JP2001099888A - Tuner for measuring load pull or source pull - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a prior art tuner that an efficient measurement can not be expected through a triplexer when the VSWR thereof is low or a loss is present. SOLUTION: The tuner for measuring load pull or source pull comprises a tuner body section 13 comprising a rod-like central conductor 13a and a tubular ground conductor 13b including a large number of metal pieces 13c a part of which are movable perpendicularly to the central conductor 13a, and a impedance converting section 12 comprising a rod-like conductor 12a, an outer conductor 12b movable vertically and a metal piece 12c movable in the vertical and horizontal directions wherein the VSWR of an arbitrary phase can be increased with respect to the impedance viewed from a high frequency transistor 8 side toward the tuner body 13 side. Since the VSWR of an arbitrary phase can be increased without requiring a large number of phase regulation lines corresponding to the high frequency transistor 8, an efficient measurement can be expected easily.

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. Accordingly, load-pull measurement or source-pull measurement for examining electrical characteristics such as load dependence and input power dependence of output, efficiency, and distortion characteristics of the high-frequency transistor is performed.

In microwave semiconductor elements and devices, not only fundamental frequency but also higher harmonics such as twice (second harmonic) and triple (third harmonic) the fundamental frequency are used. It is known that the electrical characteristics are improved by taking into account the load. In load-pull measurement or source-pull measurement, measurements are also made in consideration of higher-order harmonics.

FIG. 3 shows a schematic configuration diagram of a conventional load-pull measurement system considering such third harmonics.

In FIG. 3, 21 is an input signal source, 22 is an amplifier for amplifying the signal of the input signal source 21, 23 is a power meter for measuring the power of the input signal, and 24 is a power meter 23 connected to a signal system. 25 is an isolator for preventing signal reflection / leakage to the input signal source 21 side, 26
Is a bias tee for supplying power to the device under test 28, 27 is a tuner for source pull measurement connected between the signal system and the input terminal of the device under test 28, The impedance is set to a desired value in accordance with the specification of the measurement, for example, optimization is performed so as to obtain high gain and low distortion.

Reference numeral 28 denotes a device under test (Device Under Test).
, Hereinafter referred to as DUT), for example, GsAsFE.
It is a high-frequency transistor such as T. Numeral 32 is a load-pull measurement tuner for the fundamental frequency connected between the output terminal of the DUT 28 and the signal system via the triplexer 29, and numerals 30 and 31 are for the load-pull measurement for the second and third harmonics, respectively. Tuner. These load-pull measurement tuners 30 to 32 change the impedance of the output side when viewing the output side from the output terminal of the DUT 28 according to the specification of the measurement, and set it to a desired value, for example, high efficiency and low distortion. And optimize. This allows
The load conditions for obtaining the maximum output of the high-frequency transistor as the DUT 28 and the load conditions for obtaining the maximum efficiency and low distortion are obtained.

The tuner 27 having the same configuration as the tuner 27 for measuring the source pull and the tuners 30 to 32 for measuring the load pull is basically used. This tuner has, for example, an elongated cylindrical outer conductor having a U-shaped cross section, a rod-shaped center conductor having a length equal to the length of the outer conductor, disposed in parallel with the center thereof, and electrically connected to the outer conductor. And a movable metal piece set at a predetermined position at a predetermined interval. The outer conductor and the movable metal piece are connected to the ground system of the measurement system, the center conductor is connected to the signal system of the measurement system, and the center conductor has a characteristic impedance.
A predetermined capacitance component that functions as a distributed constant line regarded as a 50Ω transmission line and is determined by the facing area and facing distance of the portion where the center conductor and the movable metal piece face each other, and the transmission line obtained by the remaining portion of the center conductor By changing the length, desired measurement conditions are obtained.

Reference numeral 33 denotes a bias tee for supplying power to the DUT 28; 34, a power meter for measuring the power of the output signal; 35, a coupler for connecting the power meter 34 to a signal system; This is a spectrum analyzer for analyzing frequency components.

The source-pull measurement tuner 27 and the load-pull measurement tuners 30 to 32 are provided with various types of RF components used in a measurement system including a tuner body based on data calibrated by a network analyzer in advance. For example, a personal computer (not shown) is connected as a control device for controlling the position (impedance).

However, in the measurement system having the above configuration, the VSWR (Voltage Stand-Alone) of the triplexer 29 is used.
In the case where the ing wave ratio (voltage standing wave ratio) is bad or the triplexer 29 has a loss, the VSWR measurable by this measurement system is a load-pull measurement tuner 30 to 32.
May be smaller than VSWR. Therefore, for example, FETs used in power amplifiers for mobile phones
However, there is a problem that a sufficient VSWR may not be obtained when the DUT 28 having a low impedance is measured.

In order to solve such a problem, FIG.
The desired VS can be obtained by using a measurement system having the configuration shown in FIG.
Getting the WR was going on. In FIG. 4, FIG.
The same parts as in are denoted by the same reference numerals. Reference numeral 38 denotes an impedance converter. When a low-impedance DUT 28 such as an FET used in a power amplifier for a mobile phone is to be measured, the characteristic impedance of the transmission line due to the center conductor of the load-pull measurement tuner 32 with respect to the fundamental frequency is 50Ω. In this case, the impedance is set to be lower than 50Ω, such as 30Ω or 20Ω. Reference numeral 37 denotes a phase adjustment line, for example, an air line. The length of the line 37 rotates the load phase to a desired position. The characteristic impedance of this line 37 is 50Ω which is the same as the characteristic impedance of the transmission line of the tuner 32.

By connecting the impedance converter 38 and the phase adjusting line 37 between the DUT 28 and the tuner 32 as described above, the absolute value of the reflection coefficient is increased (the VSWR is increased) by the impedance converter. Since the phase of the DUT 28 is adjusted to a phase at which the performance of the DUT 28 can be extracted by the phase adjustment line, a sufficient VSWR can be obtained, and appropriate measurement can be performed for the DUT 28 having a low impedance.

[0014]

However, the VSWR of the triplexer 29 in the conventional measurement system as shown in FIG.
When the measurement cannot be performed due to poor quality or loss, a measurement system is configured using an impedance converter 38 and a line 37 for phase adjustment as a measurement system as shown in FIG. In that case, DUT28 or its DUT
Since the required amount of phase adjustment (the amount of phase rotation) is different if the target system of 28 is different, there is a problem that a line 37 for phase adjustment must be prepared for the necessary amount.

Therefore, not only is the measuring system itself expensive as the number of lines 37 required is increased, but also it takes time to adjust the phase by the lines 37, which requires a troublesome operation. Was.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a conventional method for each phase rotation amount required according to the specification of a high-frequency transistor as a device to be measured. A load pull that can easily perform phase adjustment without preparing a large number of phase adjustment lines, and can perform appropriate measurements on low-impedance high-frequency transistors even when the VSWR of the triplexer is bad or the triplexer has loss. Another object is to provide a tuner for measuring a source pull.

[0017]

A tuner for measuring a load pull or a source pull according to the present invention is connected to an input side or an output side of a high frequency transistor, and a load pull or a source pull measuring tuner for evaluating an electrical characteristic of the high frequency transistor. And comprises a rod-shaped center conductor and a cylindrical grounding conductor arranged around the center conductor,
A tuner body composed of a large number of metal pieces whose part along the axial direction of the ground conductor is movable in a direction perpendicular to the center conductor, a rod-shaped conductor, and a rod-shaped conductor around the rod-shaped conductor A groove-shaped external conductor movably disposed in a direction perpendicular to the conductor, and a metal piece movably disposed in a direction perpendicular and parallel to the rod-shaped conductor over the opening of the external conductor. And one end of the rod-shaped conductor is connected to the center conductor at an end face thereof, and the external conductor is provided with an impedance conversion unit electrically connected to the ground conductor. .

According to the load-pull or source-pull measuring tuner of the present invention, the tuner main body is composed of the central conductor for transmitting the high-frequency electric signal and the cylindrical ground conductor disposed around the central conductor, and the axial direction of the ground conductor Is composed of a large number of metal pieces movable in the vertical direction with respect to the center conductor. By moving in the direction, a variable capacitance can be formed at a desired position, and scaling can be performed for measurement. Therefore, even when the center conductor is bent or inclined, the variable range of the capacitance can be widened and the measurement range can be widened, enabling measurement under a wide range of conditions and excellent reproducibility of measurement. It becomes a tuner for measuring load pull or source pull.

Further, according to the load pull or source pull measuring tuner of the present invention, in addition to the tuner main body, a rod-shaped conductor whose end faces are connected to a center conductor of the tuner main body, and a bar-shaped conductor arranged around the rod-shaped conductor are provided. A groove-shaped external conductor movably disposed in a direction perpendicular to the rod-shaped conductor, and movably disposed in a direction perpendicular and parallel to the rod-shaped conductor over the opening of the external conductor. Since the external conductor includes an impedance converter electrically connected to the ground conductor, the ground conductor disposed around the rod-shaped conductor is perpendicular to the rod-shaped conductor. Since it is movable in any direction, it has a characteristic impedance different from that of the center conductor of the tuner body, and thus functions as an impedance conversion unit that can increase the VSWR. In addition, the phase of the impedance can be arbitrarily adjusted by changing the capacitance component determined by the opposing area and opposing interval of the portion where the rod-shaped conductor and the movable metal piece oppose, and the transmission line length obtained by the remaining rod-shaped portion Since the VSWR also has a function that can be performed, the VSWR can be increased at a desired phase. Therefore, the VSW of the triplexer used in the measurement system
Even if R is bad or lossy, there is no need to prepare many separate lines for phase adjustment depending on the DUT and the system to be targeted by the DUT as in the conventional measurement system.
The complicated phase adjustment using the phase adjustment line is not required, and the measurement system itself can be configured at low cost.

[0020]

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.

FIG. 1 is a schematic configuration diagram showing an example of a measurement system using the load pull or source pull measurement tuner of the present invention and taking into account the third harmonic.

In FIG. 1, 1 is an input signal source, 2 is an amplifier for amplifying the signal from the input signal source 1, 3 is a power meter for measuring the power of the input signal, and 4 is a power meter for the power system. Coupler for connection, 5 is input signal source 1
6 is a bias tee for supplying power to the DUT 8, and 7 is a source pull measurement tuner connected between the signal system and the input terminal of the DUT 8. Yes, the impedance on the input side viewed from the DUT 8 is set to a desired value in accordance with the specification of the measurement, for example, optimization is performed to obtain high gain and low distortion.

Reference numeral 8 denotes a GaAs FET as a DUT, for example.
And 9 is a triplexer.

Then, 14 is a DU through the triplexer 9.
It is a load pull measurement tuner of the present invention relating to a fundamental frequency, which is connected between an output terminal of T8 and a signal system.
The load-pull measurement tuner 14 of the present invention includes a tuner body 13 and an impedance converter 12. Reference numerals 10 and 11 denote load-pull measurement tuners for the second harmonic and the third harmonic, respectively.
The impedance on the output side when the output side is viewed from the output terminal of the UT 8 is optimized according to the specification of the measurement, and is set to a desired value, for example, a value that provides high efficiency and low distortion.

Reference numeral 15 denotes a bias tee for supplying power to the DUT 8, 16 denotes a power meter for measuring the power of an output signal, 17 denotes a coupler for connecting the power meter 16 to a signal system, and 18 denotes an output signal. This is a spectrum analyzer for analyzing frequency components.

In measurement, RF components used for measurement including the source pull measurement tuner 7 and the load pull measurement tuners 10, 11, and 14 are controlled to various positions (impedance) based on data calibrated by a network analyzer in advance. Control equipment for
For example, a personal computer (not shown) is connected.

The load pull measurement tuner 14 of the present invention shown in FIG. 1 is a tuner for a fundamental frequency in this embodiment. An example of the embodiment of the load-pull measurement tuner 14 is shown in FIG. 2A in a cross-sectional view along a signal transmission direction. FIG. 2B shows an impedance conversion unit.
FIG. 2C is a cross-sectional view of the tuner body 13 in a direction perpendicular to the signal transmission direction, and FIG.

As shown in FIGS. 1 and 2, the load-pull measurement tuner 14 of the present invention includes a tuner body 13 and an impedance converter 12. In this example, they are configured in a housing 14a that forms a common external conductor.
14b and 14c are connectors for connecting to the triplexer 9 and the bias tee 15, respectively.

The tuner body 13 has a rod-shaped center conductor 13a.
And a cylindrical grounding conductor 13b arranged around the center conductor 13a, an elongated cylindrical grounding conductor 13b having a U-shaped cross section in this example, and an axial direction corresponding to an opening of the grounding conductor 13b. And a plurality of metal pieces 13c individually movable in a direction perpendicular to the center conductor 13a. The ground conductor 13b is arranged parallel to the center conductor 13a, and the length of the ground conductor 13b and the length of the metal piece 13c are substantially equal to the length of the center conductor 13a. The cross-sectional shape of the ground conductor 13b may be U-shaped or circular. The center conductor 13a of the tuner body 13 is set so as to function as a distributed constant line which is normally regarded as a transmission line having a characteristic impedance of 50Ω.

The plurality of metal pieces 13c arranged so as to constitute a part of the cylindrical ground conductor 13b are electrically connected to the ground conductor 13b and move the individual metal pieces 13c with respect to the center conductor 13a. In this figure, the metal pieces are arranged so as to be movable in the vertical direction, that is, in the direction perpendicular to the center conductor 13a.
13C shows a state in which 13c is arranged at the same interval with respect to the center conductor 13a.

A large number of metal pieces 13c arranged in this manner
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 13a. As a result, a predetermined capacitance component determined by the opposing area and opposing interval is obtained at a position where the metal piece 13c arbitrarily combined opposes the center conductor 13a, and is obtained by the capacitance component and the remaining portion of the center conductor 13a. With the transmission line used, the impedance on the output side of the DUT 8 can be changed to a desired condition according to the specification of the measurement. As a result, the measurable VSWR can be increased, and the measurement range can be widened.

Further, since each of the large number of metal pieces 13c is fixed at a fixed position in the horizontal direction and movable only in the vertical direction, the reproducibility of the set position of the metal piece 13c is high, and various conditions can be set. When the measurement is repeated, the reproducibility of the measurement can be improved.

The impedance conversion section 12 has a rod-shaped conductor 12a whose one end is connected to the center conductor 13a of the tuner body 13 at its end faces, and is disposed around the rod-shaped conductor 12a and is perpendicular to the rod-shaped conductor 12a. A groove-shaped outer conductor 12b movable in the direction, and a metal piece 12a movably arranged in a direction perpendicular and parallel to the rod-shaped conductor 12a across the opening of the outer conductor 12b. The conductor 12b and the ground conductor 13b are electrically connected via a housing 14a of the tuner 14.

The cross-sectional shape of the outer conductor 12b may be a U-shape as well as a U-shape as shown in FIG. Further, since the outer conductor 12b is movable in the vertical direction with respect to the center conductor 12a, the characteristic impedance of the center conductor 13a of the tuner body 13 is normally 50Ω, and the distribution constant is regarded as a transmission line having a lower characteristic impedance. It is set as a line, and a low impedance DUT 8 can be measured.

The metal piece 12c arranged across the opening of the groove-like ground conductor 12b is electrically connected to the external conductor 12b so that the metal piece 12c can be set at a predetermined distance from the center conductor 12a. In the figure, they are arranged so as to be movable vertically or horizontally, that is, vertically or parallel to the center conductor 12a.

According to the metal piece 12c arranged as described above, a predetermined capacitance component determined by the facing area and facing distance is obtained at the position where the metal piece 12c faces the center conductor 12a, and the capacitance component The transmission line obtained by the remaining portion of the center conductor 12a can increase the VSWR that can measure the impedance on the output side of the DUT 8 according to the measurement specification, and can obtain the necessary phase rotation. , The measurement range can be widened. This is because the distance between the metal piece 12c and the center conductor 12a can be arbitrarily determined, so that the capacitance component consisting of the metal piece 12c and the center conductor 12a can be changed arbitrarily, thereby obtaining a desired phase rotation. Depends on

As described above, according to the load-pull or source-pull measuring tuner 14 of the present invention, the impedance converter 12 having the above-described configuration is connected to the tuner body 13 so that it can be used as a power amplifier for a portable telephone. F
When measuring the low impedance DUT 8 such as ET, when the characteristic impedance of the transmission line of the center conductor 13a of the tuner body 13 is 50Ω, 50Ω such as 30Ω or 20Ω is used.
Since the impedance can be arbitrarily set to a lower impedance, even if the VSWR of the triplexer 9 used in the measurement system is bad or lossy, the impedance conversion unit can be used.
According to the specifications of the DUT 8, the impedance viewed from the output terminal of the DUT 8 to the output side can be optimized and set to a desired value, for example, a value that makes the characteristics of the DUT 8 high gain and low distortion according to the specifications of the DUT 8. VSWR at desired phase
Can be increased.

As a result, it is advantageous in that the VSWR can be increased while keeping the loss including the triplexer 9 and the tuner 14 as a whole low. Therefore, it is possible to appropriately measure the low impedance DUT 8 while obtaining a sufficient VSWR. Can do it.

The amount of phase rotation by the impedance converter 12 in the tuner 14 for measuring load pull or source pull of the present invention is determined by, for example, the following procedure. First, a tuner control device (not shown) such as a personal computer supplies a phase for which VSWR is to be increased and its V
The absolute value of the reflection coefficient corresponding to SWR is input. Thereafter, the tuner control device performs scaling of the tuner body 13 and the impedance conversion unit 12 according to the values, and determines a phase adjustment value by the impedance conversion unit 12. Then, according to the phase adjustment value, the impedance point for actually performing the load-pull measurement or the source-pull measurement can be freely moved in the vertical direction and the parallel direction of the many metal pieces 13 c movable in the vertical direction of the tuner body 13 and the impedance conversion unit 12. The desired amount of phase rotation is determined by setting the metal pieces 12c at predetermined intervals and predetermined positions and setting the vertically movable outer conductor 12b at predetermined intervals.

It should be noted that the present invention is not limited to the above-described example, and that various changes and improvements can be made without departing from the scope of the present invention. For example, in the above example, the tuner for the fundamental frequency has been described as an example of the load pull measurement tuner of the present invention.
Depending on the specifications of T and measurement, for example, the frequency at which the impedance point is determined is set to the second or third harmonic to be used as a tuner for the second or third harmonic, or the source pull measurement on the source side of the DUT Needless to say, it can also be used as a tuner.

[0041]

As described above, according to the load-pull or source-pull measuring tuner of the present invention, the tuner body is composed of the center conductor and the cylindrical grounding conductor, and a part of the grounding conductor along the axial direction is centered. Since it is constituted by a large number of metal pieces movable in the vertical direction with respect to the conductor, by moving these many metal pieces alone or in any combination with respect to the central conductor in the vertical direction, A variable capacitance is formed at the position of, and scaling is performed for measurement. Therefore, the variable range of the capacitance can be widened and the measurement range can be widened, so that a tuner for load-pull or source-pull measurement capable of performing measurement under a wide range of conditions and having excellent measurement reproducibility can be obtained.

According to the load-pull or source-pull measuring tuner of the present invention, in addition to the tuner body, a rod-shaped conductor whose one end is connected to the center conductor of the tuner body at its end faces, and a periphery of the rod-shaped conductor And a groove-shaped external conductor movably arranged in the vertical direction with respect to the rod-shaped conductor, and movably disposed in the vertical and horizontal directions with respect to the rod-shaped conductor over the opening of the external conductor. Since it is provided with an impedance conversion section composed of a metal piece that has been made, it functions as an impedance conversion section that can increase the VSWR and also has a function that can arbitrarily adjust the impedance phase. And the phase can be easily adjusted. Therefore, even when the VSWR of the triplexer used in the measurement system is bad or lossy, it is not necessary to prepare a large number of separate lines for phase adjustment depending on the DUT and the system to be subjected to the DUT unlike the conventional measurement system. This eliminates the need for complicated phase adjustment using the phase adjustment line, shortens the time required for adjustment and fabrication of the phase adjustment line, and allows the measurement system itself to be configured at low cost.

As described above, according to the present invention, for each phase rotation amount required according to the specification of the high-frequency transistor as the device to be measured, it is easy to prepare a large number of phase adjustment lines unlike the related art. It is possible to provide a tuner for load-pull or source-pull measurement capable of performing phase adjustment and performing appropriate measurement even for a low-impedance high-frequency transistor even when the VSWR of the triplexer is bad or the triplexer has a loss.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a measurement system using a load-pull or source-pull measurement tuner of the present invention and considering up to the third harmonic.

2A is a cross-sectional view in a direction along a signal transmission direction showing an example of an embodiment of a load-pull or source-pull measurement tuner of the present invention, and FIG. 2B is a view in a signal transmission direction in an impedance conversion unit. Cross section in a vertical direction,
(C) is a sectional view of the tuner body in a direction perpendicular to the signal transmission direction.

FIG. 3 is a schematic configuration diagram showing an example of a measurement system using a conventional load-pull or source-pull measurement tuner and considering up to the third harmonic.

FIG. 4 is a schematic configuration diagram showing another example of a measurement system using a conventional load-pull or source-pull measurement tuner and considering up to the third harmonic.

[Explanation of symbols]

 8 DUT (high-frequency transistor) 12 Impedance converter 12a Bar-shaped conductor 12b External conductor 12c Metal piece 13 Tuner main body 13a Central conductor 13b Ground conductor 13c Metal piece Tuner for load pull measurement

Claims (1)

[Claims] 1. A load-pull or source-pull measuring tuner connected to an input side or an output side of a high-frequency transistor for evaluating electrical characteristics of the high-frequency transistor, comprising: a rod-shaped center conductor; A tuner body composed of a large number of metal pieces, a part of which in the axial direction of the ground conductor is movable in a direction perpendicular to the center conductor; A conductor, a groove-shaped outer conductor disposed around the rod-shaped conductor so as to be movable in a direction perpendicular to the rod-shaped conductor,
A metal piece movably disposed in a direction perpendicular and parallel to the rod-shaped conductor over the opening of the external conductor, and one end of the rod-shaped conductor is connected to the center conductor and end faces thereof. A load pull or source pull measurement tuner, further comprising: an impedance conversion section in which the external conductor is electrically connected to the ground conductor.