JPH0371703A - Connection method for multi-layer substrate - Google Patents

Abstract

PURPOSE:To decrease a change in the characteristic impedance and to improve the performance and reliability by removing partly an inner layer ground conductor (earth) so as not to change the characteristic impedance even when the width of pattern is widened to provide soldering lands for component connection. CONSTITUTION:When a soldering land pattern 2 for connecting a component is provided to a microstrip line 1 comprising a multi-layer substrate, the inner layer earth pattern 6 for the part of the soldering land pattern 2 is removed and a lower layer earth pattern is used as an earth pattern of the microstrip line. Thus, even when the pattern width of the soldering land pattern 2 is widened by the share of increased thickness, the soldering land pattern 2 is provided without changing the characteristic impedance and the pattern strength is kept and the reliability is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a multilayer board for a high frequency circuit, and connects a soldered land pattern for connecting components to a microstrip line having a specific characteristic impedance. The present invention relates to a multilayer board connection method.

[Conventional technology]

If we apply this method by changing the plate thickness to match the change in characteristic impedance, we can consider changing the plate thickness so that the characteristic impedance remains constant even if the microstrip line width is changed. Related examples of this type include, for example, Japanese Utility Model Application Publication No. 55-31373.

[Problem to be solved by the invention]

In the conventional technology, miniaturization is achieved by narrowing the width of the microstrip line by multilayering, but a certain soldering land pattern is required to connect components, and it is necessary to use a certain characteristic impedance! If the soldering land pattern width is wider than the iA path width, it is necessary to widen the line width in that portion. However, by widening the pattern width, this soldered land pattern changes the characteristic impedance of the microstrip line, causing mismatching. There was a problem of deterioration.

[Means for solving the problem] In order to solve the above problem, the inner layer was grounded with a ground conductor (hereinafter referred to as
When a soldered land pattern is provided on a microstrip line made of a multilayer board (referred to as grounding), by excluding the grounding pattern on the inner periphery of the soldering land pattern and making it a lower layer grounding pattern, equivalently increasing the board thickness,
In order to maintain the same characteristic impedance, the line width can be widened, and the change in the characteristic impedance of the microstrip line is small, resulting in less performance deterioration. On the other hand, by optimizing the soldering pattern, pattern strength can be maintained and reliability can be improved.

[Effect]

The characteristic impedance Zo of the microstrip line is
Zo=337/(ty/h)・J'L (1+(1,7
35Er) (w/h)-0,1+3@), the permittivity of the substrate is ε1. It is determined by the pattern width W and the thickness of the substrate. Also, from the equation, if the dielectric constant of the substrate is constant and the ratio of pattern width to board thickness is constant, the characteristic impedance will not change. Therefore, even if a soldering land pattern with a wide pattern width is provided on a microstrip line using a multilayer board, the same can be achieved by excluding the inner layer grounding pattern of the soldering land pattern portion and providing the grounding pattern on the lower layer to increase the board thickness. A characteristic impedance of is obtained.

In addition, the microwave power distribution of the microstrip line is concentrated at an angle of about 45 degrees from the pattern edge of the microstrip line with respect to the ground plane. This is obtained by removing the inner layer ground pattern at a portion extending 45 degrees from the pattern.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

When a soldering land pattern 2 for connecting components is provided to a microstrip line 1 made of a multilayer board, the lower layer grounding pattern can be used as the grounding pattern of the microstrip line, except for the inner layer grounding pattern 6 in the part of the soldering land pattern 2. By doing this, even if the pattern width of soldering land pattern 2 is increased by increasing the board thickness, the characteristic impedance does not change and the soldering land pattern 2
, the strength of the pattern can be maintained and reliability can be improved.

FIG. 3 shows a conventional example. In the case of FIG. 3, the characteristic impedance changes due to the soldering land pattern 2, causing mismatch and deteriorating performance.

〔Effect of the invention〕

According to the present invention, even if a soldered land pattern for connecting components to a microstrip line on a multilayer board is provided, changes in characteristic impedance are reduced and performance and reliability are improved.

[Brief explanation of drawings]

FIG. 1 is a top view of one embodiment of the present invention, FIG. 2 is a sectional view of one embodiment of the present invention, and FIG. 3 is a perspective view of a conventional example. 1... Microstrip line, 2... Soldered land pattern, 3... 1M board, 4... 2-layer board, 5...
・3-layer board, 6, 7...inner layer pattern, 8
...lower pattern. 1st 7 2nd 777° 5th

Claims (1)

[Claims] In a high-frequency circuit connection method in which a microstrip line is formed using a conductor on the surface of a multilayer dielectric substrate, an inner layer is used to prevent the characteristic impedance from changing even if the line width is widened in order to provide soldering lands for connecting components. A method for connecting a multilayer board characterized by partially removing a ground conductor (earth).