JPS59117801A - Microstrip circuit - Google Patents

Abstract

PURPOSE:To attain easy and accurate adjustment by providing a metallic grounding plate having a groove at a position opposite to a line under a dielectric base provided with a mu strip line and inserting a dielectric substance into this groove so as to change the amount of insertion. CONSTITUTION:The groove 7 along the mu strip 4 having a constant physical length is provided to the metallic grounding plate 6 under the dielectric base 5 provided with the strip line 4. The dielectric plate 8 having a >=1 dielectric constant is inserted into the groove 7 so as to make the equivalent dielectric constant of a part where the dielectric plate 8 is not placed different from the dielectric constant of the plate 8, and the electric length of the strip line is changed by changing the insertion length of the dielectric plate 8. That is, since two parts having different shortening coefficient of wavelength have different shortening coefficient of wavelength and characteristic impedance, the electric length of the entire line is changed depending on the change in the rate of physical length in the line having the constant physical length.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to microstrip circuits.

I] Technical background of the invention and its problems 1 - A microstrip circuit is a circuit that handles ultra-high frequencies such as microwaves. This circuit is made by etching a conductor such as a copper plate bonded onto a dielectric substrate placed on a conductive ground plate.
It is obtained by shaping the circuit pattern into a shape IJ17.

In such a microstrip circuit, it is necessary to adjust the circuit in order to correct various errors caused by variations in characteristics of semiconductor parts used in the circuit. For this purpose, a method is often used to change the electrical length of the strip line. FIG. 1 shows a conventional example. In this example, in order to make the length of the stub 2 attached to the main line 1 variable,
Land 3 is installed, and the electrical length adjustment is performed using stub 2.
This is done by electrically connecting land 3 to .

However, with this method, the change in electrical length must be discrete, and in order to make fine adjustments, the dimensions of the land must be made extremely small.As the frequency handled by the circuit increases, the adjustment work becomes more difficult. There was a drawback that it was difficult to

[Object of the Invention] An object of the present invention is to improve the above-mentioned drawbacks of the conventional microstrip circuit and to provide a microstrip circuit having easy adjustment means.

[Summary of the Invention] The present invention provides an electrically conductive board on which a microstrip line is disposed, and a position opposite to the microstrip line.
Provide a metal grounding plate with N, K m and 91 in the groove.
This is a microstrip circuit that makes it possible to change the electrical length of the strip line without changing its physical length by inserting a body and changing the amount of insertion.

[Effects of the Invention] By adopting the above-mentioned configuration, the electrical length of the strip line can be adjusted by a non-discrete mechanical operation in which the core plate is moved, which is superior to the land in the prior art. Adjustment work is easier and more precise than electrical connections.

[Embodiments of the invention] A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a cross-sectional view of the microscopy IJ tube circuit of the present invention viewed from the axial direction of the strip line, and FIG. 3 is a cross-sectional view of the same circuit viewed from the side.

In the present invention, the physical length of the microstrip line 4 is constant, and this microstrip line 4 is disposed.

A groove 7 formed in the strip line 4 is provided in the metal grounding plate 6 under the t14f1 board 5. Compared to this groove 7! 1! Insert a dielectric plate 8 whose electric constant is larger than 1, and if the equivalent relative permittivity of the part where the dielectric plate 8 is inserted is different from the equivalent relative permittivity of the part where the intercalary plate 8 is not and the uvit,
By changing the insertion length of the body plate 8, the electrical length of the strip line is changed. In other words, the above two parts having different equivalent relative dielectric constants have different wavelength shortening rates and characteristic impedances, so they have a constant physical length.
Due to changes in the proportion of the physical length occupied by each of the two parts,
The electrical length of the entire strip line can be changed.

The wavelength shortening rate and characteristic impedance of the IJ tube line are determined by the ratio of the thickness dl of the dielectric substrate 5 in FIG. 2 to the depth of the groove 7, that is, the thickness dl of the dielectric plate 8 in FIG. 3. , and the ratio of the dielectric constant ε1 of the dielectric substrate 5 to the dielectric constant ε2 of the dielectric plate 8 can be freely selected by Kokichi.

For example, the dielectric constant of the dielectric substrate 5 is 2.5, and the dielectric constant of the groove 7 is 1.
Let the relative dielectric constant of the dielectric plate 8 holding the dielectric plate 8 be 10, the relative permittivity of the portion of the groove 7 without the dielectric plate 8 be 1, which is the relative permittivity of air, and dt:dz = 2:1. For example, the equivalent dielectric constant of the strip line is 3. at the part where the dielectric plate 8 is inserted.
4. , + is 1.7 in the part without the electric body, and the wavelength shortening ratio is 0.54 and 0.0, respectively, relative to the free space wavelength.
It will be 77.

FIG. 4 corresponds to FIG. 1 which shows the prior art, and the electrical length of the stub 9 of the microstrip circuit is changed by the movement of the taste plate 10.

This circuit can be used as an input and output impedance matching circuit of a transistor amplifier.

FIG. 5 is a top view of a phase shift circuit to which the present invention is applied. In this example, a groove II is provided below the main line 16, and g< body plates A, B, and C having different dielectric constants are inserted into this groove 11. dielectric plate 17a,
17b and 17c, the characteristic impedance of the line deviates from the impedance 20 of the input end 12 and output end 13 of the circuit, so in the input/output example, tapered impedance matching circuits 14 and 15 are provided, and further 3 Among the dielectric plates 17a, 17b, 17c, the length of the central dielectric plate 17b is one-fourth of the wavelength in terms of electrical length, and the length of the three dielectric plates 17a, 17b, 1
By choosing the ratio of relative permittivity of 7c, υz22 =z, -
z3 relationship, and impedance matching from Zl to Z3 is measured. In this example, the dielectric plate 17a, the dielectric plate 17a,
By sliding the slides 17b and 17c, the electrical length of the entire shaft can be changed, and the phase between input and output can be changed continuously.

In this example, if the electrical length of the central dielectric plate 17b is a quarter wavelength and the relationship z22 ==z1・z3 holds, then any one of the dielectric plates 17a, 17b, and 17C can be replaced with air. Can be substituted.

[Brief explanation of drawings]

FIG. 1 is a top view of a conventional microstrip circuit. Figure 2 shows the microstrip circuit of the present invention.
A cross-sectional view of the J-tube line viewed from the axial direction, and Figure S is a cross-sectional view of the same circuit viewed from the side. 4 and 5 are top views of embodiments of the microstrip circuit of the present invention. 4.16...) IJ knob track, 5... Visiting body board. 6. Metal conductor plate, 7, 11... Groove, 8, 10, 17a, t7b, 17c. u electrical board. Agent: Patent attorney Kensuke Chika (and 1 other person)

Claims (1)

[Scope of Claims] A microstrip circuit having a strip line on an S electric body substrate having a gold 1.1 conductor grounding plate attached to the lower surface, the above-mentioned IJ tube of the metal conductor grounding plate A microstrip circuit characterized in that the electrical length of the strip line is changed to ar by boring a groove at a position facing the line, inserting a dielectric plate into the groove, and changing the insertion amount.