Miniature ultra-wideband common mode noise suppression circuit

Abstract

The invention discloses a miniature ultra-wideband common mode noise suppression circuit which comprises a quarter-wavelength stepped impedance resonator layer, an embedded differential coupling microstrip line layer, a half-wavelength resonator layer and a reference ground layer, wherein the layers are separated by dielectric substrates. The quarter-wavelength stepped impedance resonator layer comprises a quarter-wavelength stepped impedance resonator, wherein one end of the quarter-wavelength stepped impedance resonator is open circuit, and the other end of the quarter-wavelength stepped impedance resonator is connected with a first branch in parallel. The tail end of the first branch is connected with the reference ground layer through a metal via. The embedded differential coupling microstrip line layer comprises an embedded differential coupling microstrip line. The half-wavelength resonator layer comprises a half-wavelength resonator, and both ends of the half-wavelength resonator are open circuit. The circuit is applicable to the GHz frequency band, and the signal integrity of differential signal transmission can be ensured while common mode noise suppression is realized.

Description

technical field [0001] The invention belongs to the field of signal integrity, and in particular relates to a miniaturized ultra-wideband common-mode noise suppression circuit. Background technique [0002] In high-speed electronic circuit systems, differential signals are widely used to transmit high-speed digital signals due to their advantages of anti-noise and low electromagnetic interference. For example, high-speed interfaces such as HDMI, USB3.0, SATA-Ⅲ, and PCI-E all use differential wiring to transmit Gbps high-speed digital signals. However, in actual circuits, due to the asymmetry of differential wiring and the imbalance of differential signals, such as unequal rise and fall times, inconsistent amplitude and phase, common mode noise will be effectively excited, thereby affecting the transmission of differential signals; especially , when the common mode noise is transmitted to the cable together with the differential signal, it will cause serious electromagnetic ...

AI Technical Summary

Problems solved by technology

[0003] At present, the technologies used in common mode noise suppression circuits are mainly divided into three types: (1) Coil winding on ferrite, the disadvantage is that it is suitable for MHz frequency band, and the size is too large to adapt to modern miniaturized circuit systems to transmit Gbps high-speed digital Signal requirements; (2) Introducing a defective ground structure (DGS, Defect Ground Structure) on the reference ground plane of the coupled microstrip line is equivalent to introducing LC resonance on the common-mode noise loop path, thereby achieving GHz common-mode noise suppression, However, when the DGS structure is applied to multilayer circuits, if there is a metal plane under the DGS reference ground plane, the common mode noise suppression effect will be significantly deteriorated; (3) multilayer circuit technology, the main process technology involved is multilayer PCB Process and low temperature co-fired ceramic (LTCC, Low Temperature Co-Fired Ceramic) process

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