improvement of isolation characteristics to a certain extent. For example, in order to achieve miniaturization, generally Use as few components as possible or reduce the size of components, but this will also make some sacrifices in the performance parameters of the duplexer. Similarly, in order to improve the performance of parameters such as isolation, it will inevitably cause circuit The increase of structural size is not conducive to the realization of miniaturization design

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