JPH0756481Y2 - Bias network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a bias network capable of applying a large DC current to a high-frequency signal line.

[Conventional technology]

A conventional bias network for superimposing a direct current signal on a high frequency signal is shown in a front view in partial section in FIG.
A coaxial line including the center conductor 1 is used to transmit a high-frequency signal between the terminals 31 and 32, and the DC signal supplied from the terminal 4 is output only to one of the terminals 31 so that the terminals of the center conductor 1 can be output. The insulator 2 is sandwiched at a specified position on the 32 side. The DC signal is transmitted from the DC input terminal 4 through the conductor 5 to the center conductor 1
Is applied to.

[Problems to be solved by the invention]

In such a conventional bias network, in order to make the impedance of the DC line higher than the impedance of the high frequency transmission line, a conductor as thin as possible is used for the DC input line 5. For example, when a DC current of about 5 A is required when measuring the high frequency characteristics of a high frequency semiconductor device, the current capacity that can be applied from the DC input terminal 4 is small, so a bias network having a plurality of this input terminal (4) is provided. There is. However, there is a drawback that the adverse effect on the high frequency signal increases due to the limitation of the external dimensions and the increase of the DC input points.

An object of the present invention is to eliminate the above drawbacks and to provide a bias network capable of applying a large DC current to a DC input line.

[Means for solving problems]

The structure of the present invention is inserted into the DC input line in a bias network in which a high frequency signal input / output terminal is connected to a center conductor that transmits a high frequency signal and a DC input line that applies a DC signal is connected to the center conductor. A matching circuit made of a cylindrical insulator is provided, and the distance between the matching circuit and the central conductor can be varied to perform impedance matching.

〔Example〕

 Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention. Terminal 3
Insulator 2 in the middle of the central conductor 1 in the high frequency transmission line between 1,32.
A high-frequency signal is input from the terminal 32, passes through the central conductor 1, and is output to the terminal 32. On the other hand, a DC signal is applied to the central conductor 1 from the DC input terminal 4 through the conductor 5, but an insulator 2 is provided on the central conductor 1 to output the DC signal only to the terminal 32. in this case,
Cylindrical insulator 6 with excellent high frequency characteristics for DC input line 5
By adjusting the distance L between the central conductor 1 and the insulator 6 by inserting, the impedance of the central conductor 1 and the DC input line 5 can be matched. That is, since a conductor wire having a diameter larger than that of the conventional direct-current conductor wire 5 is used, the insulator 6 is provided so that the high-frequency circuit can be matched and the adverse effect on the high-frequency signal is eliminated.

FIG. 2 is a partial sectional front view of an example of a high frequency signal separation circuit related to the present invention. This circuit example applies a high-frequency signal from the terminal 31 to separate the high-frequency signal on the coaxial line from the terminal 3
In the case of outputting to 2,33, the impedance changes at the signal separation point. The high frequency signal is reflected or lost at this impedance change point.

In this circuit example, the insulator 7 for impedance matching is provided in the center conductor 1 between the signal separation point and the terminals 32 and 33, and the distances L ₁ and L ₂ between the insulator 7 and the signal separation point are adjusted. By doing so, impedance matching is measured.

In this circuit example, the impedance can be adjusted with respect to an arbitrary high frequency signal, so that there is an advantage that the high frequency signal can be separated in a wide frequency range.

[Effect of device]

As described above, according to the present invention, a matching circuit is added to the DC input line to perform impedance matching so as to eliminate adverse effects on high-frequency signals. On the other hand, prescribed high frequency and DC signals can be applied.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention in a partial cross section,
FIG. 2 is a front view showing an example of a high frequency signal separation circuit related to the present invention in a partial cross section, and FIG. 3 is a front view of a partial cross section showing an example of a conventional bias network. 1 ... Coaxial line center conductor, 2, 6, 7 ... Insulator, 31, 32, 33 ... High frequency signal input / output terminal, 4 ... DC input terminal, 5 ... DC input line, L ... Insulator 6 and center conductor 1 Distance, L ₁ , L ₂ ... Distance between signal separation point and insulator 7.

Claims (1)

[Scope of utility model registration request] 1. A cylinder inserted into the DC input line in a bias network in which a high-frequency signal input / output terminal is connected to a center conductor for transmitting a high-frequency signal, and a DC input line for applying a DC signal is connected to the center conductor. A bias network, wherein a matching circuit made of an insulating material is provided, and a distance between the matching circuit and the central conductor is varied so that impedance matching can be performed.