Filter

Abstract

The invention discloses a filter. The filter comprises a dielectric substrate, a grounding layer, a circuit layer, a signal path and a grounding path. The dielectric substrate is disposed between the grounding layer and the circuit layer. The circuit layer comprises at least three microstrip line resonance elements, a common electrode, an input endpoint and an output endpoint. The input endpoint and the output endpoint are respectively connected with the microstrip line resonance element. The microstrip line resonance element extends outwards from the common electrode. The signal endpoint of the grounding layer is connected with the input endpoint and the output endpoint through a signal path. The grounding plane of the grounding layer is connected to the common electrode via a ground path. The filter also comprises a capacitive coupling unit which is electrically coupled between two adjacent microstrip line resonance elements.

Description

technical field [0001] The invention relates to a filter, in particular to a filter using microstrip technology. Background technique [0002] As the functions of mobile terminals such as smart phones become more and more powerful, more and more network frequency bands need to be applied. Radio Frequency Front End Module (RFFEM), as the core device of the communication system, its performance It directly determines important performance indicators such as the communication mode supported by the mobile terminal, received signal strength, call stability, and transmit power. [0003] Typically, high-end smartphones must filter the transmit / receive paths of up to dozens of frequency bands, and at the same time filter the receive paths such as Wi-Fi and Bluetooth. In addition to the need to isolate the signals of each receiving path, other external signals from too many sources must be suppressed. For this purpose, multi-band mobile phones usually require several filters, other...

AI Technical Summary

Problems solved by technology

[0005] However, in applications with higher frequencies, SAW filters and BAW filters will cause problems such as increased passband loss and decreased stop band suppression effect.

According to the data, the currently used surface acoustic wave filter and bulk acoustic wave filter can no longer meet the needs of high-frequency communication technology in the millimeter wave band (Millimeter Wave, mmWave).

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