JP3015774B2 - Non-reciprocal circuit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-reciprocal circuit device used for a microwave circuit or the like.

[0002]

2. Description of the Related Art In microwave circuits, there are many non-reciprocal circuit elements such as circulators and isolators in which one terminal of the circulator is non-reflectively terminated to improve impedance matching, noise figure, or stabilize oscillation and amplification. It is used.

FIG. 8 is a perspective view showing a microstrip line type three-terminal circulator which is a conventional general non-reciprocal circuit device. A ferrite substrate 1 has a ground conductor 2 formed on the back surface of the ferrite substrate 1 and a pattern conductor 3 formed on the front surface of the ferrite substrate 1. Above the pattern conductor 3, a magnet 4 is provided.
A non-magnetic spacer 5 is disposed between the magnet and the magnet 4. In addition, three terminals 6, 7, 8 are provided around the pattern conductor 3 at intervals of approximately 120 degrees. The ground conductor 2 and the pattern conductor 3 are in close contact with the ferrite substrate 1.

[0004] In recent years, microwave circuits and other passive elements, and remarkable development of dielectric substrate materials have led to miniaturization of microwave circuits, and microwave integrated circuits using planar circuits have become mainstream. The non-reciprocal circuit device occupies a large area in such a microwave integrated circuit, and is therefore required to be reduced in size.

Various proposals have been made for miniaturizing non-reciprocal circuit devices, and lumped constants are one of the promising proposals among them. However, the lumped-constant type has a problem in that, as the frequency increases, the power durability decreases due to a structural problem. Further, the frequency band of 1 to 2 GHz is a frequency band serving as a boundary between the lumped constant type and the distributed constant type, and miniaturization of the distributed constant type is desired.

Under such circumstances, a proposal has been made to reduce the size of the distributed constant type. Fig. 9 shows an example of miniaturization. IEEE TRANSACTION ON MICROWAVE THEORY AND TECHN
IQUES, VOL. MTT-28, NO.6, JUNE, 1980, pp616-621. In FIG. 9 which is a plan view, reference numeral 3 denotes a circular pattern conductor having a radius R, and three input / output terminals 6, 7, 8 are formed on a circumferential portion of the pattern conductor 3. A slit 9 having a length S toward the center is formed in a circumferential portion facing each of the terminals 6, 7 and 8. It is shown that the mode resonance frequency of the pattern conductor 3 decreases as the length S of the slit 9 increases.

A similar example is MICROWAVE SYS
What was published in TEM NEWS, JUNE / JULY, 1975, pp. 50 is shown in a plan view in FIG. Furthermore, as a proposal for improving the power characteristics of the above example, Patent Application No. 1995 3268
An example of No. 50 is shown in a plan view in FIG. FIG. 11 shows the radius R
Three terminals 6 on the circumference of the circular pattern conductor 3
7 and 8 are formed. Then, a length S toward the center in a circumferential portion facing each of the terminals 6, 7, 8 is defined as:
A slit 9 having a width d is formed. At the end of the slit 9 near the center of the pattern conductor 3, a slit 14 is provided on both sides of the slit 9 perpendicular to the slit 9.

In any case, the conventional resonance frequency determined by the diameter of the circular pattern conductor 3 is reduced by the formation of the slit 9, and in other words, the size can be reduced.

However, FIG. 9, FIG. 10 and FIG.
It has been experimentally confirmed that the method of miniaturization by the method described above increases the insertion loss as the length of the slit approaches the center of the pattern conductor. FIG. 12 shows a slit length S (horizontal axis, mm) and a nonreciprocal circuit element when a pattern conductor having a diameter of 18 mm and a slit of 0.25 mm width is provided on a ferrite substrate having a thickness of 1 mm at a frequency of 2 GHz. Is the experimental data showing the relationship between the insertion loss L (vertical axis, dB).

The reason why the insertion loss increases as described above is considered to be that the transmission distance of the microwave signal from the input terminal to the output terminal becomes longer due to the provision of the slit.

[0011]

FIG. 13 shows a slit S
7 is a graph showing power characteristics of insertion loss when there is no (S = 0) and when there is (S). The horizontal axis in FIG. 13 is the input power P _i (W), and the vertical axis is the insertion loss L (dB).
From this graph, it can be seen that when the slit 9 is provided, the insertion loss starts increasing at a low input power regardless of the length.

This is because the concentration of the high-frequency current near the slit 9 increases the strength of the high-frequency magnetic field.
This is because a nonlinear phenomenon has occurred. Therefore, even when the insertion loss is low at low power, the insertion loss increases at high power, and for example, when used in a microwave amplifier, the power at the output side of the non-reciprocal circuit element is reduced. Furthermore, in the use of multi-frequency amplifiers in recent years with the digitization of communication, if a nonlinear phenomenon occurs in a nonreciprocal circuit element, a pseudo signal due to cross-modulation appears near a desired signal, and the reliability of communication is impaired. Occurs.

The present invention solves the above-mentioned drawbacks and provides an irreversible circuit element in which an increase in insertion loss and a deterioration in cross-modulation characteristics are reduced when a slit is provided in a pattern conductor. Aim.

[0014]

According to the present invention, there is provided a ferrite substrate, a ground conductor formed on one surface of the ferrite substrate, and a ground conductor formed on the other surface of the ferrite substrate. And having a plurality of terminals in the periphery,
In a non-reciprocal circuit device of a microstrip line type including a pattern conductor having a slit substantially directed toward a center between predetermined terminals and a magnet for applying a magnetic field to the pattern conductor portion, the pattern conductor is a transmission module.
The first terminal to which the antenna is connected and the first terminal to which the antenna is connected
The second terminal and the third terminal to which the receiving module is connected
And a slit between the first terminal and the second terminal.
And there is a slit between the other terminals .

Further, a pattern conductor having a plurality of terminals around the periphery and having a slit extending substantially in the direction of the center between predetermined terminals, and two ferrite substrates arranged so as to sandwich the pattern conductor And a ground conductor formed on the two ferrite substrates, the non-reciprocal circuit device being a three-conductor stripline type circulator, wherein the pattern conductor is a third conductor to which a transmission module is connected.
One terminal, the second terminal to which the antenna is connected, and the receiving
A third terminal to which the module is connected;
There is no slit between the terminal and the second terminal, and the other end
There is a slit between the children .

Also, a ferrite substrate and the ferrite
A ground conductor formed on one surface of the substrate;
Formed on the other side of the board and have multiple terminals around
Has a slit between the predetermined terminals
The pattern conductor provided and the pattern conductor
Microstrip line type with a magnet that gives a field
In the non-reciprocal circuit device according to (1), the pattern conductor is
And a second terminal, and a third terminal to which the terminator is connected.
A slit is provided between the first terminal and the second terminal.
In addition, there is a slit between the other terminals .

Further , a plurality of terminals are provided in the periphery, and
There is a slit between the fixed terminals
Arranged so as to sandwich the patterned conductor and the patterned conductor
Two ferrite substrates, and the two ferrites
Three-conductor strip having a ground conductor formed on a substrate
In the line type non-reciprocal circuit device, the pattern
The body has a first and a second terminal and a third
Having a terminal, between the first terminal and the second terminal
There is no slit, and there is a slit between the other terminals .

Further , on both sides with respect to the extension direction of the slit.
It has a second slit extending.
In addition, the first extending to one side with respect to the extension direction of the slit
It is characterized by having two slits .

According to the above configuration, the miniaturization rate is extremely slightly reduced as compared with a nonreciprocal circuit device having a structure in which a slit exists between all terminals. Without this, a non-linear phenomenon due to current concentration is unlikely to occur, so that a microwave signal can be transmitted with a small insertion loss. Further, even at a power level at which the non-linear phenomenon does not occur, the insertion loss between terminals without slits is smaller than that between terminals with slits.

[0020]

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a schematic perspective view.

Reference numeral 1 denotes a ferrite substrate. A ground conductor 2 is formed on the back surface of the ferrite substrate 1, and a circular pattern conductor 3 having a radius R is formed on the front surface of the ferrite substrate 1. A magnet 4 is provided above the pattern conductor 3, and a non-magnetic spacer 5 is arranged between the pattern conductor 3 and the magnet 4. In addition, three terminals 6, 7, 8 are provided around the pattern conductor 3 at intervals of approximately 120 degrees. The ground conductor 2 and the pattern conductor 3 are in close contact with the ferrite substrate 1.

Further, linear slits 9 each having a length S are provided in the circumferential portion of the pattern conductor 3 substantially facing the terminals 6 and 7 toward the center. There is no slit in the circumferential portion of the pattern conductor 3 almost facing the terminal 8. The design parameters are also the same as those described above.

In the case where a nonreciprocal circuit device is formed using the pattern conductor of FIG. 1, the transmission characteristics between the terminals 7 and 8 and between the terminals 8 and 6 are low due to the insertion loss and the high The loss increases due to the non-linear phenomenon at the time of electric power. The concentration of the high-frequency current flowing through the center of the pattern conductor 3 is eliminated between the terminals 6 and 7 having no slit 9 between the terminals, so that the insertion loss between the terminals 6 and 7 and the non-linear phenomenon at high power are suppressed. Also, the intermodulation distortion is improved.

FIG. 2 shows the power characteristics of the insertion loss of the nonreciprocal circuit device having the structure of FIG. 1 of the present invention. The horizontal axis represents the input power (W), and the vertical axis represents the insertion loss (dB). The broken line indicates the insertion loss between the terminals 7 and 8, and the solid line indicates the insertion loss between the terminals 6 and 7. As can be seen, the insertion loss between the terminals 6 and 7 without the slit 9 does not show a non-linear phenomenon at low powers up to 15 W.
8 and smaller than the insertion loss between 8,6. The insertion loss between the terminals 7 and 8 and between the terminals 8 and 6 starts to increase from about 10 W due to the nonlinear phenomenon, and is larger than the insertion loss between the terminals 6 and 7 even at a low power up to 10 W. The non-reciprocal circuit device having such characteristics has a great advantage in, for example, a small radar transmitting / receiving module.

FIG. 3 is a schematic plan view showing an example in which the transmitting module 10 is connected to the terminal 6, the antenna 11 is connected to the terminal 7, and the receiving module 12 is connected to the terminal 8. By doing so, the insertion loss between the terminals 6 and 7 that transmit a large amount of power can be suppressed without causing a non-linear phenomenon, and the transmission power (solid arrow in the figure) is supplied to the antenna 11 with a slight loss. it can. The radar radio signal reflected from the target (dashed arrow in the figure) is transmitted from the antenna 11 to the terminal 7.
To the receiving module 12 of the terminal 8. Since the magnitude of the received signal is weak, the signal is transmitted to the receiving module with a slight loss without causing a non-linear phenomenon between the terminals 7 and 8. In particular, in a phased array antenna in which hundreds to thousands of small radar modules are integrated, the reduction in size of the nonreciprocal circuit element has a remarkable effect on reducing the size and weight of the entire device.

FIG. 4 shows the second slits 14 on both sides of the tip of the first slit 9 extending toward the center of the circular pattern conductor 3.
In the plan view showing an example in which the same operation frequency is obtained with the circular pattern conductors 3 of the same size due to the miniaturization effect of the second slit 14, the length of the first slit 9 is short. The difference in the magnitude of the insertion loss between the terminals 6 and 7 where the slits 9 and 14 are not present and the terminals 7 and 8 where the slits 9 and 14 are present is the same as in the example of FIG.

FIG. 5 is an example in which the second slit 14 in FIG. 4 is extended to one side of the first slit 9 and FIG.
Is an example in which the second slit is provided not in the tip of the first slit but in the middle thereof, and the same effect as in FIGS. 2 and 4 can be obtained.

In the above description, the shape of the pattern conductor 3 is circular. However, the same applies to a symmetrical substantially circular shape, a regular triangle or a triangle close to a regular triangle.

In the above description, a microstrip line type non-reciprocal circuit device has been described. However, two ferrite substrates are arranged so as to sandwich a pattern conductor, and a ground conductor is formed on the two ferrite substrate surfaces. The present invention is also applicable to a three-conductor stripline type non-reciprocal circuit device having a structure in which a magnetic field is applied to a pattern conductor portion by a magnet. In the above description, the circulator has been treated as a non-reciprocal circuit element. However, the same result can be obtained with an isolator in which one terminal of the circulator is non-reflectively terminated. FIG. 7 shows an isolator having a structure in which there is no slit between the terminals 6 and 7, and a slit 9 is provided between the terminals 7, 8 and 8, 6 which sandwich the terminator 13.

With this arrangement, for example, when the present isolator is applied to the output stage of a microwave amplifier, the transmission loss between the input and the output can be reduced due to the non-linear phenomenon because there is no slit in the path. Unnecessary reflected power from the terminal load (in the worst case, complete reflection) has the advantage that the withstand power of the terminator can be reduced if the nonlinear phenomenon due to the slit in the path is positively operated.

[0031]

According to the present invention, a non-reciprocal circuit device having a small size and excellent characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the present invention.

FIG. 2 is a diagram illustrating the present invention.

FIG. 3 is a plan view illustrating the present invention.

FIG. 4 is a plan view illustrating the present invention.

FIG. 5 is a plan view illustrating the present invention.

FIG. 6 is a plan view illustrating the present invention.

FIG. 7 is a plan view illustrating the present invention.

FIG. 8 is a perspective view illustrating a conventional example.

FIG. 9 is a plan view illustrating a conventional example.

FIG. 10 is a plan view illustrating a conventional example.

FIG. 11 is a plan view illustrating a conventional example.

FIG. 12 is a diagram illustrating a conventional example.

FIG. 13 is a diagram illustrating a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ferrite board 2 ... Ground conductor 3 ... Pattern conductor 4 ... Magnet 5 ... Spacer 6, 7, 8 ... Terminal (input / output terminal) 9 ... First slit 10 ... Transmitting module 11 ... Antenna 12 ... Receiving module 13 ... Terminator 14 ... Second slit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01P 1/387 H01P 1/36

Claims (6)

(57) [Claims] A ferrite substrate, a ground conductor formed on one surface of the ferrite substrate, and a plurality of terminals formed on the other surface of the ferrite substrate, and having a plurality of terminals around the ferrite substrate. In a microstrip line type non-reciprocal circuit device comprising a pattern conductor provided with a slit extending substantially toward the center and a magnet for applying a magnetic field to the pattern conductor portion, the pattern conductor is a transmission module.
The first terminal to which the antenna is connected and the antenna to which the antenna is connected
Second terminal and the third end to which the receiving module is connected
A terminal between the first terminal and the second terminal.
A non-reciprocal circuit device having no lit and having a slit between other terminals . 2. A pattern conductor having a plurality of terminals in the periphery and having a slit extending substantially in the center between predetermined terminals, and two ferrite substrates arranged so as to sandwich the pattern conductor. When, in the nonreciprocal circuit device is a three-conductor stripline type circulator; and a ground conductor formed in said two ferrite substrate, before
The pattern conductor is the first end to which the transmitting module is connected.
And a second terminal to which the antenna is connected, and a receiving module.
And a third terminal connected to the first terminal.
There is no slit between the second terminal and the other terminal
Is a non-reciprocal circuit device having a slit . 3. A ferrite substrate, and the ferrite substrate
A ground conductor formed on one surface of the ferrite substrate;
Formed on the other side of the
And a slit is formed between the predetermined terminals,
Magnetic field on the patterned conductor
And a magnet that provides
In the non-reciprocal circuit device, the pattern conductors are first and second.
It has a second terminal and a third terminal to which the terminator is connected.
A slit is provided between the first terminal and the second terminal.
And there is a slit between the other terminals
Non-reciprocal circuit element. 4. A device having a plurality of terminals in the periphery and a predetermined
A hole with a slit between the terminals
A turn conductor and the pattern conductor are interposed therebetween.
Two ferrite substrates, and the two ferrite substrates
Conductor strip line having a ground conductor formed on the conductor
In the non-reciprocal circuit device of the type, the pattern conductor is
First and second terminals and a third terminal to which the terminator is connected
And a slot between the first terminal and the second terminal.
There is no slot and there is a slit between other terminals
Irreversible circuit element. 5. A method according to claim, characterized in that it comprises a second slit extending to both sides with respect to the extending direction of the slit
The non-reciprocal circuit device according to claim 1 . 6. A claim, characterized in that it comprises a second slit extending to one side with respect to the extending direction of the slit
The non-reciprocal circuit device according to claim 1 .