JPH07235740A - Grounding circuit for high-frequency active element - Google Patents

Abstract

PURPOSE:To provide a circuit for grounding high-frequency active elements perfectly. CONSTITUTION:The emitter E of a transistor 11 mounted on an electronic circuit board and operated by a high-frequency signal is grounded by connecting it through a through hole to a shield conductor formed on the rear of the board, and is also connected to one end of an open stub 15 of a length of 1/4lambda with respect to the operating frequency of the transistor 11. By doing this way, the voltage amplitude of the open stub 15 of a length 1/4lambda becomes maximum at its open end, and zero at the other end, so the emitter E terminal of the transistor 11 is grounded in terms of high frequency. Consequently, the high-frequency grounding of the transistor 11 becomes perfect, and it becomes possible for the transistor 11 to exhibit its performance fully without causing oscillation, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grounding circuit for a high frequency active device mounted on an electronic circuit board.

[0002]

2. Description of the Related Art Conventionally, to ground a terminal of a high frequency active element such as a transistor mounted on an electronic circuit board or a field effect transistor (FET), it is provided on the electronic circuit board 1 as shown in FIG. The ground terminal 3a of the high frequency active element 3 was connected to the shield conductor 4 formed on the other surface through the through hole 2.

[0003]

However, when the signal frequency for operating the high frequency active element 3 becomes higher and the wavelength becomes shorter, the length of the through hole 2 (the thickness t of the electronic circuit board) can be ignored. Then, the through hole 2 comes to function as an inductance. Therefore, high-frequency grounding of the high-frequency active element 3 becomes incomplete, and the performance of the active element cannot be fully exhibited.
It was a cause of oscillation.

In view of the above problems, an object of the present invention is to provide a high frequency active element grounding circuit which can obtain a completely grounded state in terms of high frequency.

[0005]

In order to achieve the above object, the present invention provides a ground terminal of a high frequency active element such as a field effect transistor mounted on an electronic circuit board with an operating signal frequency of the high frequency active element. We propose a high-frequency active device grounding circuit based on a quarter-wavelength open-ended strip line.

[0006]

According to the present invention, the ground terminal of the high frequency active element is connected to the one end open type strip line having a length of a quarter wavelength based on the operating signal frequency of the high frequency active element. The one end open type strip line having a length of a quarter wavelength has a maximum voltage amplitude at the open end and a voltage amplitude of zero at the other end, and a grounded state is obtained at high frequencies.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 3 is a configuration diagram of the embodiment, and FIG. 4 is a side sectional view showing a main part of the embodiment. In the figure, reference numeral 11 denotes a transistor operated by a high frequency signal, which is mounted on an electronic circuit board (hereinafter referred to as a board) 12, and its emitter E is a shield formed on the back surface of the board 12 through a through hole 13. It is connected to the conductor 14 and grounded. Further, the emitter of the transistor 11 is connected to the other end of the open stub 15 which is provided on the surface of the substrate 12 and which is an open-ended microstrip line. The open stub 15 has a length of 1 / 4λ based on the operating signal frequency of the transistor 11. The base B and the collector C of the transistor 11 are connected to the corresponding microstrip lines 16 and 17, respectively.

According to the above-mentioned structure, since the operating signal frequency of the transistor 11 is a high frequency, the through hole 13
(The thickness t of the substrate 12) cannot be ignored, and the through hole 13 acts as an inductance, but the open stub 15 connected to the emitter E provides a high-frequency grounded state.

That is, as shown in FIG. 5, the open stub 15 having a length of 1 / 4λ has a maximum voltage amplitude at the open end and a zero voltage amplitude at the other end, so that the emitter E terminal of the transistor 11 is closed. At, a grounded state can be obtained at high frequency.

As a result, the high-frequency grounding of the transistor 11 is completed, the performance of the transistor 11 can be sufficiently exhibited, and oscillation or the like will not occur.

In this embodiment, the grounding circuit of the transistor operating by the high frequency signal is shown. However, the present invention is not limited to this, and the present invention can be applied to other high frequency active elements to obtain the same effect. Is what you can get.

[0012]

As described above, according to the present invention, the strip line of the one-end open type having the length of the quarter wavelength has the maximum voltage amplitude at the open end and has the zero voltage amplitude at the other end. And the grounded state can be obtained at high frequency,
The high-frequency grounding of the high-frequency active element is complete, the performance of the active element can be fully exhibited, and oscillation or the like is not caused.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing a main part of a conventional example.

FIG. 3 is a configuration diagram showing an embodiment of the present invention.

FIG. 4 is a side sectional view showing an essential part of an embodiment of the present invention.

FIG. 5 is a diagram for explaining the operation of the embodiment of the present invention.

[Explanation of symbols]

11 ... Transistor, 12 ... Electronic circuit board, 13 ... Through hole, 14 ... Shield conductor, 15 ... Open stub, 16, 17 ... Microstrip line, E ... Emitter, C ... Collector, B ... Base.

Claims (1)

[Claims] 1. A strip, which is open at one end and has a length of a quarter wavelength based on an operating signal frequency of the high frequency active element, is connected to a ground terminal of a high frequency active element such as a field effect transistor mounted on an electronic circuit board. A high-frequency active element ground circuit characterized by connecting lines.