JP2644561B2 - Hybrid circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid circuit, for example, a small-sized hybrid circuit that can be used in a microwave integrated circuit and distributes and combines high-frequency signals. .

[Conventional technology]

FIG. 3 shows an example of a conventional hybrid circuit. Here, 11 ₁ to 11 ₄ are terminals for signal input and output, _{131-134 3} transmission line having a length of a quarter wavelength for the frequency to be used,
13 ₄ is also 3/4 wavelength transmission line.

In this hybrid circuit, when the output impedance is Z _0, the characteristic impedance of the transmission line _131-134 Then, it is known that each terminal can be matched.
Here, the transmission line 13 ₄ and the transmission line _{131-134 3} 1/2
There is a wavelength line length difference.

For example, when the signal from the terminal 11 ₁ is input, the signal of equal amplitude appears opposite phases to each other in the terminal 11 ₂ and the terminal 11 _3, the terminal 11 _4, the transmission line 13 ₂ side and the transmission line 13 ₃ No signal appears because the signals from the sides cancel each other. Also,
Signal input from the terminal 11 ₃ is distributed in phase with each other in the terminal 11 ₁ and the terminal 11 _4, signal does not appear at the terminal 11 _2.

Such a hybrid circuit operates in the same manner as Magic T in a waveguide circuit and can be formed planarly on a dielectric substrate, for example, so that it is widely used as a component of a microwave integrated circuit such as a frequency conversion circuit. Have been done. However, in the hybrid circuit, as it is clear from FIG. 3 3/4 wavelength transmission lines 13 ₄ and 4
Circuit size because of using a transmission line _{131-134 2} min 1 wavelength becomes extremely large.

FIG. 4 shows a conventional example in which a required phase difference is obtained without using the line length difference as shown in FIG. This hybrid circuit is miniaturized by using a combination of a capacitor and a transmission line or inductor having a high impedance.

In Figure 4, 21 ₁ to 21 ₃ of the high-impedance coplanar line, 23 ₁ to 23 ₃ are lumped capacitors using gap capacitance between the conductors, between 25 _to 253 ₁₀ ground conductors (indicated by hatching) Bridges that connect to each other. In this hybrid circuit, the transmission line 13 of three quarter wavelength and one quarter wavelength in the conventional example shown in FIG. 3 is replaced with a network composed of a short high impedance transmission line and a lumped capacitor. The hybrid circuit, by selecting the coplanar line 21 ₁ to 21 ₃ of the length and the constant lumped capacitors 23 _{1-23 3} optimal, the same operation as the circuit of Figure 3.

For example, when the signal from the terminal 27 ₁ is input, the signal of equal amplitude appears opposite phases to each other in the terminal 27 ₂ and the terminal 27 _3, the terminal 27 ₄
No signal appears. Further, the signal inputted from the terminal 27 ₃ is distributed in phase with each other in the terminal 27 ₁ and the terminal 27 ₄ pin 27
_No signal appears at ₂ . In this conventional example, the circuit size is small because the circuit is composed only of a high impedance line of about 1/8 wavelength and a capacitor.

[Problems to be solved by the invention]

For example, FIG. 5 shows an example in which the above-described conventional hybrid circuit is used for a balanced frequency conversion circuit.

Here, 31 microwave hybrid circuit using the hybrid circuit of the prior art, 33 _1, 33 ₂ is a unit mixer. In this balanced frequency conversion circuit, the input terminal 35 ₁
Received signal from the (RF), input from the terminal 35 _second local oscillator output signal (LO) is supplied, the two units mixers 33 _1,
33 ₂ generated intermediate frequency component (IF) is taken out from an output terminal 37.

The microwave terminal and the terminal 27 ₁ of the hybrid circuit of the terminal 32 ₁ Figure 4 microwave hybrid circuit 31 the relationship between the terminals of the hybrid circuit shown in FIG. 4 of the hybrid circuit 31, terminals 32 ₂ are terminals 27 ₂ , the terminal 32 ₃ terminals 27 _3, the terminal 32 ₄ corresponds to terminals 27 _4. In the microwave hybrid circuit 31, the terminals 32 ₁ which are in the facing relationship are arranged.
And the terminal 32 ₄ is an input terminal and an output terminal.

If integrally formed such balanced frequency converting circuit, for example on a dielectric substrate, an input terminal of the local oscillator output signal is input 35 ₂ and the microwave hybrid circuit 3
A line connecting the first and the terminals 32 _1, it is impossible to avoid the terminals 32 ₂ and the unit mixers 33 ₂ and intersection 39 between the line connecting the microwave hybrid circuit 31. Therefore, unnecessary signal leakage occurs due to inter-line coupling based on the intersection 39, and the balance of the circuit deteriorates due to signal reflection and phase rotation at the intersection 39. Further, the circuit layout on the balanced frequency conversion circuit becomes complicated, and the entire circuit becomes larger.

As described above, the conventional hybrid circuit has an improper terminal arrangement, so that when applied to a frequency conversion circuit or the like, an inconvenient line crossing occurs, and the electric characteristics are reduced due to the inconvenient line crossing. There was a disadvantage of deterioration.

The present invention has been made in view of such a point, and an object of the present invention is to provide a hybrid circuit having a terminal arrangement suitable for application to a frequency conversion circuit or the like.

[Means for solving the problem]

In order to achieve such an object, in the present invention, at least a ground conductor, a first to a fourth terminal,
A second capacitor formed between a first capacitor formed of a first electrode, a second electrode and an insulating film and a ground conductor,
A capacitor and first to third lines are formed.

The first to fourth terminals are for inputting or outputting a signal.

The first electrode forming the first capacitor is connected to the first terminal. Further, the second electrode forming the first capacitor is disposed to face the first electrode via the insulating film, and is connected to the second terminal.

The second capacitor is formed between the first conductor connected to the third terminal and the ground conductor.

The third capacitor is formed between the second conductor connected to the fourth terminal and the ground conductor.

A first line is formed to connect between a first electrode of the first capacitor and a first conductor of the second capacitor.

A second line is formed to connect between the first conductor of the second capacitor and the second conductor of the third capacitor.

A third line is formed to connect between a second electrode of the first capacitor and a second conductor of the third capacitor.

As a whole, a conductor system composed of the first terminal, the first electrode and the first line and a conductor system composed of the second terminal, the second electrode and the third line are interposed at the position of the first capacitor via the insulating film. It is configured to intersect.

(Operation)

According to the present invention, a conductor system composed of the first terminal, the first electrode and the first line and a conductor system composed of the second terminal, the second electrode and the third line are placed there at the position of the first capacitor. They intersect via the included insulating film. Therefore, for example, when applied to a frequency conversion circuit, the first terminal and the fourth terminal that are input of two signals do not cross other terminals that output the converted frequency signal.

Accordingly, line crossing due to improper terminal arrangement as in the conventional hybrid circuit does not occur, and the drawback in electrical characteristics due to line crossing is eliminated.

〔Example〕

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

FIG. 1A shows a configuration of a hybrid circuit according to one embodiment of the present invention. Here, 41 ₁ , 41 ₂ , and 41 ₃ are high impedance transmission lines, and 43 ₁ , 43 ₂ , and 43 ₃ are lumped constant capacitors. One lumped capacitors 43 ₁ near the enlarged plane in FIG. (B), shows the A-A 'seen from cross section in FIG. (B) in FIG. (C). In the figure, 45 ₁ , 45 ₂ ,
45 _3, 45 ₄ are terminals for signal input and output, which extends in coplanar line form, 47 _1, 47 ₂ through holes 49 ₁ to 49 ₁₀ is a bridge for connecting the ground conductor (indicated by hatching).

1 (a) to 1 (c), a lumped capacitor
43 ₁ electrodes 42 _1, 42 ₂ and the insulating film for insulating them from one another
Consists of 44. Here, the lower electrode 42 ₁ is in a plane Z
Has a shape, it faces the distal end portion of the conductor that projections and one end is connected to the terminal 45 _2, between their mutual are electrically connected via the through holes 47 _1. Also, projections and other end of the lower electrode 42 ₁ is opposed to the front end portion of the center conductor of the transmission line 41 _3, between their mutual are electrically connected through another through-hole 47 ₂ .

Upper electrode 42 ₂ forming lumped constant capacitor 43 ₁ is a terminal
45 ₁ and the center conductor of the transmission line 41 ₁ . There is a gap in between are opposed to each other and connected to conductors on the upper electrode 42 ₂ and the terminal 45 _2, likewise, voids therebetween are opposed to each other and the upper electrode 42 ₂ and the transmission line 41 ₃ There is.

 Here, the present invention is associated with embodiments.

The first to fourth terminal corresponding to the terminal 45 ₁ to 45 ₄ for signal input and output. The first electrode and the second electrode are an upper electrode 42 ₂ and a lower electrode 42 ₁
Corresponding to First through third capacitors corresponding to the lumped capacitor 43 _{1-43 3.} The first to third lines correspond to high impedance transmission lines 41 ₁ , 41 ₂ , and 41 ₃ .

By a structure as shown in FIG. 1, swapping the positions of the terminals 45 ₁ and the terminal 45 ₂ of a conventional hybrid circuit to each other and the operation (distributing and combining the high-frequency signal) in the same manner as in the conventional example.

Here, the hybrid circuit according to the present embodiment is applied to, for example, a balanced frequency conversion circuit shown in FIG. In this case, the relationship between the terminal of the microwave hybrid circuit 31 shown in FIG. 5 and the terminal of the hybrid circuit according to the embodiment of FIG. ₁ is such that the terminal 321 of the microwave hybrid circuit 31 is the terminal of the hybrid circuit of FIG. 45 ₁ , terminal 32 ₂ is terminal 45
_2, the terminal 32 ₃ terminals 45 _3, the terminal 32 ₄ corresponds to terminals 45 _4.

Microwave hybrid circuit 31 included in the balanced frequency conversion circuit, in the case of applying the hybrid circuit according to the present invention embodiment, it becomes its signal input terminal pins 45 _1, a terminal 45 _4. Both terminals 45 _1, 45 ₄ in this embodiment are adjacent to each other. Therefore, be formed integrally on dielectric substrate applied to balanced frequency conversion circuit shown in FIG. 5, an input terminal 35 ₁ the local oscillator output signal is input
A line connected to, does not intersect the line connecting the ₂ microwave hybrid circuit 31 and a unit mixer 33.

Thus, to perform by using a capacitor that constitutes the hybrid circuit cross pin 45 ₁ and the terminal 45 _2, does not cause signal leakage and signal reflection problems as found in the intersection of a normal transmission line. By enabling such a terminal arrangement, it is possible to eliminate the drawbacks caused by line crossings as described with reference to FIG. 5 when applied to a frequency conversion circuit or the like.

As described above, in the present embodiment, the capacitor used in the hybrid circuit is composed of two conductors with the insulating film interposed therebetween, and the conductors are crossed using this structure. This intersection of the conductors is not present in the conventional hybrid circuit, and a desired terminal arrangement is realized by this intersection.

FIG. 2 shows a configuration of a hybrid circuit according to another embodiment of the present invention. This alternative embodiment uses a lumped constant inductor instead of the high impedance line in the above embodiment.

In FIG. 2, 53 is a lumped constant capacitor, 55 ₁ , 55 ₂ ,
55 _3, 55 ₄ are terminals for signal input and output, the 59 _{1-59 10} bridges connecting the grounding conductor, 61 _1, 61 _2, 61 ₃ is a lumped inductor. Here, the lumped inductor 61 _1, 61 ₂ and lumped inductor 61 _3, its shape, such as the length is different,
Its transmission characteristics are the same.

In Figure 2, the mutual lumped capacitor 53 and the lumped constant inductor 61 _1, 61 _2, 61 ₃ is interposed to form a path for signal transmission.

By the way, the first line, the second line, the third line in the present invention.
The line is a lumped inductor in this alternative embodiment.
61 _1, 61 _2, corresponding to 61 _3.

Even in this structure, the position of the terminal 55 ₁ and the terminal 55 ₂ is interchanged with each other, (distributing and combining the high-frequency signal) the operation is similar to the embodiment described conventional example and the aforementioned.

The hybrid circuit according to this embodiment, when applied to a balanced frequency conversion circuit shown in FIG. 5, the terminal 55 ₁ of the hybrid circuit of the terminal 32 ₁ of the microwave hybrid circuit 31 is a second view, the terminal 32 ₂ terminal 55 ₂ , terminal 32 ₃ is terminal 5
5 _3, terminals 32 ₄ corresponds to terminals 55 _4. As described above, even when the hybrid circuit according to the other embodiment is applied, the signal input / output terminals become the two adjacent terminals 55.
_1, 55 is _4, and the line of the local oscillator output signal is input, does not intersect the connecting line to the unit mixer 33 _2. Therefore, there is no problem of signal leakage or signal reflection as seen in a normal transmission line crossing, and this alternative embodiment also has an ideal terminal arrangement when applied to a frequency conversion circuit or the like. .

The hybrid circuit is formed on a substrate such as a semiconductor substrate in addition to the dielectric substrate. Further, it goes without saying that the present invention has various modifications in addition to the above-described embodiment.

〔The invention's effect〕

As described above, according to the present invention, terminals are crossed using the first electrode and the second electrode of the capacitor constituting the hybrid circuit, and a desired terminal arrangement is realized to eliminate the line crossing. There is no deterioration in circuit balance due to signal leakage, signal reflection and phase rotation based on the signal. Further, since the circuit layout can be simplified, the size of the circuit can be reduced.

[Brief description of the drawings]

1 is a configuration diagram of a hybrid circuit according to one embodiment of the present invention, FIG. 2 is a configuration diagram of a hybrid circuit according to another embodiment of the present invention, FIG. 3 is a configuration diagram of a conventional example, and FIG. FIG. 5 is a block diagram showing a configuration of a conventional frequency conversion circuit. In the figure, 11, 27, 37, 45, 55 are terminals, 13, 14 are transmission lines, 21 is a coplanar line, 23, 43, 53 are lumped capacitors, 25, 49, 59 are bridges, and 31 is a microwave hybrid. Circuit, 33 is a unit mixer, 35 is an input terminal, 39 is an intersection, 42 is an electrode, 44 is an insulating film, 47 is a through hole, and 61 is a lumped constant inductor.

Claims (1)

(57) [Claims] A first conductor connected to the first terminal, a first electrode connected to the first terminal, a first electrode connected to the first electrode, and connected to the second terminal. A second electrode, the first
A first capacitor formed of an insulating film interposed between an electrode and a second electrode; a second capacitor formed between a first conductor connected to the third terminal and the ground conductor; A third capacitor formed between a second conductor connected to a terminal and the ground conductor; a first line formed to connect between the first electrode and the first conductor; A second line formed to connect between a first conductor and the second conductor; and a third line formed to connect between the second electrode and the second conductor. At least a conductor system formed on the substrate and including the first terminal, the first electrode, and the first line, and a conductor system including the second terminal, the second electrode, and the third line are disposed at the position of the first capacitor. A hybrid configured to intersect via the insulating film. Circuit.