JPH03119803A - Microwave plane circuit adjusting method - Google Patents

Abstract

PURPOSE:To enable line length or stub length to be adjusted successively with simple work by providing plural recessed parts with depth sufficiently less than 1/4 the wavelength lambdamu of the upper limit frequency of a signal to be transmitted at part of a microstrip line at an interval sufficiently less than lambdamu/4 so as not to deform characteristic impedance. CONSTITUTION:A strip line 1 nonreflectively terminated with a resistor 14 whose tip is provided with a resistance value R=Zo is coupled with a dielectric resonator 13 in spatial fashion, and is connected to the gate G of a FET at a part where it is separated by distance D. By forming the strip line between the dielectric 13 and the gate G in a rugged line 8, and adjusting the electrical length of D by filling the recessed part with a bonding wire 9, an oscillation condition can be satisfied at the optimum state. In such a way, the line length and the stub length can be adjusted successively with simple work.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for adjusting a microwave planar circuit using a strip line.

[Summary of the Invention] In a part of the stub or line that requires 5I adjustment, four parts with a depth sufficiently shorter than 1/4 of the wavelength λu of the upper limit frequency of the signal to be transmitted are placed at a depth sufficiently shorter than λu/4. A concave-convex line is formed by providing a plurality of lines at short intervals so that the characteristic impedance does not change, and the electrical length of the line or stub is adjusted by wire bonding or attaching a conductive ribbon to this line.

[Prior art] In microwave circuits, the line length and stub length of strip lines must be adjusted due to variations in the mounting positions of components such as FETs, diodes, and dielectric resonators, and variations in semiconductor characteristics. The need may arise.

FIG. 15 shows an example of a conventional stub length adjustment method, in which 1 is a strip line, 2 is an open stub, 3 is a land for stub length adjustment, and 4 is a bonding wire. The adjustment land 3 is connected to the stub 2 by bonding wire 4, conductor ribbon, solder filling, etc., as necessary, and the stub length is adjusted.

FIG. 17 shows an example of a conventional line length adjustment method, in which parts of the strip lines on the input side and the output side are arranged parallel to each other with an interval 7 between them, and a gold ribbon 6 or a chip is placed at an appropriate position on this parallel part. The line length between the input and output shown in the figure is adjusted by soldering capacitors and connecting them with bonding wires.

[Problems to be Solved by the Invention] However, the stub length obtained by the method shown in FIG. 15 is discrete, making it impossible to finely adjust the stub length required for SHF band circuits. Furthermore, in the case of a stub whose tip end is short-circuited by a through hole 5 as shown in FIG. 16, the stub length could not be adjusted using this method.

In the method shown in Fig. 17, the remaining portion after the gold ribbon is connected, that is, the strip line above the dotted line in the figure, will act as a stub unless it is separated, so it is cut along the dotted line by laser trimming or the like. Since there is only a very short distance between the cut portion and the strip line 1 due to the cut, spatial coupling is likely to occur between the two. Therefore, depending on the shape of the cut portion, it may function as a band rejection filter that blocks transmission of the used band frequency, deteriorating the transmission characteristics.

[Object of the Invention] The present invention has been made to eliminate these drawbacks, and an object of the present invention is to enable continuous adjustment of the line length and stub length by simple operations, and to adjust the line length and stub length by inserting adjustment points. An object of the present invention is to provide a method for adjusting a microwave circuit with little deterioration in transmission characteristics.

[Means for Solving the Problems] In order to achieve the above object, the microwave adjustment method according to the present invention provides a microwave adjustment method in which a part of the microstrip line has a wavelength λu higher than 1/4 of the upper limit frequency of the signal to be transmitted. A plurality of recesses with a sufficiently short depth are provided at intervals sufficiently shorter than λu/4 so that the characteristic impedance does not change, and the conductors on both sides of the recesses are connected with a bonding wire of an appropriate length, or The gist of this method is to adjust the electrical length of the line by thermocompressing or soldering a conductor ribbon of an appropriate size into the recess.

[Operation] By simple operations such as cowire bonding and attaching conductor ribbons, the line length and stub length of microwave planar circuits can be continuously adjusted, and there is almost no deterioration in transmission characteristics due to insertion of adjustment points.

[Example] The present invention will be explained in more detail using examples below with reference to one drawing, but these are merely illustrative, and various modifications and improvements can be made without going beyond the scope of the present invention. Of course it is possible.

First, a transmission line in which a plurality of concave and convex portions are formed on a strip line as shown in FIG. 1 will be explained in detail. A concavo-convex line 8 is formed by providing a plurality of concave portions having a depth ρ and a width d at intervals of d2 in a part of a strip line having a characteristic impedance Z0 and a line width W. For the sake of simplicity, if we do not take into account the effect of coupling between adjacent convex lines of length Q, this uneven line becomes a strip line with a line width W-Ω and a characteristic impedance Z1 as shown in Fig. 2. It can be considered that open stubs of length α are connected periodically.

Characteristic impedance 20.2. Let the inductance L per unit length of the strip line be respectively. .

Ll, capacitance per unit length C, respectively
Assuming C1, generally the narrower the width of the center conductor, the larger L will be and the smaller C will be, so Lo<Ll ・
...(1) C0>C1...(2) It becomes. Since characteristic impedance 2=2, it becomes 1
From formulas (1) and (2), 2. <2. - The relationship (5) holds true. The signal with frequency f is Z. λ respectively for the wavelength λ when propagating through the line of I Zl. and, then λ=
1. / (f v'T"'), but the formula (
]), From the relationship in (2), approximately ■. Co: L, C
, so λ. 2 λ,
...The relationship in (8) holds true. For example, dielectric>
$9.9, JisaQ, 635[nml] Regarding the strip line formed on the alumina substrate, W” 0,
64 [mm].

If Q = 0.35 [mm], z0 = 50 [Ω, z
, =70[Ω], 12G)iz = λ, =9.6[:ny
n-ko.

λ1=9.9 [Since this is a hired company, it can be seen that the relationships in equations (5) and (8) hold true.

Let λu be the wavelength of the upper limit frequency of a signal to be transmitted.

In Fig. 2, if Q is sufficiently smaller than λu/4π, the open stub can be replaced with a lumped constant capacitor with a capacitance C2 as shown in Fig. 3;
This will be explained using figures.

For an open stub with characteristic impedance Z2 and stub length Q, the reflection coefficient F when looking to the right from the dotted line in FIG. 4 is defined as r2. Here, the value of 1 reflection coefficient 1' differs depending on what characteristic impedance is determined as a reference, so in the following explanation, it will be referred to as characteristic impedance Z. Let's express ■゛ when referenced as I'' (Z(1).If the wave number of the signal is β2 and the impedance seen from the dotted line is Z, then the reflection coefficient F2 when Z2 is used as the reference
is Z+72, so from this Z becomes Z valve... (14) Here, if we try to find the wavelength of the signal, we get 2β, Q=
4πQ/λ2 (11), so Q
In the range where is sufficiently smaller than λ2/47c,

becomes. Substituting this into equation (10), 4πQ 1+1-j λ2 λ.

2...(13) 2πQ λ2. On the other hand, the impedance Z of the capacitance C2 as shown in Fig. 5 is Z=...(]5)jω2
C2, so if we set C2=ρ/v, Z2, we get Equation (14)
and 2 in equation (15) match. Therefore, Q is λu/4
In a range sufficiently smaller than π, the circuit in Fig. 2 becomes the third
It was shown that it is possible to replace the circuit with the one shown in the figure.

Here, d=d1+d2. If we set C' = C, /d, then
If d is sufficiently larger than λυ, the circuit shown in Fig. 3 has a transmission line of characteristic impedance Z1 with C' per unit length.
It is considered that a capacitance of C' changes depending on the values of Q, d, d2, but by appropriately determining these values, Z=70 can be achieved. At this time, since the characteristic impedance of the concave-convex line portion in FIG. 1 is equal to the characteristic impedance of the strip lines on both sides, electromagnetic waves can be propagated without reflection at the connection between the two. The wavelength λ of the signal propagating on this uneven line is as follows. Comparing Equation (7) and Equation (18), λ×λ,
Therefore, considering the relationship in equation (8), λ×λ. ...(19), that is, the wavelength λ on the uneven line shown in FIG. 1 is the wavelength λ on the strip lines on both sides. will be shorter than Therefore, this uneven line and the characteristic impedance Z of the same length
0. L=L,.

When comparing a strip line with C=C, the characteristic impedance of both is equal, and the electrical length of the uneven line is longer than that of the strip line.

Here, the circuit shown in FIG. 3 has a characteristic impedance zf
The fact that it can be considered as a transmission line of l=Li C□+c' will be explained in detail using FIGS. 6 and 7. About this.

The characteristics of the circuit shown between dotted lines PP' and RR' in FIG. 6 are the length d and characteristic impedance Z shown between dotted lines SS' and TT' in FIG. , L=L1゜C=C-work+
It suffices to show that the characteristics of C' are the same as those of the transmission line.

As shown in Figure 6, if the reflection coefficients viewed from the dotted lines PP' and QQ'RR' to the right are r, and the I'Ol impedances are z, z', and z, respectively, then the reference characteristic impedance is 21 when r
o is z''+z Substituting formula (2o) into formula (21), formula (4) is obtained.

If we rearrange using (17).

... (22) becomes. The reflection coefficient F' when looking to the right from the dotted line QQ' is Z
Let β1 be the wave number of the signal propagating through the line l.

r" (z,) = r'. (Zt)exp (-j2β
,Q) ・(2,3)β1=2π/λ1
...(24), where 2
When β1d(1, that is, d (λ1/4π
...within the range of (25).

4πd exp (-j2β, d) half 1-j λ1 = 1-j2ωdv'π7 ears...(26) However, ω=2 π f Therefore, substituting equations (22) and (26) into equation (23), we get , r'(Z,)4 (1j2c, +dfrRs)
A=((at −−f’+(s) +(V at 10fσ−Rs) I”, (Z,)B=(
v' is 1 + fυ' + (-) + (,/'', -a) I', (Z,) ・ (2
7) The impedance Z□ on the right side from the dotted line QQ' is given by the above formula, E = (1-ro (Z,)) ff + jωdv'r",
(Zo))F= (t+r, (Z,))! G -jωdv'U core I × ((fG-fe7G) + (7G at J”fr +V)
Fo(Zo)) ... (29) 6 Therefore, PP
Impedance 2 when looking to the right from ' is Z Z' HG= (1
−r, (ZQ) ) C, C'+C, )+jωdc
, 4-
))+j i, ic' d (1+r", (zo)
) V/T-Has+cu'd2L□C,C' X ((1-s/T:F:'7?:'; )÷(1+f
i) r O(zo )>H= (1+r”O(Zll
) ) 4-1jωdL, Ako×((Vhyaku-fbishiT)+(v'be+(shioki)F,(Z
, )) (30) However, considering equation 1 (25), ω of the fourth term in the numerator of the above equation
Since 2d"L, C, = β, 'd2 well O, the fourth term can be set as 20. Therefore, formula (30)% formula% () 10 Buddhas) r'o
(Za) ) K=1+P, (Zo) −jωd40
``v'?'7 becomes x)r, (zo))... (31).

On the other hand, in FIG. 7, if the reflection coefficient when looking to the right from the dotted line Ss' is ``, the impedance is Z, the reflection coefficient when looking from the dotted line TT' to the right is Fo, the wave number of the signal is β, and the wavelength is λ, then 1 ' (Za) = r”a (Za) ・e x p (
−j2βd) −(32)d(In the range of λ/4π, it becomes 2βdc1, so expc−j2βd)41−
j2βd = 1,) 2 ωd x Ct + C co...
(33) holds true.

However, in addition to this, equations (17), (32), (33
) becomes the % expression %() )) () ()) Comparing equation (31) and (3S), we find that C' is 6
It can be seen that both equations match within a range sufficiently smaller than 1. Therefore, the characteristics of the circuits shown in FIG. 6 and FIG. 7 are the same, and the circuit of FIG. 3 has impedance Z, L=LL, C=
It has been shown that it is possible to replace the transmission line with a C+C' transmission line.

The present invention takes advantage of the properties of such an uneven line, creates the above uneven line on a part of the stub or line that requires adjustment in advance, and attaches wire bonding or conductor ribbon to this uneven part, thereby improving the line. This paper proposes a microwave planar circuit adjustment method that continuously changes the electrical length of the microwave.

FIG. 8 shows an embodiment of the line length adjustment method according to the present invention, in which conductors on both sides of a part of the concave part of the concave and convex line 8 of FIG. It is filled with bonding wire. 10 shows a state in which the recess is completely filled with the bonding wire. In this case, the part 10 becomes a strip line with a line width W, so the electrical length between the input and output in Figure 8 is the same as that between the input and output in Figure 1. shorter than the electrical length. 11 shows a state in which a part of the recess is filled with a bonding wire. It is thought that the characteristic impedance of this part deviates from Z, but in reality, the deviation is small and the reflection that is thought to occur due to this is sufficiently small, so it does not pose a practical problem.11
The more the part of the concave part filled with bonding wire, the shorter the electrical length becomes, so by adjusting the amount of solder in this part, continuous and fine line length adjustment can be made.

FIG. 9 shows an embodiment of the method for adjusting the stub length of a short-circuit stub according to the present invention, in which a part of the short-circuit stub 2 shown in FIG. I do. in this way,
By using this method, it becomes possible to continuously adjust the stub length of the short-circuit stub, which has been difficult in the past.

FIG. 10 shows an example in which the stub length adjustment method of an open stub according to the present invention is combined with the conventional stub length adjustment method using the adjustment land 3. Rough adjustment of the stub length is performed by connecting the adjustment land 3 to the stub 2 using a bonding wire 9 or the like, and fine adjustment is performed by attaching a bonding wire 9 to the uneven line 8. By doing so, the stub length can be adjusted over a wide range and continuously.

In the above explanation, the uneven line was constructed by providing a plurality of recesses on one side of the strip line, but as shown in Fig. 11, recesses of appropriate depth and width are formed on both sides of the strip line. It is clear from the above-mentioned principle that by providing them at intervals, it is possible to construct a concavo-convex line whose characteristic impedance is equal to zo and which can be used in the present invention.

Furthermore, in order to more smoothly convert between the strip line and the uneven line, a recess 12 having a depth shorter than Q may be provided at the connection between the two, as shown in FIG.

FIG. 13 shows an embodiment of a method for adjusting a bandpass filter according to the present invention. By forming part of the strip line constituting the band-pass filter into a concave-convex line 8 and filling the concave portion with a bonding wire 9, the frequency of the pass band can be adjusted.

FIG. 14 shows an embodiment in which the electrical length between the dielectric 13 and the gate G of the FET is adjusted using the line length adjustment method of the present invention in a dielectric resonant circuit used in a dielectric oscillator or the like. The tip has resistance value R=Z.

The strip line 1, which is non-reflectively terminated with a resistor 14, is spatially coupled to the dielectric resonator 13 at the position indicated by the dotted line in the figure, and connected to the gate G of the FET at a distance from there. . The characteristics of the dielectric oscillator are influenced by the value of D, so if D deviates from the optimum value due to positional variations in the mounting of the dielectric 13,
It is necessary to adjust the electrical length during this time. As shown in FIG. 14, the strip line between the dielectric 13 and the gate G is made into an uneven line 8, and the concave portion is filled with a bonding wire 9 to adjust the electrical length of D, thereby optimizing the conditions for one oscillation. Therefore, a dielectric oscillator with good characteristics can be created.

18, 19, 20, 21, and 22 are modified examples of the embodiments shown in FIGS. 8, 9, 10, 13, and 14, respectively. , a conductor ribbon 9' is used in place of the bonding wire 9, and its attachment method is thermocompression bonding or soldering.

The effects of each of the above modifications are the same as those of the corresponding embodiments.

Note that the range in which the approximate equations (12), (26), and (33) hold true is when Q and d are sufficiently shorter than λu/4π, but in the range where the approximate equations above hold insufficiently. Even if there is such a structure, characteristics similar to those of the above-mentioned uneven line may be obtained, and it can also be used in the adjustment method of the present invention.

However, even in this case, it is necessary that Q and d are sufficiently shorter than λu/4π.

[Effects of the Invention] As explained above, according to the present invention, it is possible to adjust the line length and stub length continuously by simple operations, and to adjust the microwave circuit with less deterioration of transmission characteristics due to insertion of adjustment points. How can you get it?

[Brief explanation of drawings]

FIG. 1 is a diagram showing a concave-convex line used in the present invention, and FIG. 2 is a diagram for explaining the concave-convex line of FIG. 1. 3 is a diagram showing a circuit equivalent to that in FIG. 2, FIGS. 4 and 5 are diagrams for explaining that the circuits in FIGS. 2 and 3 are equivalent, and FIGS. The figure shows that the characteristics of the circuit shown in FIG. 3 are L=L1. Figure 8 for explaining that C = C + C' is equal to a transmission line with characteristic impedance Z0.
The figure shows an embodiment of the line length adjustment method according to the present invention.
FIG. 9 is a diagram showing an embodiment of the stub length adjustment method for a short-circuit stub according to the present invention, FIG. 10 is a diagram showing a stub length adjustment method for an open stub according to the present invention, and FIGS.
Figure 1 shows another example of the uneven line used in the present invention.
3 is a diagram showing an example of a method for adjusting a bandpass filter according to the present invention, and FIGS. 1-4 are diagrams showing an example of a method for adjusting variations in the dielectric fixing position of a dielectric generator according to the present invention, Figures 1-5 are diagrams showing a conventional method for adjusting the stub length of an open stub, Figure 16 is a diagram showing a conventional short-circuit stub, Figure 17 is a diagram showing a conventional method for adjusting the line length, and Figures 18- FIG. 22 is a diagram showing a modification corresponding to each embodiment of the present invention.6], ...... Microstrip line, 2.
...Stub, 3...Stub adjustment land, 4...Bonding wire, 5.
......Through hole, 6...Gold ribbon, 7...Strip line nJf spacing, 8...Concave and convex line, 9・・・・・・Bonding wire, 9゛・・・・・・Conductor ribbon,
1-0......A part where the entire recess is filled with half a liter], 11......A part where a part of the recess is filled with solder, 12...・・・・・・Concavity whose depth is shorter than Q, ]3 ・・・・・・Dielectric, 14...
...Resistor. 15...FET.

Claims (2)

[Claims] (1) A plurality of recesses with a depth sufficiently shorter than 1/4 of the wavelength λu of the upper limit frequency of the signal to be transmitted are formed in a part of the microstrip line so that the characteristic impedance does not change. A method for adjusting a microwave plane circuit, characterized in that the electrical length of the line is adjusted by providing the conductors at sufficiently short intervals and connecting the conductors on both sides of the recessed portion with a bonding wire of an appropriate length. (2) A plurality of recesses with a depth sufficiently shorter than 1/4 of the wavelength λu of the upper limit frequency of the signal to be transmitted are formed in a part of the microstrip line so that the characteristic impedance does not change. Provide them at sufficiently short intervals, and heat-bond or solder a conductor ribbon of an appropriate size to the recess.
A method for adjusting a microwave plane circuit, comprising adjusting the electrical length of the line.