JPH04360302A - Strip line - Google Patents

Abstract

PURPOSE:To make the circuit small by making a recessed groove with a required depth for each dielectric board in existence between microstrip lines opposite to each other. CONSTITUTION:A groove 4 with a depth D' is made to each dielectric board between microstrip lines 3 opposite to each other formed on the dielectric board 1. Thus, the line capacitance of the strip lines 3 with respect to the capacitance through the inside of the dielectric board 1 is decreased because the inter-line distance is prolonged. Moreover, since the dielectric constant of the dielectric board 1 is usually larger than that of air, the capacitance through air is largely decreased more than the capacitance through the inside of the dielectric board 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strip line used for high frequency power transmission.

0002

2. Description of the Related Art FIG. 3 is an external perspective view of a conventional strip line. In this figure, 1 is a dielectric substrate, 2 is a back conductor of this dielectric substrate 1, and 3 is a microstrip line formed on one main surface of the dielectric substrate 1. Figure 4
3 is a sectional view taken along line BB in FIG. 3. FIG.

Next, the operation will be explained. A back conductor 2 is formed on the entire back surface of a dielectric substrate 1 having a determined dielectric constant ε. On the surface side of the dielectric substrate 1, the microstrip line 3 is arranged with an impedance determined from the required length, the dielectric constant ε of the dielectric substrate 1, the thickness of the dielectric substrate 1, and the width of the microstrip line 3. There is. Since it is necessary to fit the required length within the predetermined area of the dielectric substrate 1, the microstrip lines 3 are arranged in a meandering manner with the line width W and line spacing D equally divided, as shown in FIG. There is.

0004

[Problem to be Solved by the Invention] In the above-mentioned strip line, since the line spacing D between opposing lines is narrow,

[0005]

[Equation 1] The line capacitance shown in equation (1), that is, the capacitance generated through the air between opposing lines (term a of equation (1)) and the capacitance generated through the inside of the dielectric substrate 1 There were problems such as the sum of (term b in equation (1)) becoming large.

The present invention has been made to solve these problems, and an object of the present invention is to obtain a strip line that is miniaturized.

[0007]

[Means for Solving the Problems] A strip line according to the present invention has a dielectric substrate portion between microstrip lines formed into a concave groove.

[0008]

[Operation] The line capacitance of the strip line in the present invention is
The capacitance through the dielectric substrate becomes smaller because the distance between the lines becomes longer.

[0009]

[Example] The present invention will be explained below. FIG. 1 is an external perspective view of a strip line showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. 1. In these figures, the same reference numerals as in FIGS. 3 and 4 indicate the same components, and 4 is a groove formed in a concave shape in each portion of the dielectric substrate 1 between the opposing lines of the microstrip line 3.

Next, the operation will be explained. A groove 4 is formed in a concave shape at a depth D' in each dielectric substrate 1 between opposing lines of microstrip lines 3 formed on the dielectric substrate 1.

[0011]

##EQU00002## From equation (2), it can be seen that the capacitance value generated through the dielectric substrate 1 is 1/3 of the conventional value. In addition, between the capacitance through the air (term a in equation (2)) and the capacitance through the inside of the dielectric substrate 1 (term b in equation 2), the dielectric constant ε of the dielectric substrate 1 is usually larger than that of air. Therefore, the ratio of the term b in Equation 2 to the line capacitance is large. A very large capacity reduction is thus achieved.

0012

[Effects of the Invention] As explained above, according to the present invention,
Since each dielectric substrate between the opposing lines of the microstrip line is formed into a concave groove of a required depth, the inter-line capacitance is reduced and the characteristics are improved. Moreover, it becomes possible to bring the strip lines close to each other, and it becomes possible to miniaturize the circuit.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a strip line showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG. 1;

FIG. 3 is an external perspective view showing a conventional strip line.

FIG. 4 is a sectional view taken along line BB in FIG. 3;

[Explanation of symbols]

1 Dielectric substrate 2　Back conductor 3 Microstrip line 4 Concave groove

Claims (1)

[Claims] 1. A strip line used for high frequency power transmission, characterized in that each dielectric substrate portion between opposing lines of microstrip lines formed on a dielectric substrate is formed into a concave groove. strip line.