JPH0366842B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to widening the band of a semiconductor phase shifter that continuously changes the phase of microwaves.

[Conventional technology]

Figure 4 For example, Institute of Electronics and Communication Engineers technical research report MW80
102 is a diagram showing the configuration of the conventional double-balanced modulator shown in FIG. In the figure, 1
is a dielectric substrate, 2 is a strip conductor of a microstrip line, 3 is a ground conductor of a microstrip line, 4 is a branch line type 3dB hybrid coupler, 5 is a first input/output terminal, and 6 is a matching termination. Terminal 7 is a termination resistor connected to this matching termination terminal, and one end is connected to ground conductor 3. 8 and 9 are the first
The first coupling terminal, the second coupling terminal where the radio waves incident from the input/output terminal 5 of the
The connection terminals 10 and 11 are the first annular slot line and the second annular slot line formed by a gap provided in the ground conductor 3, and 12 and 13 are the three branches provided in the first and second annular slot lines. first and second branch slot lines with short-circuited ends connected to;
15, 16, 17 are first conductor surfaces 18 surrounded by first and second annular slot lines 10, 11;
This diode has one electrode connected to the second conductor surface 19, and diodes 14, 15 and 16, 17 form a pair, and each pair is connected with opposite polarity.

diodes 14, 15 and diode 16,
The other electrode 17 is connected to the ground conductor 3 so as to bridge the narrow ends of the first and second annular slot lines 10 and 11 and sandwich the first and second branch slot lines 12 and 13, respectively. Connected.

The bias applied to the diodes 14 and 15 is
the first conductor surface 18, the ground conductor 3, the diode 16,
The bias applied to 17 is applied via the second conductor surface 19 and the ground conductor 3, but is not shown in FIG. 20 is a Wilkinson type 3 dB power divider, 21 is a resistor, and 22 is a second input/output terminal. The strip conductors 2 of the first and second coupling terminals 8, 9 of the branch line type 3 dB hybrid coupler 4 are arranged perpendicularly to the first and second annular slot lines 10, 11, respectively. , the strip conductors 2 of the first and second distribution terminals 23 and 24, in which the radio waves incident on the 3dB power divider 20 from the second input/output terminal 22 appear in the same phase and with the same amplitude, are connected to the first and second branches, respectively. By arranging them orthogonally to the slot lines 12 and 13, smooth conversion between waves propagating through the microstrip lines and waves propagating through the slot lines can be achieved.

The conventional double-balanced modulator is constructed as described above, and becomes an analog type semiconductor phase shifter with a phase variable range of 360 degrees by applying a bias to the diode described below.

FIG. 5 is a diagram for explaining the operation of a balanced modulator out of the double balanced modulator, and shows the state seen from the ground conductor 3 side of FIG. 4.

When the bias voltage V applied to the bias terminal 26 of the bias circuit 25 consisting of a conductor wire is a positive voltage +Vo, the diode 14 is applied with a forward bias and has a low impedance, and the diode 15 is applied with a reverse bias and has a high impedance.
The wave incident from the branch slot line 12 propagates clockwise through the first annular slot line 10, is converted into a microstrip line, and appears at the first coupling terminal 8. On the other hand, bias voltage V is set to negative voltage −Vo
Then, the diodes are each in a bias state opposite to the above, and the wave incident from the first branch slot line 12 propagates counterclockwise through the first annular slot line 10 and is converted into a microstrip line.
The current is passed to the coupling terminal 8 of. As described above, depending on the polarity of the bias voltage applied to the bias terminal 26, the direction of propagation of the radio waves propagating through the annular slot line differs, and the two have opposite phases at the conversion section with the microstrip line. Therefore, the phase of the radio wave appearing at the first coupling terminal 8 is reversed by 180 degrees by changing the bias voltage from +Vo to -Vo.
FIG. 6 is a vector diagram showing an overview of the relationship between the bias voltage and the amplitude and phase of the radio waves appearing at the first coupling terminal 8. In this way, the balanced modulator can control the amplitude to any desired amplitude while keeping the phase of the output radio wave at 0° and 180° by continuously changing the bias voltage from +Vo to -Vo.

FIG. 7 is a diagram for explaining the operation of an analog phase shifter with a phase change range of 360° using a double-balanced modulator. The bias terminal of the first balanced modulator 26 is
5. Connect the bias terminal of the second balanced modulator 27 to 28
shall be.

Here the bias terminal 2 of the first balanced modulator 26
The voltage applied to 5 is determined by the time change of the amplitude of the output voltage of the balanced modulator shown in _FIG .
is driven so that the time is proportional to sinω ₁ t.
On the other hand, the bias terminal 28 of the second balanced modulator 27
For the voltage applied to
Drive in proportion to cosω ₁ t. When the voltage applied to the diode is driven with such a time change, the radio waves incident on the 3 dB power divider 20 from the second input/output terminal 22 are divided into two equal parts, and then the electric waves are sent to the first and second balanced modulators, respectively. 26 and 27, power is combined in a 3 dB hybrid coupler 4 with a phase difference of 90 degrees, and appears at the first input/output terminal 5. The radio wave appearing at the first input/output terminal 5 is represented by a solid line as a composite vector of the radio wave passing through the first balanced modulator 26 (dotted line vector) and the radio wave passing through the second balanced modulator 27 (dotted line vector). It can be expressed as shown in FIG.

That is, the first and second balanced modulators 26,
The composite vector of the outputs of 27 is a vector whose amplitude is constant according to the change in the amplitude of each output voltage, and whose phase changes continuously at an angular velocity of ω ₁ , and the phase change range is
This means that a 360° semiconductor phase shifter can be realized.

[Problem that the invention seeks to solve]

In the conventional semiconductor phase shifter as described above, the slot line is constructed using the ground conductor of the microstrip line.

Therefore, as a 3dB hybrid coupler, there are a branch line type 3dB hybrid coupler composed of microstrip lines, and an interdigital type 3dB hybrid coupler.
A 3dB hybrid coupler is used, but the former has a narrow usable band of about 10%, and
The latter is configured in a non-uniform medium, so the propagation constants of the even and odd modes of the coupled line are different, making it difficult to increase the usable bandwidth to more than one octave.The output of the balanced modulator is used to drive the bias voltage. Although it is possible to obtain the required output over a wide band by using a read-only memory (ROM) and a digital-to-analog converter (D/A converter), the bandwidth of a 3 dB hybrid coupler makes it possible to obtain this type of microwave semiconductor transfer. There was a problem that the usage band of the phase converter was limited.

Furthermore, this type of phase shifter that vectorially combines the outputs of the balanced modulators has a problem in that when the first balanced modulator is in a cut-off state, the frequency fluctuation of the combined voltage output increases. This is explained as follows. A balanced modulator in the blocked state is nearly completely reflective. Therefore, if the isolation of the 3dB hybrid coupler is S ₄₁ and the coupling is 1/√2, the maximum and minimum amplitude Vout of the radio wave appearing at the output terminal is Vout = (1/√2) ² | 1±S ₄₁ | is given by. If the isolation is 15dB, the output will vary between -4.6bB and -7.7dB.
This means that changing the frequency will increase the output level to its maximum level.
This indicates a 3.1 dB fluctuation, and in order to reduce the loss fluctuation of this phase shifter, a 3 dB hybrid coupler with large isolation must be used, which has the problem of narrowing the usable band. .

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain a semiconductor phase shifter that has a phase variable range of 360 degrees and has little loss fluctuation over a wide band of one octave or more.

[Means for solving problems]

The microwave semiconductor phase shifter according to the present invention has three
A 3dB hybrid coupler using a triple-plate strip line coupled line using a layered dielectric substrate.
A Wilkinson type 3 dB power divider is configured, a balanced modulator is configured using a bilateral fine line consisting of opposing slits and waveguides provided on both sides of the ground conductor of a triplate type strip line, and two balanced modulators are configured. Balanced modulators are connected in a balanced manner using two 3dB hybrid couplers, and two sets of balanced modulators connected in this balanced manner are used.

[Effect]

The microwave semiconductor phase shifter in this invention includes:
A coupled line type 3dB hybrid coupler composed of triplate strip lines has wideband performance, and since the conversion between the triplate stripline and bilateral fline is performed smoothly, wideband performance can be obtained. Furthermore, since two balanced modulators are connected in a balanced manner and used as a set of balanced modulators, loss fluctuations due to lack of isolation in the 3 dB hybrid coupler can be reduced.

〔Example〕

FIG. 1A is a perspective view showing the structure of an embodiment of the present invention, and FIG. 1B is a sectional view along line AA of FIG. 1A.

In FIG. 1, 29 is a dielectric upper layer substrate, 30
31 is a dielectric middle layer substrate, 32 is a dielectric lower layer substrate, and 32 is a dielectric lower layer substrate.
33 is the first ground conductor of the triplate strip line, and 33 is the second ground conductor of the triplate strip line.
, 34 is a first metal casing, 35 is a second metal casing that constitutes the waveguide 36 together with the first metal casing 34, 37 is the first and second ground conductor 32,
33 is the slit provided, 38 is the slit 37
This is a bilateral in-line composed of first and second metal casings 34 and 35.

FIG. 2 is a block diagram of an embodiment of the present invention. 39 is the first balanced modulator, 40 is the second
41 is a third balanced modulator, 42 is a fourth balanced modulator, 43 is a coupled line type 3 dB hybrid coupler, 44 is a Wilkinson type 3 dB power divider, and 45 is a resistor for matched termination. ,46,47
are input/output terminals.

Furthermore, a first set of balanced modulators 48 is configured by connecting the first balanced modulator 39 and the second balanced modulator 40 in a balanced manner with two coupled line type 3 dB hybrid couplers 43, and , third balanced modulator 4
1. The fourth balanced modulator 42 is two coupled line type
A second set of balanced modulators 49 is configured by connecting them in a balanced manner with a 3 dB hybrid coupler 43. FIG. 3 is an exploded view showing the configuration of the second set of balanced modulators 49 surrounded by dotted lines in FIG. 2.

At the connection part between the annular bilateral inline 38 and the straight bilateral inline 38, there are 4
Two diodes 50 are connected to bridge the slit 37. Two diodes 50 connected to the same ground conductor plane have opposite polarities, and two opposing diodes 50 between different ground conductor planes are connected with the same polarity. A bias voltage is applied to each diode 50 between the conductor surface surrounded by the annular bilateral inline 38 and the first and second housings 34, 35. For simplicity, illustration of the bias circuit is omitted here.

The third balanced modulator 41 and the fourth balanced modulator 42, which are composed of the bilateral fine line 38 and the diode 50, are converted into a triplate strip line 51 to form an input/output line, and two coupled lines. It is connected in a balanced manner to a 3 dB hybrid coupler 43 to form a second set of balanced modulators 49.
The configuration shown in FIG. 3 is the same for the first set of balanced modulators 48.

In the microwave semiconductor phase shifter configured as described above, the first and second balanced modulators 39 and 40 in the first set of balanced modulators 48 have a power distribution difference of the coupled line type 3 dB hybrid coupler 43. The first and second balanced modulators 39 and 40 both have sinω ₁ t (or
cosω ₁ t). Here, ω ₁ is the angular frequency and t is the time. Therefore, the output of the first set of balanced modulators 48 is sinω ₁ t (or
cosω ₁ t).

Similarly, the output of the second set of balanced modulators 49 is
Drive so that cosω ₁ t (or sinω ₁ t). At this time, the waves incident from the input/output terminal 46 are equally distributed with the same phase by the Wilkinson type 3 dB power divider 44, and pass through the first set of balanced modulators 48 and the second set of balanced modulators 49, and the phase difference is At 90 degrees, the power is combined vectorwise by a coupled line type 3dB hybrid coupler 43 for power combination, and the phase is variable with equal amplitude.
It becomes a 360° phase shifter.

Here, the output of the first set of balanced modulators 48 is assumed to be 1, and the output of the second set of balanced modulators 49 is assumed to be 0. Now, a case can be considered where sufficient isolation of the coupled line type 3 dB hybrid coupler 43 for power combining cannot be obtained. At this time, the radio waves leaking into the second set of balanced modulators 49 are transmitted to the third and fourth balanced modulators 49.
The signal is completely reflected by the balanced modulators 41 and 42, absorbed by the resistor 45 connected to the coupled line type 3 dB hybrid coupler 43, and does not appear at the input/output terminal 47.
In other words, loss fluctuations caused by insufficient isolation can be suppressed.

Furthermore, since the phase shifter of this configuration uses a coupled line type 3 dB hybrid coupler 43 with equal phase velocities in even mode and odd mode, broadband performance can be obtained. The conversion section 51 has wideband performance, and because it can be integrated into a three-layer single board, it has wideband performance.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to achieve a wide band by configuring a balanced modulator using a bilateral in-line and a coupled line type 3 dB hybrid coupler using a triplate strip line. By connecting the modulators in a balanced manner to form one set of balanced modulators, and configuring two sets of these modulators, it is possible to reduce fluctuations in loss with respect to frequency and fluctuations in loss when the phase is changed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a microwave semiconductor phase shifter according to an embodiment of the present invention, in which FIG. 1a is a perspective view, FIG. 1b is a cross-sectional view along AA of FIG. A configuration block diagram of an embodiment of the present invention, FIG. 3 is an exploded diagram showing the structure of a set of balanced modulators,
Fig. 4 is a perspective view showing the structure of a conventional microwave semiconductor phase shifter, Fig. 5 is a partial view showing only the balanced modulator in Fig. 4, Figs. 6, 7, and 8. 1 is an explanatory diagram of the operation of a conventional semiconductor phase shifter. In the figure, 29 is a dielectric upper layer substrate, 30 is a dielectric middle layer substrate, 31 is a dielectric lower layer substrate, 32 is a first ground conductor, 33 is a second ground conductor, 34 is a first metal casing, 35 36 is a waveguide, 37 is a slit, 38 is a bilateral in-line, 39 is a first balanced modulator, 40 is a second balanced modulator, and 41 is a third balanced modulator. 42 is a fourth balanced modulator, 43 is a coupled line type 3 dB hybrid coupler, 44 is a Wilkinson type 3 dB power divider, 45 is a resistor, 46 and 47 are input/output terminals,
48 is a first set of balanced modulators, 49 is a second set of balanced modulators, 50 is a diode, and 51 is a triplate strip line. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1 Connect the input terminal of a balanced modulator to each of the two output terminals of the Wilkinson type 3 dB power divider where the input power is equally distributed, and connect the output terminals of these balanced modulators to the mutually isolated terminals of the 3 dB hybrid coupler. The other terminal of the above 3dB hybrid coupler is configured as a matching termination and the remaining terminal as an output terminal, and a Wilkinson type 3dB power divider and a 3dB
The hybrid coupler is formed of a triplate stripline, and the balanced modulator is composed of a conversion section between the triplate stripline and the bilateral fline, a loop-shaped bilateral fline, and a diode loaded on the bilateral fline. The amplitudes of the output radio waves of the two balanced modulators are controlled by bias currents applied to the diodes in the balanced modulators so that they have the relationship of a sine function and a cosine function, respectively, and the output radio waves are spectrally synthesized. In a semiconductor phase shifter consisting of a semiconductor phase shifter, two identical balanced modulators configured with bilateral in-line are connected in a balanced manner using two 3dB hybrid couplers to form a set of balanced modulators, and this balanced modulation A microwave semiconductor phase shifter characterized by using two devices.