JPS5950124B2 - Slot coupled line oscillator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slot coupled line oscilloscope using three-terminal active elements.

As a conventional MIC-based 3-terminal active element oscillator, the one shown in FIG. 1 is known.

In FIG. 1, a three-terminal active element 1 is a FET (field effect transistor) chip, each terminal of which is connected to a microstrip line by a gold wire 2.
3 is a gate terminal, 4 is a source terminal, and 5 is a drain terminal.

The microstrip line 6 connected to the gate terminal 3 is a stub for adjusting the oscillation frequency, and the microstrip line 7 is for current feedback, and in order to short-circuit the tip at high frequency, the short-circuit conductor 8 connects it to the ground conductor. It is connected to the.

Further, the oscillation output is taken out to the output port 10 through the microstrip line 9.

Note that the bypass circuit is omitted.

In this way, F constructed from microstrip lines
In the ET oscillator, when grounding the high-frequency circuit (source grounding in the case of Figure 1), short-circuit conductor 8 is used as shown in Figure 1, or a quarter-wavelength open-ended microstrip line is used to short-circuit the circuit. However, in the former case,
In the case of high frequency bands, it becomes difficult to improve manufacturing accuracy and it becomes difficult to apply oscillator design theory, and in the latter case, since a grounding circuit is used in common with the current feedback circuit, the feedback circuit design In some cases, the line length is not necessarily one-fourth the wavelength of the specified frequency, making it difficult to use in common with high-frequency short circuits. High-frequency short circuits had to be realized by connecting to the line, and the circuit shape had to be large.

Therefore, with such a circuit configuration, it is difficult to push forward the frequency of the FET oscillator.

The present invention provides a slot coupled line shape vibrator with an improved high frequency short circuit in order to eliminate the drawbacks of the conventional example.

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 2 shows one embodiment of the present invention, in which 1 is an FE
T chip, 2 is gold wire, 3 is gate terminal, 4 is source terminal, 5 is drain terminal, 10 is output port, 11
, 12, 13 are slot coupled lines (coplanar lines), and these slot coupled lines can also be considered as coplanar lines designed and used in odd mode.

Further, 11 is a short-circuit line at the end for current feedback, 12 is an output line, and 13 is a short-circuit line at the end for frequency adjustment.

The equivalent circuit of FIG. 2 is as shown in FIG. 7.

The three-filament distributed constant line represents a coupled slot line, and the tips of the coupled slot lines 11 and 13 are short-circuited.

The input impedance of these coupled slot lines is Za
, Zb, and the load impedance connected to the drain side is Zl. FIG. 8 is a lumped constant circuit representation of FIG. 7.

This circuit can be modified and represented as shown in FIG.

From FIG. 9, it is clear that the output side (drain side) is connected to the input side (gate side) through a feedback loop composed of Za and Zb.

This loop causes it to operate as an oscillator.

The oscillation frequency of this circuit is determined by the condition that the input voltage on the input side and the output voltage on the output side are equal.

In this embodiment configured as described above, since a coplanar shadow line is used, a short-circuit line at the tip can be easily and accurately obtained, and the design theory of the oscillation circuit can be reflected in the circuit design. .

Further, unlike the microstrip line configuration, the line length can be easily changed as shown in FIG. 3, and the oscillation characteristics can be finely adjusted.

That is, 14 is a short-circuited line before adjustment, and 15 is a short-circuited line after adjustment by gold wire 16.

In addition, since the oscillation output is propagated by oddly exciting the slot coupled line 12, if necessary, it can be easily propagated to the microstrip line by a slot line-microstrip line conversion circuit as shown in FIG. .

In FIG. 4, 17 is a slot line, 18 is an open-ended quarter-wavelength microstrip line, 19 is a microstrip line, and 20 is an output port.

Moreover, the dotted line indicates that it is provided on the back side of the board.

FIG. 5 shows an embodiment in which an open-ended line 21 is connected to the gate terminal, and the circuit for converting this output into a microstrip line is the same as that in FIG. 4.

FIG. 6 shows an oscillation circuit including a bias circuit, where 22 is a common source bias terminal, 23 is a gate bias terminal, 24 is a drain bias terminal, 25 is a high frequency blocking high impedance filter, and 26 is a common source bias terminal. Chip capacitor, 27 is a strip conductor, 28 is a short circuit conductor, 29
is a slit provided to separate the ground conductors on the gate side and the source side in terms of direct current.

In FIG. 6, the dotted line is on the back side of the substrate, and the drain bias terminal 24 is also provided on the back side.

As explained above, since the present invention is composed of a coplanar shadow line from which it is easy to obtain a high-frequency short circuit, it is possible to precisely realize an oscillation circuit by strictly prototyping the tip short circuit. Also, since fine tuning can be easily performed, grounding is easier in higher frequency bands than before.
It has the advantage that fine adjustment is possible.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional MIC FET oscillator;
The figure is a block diagram of an embodiment of the present invention, FIG. 3 is a diagram showing the fine adjustment method of FIG. 2, FIG. 4 is a diagram of extracting the output from the microstrip line, and FIGS. , is a configuration diagram of another embodiment of the present invention. 7 is an equivalent circuit of FIG. 2, FIG. 8 is a lumped constant circuit diagram of FIG. 7, and FIG. 9 is a diagram of FIG. 8 further modified. 1...FET chip, 2,16...
gold wire, 3. 4. 5... FET terminal, 10... Output port, 11. 12. 1
3. 14. 15. 21...Slot coupled line (coplanar line), 17°29...Slot line, 18,19...Microstrip line, 20...Output port, 22, 23.24
... Bias terminal, 25 ... High frequency blocking filter, 26 ... Chip capacitor, 27
...Strip conductor, 28...Short conductor.

Claims (1)

[Claims] 1. In four sets of coupled slot lines that share a ground conductor, two of these sets have one end short-circuited, the other set has one end short-circuited or open, and the remaining set is used as an output port, A slot coupled line tokenizer characterized in that these are arranged radially and a three-terminal active element is connected to the center thereof.