JPH0321003A - Transmission line transformer - Google Patents

Abstract

PURPOSE:To simplify connection with other circuits as well as improving mass productivity by providing input/output connection patterns for connection with other circuits on line patterns overlapped on both surfaces of an elastic substrate to give a desired characteristic impedance. CONSTITUTION:Line patterns L1 to L4 having a desired characteristic impedance formed to overlap with each other on both surfaces of an elastic substrate 10 of specified dielectric constant and thickness, and input/output connection patterns 11 to 14 connected to these line patterns L1 to L4 are provided. Therefore these transmission line transformers T3, T4 have elasticity so that they can be connected to other circuits via the input/output connection patterns 11 to 14 with desired characteristic impedance. Thus the transmission line transformers T3, T4 with high a mass productivity and easy to mount to other circuits can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application Field of the Present Invention The present invention relates to a transmission line transformer used in a high frequency circuit.

Prior Art In high-frequency circuits, transmission line transformers are mainly used for purposes such as impedance conversion and phase inversion.

FIG. 9 is a circuit diagram configuring a 1:4 impedance conversion circuit using two sets of transmission line transformers T1 and T2, and for the impedance Z of the circuit connected between terminals 1 and 2, If the impedance of the circuit connected between terminals 3 and 4 is set to 4.Z, signal transmission between the circuits can be performed with the least loss (however, the characteristic impedance of transmission line transformers T1 and T2 is 2.・Z
>.

The two sets of transmission circuit transformers TI and T2 are configured to form an inductance by, for example, two conductive wires adjacent to each other, and a distributed constant is applied to signals with a frequency lower than the line length. It operates as a lumped constant circuit for frequency signals close to the circuit or line length, making wideband signal transmission possible.

In order to achieve especially efficient broadband signal transmission, it is necessary to form a large inductance with a short line, so it is necessary to wind the conductor around a core material with high magnetic permeability, or use a coaxial cable as shown in Figure 10. 6, 6 is a cylindrical core 7,
7 to form a transmission line transformer so that it can be used in a wide band (8 is a circuit board, 9 is a relay terminal).

Problems to be Solved by the Invention> However, with the transmission line 1 and lance as described above, processing of the end of the coaxial cable 6 (or conducting wire) is complicated, making it difficult to uniformly mount the coaxial cable 6 (or conductor) on other circuits, There is a problem in that the impedance of the line changes significantly at high frequencies due to this treatment at the end, and the transmission characteristics at high frequencies differ significantly depending on the circuit.

In particular, when attempting to transmit signals from several 100 MHz to several GHz using a transmission line transformer such as the one described above, adjustment is required for each circuit, which significantly reduces mass productivity.

An object of the present invention is to provide a transmission line transformer that solves this problem.

Means for Solving the Problems> In order to solve the above problems, the transmission line transformer of the present invention is provided by forming a flexible substrate having a predetermined dielectric constant and thickness so as to overlap each other on both sides thereof, thereby achieving a desired characteristic impedance. and an input/output connection pattern connected to the line pattern.

Therefore, this transmission line transformer has flexibility,
It can be connected to other circuits via the input/output connection pattern with the desired characteristic impedance, and has high mass productivity.
It can be easily mounted on other circuits.

Examples of the present invention> (Figures 1 to 3) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a front view showing the structure of a 1:4 impedance conversion circuit (hereinafter referred to as a conversion circuit) using the transmission line transformer of the present invention, and FIG. 2 is a rear view of FIG. 1.

Further, FIG. 3 is a perspective view showing only the pattern portion, and FIG. 4 is a diagram showing an equivalent circuit of one embodiment.

This conversion circuit has two sets of transmission line transformers T3 and T4 patterned by etching on both sides of a substantially square substrate 1o made of a polyimide resin film with high flexibility and heat resistance.

The first transmission line transformer T3 has a U-shaped line pattern [1, L
Similarly, the second transmission line transformer T4 is constituted by line patterns L3 and L4 which are U-shaped and substantially symmetrical to the line patterns L1 and L2.

Each line pattern 1 to L4 is a transmission line transformer T3,
So that the characteristic impedance of T4 is approximately 25Ω,
The line width W is set to approximately 4 mm, and the line length l is set to 2.
5GH. It is set to approximately 3Qmm, which corresponds to 1/4 wavelength of Z.

One end L1a of the line pattern L1, one end L3a of the line pattern L3, one end L2a of the line pattern 2, and one end L4a of the line pattern 4 are connected by through-hole processing, respectively, and the line patterns L2 and L3 are connected to each other by through-hole processing. The other end side is pattern-connected, and the connections shown in the equivalent circuit of FIG. 4 are made.

Also, both ends L1a, L1b, of the line patterns L1, L4,
Connection conductors 11, 12, 13, and 14 extending to the ends of the substrate 10 are patterned on L4a and L4b.

Therefore, the impedance 12 in the connecting conductors 11 and 12
．． When a 5Ω circuit is connected and a circuit with an impedance of 50Ω is connected to the connection conductors 13 and 14, signal transmission between the circuits can be performed over a wide band (several 100 MHz to 2 GHz) with little loss.

When mounting this conversion circuit, the connection conductors 11 and 12 on one side of the board 10 are connected to the circuit board 2 as shown in FIG.
If the connecting conductors 13 and 14 on the other side are soldered onto the circuit board 2o by curving the board 10 and soldering them onto the circuit board 2o, the mounting area can be reduced. Also, Figure 5 (
As shown in b), the board 10 can also be mounted horizontally so as to close the hole 21 provided in the circuit board 20.

In addition, in this embodiment, it is also possible to provide a connection conductor 15 at the connection portion of the line patterns L2 and L3 and use it as a phase inversion circuit.

Other Embodiments of the Present Invention In the above embodiments, the transmission line L/lance was formed with a U-shaped line pattern, but the front and rear views are shown in FIGS. 6 and 7. As shown, a 21 liter transmission line 1/lance may be formed using annular line patterns L5, L6 and line patterns L7, L8.

Further, in the above embodiment, a polyimide resin film was used as the substrate 10, but this does not limit the present invention, and a polyester film, a glass epoxy film, or the like may be used.

In addition, in the above embodiment, the range from several'loOMHz to several GHz
Although we have explained the case of transmitting signals up to ).

<Effects of the Present Invention> The transmission line transformer of the present invention is constituted by a line pattern that is formed so as to overlap on both sides of a flexible substrate and has a desired characteristic impedance, and has an input/output line for connection with other circuits. Since it has a connection pattern, there is no need for complicated adjustment of the end portion, uniform characteristics can be obtained, connection with other circuits is extremely easy, and mass productivity is greatly improved.

[Brief explanation of drawings]

FIG. 1 is a front view showing the appearance of a circuit to which the present invention is applied;
2 is a rear view of FIG. 1, FIG. 3 is a perspective view showing essential parts of one embodiment, and FIG. 4 is an equivalent circuit diagram of one embodiment. FIG. 5(a) is a perspective view for explaining a circuit mounting method of one embodiment, FIG. 5(b) is a sectional view for explaining another mounting method of one embodiment, and FIG. FIG. 7 is a front view showing another embodiment of the present invention, and FIG. 7 is a rear view of FIG. 6. FIG. 8 is a front view showing another embodiment of the present invention. FIG. 9 is a diagram showing an example of a circuit using a transmission line transformer, and FIG. 10 is a perspective view showing a conventional transmission line transformer. 10... Board, T3, T4... Transmission, transmission line transformer, 1 to L4... Line pattern.

Claims (1)

[Scope of Claims] A line pattern having a desired characteristic impedance and formed so as to overlap each other on both sides of a flexible substrate having a predetermined dielectric constant and thickness; and an input/output connection pattern connected to the line pattern. A transmission line transformer characterized by being equipped with.