High frequency and wide band impedance matching via

Abstract

A high frequency and wide band impedance matching via is provided. As an application to multi-layer printed circuit boards, for example, the multi-layer circuit board has several signal transmission traces, several ground layers, signal transmission vias and ground vias. The signal transmission traces and the ground layers are sited on different circuit layers, and each signal transmission trace is opposite to one of the ground layers. The signal transmission vias are connected between the signal transmission traces. The ground vias are connected between the ground layers. The ground vias are opposite to the signal transmission vias, and the ground vias corresponding to the signal transmission vias are sited to stabilize the characteristic impedance of the transmission traces.

Description

BACKGROUND [0001] This Non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 94101223 filed in Taiwan on Jan. 14, 2005, the entire contents of which are hereby incorporated by reference. FIELD OF INVENTION [0002] The invention relates to a conductive via to be applied to several substrates, such as multi-layer circuit boards, low temperature co-fired ceramics (LTCCs), integrated circuits (ICs), thick-film ceramics, thin-film ceramics or silicon-on-glass substrate processes, and more particular, to a high frequency and wide band impedance matching via. DESCRIPTION OF THE RELATED ART [0003] In products related to electronic systems, such as the multi-layer circuit boards, LTCCs, ICs, thick-film ceramics, thin-film ceramics and silicon-on-glass substrate processes, the printed circuit board (PCB), which supports electronic components generally, is a plan substrate which was made up of glass fibers and on which conductive circuitry was printed...

AI Technical Summary

Benefits of technology

[0008] The structure has two ground vias, which are symmetrically sited around the signal via to be similar to a coplanar waveguide, and further, the structure has at least two ground vias which are symmetrically sited around the signal via to be similar to a coaxial cable. Furthermore, each ground via is connected to another by a conductor portion, thereby promoting electric characteristics of the structure.

Problems solved by technology

Once the number of layers of the PCB is increased, it results such serious interference that signal transmission lines must be through each layer.

Further, since the prevailing trend in electronic products is high frequency, high transmission speed and a higher requirement for accuracy of the transmission impedance and efficiency of the signal transmission, the impedance dis-matching results in the signal bounce to cause many problems.

In light cases, the system will work unstable, and in serious cases, the system will be damaged.

However, the circuitry design for the conventional PCB is chiefly and simply aimed at the signal transmission in a plane and not aimed at the signal transmission in a perpendicular.

A difficult point of the circuitry design for the multi-layer circuit board is the signal transmission between the different layers in a perpendicular direction, so it will avoid vertically transmitting the signals over the vias between the layers in a perpendicular direction in many high-frequency circuitry designs.

However, this circuitry design is complicated, so that flexibility in circuit application is decreasing and precision control of its PCB is not easy.

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