A multi-layer self-packaged balanced filter with integrated impedance transformation function

Abstract

The invention discloses a multilayer self-packaging balanced filter capable of integrating with an impedance conversion function. The filter comprises a top layer metal earth plate, a middle-upper-layer strip transmission line, a middle-lower-layer strip transmission line and a bottom-layer metal earth plate, wherein the top layer metal earth plate, the middle-upper-layer strip transmission line,the middle-lower-layer strip transmission line and the bottom-layer metal earth plate are arranged from top to bottom in sequence; the top layer metal earth plate and the middle-upper-layer strip transmission line are connected through a first metal column and a second metal column; the top layer metal earth plate and the middle-lower-layer strip transmission line are connected through a third metal column and a fourth metal column; and the middle-lower-layer strip transmission line and the bottom-layer metal earth plate are connected through a fifth metal column and a sixth metal column.

Description

technical field [0001] The invention relates to the technical field of microwave passive devices. In particular, it is a multilayer self-encapsulated balanced filter with integrated impedance transformation function. Background technique [0002] In recent years, balanced circuits have received more and more attention. Compared with single-ended circuits, balanced circuits have the potential advantage of high immunity to environmental noise, crosstalk, and electromagnetic interference. It is widely used in modern communication systems. In particular, a balanced bandpass filter (Balance bandpass filter) has an outstanding function in suppressing unwanted common-mode signals while obtaining the desired differential-mode response. [0003] Document 1 [Z.–A.Ouyang and Q.–X.Chu, “An improved wideband balanced filter using internal cross-coupling and 3 / 4λ stepped-impedance resonator,” IEEE Microw.Wireless Compon. Lett., vol.26, no. 3, pp.156-158, Mar.2016.] By using the interna...

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Problems solved by technology

[0003] Document 1 [Z.–A.Ouyang and Q.–X.Chu, “An improved wideband balanced filter using internal cross-coupling and 3 / 4λ stepped-impedance resonator,” IEEE Microw.Wireless Compon. Lett., vol.26, no. 3, pp.156-158, Mar.2016.] By using the internal cross-coupling of the stub line structure and the three-quarter wavelength stepped impedance resonator, the design of the balanced bandpass filter is realized. However, this balanced bandpass filter circuit Complex structure, narrow passband under differential mode excitation

[0004] Literature 2 [T.B.Lim and L.Zhu, "Differential-mode ultra-wideband bandpassfilter on micostrip line," Electron.Lett., vol.45, no.22, pp.1124-1125, Oct.2009.] Based on branch line structure An ultra-wideband balanced filter is proposed, but the circuit is bulky, the common-mode rejection effect is not ideal, and the bandwidth rejection is limited

[0005] Document 3 [H.W.Liu, Y.Song, B.P.Ren, P.Wen, X.H.Guan, and H.X.Xu, "Balanced tri-band bandpass filter design using octo-section stepped-impedance ringresonator with open-stubs," IEEE Microw.Wireless Compon.Lett.,vol.27,no.10,pp.912-914,Oct.2017]Using a stepped impedance ring resonator with an open-circuit stub, a three-pass band-balanced filter is designed, and the proposed circuit The structure can control the differential mode and common mode response to a certain extent, but the circuit is large in size and complex in structure, and the common mode suppression effect is not ideal

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