JP3329759B2 - Microwave phase shift circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave phase shift circuit used for a high frequency circuit of a radio communication device or the like.

[0002]

2. Description of the Related Art FIG. 8 is a diagram showing an equivalent circuit of a conventional microwave phase shift circuit, and shows a configuration of a load line type phase shifter. In the figure, numeral 1a denotes an input terminal, 1b denotes an output terminal, and 12a and 12b denote switches F.
ET and 13 represent a quarter wavelength line of the characteristic impedance Zc.

[0003] This conventional example is described in a document "Monolithic microwave integrated circuit by Aikawa, Ohira, Tokumitsu, Hirota, Muraguchi, IEICE first edition published in 1997, first edition pp. 182".
It is described in.

In this configuration, the switch FET 12a,
By switching ON / OFF of 12b, it is switched to two states to generate a phase shift difference. The matching condition and the phase shift amount of the circuit in this case will be described with reference to FIG. FIG. 9 (a)
9 is an equivalent circuit of a conventional microwave phase shift circuit.
(B) is an equivalent circuit of an admittance circuit connected to a quarter wavelength line of characteristic admittance Yc.

[0005] From these equivalent circuits, see "Paper by Matsunaga and Katagi; Series transformer type rodeline line phase shifter, IEICE Transactions, CI Vol. J77-C-IN."
0.10 pp. 542-550, issued in October, 1994, the input / output admittance is Yo.
When the characteristic admittance of the 波長 wavelength line is Yc and the susceptance of the parallel loading circuit to the main line is Bi, the matching condition is Yc = (Yo ² + Bi ² ) ^1/2 . Bi-state susceptance component by switching
It can be seen that the matching condition is satisfied when the following equation is satisfied. At this time, the passing phase is given as “Equation 1”, and the change in the phase shift amount due to the switching between the two states becomes “Equation 2”. Control becomes possible.

[0006]

(Equation 1)

[0007]

(Equation 2)

[0008]

In the conventional example as described above, since a plurality of transmission lines of about 1/4 wavelength are used, the shape becomes very large. In particular, when obtaining a multi-level phase shift amount, a cascade connection of a plurality of phase shifters is required, so that the effect becomes very remarkable. SUMMARY OF THE INVENTION An object of the present invention is to provide a phase shifter having a small circuit area that does not require a transmission line, which is a main factor for increasing the shape.

[0009]

SUMMARY OF THE INVENTION The main feature of the present invention is to construct a phase shifter having a small circuit area which does not require a transmission line, which is a main factor for increasing the shape. As means for realizing the phase shift circuit, the reactance values of the odd-numbered reactance circuits from 1 to 2n-1 are x, and the reactance values of the even-numbered reactance circuits from 2nd to 2n are -x And the first to second n reactance circuits are connected in series. One end of the first reactance circuit is connected to the input terminal, and one end of the 2n reactance circuit is connected to the output terminal.

A susceptance circuit having a susceptance value of 2 (1 / x ² -1) ^1/2 having one end grounded is connected to each of the first to 2n-1 connection points of the reactance circuit. I have.

The input terminal is connected to a reactance circuit having a reactance value of -x, one end of which is grounded, and a susceptance circuit having a susceptance value, one end of which is grounded. The output terminal is connected to a reactance circuit having a reactance value x having one end grounded and a susceptance circuit having a susceptance value (1 / x ² -1) ^1/2 having one end grounded.

This is a microwave phase shift circuit that obtains a change in the passing phase by inverting the signs of all the susceptance circuits, and its equivalent circuit is as shown in FIG. The microwave phase shift circuit shown in the figure is analyzed using a K matrix.

A susceptance circuit connected in parallel and having a susceptance value b whose one end is grounded is represented as "Equation 3" in the K matrix, and is represented by Kb.

[0014]

(Equation 3)

A reactance circuit having a reactance value x connected in series can be expressed by "Equation 4", which is represented by Kx +.

[0016]

(Equation 4)

A reactance circuit having a reactance value x, one end of which is grounded and connected in parallel, can be expressed as "Equation 5", which is represented by Km +.

[0018]

(Equation 5)

The K matrix of the n + 1 microwave phase shift circuit (in this case, the number of stages in the reactance circuit is 2, so the number of stages is 2) K _{M = 2} , b = (1 / x ² -1) ^{1 If it is set to / 2} , it can be represented by “Equation 6”.

[0020]

(Equation 6)

[0021]

(Equation 7)

At this time, “Equation 7” is equivalent to the K matrix of the transmission line θ, and the microwave phase shift circuit can be treated as a transmission line of the passing phase shift θ. At this time, by inverting the signs of all the susceptance circuits, a phase change of "Equation 8" is obtained.

[0023]

(Equation 8)

That is, it operates as a 1-bit variable phase shifter. Also, the reactance values of the odd-numbered reactance circuits from the first to the 2n + 1 are x, and the reactance values of the even-numbered reactance circuits from the second to the 2n are -x. A reactance circuit is connected in series.

One end of the first reactance circuit is connected to an input terminal, and one end of the n-th reactance circuit is connected to an output terminal. A susceptance circuit having a susceptance value of 2 (1 / x ² -1) ^1/2 having one end grounded is connected to each of the first to second n connection points of the reactance circuit.

Connected to the input / output terminals are a reactance circuit having a reactance value of -x, one end of which is grounded, and a susceptance circuit having a susceptance value of (1 / x ² -1) ^1/2 , which is grounded at one end. I have. This is a microwave phase shift circuit characterized in that a change in the passing phase is obtained by inverting the signs of all the susceptance circuits. FIG. 1 shows an equivalent circuit diagram. The microwave phase shift circuit shown in FIG. 2 is analyzed using a K matrix.

K matrix K of microwave phase shifter for n = 1
_M−3 can be represented by “Equation 9”, where b = (1 / x ² −1) ^1/2 .

[0028]

(Equation 9)

[0029]

(Equation 10)

[0030]

[Equation 11]

At this time, “Equation 10” represents the K of the transmission line θ.
This is equivalent to a matrix, and the microwave phase shift circuit can be treated as a transmission line with a passing phase shift θ. At this time, by inverting the signs of all the susceptance circuits, a phase change of "Equation 11" is obtained. That is, it operates as a 1-bit variable phase shifter. When the number of stages is an even number, the K matrix is expressed as
2 ".

[0032]

(Equation 12)

Further, the K matrix at the odd stage is represented by "Expression 13", and the phase shift of "Expression 14" is changed by changing the state of the sign of the susceptance circuit. Operate.

[0034]

(Equation 13)

[0035]

[Equation 14]

As means for realizing the susceptance circuit, a susceptance element and a variable capacitance element are connected in parallel, and by changing the value of the variable capacitance element, susceptance values having different signs can be obtained.

Here, the susceptance value (1 / x ² -1)
A susceptance value of a susceptance element constituting a susceptance circuit having ^1/2 , 2 (1 / x ² -1) ^1/2 and a variable capacitance ratio are represented by N (Cmax-NCmin),
5 ”, and the minimum value of the variable capacitance is“ Equation 16 ”(the angular frequency is ω
In this case, by changing the value of the variable capacitance element from the minimum value to the maximum value, the condition of no reflection and no loss can be satisfied, and the phase shift change of “Expression 14” can be realized.

[0038]

(Equation 15)

[0039]

(Equation 16)

As means for realizing the susceptance circuit, a susceptance element and a variable capacitance element are connected in series, and by changing the value of the variable capacitance element, susceptance values having different signs can be obtained.

Here, the susceptance value (1 / x ² -1)
The reactance value of the susceptance element constituting the susceptance circuit having ^1/2 , 2 (1 / x ² -1) ^1/2 is expressed by the following equation (1), where the variable capacitance ratio is N (Cmax = NCmin).
7 ", and when the minimum value of the variable capacitance is" Expression 18 "(assuming that the angular frequency is ω), the condition of the non-reflection and no loss is obtained by changing the state of the variable capacitance element from the minimum to the maximum. Is satisfied, and the phase shift change of “Equation 14” can be realized.

[0042]

[Equation 17]

[0043]

(Equation 18)

As means for realizing the susceptance circuit, the input terminals of a one-input / two-output changeover switch are connected, and the susceptance values of the two outputs of the changeover switch are respectively ± (1 / x ² -1) ^{1 / 2} , ± 2 (1 / x ² -1)
Connect the susceptance circuit grounded ^1/2 of one end, by changing the state of said changeover switching switch, satisfies the nonreflective, lossless conditions, can be realized phase change in the "number 14".

[0045]

FIG. 1 is a diagram showing an equivalent circuit of a microwave phase shift circuit according to a first embodiment of the present invention, and corresponds to the first aspect of the present invention. In the figure, first to second n reactance circuits 2 and 3 are connected in series.

The reactance values of the odd-numbered reactance circuits 2 from the first to the (2n-1) -th are x,
The reactance values of the even-numbered reactance circuits 3 from (1) to (2n) are -x. (In the figure, the reactance circuit is indicated by “X” and the susceptance circuit is indicated by “B” in order to avoid complicated display. The same applies to FIG. 2 described below.)

One end of the first reactance circuit is connected to the input terminal 1a, and one end of the 2n reactance circuit 3 is connected to the output terminal 1b. A susceptance circuit 4 having a susceptance value of 2 (1 / x ² -1) ^1/2 having one end grounded is connected to each of the first to 2n-1 connection points of the reactance circuit.

The input terminal is connected to a reactance circuit having a reactance value of -x, one end of which is grounded, and a susceptance circuit 5 having a susceptance value of (1 / x ² -1) ^1/2 , which is grounded at one end. I have.

The output terminal is connected to a reactance circuit having a reactance value X having one end grounded and a susceptance circuit 5 having a susceptance value (1 / x ² -1) ^1/2 having one end grounded. By inverting the sign of all susceptance circuits, the microwave phase shift circuit obtains a passing phase change.

In the microwave phase shift circuit, the signal input from the input terminal 1a is applied to the output terminal 1b by inverting the signs of all the susceptance circuits.
= 2n, it is possible to realize the phase shift change of "Equation 14".

FIG. 2 is a diagram showing an equivalent circuit of a microwave phase shift circuit according to a second embodiment of the present invention, and corresponds to the second aspect of the present invention. In the figure, first to second (n + 1) th reactance circuits are connected in series. The reactance values of the odd-numbered reactance circuits 2 from the first to the (2n + 1) th are x.

The reactance values of the even-numbered reactance circuits 3 from the second to the 2nth are -x. One end of the first reactance circuit 2 is connected to the input terminal, and one end of the 2n + 1 reactance circuit 2 is connected to the output terminal.
A susceptance value 2 having one end grounded at each of the first to second n connection points of the reactance circuit.
(1 / x ² -1) ^1/2 susceptance circuit 4 is connected.

The input / output terminal is connected to a reactance circuit 3 having one end grounded and having a reactance value of -x, and a susceptance circuit 5 having one end grounded and having a susceptance value of (1 / x ² -1) ^1/2. ing. By inverting the sign of all susceptance circuits, the microwave phase shift circuit obtains a passing phase change.

In the microwave phase shift circuit, the signal input from the input terminal 1a is applied to the output terminal 1b by inverting the sign of all the susceptance circuits.
= 2n + 1, it is possible to realize the phase shift change shown in the above “Equation 14”.

FIG. 3 is a diagram showing a first example of a susceptance circuit of a microwave phase shift circuit according to the present invention, and corresponds to the third aspect of the present invention. Here, the susceptance value (1 / x
^{2 -1) 1/2, 2 (1} / x 2 -1) susceptance values of the susceptance elements 6 constituting the susceptance circuit having ^1/2, the variable capacitance ratio as N (Cmax-NCmin) "number 15" , And the minimum value of the variable capacity is expressed by the above “Equation 16”
When the angular frequency is ω, the value of the variable capacitance element 7 is changed from the minimum to the maximum to satisfy the condition of no reflection and no loss, and realizable.

FIG. 4 is a diagram showing a second example of the susceptance circuit of the microwave phase shift circuit according to the present invention, and corresponds to claim 4 of the present invention. Susceptance value (1 / x ² -1)
The reactance value of the susceptance element 6 constituting the susceptance circuit having ^1/2 , 2 (1 / x ² -1) ^1/2 is:
When the variable capacitance ratio is N (Cmax-NCmin), and when the minimum value of the variable capacitance is "Expression 18" (the angular frequency is ω), the value of the variable capacitance element 7 is changed from the minimum value to the maximum value. By changing the state, the condition of no reflection and no loss can be satisfied, and the phase shift change of "Equation 14" can be realized.

FIG. 5 is a diagram showing a third example of the susceptance circuit of the microwave phase shift circuit according to the present invention, and corresponds to the fifth aspect of the present invention. The susceptance circuit 5 connects the input terminals of a one-input / two-output changeover switch 8 and connects two outputs of the changeover switch 8 to susceptance elements having one end grounded and having different susceptance values. By changing the state of the changeover switch 8, a desired phase shift amount is set.

According to the susceptance circuit, in the microwave phase shift circuit according to the first aspect, the signal input from the input terminal 1a is such that the two outputs of the changeover switch 8 have a susceptance value of ± (1 / x ² -1) ^1/2 , ± 2 (1
/ X ² -1) When ^1/2 is selected, the condition of the non-reflection and no loss is satisfied by changing the state of the changeover switch 6 and the phase shift change of "Equation 14" can be realized.

FIG. 6 is a diagram showing a fourth example of the susceptance circuit of the microwave phase shift circuit according to the present invention, and corresponds to the third and fourth aspects of the present invention. In the microwave phase shift circuit, the variable capacitance element 7 is a gate voltage controlled FET 9,
3. The microwave phase shift circuit according to claim 1, comprising a capacitance between the gate 9a and the drain 9b and a capacitance between the gate 9a and the source 9c.

FIG. 7 is a diagram showing a fifth example of the susceptance circuit of the microwave phase shift circuit according to the present invention, and corresponds to the third and fourth aspects of the present invention. In this example, in the microwave phase shift circuit according to claim 1 or 2, the variable capacitance element 8 of the susceptance circuit is constituted by the variable capacitance diode 10.

[0061]

The microwave phase shift circuit according to the present invention does not require a transmission line which causes an increase in the circuit area, so that the circuit area can be greatly reduced. In particular, when the phase shifters are cascaded to control the multi-level phase shift amount, the effect on the circuit area reduction is enormous.

When a gate-source capacitance and a gate-drain capacitance of a gate voltage-controlled FET are used as the variable capacitance element, there is no potential difference between the source and the drain.
Since no current flows through the FET, control can be performed with zero power consumption.

[Brief description of the drawings]

FIG. 1 is a diagram showing an equivalent circuit of a microwave phase shift circuit according to a first example of an embodiment of the present invention.

FIG. 2 is a diagram illustrating an equivalent circuit of a microwave phase shift circuit according to a second example of the embodiment of the present invention;

FIG. 3 is a diagram illustrating a first example of a susceptance circuit.

FIG. 4 is a diagram illustrating a second example of the susceptance circuit.

FIG. 5 is a diagram illustrating a third example of the susceptance circuit.

FIG. 6 is a diagram illustrating a fourth example of the susceptance circuit.

FIG. 7 is a diagram illustrating a fifth example of the susceptance circuit.

FIG. 8 is a diagram showing an equivalent circuit of a conventional microwave phase shift circuit.

FIG. 9 is a diagram illustrating a matching condition and a phase shift amount according to a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1, 1a input terminal 1b output terminal 2 reactance circuit 3 reactance circuit 4 susceptance circuit 5 susceptance circuit 6 susceptance element 7 variable capacitance element 8 changeover switch 9 FET 9a gate terminal, 9b source terminal, 9c drain terminal 10 variable capacitance diode 11 control terminal

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-48-14248 (JP, A) JP-A-50-24038 (JP, U) JP-B-44-17922 (JP, B1) 508060 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01P 1/185

Claims (7)

(57) [Claims] 1. A microwave phase shift circuit which satisfies the following conditions (1) to (7) and obtains a change in a passing phase by inverting the signs of all susceptance circuits. (1) First to second n reactance circuits are connected in series. (2) The reactance values of the odd-numbered reactance circuits from the first to the (2n-1) th are x. (3) The reactance values of the even-numbered reactance circuits from the second to the 2n are -x. (4) One end of the first reactance circuit is connected to the input terminal, and one end of the 2n reactance circuit is connected to the output terminal. (5) From the first connection point of the reactance circuit to the second n−
One connection point is connected to a susceptance circuit having a susceptance value of 2 (1 / x ² -1) ^1/2 with one end grounded. (6) The input terminal is connected to a reactance circuit having a reactance value of -x, one end of which is grounded, and a susceptance circuit having a susceptance value of (1 / x ² -1) ^1/2 , which is grounded at one end. (7) The output terminal is connected to a reactance circuit having a reactance value x having one end grounded and a susceptance circuit having a susceptance value (1 / x ² -1) ^1/2 having one end grounded. 2. A microwave phase shift circuit which satisfies the following conditions (1) to (7) and obtains a change in a passing phase by inverting the signs of all susceptance circuits. (1) First to second (n + 1) th reactance circuits are connected in series. (2) The reactance values of the odd-numbered reactance circuits from the first to the (2n + 1) th are X. (3) The reactance values of the even-numbered reactance circuits from the second to the 2n are −x. (4) One end of the first reactance circuit is connected to the input terminal, and one end of the 2n + 1 reactance circuit is connected to the output terminal. (5) A susceptance circuit having a susceptance value of 2 (1 / x ² -1) ^1/2 whose one end is grounded is connected to each of the first to second connection points of the reactance circuit. (6) Connected to the input / output terminals are a reactance circuit having a reactance value of -x grounded at one end and a susceptance circuit having a susceptance value of (1 / x ² -1) ^1/2 grounded at one end. . 3. The microwave phase shift circuit according to claim 1, wherein the susceptance circuit comprises a susceptance element and a variable capacitance element connected in parallel. 4. The microwave phase shift circuit according to claim 1, wherein the susceptance circuit comprises a susceptance element and a variable capacitance element connected in series. 5. One end is provided at each end of the reactance circuit.
The input terminal of a two-input changeover switch, and a susceptance element having one end grounded and having a different susceptance value is connected to each of two outputs of the changeover switch. Microwave phase shift circuit. 6. The variable capacitance element is a gate voltage controlled FE.
The microwave phase shift circuit according to claim 3, wherein the microwave phase shift circuit includes a gate-drain capacitance and a gate-source capacitance of T. 6. 7. The microwave phase shift circuit according to claim 3, wherein the variable capacitance element comprises a variable capacitance diode.