JP2006112893A - Vector network analyzer device using 6-port type joint, and its calibration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems, wherein in a calibration method of VNA mainly used for a high-frequency measuring system, connection and disconnection of several kinds of standards are required at calibration time, and the requirement causes generation of human errors, to thereby reduce the measurement accuracy. <P>SOLUTION: In an integration calibration method, calibration can be performed with only a single phase shifter and one standard having a known complex reflection coefficient, without taking a conventional complicated calibration step, and thereby calibration accuracy is improved and errors generated in the calculation of an S parameter can be reduced. Hereby, in this 6-port VNA, calibration can be performed with only one phase shifter and one standard having the known complex reflection coefficient, without taking complicated steps as in the conventional calibration method, and thereby the calibration accuracy is improved and errors generated in calculation of the S parameter can be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a phase measurement technique in a high frequency region (microwave band, millimeter wave band, submillimeter wave band, terahertz band), optical region (infrared ray, visible ray, ultraviolet ray) and the like.

The 6-port reflectometer and 6-port correlator, which are high-frequency measuring devices, are based on hardware-specific information (calibration parameters) obtained by calibration and multiple power measurement values (scalar quantities), and the amplitude ratio of the two waves And a phase difference (vector quantity).
The hardware (junction) used to realize this measurement apparatus is called “6-port type junction” by adding the expression “type” regardless of whether it is 6 ports or not. Similarly, the measurement device using the “6-port type joint” is also referred to as “6-port type reflectometer” and “6-port type correlator” with the expression “type” added thereto.
Hereinafter, a description will be given by taking 6-port hardware as an example. Therefore, they are expressed as “6-port junction”, “6-port reflectometer”, and “6-port correlator”.

Current vector network analyzer (VNA) calibration is performed by connecting several types of standard devices (short, open, load, through, line, etc.).
As shown in FIG. 1, the applicant of the present application has a 6-port junction 16, a detector 11, switches SW 1, 13, SW 2, 14, directional couplers 22, 23, a power distributor 26, an oscillation source 21, and a phase shifter 15. By using the non-reflective terminators 24 and 25, a VNA different from the measurement principle of the conventional VNA is realized. Hereinafter, this VNA is referred to as a 6-port VNA, and the measurement port 1 of this 6-port VNA is expressed as a port P1, and the measurement port 2 is expressed as a port P2.
At present, the 6-port VNA is calibrated by the integral calibration method invented by the applicant of the present application for the 6-port junction, and the same calibration method as the conventional VNA is used for the other circuit parts. Applicable.

と表わされる。この_３Ｔ_ｈ，ｔ_ｈ，_３Ｋ_ｈ，ｋ_ｈは校正によって求められる校正パラメータである。
特許第３５４０７９７号公報 As shown in FIG. 2, an oscillation source 19 is connected to port 1, a 1-port device under test (DUT) 18 is connected to port 2, and a wave b ₂ output from port ₂ and an input wave a ₂ Ratio, that is, the complex reflection coefficient γ as seen from the port 2 to the 1-port DUT 18 side
γ = a ₂ / b ₂ (1)
This measuring device is called a reflectometer.
Also, as shown in FIG. 3, the complex amplitude ratio W of the wave a ₁ input from the port ₁ and the wave a ₂ input from the port 2
W = a ₂ / a ₁ (2)
This measuring device is called a correlator.
6-port junction is under conditions where the circuit is only a single mode propagates in the linear wave _b 3 _outputs, b _4, b 5, _{b 6} is a wave _a 1, a to output to the port 1, 2 ₂ and b ₂ .
That is, b _i (i = 3, 4, 5, 6) uses a ₁ , a ₂ , b ₂ ,
b _i = A _{ia 1} + B _{ia 2} (3)
b _i = C _{ia 2} + D _i b ₂ (4)
Can be expressed as
However, A _i , B _i , C _i , and D _i are complex constants depending on the frequency inherent to the 6-port junction.
When the power value measured by the detector which is connected to the port i When P _i is P _i proportional to the square of the amplitude of the wave b _i to be output to the proportional constant alpha,
P _i = α | A _{ia 1} + B _{ia 2} | ² (5)
P _i = α | C _{ia 2} + D _i b ₂ | ² (6)
Can be expressed as Then, the power ratio ₃ P _h ports h (h = 4,5,6) with respect to port 3,

It is expressed as The _{3 T h, t h, 3} K h, k h is a calibration parameter obtained by the calibration.
Japanese Patent No. 35409797

Conventional VNA calibration methods have a problem that the calibration procedure is complicated.
The complexity of this calibration procedure can cause human error. In addition, it is necessary to connect and remove several kinds of standard devices at the time of calibration, which causes a problem of deterioration in measurement accuracy.
When calculating the S-parameters of a DUT using the 6-port VNA invented by the applicant of the present application, the conventional method requires two types of calibration parameters: calibration parameters for the 6-port junction and calibration parameters for the other circuit portions. To do.
The accuracy of the calibration parameters for the other circuit portions depends on the accuracy of the calibration parameters for the 6-port joint portion and the accuracy of the power measurement value measured during calibration of the other circuit portions. Accordingly, an error in calculating the S parameter of the DUT increases.

  The integral calibration method invented by the present applicant can be applied to any 6-port junction. A 6-port VNA obtained by adding a switch and a directional coupler to the 6-port junction can also be handled as a 6-port junction. Therefore, the integral calibration method can be applied to the 6-port VNA.

  Using the integral calibration method invented by the applicant of the present application, the 6-port VNA requires only one phase shifter and one standard unit with a known complex reflection coefficient without going through the complicated procedure of the conventional calibration method. Since the calibration can be performed, the calibration accuracy can be improved and the error in calculating the S parameter can be reduced.

Embodiments of the present invention will be described below with reference to the drawings.
In the present invention, the integral calibration method invented by the applicant of the present application is executed for each of four circuit states for measuring S ₁₁ , S ₁₂ , S ₂₁ , and S ₂₂ , and four calibration parameters are calculated.
Calculating calibration parameters calibration parameters at _{S 11} measurements calibrated for _{S 11 measurements,} calibration parameters during _{S 12} measurements calibrated for _{S 12 measured,} the calibration parameter when _{S 21} measurements calibrated for _{S 21 measurements, S 22} measured sometimes using calibration parameters calibrated for S ₂₂ measurements.

Figure 4 shows a circuit state when calculating the calibration parameters for _{S 11} Measurement of 2-port DUT17. The switches SW1 and 13 are connected to the contact (1), the switches SW2 and 14 are connected to the contact (1), and the known standard 12 is connected to the port P1. This state corresponds to the 6-port reflectometer shown in FIG. In this state, after fixing the movable part of the phase shifter 15 to the starting position, the power of P _{3 to} P ₆ of the detector 11 is measured and used as a reference.
Next, while moving the movable part of the phase shifter 15, the power of P _{3 to} P ₆ of the detector 11 is measured for one period.
Calculating the _{S 11} calibration parameters ₃ K ₄ for _{measuring, 3 K 5, 3 K 6} , k 3, k 4, k 5, k 6 of the two-port DUT17 using more power measurements.

Figure 6 shows a circuit state when calculating the calibration parameters for _{S 12} Measurement of 2-port DUT17. The switches SW1 and 13 are connected to the contact (2), the switches SW2 and 14 are connected to the contact (1), and the port P1 and the port P2 are directly connected. This state corresponds to the 6-port correlator shown in FIG. In this state, after fixing the movable part of the phase shifter 15 to the starting position, the power of P _{3 to} P ₆ of the detector 11 is measured and used as a reference.
Next, while moving the movable part of the phase shifter 15, the power of P _{3 to} P ₆ of the detector 11 is measured for one period.
The calibration parameters ₃ T ₄ , ₃ T ₅ , ₃ T ₆ , t ₃ , t ₄ , t ₅ , t ₆ for the S ₁₂ measurement of the 2-port DUT 17 are calculated using the above power measurement values.

FIG. 8 shows a circuit state when calculating calibration parameters for S ₂₁ measurement of the 2-port DUT 17. The switches SW1 and 13 are connected to the contact (1), the switches SW2 and 14 are connected to the contact (2), and the port P1 and the port P2 are directly connected. This state corresponds to the 6-port correlator shown in FIG. In this state, after fixing the movable part of the phase shifter 15 to the starting position, the power of P _{3 to} P ₆ of the detector 11 is measured and used as a reference.
Next, while moving the movable part of the phase shifter 15, the power of P _{3 to} P ₆ of the detector 11 is measured for one period.
Using the above power measurement values, calibration parameters ₃ T ₄ ′, ₃ T ₅ ′, ₃ T ₆ ′, t ₃ ′, t ₄ ′, t ₅ ′, t ₆ ′ for S ₂₁ measurement of the 2-port DUT 17 are obtained. calculate.

Figure 10 shows a circuit state when calculating the calibration parameters for _{S 22} Measurement of 2-port DUT17. The switches SW1 and 13 are connected to the contact (2), the switches SW2 and 14 are connected to the contact (2), and the known standard 12 is connected to the port P2. This state corresponds to the 6-port reflectometer shown in FIG. In this state, after fixing the movable part of the phase shifter 15 to the starting position, the power of P _{3 to} P ₆ of the detector 11 is measured and used as a reference.
Next, while moving the movable part of the phase shifter 15, the power of P _{3 to} P ₆ of the detector 11 is measured for one period.
More calibration parameters ₃ K ₄ for _{S 22} Measurement of 2-port DUT17 using power _{measurements', 3 K 5 ', 3} K 6', k 3 ', k 4', k 5 ', a _{k 6'} calculate.
By the procedure described above, the 6-port VNA can be calibrated easily and with high accuracy as compared with the conventional calibration method.

The block diagram of 6 port VNA. Reflectometer. Correlator. S ₁₁ calibration circuit diagram for measurement. 6 port reflectometer corresponding to S ₁₁ for measurement calibration circuit. S ₁₂ calibration circuit diagram for measurement. 6 port correlator corresponding to S ₁₂ for measurement calibration circuit. S ₂₁ calibration circuit diagram for measurement. 6 port correlator corresponding to the calibration circuit S ₂₁ measurements. S ₂₂ measured calibration circuit diagram. 6 port reflectometer corresponding to S ₂₂ for measurement calibration circuit.

Explanation of symbols

1, 2, 3, 4, 5, 6 Port 1 to Port 6
11 detector 12 standard device 13, 14 switch 15 phase shifter 16 6-port junction 17 DUT (2-port test device)
18 DUT (1 port EUT)
19, 20, 21 Oscillation source 22, 23 Directional coupler 24, 25 Non-reflective terminator 26 Power distributor

Claims (3)

  In a circuit composed of a 6-port junction, a detector, a switch, a directional coupler, a power divider, an oscillation source, a phase shifter, and a non-reflection terminator, all SUTs of the DUT can be connected without changing the connection of the DUT. A vector network analyzer using a 6-port junction, characterized in that a parameter is calculated.   An integral calibration method for calibrating a 6-port correlator with a single phase shifter is applied to the vector network analyzer apparatus using a 6-port junction according to claim 1 and calibrated as a 6-port correlator. A method for calibrating a vector network analyzer device using a 6-port junction.   2. An integral calibration method for calibrating a 6-port reflectometer with one phase shifter and one standard with a known complex reflection coefficient is applied to the vector network analyzer apparatus using the 6-port junction according to claim 1. And a calibration method for a vector network analyzer apparatus using a 6-port junction, wherein the calibration is performed as a 6-port reflectometer.

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