JP2000221233A - Tuner for measuring load pull or source pull - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tuner for measuring a load pull or a source pull improved in a range of measuring a load with respect to harmonics with variable load to the harmonics remaining fixed at its load to a fundamental wave. SOLUTION: The tuner for measuring a load pull or a source pull is formed by disposing a bar-like central conductor 26 parallel to a substantially center of an inside of a grooved ground conductor 27, and disposing a plurality of metal pieces 27b movably to a perpendicular direction and a parallel direction to the conductor 26 over an opening of the conductor 27 with a load variable to a fundamental and harmonics by regulating positions of the pieces 27b. Since the pieces 27b are arbitrarily combined to be able to be independently controlled and a measurement can be conducted by scaling at a desired position, the load of the harmonics to the load of the fundamental wave can be arbitrarily set, and can be measured under the conditions of a wire range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load-pull or source-pull measurement tuner used for load-pull measurement and source-pull measurement as a method for evaluating characteristics of a high-frequency transistor.

[0002]

2. Description of the Related Art In recent years, measurement or design techniques for microwave semiconductor devices and devices and microwave circuits have been remarkably advanced in the field of microwave technology, and circuit design has been carried out by evaluating the characteristics of microwave semiconductor devices and devices. In order to make effective use of such characteristics, techniques for accurately measuring these characteristics are becoming increasingly important.

Conventionally, a tuner is connected to an input / output terminal of a high-output device as a microwave semiconductor element, for example, a high-frequency transistor for microwaves, for example, to change the load of the tuner. In order to investigate electrical characteristics such as load dependency and input power dependency of output, efficiency and distortion characteristics of the high-frequency transistor, load pull measurement or source pull measurement is performed. FIG. 3 shows a schematic configuration diagram of such a measurement system for load pull measurement.

In FIG. 3, 1 is an input signal source, 2 is an amplifier, 3 is a power meter for measuring input signal power,
4 is a coupler for connecting the power meter 3 to a signal system, 5 is an isolator for preventing reflection and leakage of a signal to the input signal source 1 side, 6 is a bias tee for supplying power to the device under test, 7 is Is a source-pull measurement tuner connected between the signal system and the input terminal of the device under test 8. The input-side impedance (Z _Source , hereinafter referred to as Z _S ) viewed from the device under test 8 is used as a measurement specification. A predetermined value is set accordingly, for example, optimization is performed to obtain high gain and low distortion.

[0005] Reference numeral 8 denotes a device under test (DUT: Device Und).
er Test), for example, GaAs MESFET (Me
tal Semiconductor FET). Reference numeral 9 denotes a load-pull measurement tuner connected between the output terminal of the device under test 8 and the signal system on the output side, whereby the impedance on the output side viewed from the output terminal of the device under test 8 (Z _Load , hereinafter Z _L a) that is varied according to the specifications of the measurement, to determine and load conditions where the maximum output is obtained load condition or the maximum efficiency and low distortion of the high-frequency transistor is a device to be measured 8 is obtained belongs to.

10 is a bias tee for supplying power to the device under test, 11 is a power meter for measuring the output signal power, 12 is a coupler for connecting the power meter 11 to a signal system, and 13 is the frequency of the signal power. It is a spectrum analyzer for analyzing components.

Reference numeral 14 designates a source pull measurement tuner 7 and a load pull measurement tuner 9 at various positions (impedance) based on data obtained by calibrating an RF component used in a measurement system including a tuner body by a network analyzer in advance. Control means, such as a personal computer, for performing the above control.

FIG. 4A shows an external perspective view and FIG. 4B shows a sectional view of a conventional example of the load-pull measuring tuner 9 used in the above-described measuring system.

The tuner 9 for load pull measurement shown in FIG.
In the figure, 15 is an elongated cylindrical outer conductor having a U-shaped cross section, and 16 is coaxially arranged at the center of the outer conductor 15 in parallel with the outer conductor 15 and has the same length as the outer conductor 15 It is a rod-shaped center conductor. 3A shows a state as viewed from the output terminal side of the device under measurement 8 in FIG. 3, in which the external conductor 15 is connected to the ground system of the measurement system and the center conductor 16 is connected.
Is connected to the signal line of the measurement system, in this case, the signal line from the output terminal of the device under test 8. Thus, the center conductor 16 functions as a distributed constant line regarded as a transmission line having a characteristic impedance Z ₀ = 50Ω.

Reference numeral 17 denotes a movable metal piece, which is electrically connected to the external conductor 15 and is movable in the direction indicated by the arrow in FIG. FIG. 3A shows a state in which the movable metal piece 17 is arranged on the device under measurement 8 side of the center conductor 16. With the movable metal piece 17 arranged in this way, a predetermined capacitance component determined by the facing area and the facing interval at the position facing the center conductor 16 is obtained, and the capacitance component and the center conductor
The impedance Z _L on the output side of the device under test 8 can be changed to a desired condition according to the specification of the measurement by the transmission line length obtained by the remaining part of the device 16.

FIG. 5A is an equivalent circuit of such a load-pull measurement tuner 9, and FIG. 5B is a Smith chart showing changes in the load condition of Z _{L at} a certain frequency by the load-pull measurement tuner 9. FIG.
FIG. 5C is an example of the load of Z _L shown on the Smith chart similar to FIG. 5B.

In FIG. 5A, reference numeral 18 denotes a transmission line corresponding to the center conductor 16 of the tuner 9 for load pull measurement, and the characteristic impedance Z ₀ of the transmission line 18 is usually set to 50Ω. Reference numeral 19 denotes a capacitance component obtained by the movable metal piece 17, and reference numeral 20 denotes a transmission line length obtained by the transmission line 18 up to a portion where the capacitance component 19 is connected.

In the load pull measurement tuner 9,
By changing the distance d between the movable metal piece 17 having the area S facing the center conductor 16 and the center conductor 16, the capacitance component 19 connected to the transmission line 18 is proportional to the area S facing the area and inversely proportional to the distance d. Can be variable, so that
Capacitance component at a predetermined location with respect to transmission line 18
Performing a scaling of 19, the measurable VSWR (Volt
age Standing Wave Ratio). Also, as shown by the opposing arrow below the capacitance component 19, the movable metal piece
By changing the position of 17, the capacitor component 19 of the transmission line 18
The transmission line length 20 up to the portion where is connected can be changed, and a phase change can be created by changing the transmission line length 20.

Reference numeral 21 denotes an input impedance of a measurement system connected to the output side of the load-pull measurement tuner 9, which is also usually 50Ω.

In FIG. 5B, reference numeral 22 denotes a parallel susceptance j by a capacitance component 19 at a certain frequency f.
B (= 2πfC), and 23 is a phase change due to the transmission line length 20. Thus, the capacitance component 19 and C ₁ for example at a frequency f, the transmission line length 20
Is λ / 8 (λ: wavelength), Z _L is a load having the magnitude and phase shown in FIG. 5C.

For example, a capacitance component 19 at a frequency f ₀ of a certain fundamental wave is represented by C1, and a transmission line length 20 is represented by C1.
Assuming that 0.07λ (λ: wavelength), the load Z _{Lf0 at} the frequency f ₀ of the fundamental wave and the load Z _{L at} the frequency 2f ₀ of the second harmonic
_L2f0 is the load shown in FIGS. _{6A and 6B} , respectively.

[0017]

However, in the conventional load-pull or source-pull measuring tuner as described above, the load for harmonics such as the frequency of the second harmonic is higher than the load for the frequency of a certain fundamental wave. Fixed. Therefore, in order to achieve even lower distortion and higher efficiency, it is necessary to optimize the load of harmonics, but the load on harmonics cannot be changed while the load on fundamental waves is fixed. However, there is a problem that the load of the harmonic cannot be optimized.

The present invention has been made in view of the above-mentioned problems of the prior art, and has an object to improve the load measurement range for harmonics by changing the load for harmonics while keeping the load for fundamental waves fixed. An object of the present invention is to provide a tuner for measuring load pull or source pull.

[0019]

A load-pull or source-pull measuring tuner of the present invention is a load-pull or source-pull measuring tuner which is connected to the input side or output side of a high-frequency transistor and evaluates the electrical characteristics of the high-frequency transistor. A rod-shaped center conductor is disposed in parallel at a substantially central portion inside the groove-shaped ground conductor, and a plurality of metal pieces are arranged in a direction perpendicular to the center conductor over the opening of the ground conductor. In addition, the load on the fundamental wave and the harmonics is made variable by adjusting the position of the metal piece.

That is, the configuration of the load-pull or source-pull measuring tuner of the present invention is a load-pull or source-pull measuring tuner connected to the input side or the output side of the high-frequency transistor for evaluating the electrical characteristics of the high-frequency transistor. , Consisting of a rod-shaped center conductor and a ground conductor arranged substantially coaxially around the center conductor,
A part of the ground conductor along the axial direction is constituted by a plurality of metal pieces movable in a direction perpendicular and parallel to the center conductor.

According to the load-pull or source-pull measuring tuner of the present invention, a rod-shaped center conductor for transmitting a high-frequency electric signal and the center conductor are arranged in parallel at a substantially central portion on the inner side so as to be substantially coaxial. And a plurality of metal pieces movably arranged in the vertical and parallel directions with respect to the rod-shaped center conductor over the opening of the groove-shaped ground conductor. A part of the ground conductor along the axial direction is constituted by a plurality of metal pieces that are movable in the vertical direction and the axial direction with respect to the center conductor, and the plurality of metal pieces are perpendicular to the center conductor. And / or moving in a parallel direction to form a variable capacitance between the center conductor and the plurality of metal pieces forming a part of the ground conductor, so that the plurality of metal pieces can be arbitrarily combined. And Can be controlled vertically, and can be measured by performing scaling at a desired position, so that, for example, two sets of metal pieces separated from each other among a plurality of metal pieces are brought close to the center conductor, Even if the load on the fundamental wave is fixed, the load on the second harmonic can be made variable by a large number of combinations of the two metal pieces. As a result, the load on the harmonics changes while the load on the fundamental wave is fixed. It is possible to do.

Further, according to the tuner for measuring a load pull or a source pull of the present invention, compared with the case where the distance between the center conductor and the movable metal piece must be set to the widest position as in the conventional tuner, the grounding is performed. The distance between the metal piece and the center conductor can be set narrower at any position while preventing the contact between the metal piece and the center conductor of the conductor.As a result, the capacitance can be varied even if the center conductor is bent or inclined. It is possible to provide a load-pull or source-pull measurement tuner that can increase the measurement range by widening the range, can perform measurement under a wide range of conditions, and has excellent measurement reproducibility.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a tuner for measuring a load pull or a source pull according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following examples, and various changes and improvements can be made without departing from the scope of the present invention.

FIG. 1 is an external perspective view showing an example of an embodiment of a load pull or source pull measuring tuner of the present invention.

In the load-pull or source-pull measuring tuner 25 shown in FIG. 1, reference numeral 26 denotes a rod-shaped center conductor, and reference numeral 27 denotes a substantially cylindrical ground conductor disposed substantially coaxially around the center conductor 26. That is, the center conductors 26 are arranged substantially parallel to the center inside the ground conductor 27 so as to be parallel to each other. The ground conductor 27 has, for example, an elongated groove-shaped outer conductor 27a having a U-shaped cross section, and a central portion disposed so as to straddle the opening in a part along the axial direction corresponding to the opening of the main body 27a. It is composed of a plurality of metal pieces 27b movable in the vertical and parallel directions with respect to the conductor 26.
The outer conductor 27a is arranged in parallel with the center conductor 26, and the length of the outer conductor 27a and the length of the metal piece 27b movable in the axial direction are set to be substantially equal to the length of the center conductor 26. I have. The outer conductor 27a of the ground conductor 27 may have a U-shaped or circular cross section.

FIG. 1 shows a state as viewed from the output terminal side of the device under test 8 in FIG. 3 as in FIG. 4 (a). The external conductor 27a is connected to the ground system of the measurement system,
26 is a signal system of a measurement system, in this case, connected to a signal line from an output terminal of the device under test 8. As a result, the center conductor 26 functions as a distributed constant line regarded as a transmission line having a characteristic impedance Z ₀ = 50Ω.

The plurality of metal pieces 27b arranged across the opening so as to form a part of the ground conductor 27 in the axial direction are electrically connected to the external conductor 27a, and each metal piece 27b is electrically connected to the external conductor 27a.
The center conductor 26 is arranged so as to be movable in the direction indicated by the arrow in FIG. I have. In the figure, three metal pieces
27B shows a state in which 27b are arranged at substantially the same interval with respect to the center conductor 26.

The plurality of metal pieces 27b arranged as described above
According to the above, these can be arbitrarily combined and independently controlled, and scaling can be performed at a desired position with respect to the center conductor 26, whereby the metal piece 27 b arbitrarily combined with the center conductor 26 A predetermined capacitance component determined by the opposing area and the opposing interval is obtained at a position opposing the device, and the capacitance component and the transmission line obtained by the remaining portion of the center conductor 26 allow the output side of the device under test 8 to be obtained. The impedance Z _L can be changed to a desired condition according to the specification of the measurement.

According to the load-pull or source-pull measuring tuner 25 of the present invention, a plurality of metal pieces 27b can be set at desired positions and intervals in the opening of the groove-shaped main body 27a, and they can be arbitrarily set. Can be independently arranged in combination with each other, the facing area S can be changed according to the area of the combination of the plurality of metal pieces 27b, and it is possible to set various load conditions. Thereby, the measurable VSWR can be increased, and the measurement range can be widened.

As described above, according to the load-pull or source-pull measuring tuner 25 of the present invention, the scaling of the variable capacitance value C can be performed independently for each of the plurality of metal pieces 27b. There is also an advantage that the influence of the parallelism and the parallelism is reduced, so that it is not necessary to manufacture the center conductor 26 with high accuracy.

If the surface of the metal piece 27b facing the center conductor 26 is set to have the same curvature as that of the center conductor 26, the facing area between them can be effectively secured, and the spacing between them can be made substantially uniform. This is preferable because a stable capacitance component can be obtained close to the state. Also,
The thickness of each metal piece 27b may be set in accordance with a desired transmission line change amount (phase rotation change amount) in accordance with the measurement specifications.

The equivalent circuit of the load-pull or source-pull measuring tuner 25 of the present invention is the same as that shown in FIG. 5A, and the load-pull measuring tuner 9 is replaced by the load-pull or source-pull measuring tuner 25 in FIG. , 18 to a transmission line corresponding to the center conductor 26 of the load-pull or source-pull measurement tuner 25, 19 to a capacitance component obtained by a plurality of metal pieces 27b, 20 to
Is the transmission line length obtained by the transmission line 18 up to the portion where the capacitance component 19 is connected. In the load pull or source pull measurement tuner 25 of the present invention, the characteristic impedance Z _{0 of the} transmission line 18 is also used.
Is usually set to 50Ω.

Also, according to the tuner 25 for measuring the load pull or the source pull of the present invention, the change of the parallel susceptance jB (= 2πfC) is the same as that shown in FIG. 5B, for example, a plurality of metal pieces 27b. Assuming that the capacitance component 19 at a certain frequency f obtained by the above is C ₁ and the transmission line length 20 is λ / 8 (λ: wavelength), Z _L
Is a load as shown in FIG.

In the conventional load-pull or source-pull measurement tuner, when the load (Z _Lf0 ) for the fundamental wave is set to a certain value at the time of measurement, the capacitance component and the transmission line each become one due to the center conductor and the movable metal piece.
Each stage has a single-stage configuration, and the number of combinations is one, so that the load on harmonics such as the second harmonic is fixed. On the other hand, according to the load-pull or source-pull measuring tuner 25 of the present invention, by bringing a plurality of metal pieces 27b apart from each other out of the plurality of metal pieces 27b close to the center conductor 26, a capacitance component and a transmission line are reduced. Can be formed in a two-stage configuration of at least two each, and the number of combinations can be infinitely large depending on how to take the intermediate load (Z _{mf 0} ) of the fundamental wave. (Z _L2f0 ) can be changed. In addition, by using a larger number of metal pieces 27b, a configuration of three or more stages can be used, and the load of a higher harmonic than the third harmonic can be changed.

That is, the load-pull or source-pull measuring tuner 25 of the present invention also enables a plurality of metal pieces 27 to be measured.
The equivalent circuit when one or a set of the b is brought close to the center conductor 26 is the same as that shown in FIG. 5A as described above. Or to the tuner 25 for source pull measurement,
18 is a transmission line corresponding to the center conductor 26 of the tuner 25 for load pull or source pull measurement, and 19 is a plurality of metal pieces 27.
In the capacitance component obtained by a part of the metal pieces 27c in b, 20 is the transmission line length obtained by the transmission line 18 up to the portion where the capacitance component 19 is connected. It should be noted that the characteristic impedance Z ₀ of the transmission line 18 is usually set to 50Ω also in the load-pull or source-pull measurement tuner 25 of the present invention.

For example, a capacitance component 19 at a frequency f ₀ of a certain fundamental wave is represented by C1, and a transmission line length 20
Is 0.07λ (λ: wavelength), the load Z _{Lf0 at} the frequency f ₀ of the fundamental wave and the load Z at the frequency 2f ₀ of the second harmonic
_L2f0 is the load shown in FIGS. _{6A and 6B} , respectively.

On the other hand, by equipping two or two sets of separated metal pieces 27b as a plurality of metal pieces 27b close to the center conductor, the equivalent of the load-pull or source-pull measuring tuner 25 of the present invention in that case is obtained. Figure 2
As shown in the figure, 18 is a transmission line corresponding to the central conductor 26, 19a is a capacitance component obtained by a part of the metal pieces 27b of the plurality of metal pieces 27b, and 19b is a
Is obtained by the transmission line 18 between the portion where the capacitance component 19a is connected and the portion where the capacitance component 19b is connected, and 20a is obtained from the capacitance component obtained by the other part of the metal piece 27b separated from it. The transmission line length and 20b are the transmission line length obtained by the transmission line 18 up to the portion where the capacitance component 19b is connected. It should be noted that the characteristic impedance Z ₀ of the transmission line 18 is usually set to 50Ω also in the load-pull or source-pull measurement tuner 25 of the present invention.

Then, for example, the capacitance component 19a obtained by adjusting the load Z _Lf0 at the frequency f ₀ of a certain fundamental wave to be the same as the above is C1, and the capacitance component 19b is
Is C2, the transmission line length 20a is L1, and the transmission line length 20a is L2.
_Then , the load Z _{Lf0 at} the frequency f ₀ of the fundamental wave, 2
The load Z _{L2f0 at the} harmonic frequency 2f ₀ is shown in FIG.
The loads shown in (c) and (d) are obtained.

As described above, according to the tuner 25 for measuring load pull or source pull of the present invention, in the measuring method, the load on the fundamental wave and the harmonics of the second harmonic or more are obtained by the combination of the plurality of movable metal pieces and the plurality of transmission lines. The load on the wave can be configured, and as a result, the load on the harmonic can be changed even when the load on the fundamental wave is fixed.

[0040]

As described above, according to the load-pull or source-pull measuring tuner of the present invention, the rod-shaped center conductor for transmitting the high-frequency electric signal and the center conductor are substantially coaxial with the inner substantially central portion. And a plurality of metals movably arranged in a direction perpendicular to and parallel to the rod-shaped center conductor over the opening of the groove-like ground conductor. A variable capacitance between the center conductor and the plurality of metal pieces forming a part of the ground conductor by moving the plurality of metal pieces in a direction perpendicular and / or parallel to the center conductor. Is formed, the plurality of metal pieces can be arbitrarily combined and independently controlled, and can be scaled and measured at a desired position. 1 And a plurality of movable metal pieces and a plurality of transmission metal lines are compared with a single-stage configuration in which the load for the fundamental wave and the load for the harmonics are fixed to a set of values. A load for the fundamental wave and a load for the harmonic wave can be configured by two or more stages of the combination of the transmission lines, and as a result, even if the load for the fundamental wave is fixed, the load for the harmonic wave can be changed. Become.

Further, according to the tuner for measuring load pull or source pull of the present invention, compared with the case where the distance between the center conductor and the movable metal piece must be adjusted to the widest position as in the conventional tuner, the grounding is performed. The distance between the multiple metal pieces and the center conductor can be set narrower while preventing contact between the metal pieces of the conductor and the center conductor.As a result, the capacitance can be varied even when the center conductor is bent or inclined. It is possible to provide a load-pull or source-pull measurement tuner capable of widening the measurement range and measuring under a wide range of conditions.

Further, a wide range of measurements can be performed without producing a high-precision center conductor.

As described above, according to the present invention, it is possible to provide a load-pull or source-pull measurement tuner in which the load on the harmonics is made variable while the load on the fundamental wave is fixed and the range of the load measurement on the harmonics is improved. .

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an example of an embodiment of a load pull or source pull measurement tuner of the present invention.

FIG. 2 is an equivalent circuit diagram for an example of arrangement of a plurality of metal pieces of the tuner for measuring load pull or source pull according to the present invention.

FIG. 3 is a schematic configuration diagram of a measurement system for load pull or source pull measurement.

FIG. 4A is an external perspective view of a conventional load-pull measurement tuner, and FIG. 4B is a cross-sectional view thereof.

5 (a) is an equivalent circuit diagram of a load-pull or source-pull measurement tuner, FIG. 5 (b) is a diagram showing a change in the load condition of Z _{L at} a certain frequency by the load-pull or source-pull measurement tuner on a Smith chart, and FIG. () Is an example of the load of Z _L shown on the Smith chart similar to (b).

FIGS. 6A and 6B are diagrams showing a load Z _Lf0 at a certain fundamental frequency f ₀ by a conventional load pull or source pull measurement tuner on a Smith chart and a diagram at a second harmonic frequency 2f _{0, respectively} . Load Z
FIG. 4 is a diagram showing _L2f0 displayed on a Smith chart. (C) and (d) are figures and 2 by load-pull or Sosupuru measurement tuner of the present invention, respectively, displaying the load Z _Lf0 at a fundamental frequency f ₀ in the Smith chart
The load Z _L2f0 at the frequency 2f ₀ of the frequency doubled diagrams displayed on the Smith chart.

[Explanation of symbols]

25 Tuner for load-pull or source-pull measurement 26 Center conductor 27a Ground conductor 27a External conductor 27b Metal piece

Claims (1)

[Claims] A load-pull or source-pull measuring tuner connected to an input side or an output side of a high-frequency transistor for evaluating an electrical characteristic of the high-frequency transistor, wherein the tuner is provided at a substantially central part inside a groove-shaped ground conductor. A bar-shaped central conductor is arranged in parallel, and a plurality of metal pieces are movably arranged in a direction perpendicular and parallel to the center conductor over the opening of the grounding conductor. A load-pull or source-pull measurement tuner characterized in that a load on a fundamental wave and a harmonic wave is made variable by adjusting the position of the tuner.