Asymmetric coplanar waveguide calibration components

Abstract

This invention discloses an asymmetric coplanar waveguide calibration component, comprising a short-circuit standard, an open-circuit standard, a load standard, and a through-circuit standard. The short-circuit standard includes a first rectangular portion and a second rectangular portion arranged coaxially. The first rectangular portion is a signal line made of a metal circuit pattern, and the second rectangular portion is a ground line made of a metal circuit pattern. A coordinate system is established with the coaxial direction of the first and second rectangular portions as the y-axis, and the x-axis represents the width direction of the first and second rectangular portions. The width of both rectangular portions is greater than or equal to the tip width, and the length of the second rectangular portion is at least twice the length of the first rectangular portion. The open-circuit standard, load standard, and through-circuit standard are all fabricated based on the short-circuit standard. This invention solves the probe calibration problem for asymmetric probes. Its calibration effect is within the 10MHz-40GHz range, with a return loss of less than -20dB and an insertion loss of less than 0.5dB, exhibiting good through-circuit performance. This indicates that the calibration is accurate and can be used for practical testing.

Description

Technical Field

[0001] This invention relates to a calibration component, and more particularly to an asymmetric coplanar waveguide calibration component. Background Technology

[0002] When using a vector network analyzer for testing, the S-parameter test system must be calibrated. There are several common calibration methods, three of which are: (1) Line-Reflect-Reflect-Match (LRRM); (2) Short-Open-Load-Thru (SOLT); and (3) Thru-Reflect-Line (TRL).

[0003] Calibration must be performed using calibration kits as standards. Calibration kits can be categorized into coaxial calibration kits, waveguide calibration kits, etc., depending on the type of test port. In microwave integrated circuit testing, depending on the port, GSG coplanar waveguide calibration kits, GS or SG asymmetric coplanar waveguide calibration kits are required. Here, GSG stands for ground-signal-ground, GS for ground-signal, and SG for signal-ground.

[0004] With the increasing demand for on-chip S-parameter measurement of microwave integrated circuits, the demand for corresponding calibration components is also increasing. Currently, there is no method for preparing calibration components for asymmetric coplanar waveguides in China.

[0005] GS probe or SG probe, GS stands for ground-signal and SG stands for signal-ground. A probe contains two tips, one for connecting to the signal line and the other for grounding. Summary of the Invention

[0006] The purpose of this invention is to provide a new asymmetric coplanar waveguide calibration component that solves the above-mentioned problems and is independently developed.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: an asymmetric coplanar waveguide calibration component, used to connect the probe of a vector analyzer and calibrate the parameters of the vector analyzer, including a short-circuit standard component, an open-circuit standard component, a load standard component, and a through-circuit standard component fabricated on a dielectric substrate;

[0008] The probe is a GS probe or an SG probe, and one probe includes two tips;

[0009] The short-circuit standard component includes a first rectangular part and a second rectangular part arranged coaxially. The first rectangular part is a signal line made of a metal circuit pattern, and the second rectangular part is a ground line made of a metal circuit pattern. A coordinate system is established with the coaxial direction of the first rectangular part and the second rectangular part as the y-axis. Then the x-axis is the width direction of the first rectangular part and the second rectangular part. The width of both rectangular parts is greater than or equal to the width of the pin tip, and the length of the second rectangular part is at least twice the length of the first rectangular part.

[0010] The open circuit standard component includes a short circuit standard component, and a section is cut out between the first rectangular portion and the second rectangular portion of the short circuit standard component to disconnect the two and form an open circuit.

[0011] The load standard component includes an open-circuit standard component, and a thin-film resistor is provided at the break point of the open-circuit standard component to connect the open circuit.

[0012] The through standard component has a third rectangular portion and a fourth rectangular portion arranged coaxially along the Y-axis. The third rectangular portion is a signal line made of a metal circuit pattern, and the fourth rectangular portion is a ground line made of a metal circuit pattern. There is a gap between the two, and the gap width is such that the impedance of the through standard component is equal to 50 ohms.

[0013] Preferably, the first rectangular portion and the second rectangular portion have different widths, the dielectric substrate is made of alumina ceramic, and the metal circuit pattern is made of gold.

[0014] In the preferred load standard component, the thin-film resistor is coaxially arranged with the connected first rectangular portion and second rectangular portion, and the thin-film resistor is made of TaN material with a resistance of 50 ohms.

[0015] A verification circuit is also included as a preferred option.

[0016] The verification circuit includes a continuous standard component, and a resistor circuit is provided at the end of its fourth rectangular portion away from the third rectangular portion. The length of the resistor circuit in the x-axis direction is measured by a time delay. t delay It is expressed and calculated using the following formula;

[0017]

[0018] In the formula, l The total length of the through standard part, c The speed of light in a vacuum. ε r is the relative permittivity.

[0019] Compared with the prior art, the advantages of the present invention are: it can solve the probe calibration problem of GS or SG type asymmetric probes, and its calibration effect is less than -20dB and less than 0.5dB in the range of 10MHz-40GHz, showing good through performance, indicating that the above calibration is accurate and can be used for actual testing. Attached Figure Description

[0020] Figure 1a This is a schematic diagram showing the connection between the short-circuit standard and the probe when using the SG port in this invention;

[0021] Figure 1b This is a schematic diagram showing the connection between the short-circuit standard and the probe when using the GS port in this invention;

[0022] Figure 2a This is a schematic diagram showing the connection between the open-circuit standard and the probe when using the SG port in this invention;

[0023] Figure 2b This is a schematic diagram showing the connection between the open-circuit standard and the probe when using the GS port in this invention;

[0024] Figure 3a This is a schematic diagram showing the connection between the load standard and the probe when using the SG port in this invention;

[0025] Figure 3b This is a schematic diagram showing the connection between the load standard and the probe when using the GS port in this invention;

[0026] Figure 4a This is a schematic diagram showing the connection between the through standard and the probe when using the SG port in this invention;

[0027] Figure 4b This is a schematic diagram illustrating the connection between the through standard and the probe when using the GS port in this invention;

[0028] Figure 5a This is a schematic diagram of the verification circuit when the SG port is used in this invention;

[0029] Figure 5b This is a schematic diagram of the verification circuit when the GS port is used in this invention;

[0030] Figure 6 This is a schematic diagram of the overall invention;

[0031] Figure 7a This is a measured effect diagram of parameter S11 in Embodiment 2 of the present invention;

[0032] Figure 7b This is a measured effect diagram of parameter S22 in Embodiment 2 of the present invention;

[0033] Figure 7c This is a measured effect diagram of parameter S12 in Embodiment 2 of the present invention;

[0034] Figure 7d This is a measured effect diagram of parameter S21 in Embodiment 2 of the present invention.

[0035] In the figure: 1. First rectangular section; 2. Second rectangular section; 3. Probe; 4. Tip; 5. Thin film resistor; 6. Third rectangular section; 7. Fourth rectangular section; 8. Resistor circuit; 9. Short circuit standard; 10. Open circuit standard; 11. Load standard; 12. Through standard; 13. Verification circuit; 14. Dielectric substrate. Implementation

[0036] The invention will now be further described with reference to the accompanying drawings.

[0037] Example 1: See Figures 1a to 6 An asymmetric coplanar waveguide calibration component is used to connect the probe 3 of a vector analyzer and calibrate the parameters of the vector analyzer. It includes a short-circuit standard 9, an open-circuit standard 10, a load standard 11, and a through standard 12 fabricated on a dielectric substrate 14.

[0038] The probe 3 is a GS probe or an SG probe, and one probe 3 includes two tips 4;

[0039] The short-circuit standard component 9 includes a first rectangular part 1 and a second rectangular part 2 arranged coaxially. The first rectangular part 1 is a signal line made of a metal circuit pattern, and the second rectangular part 2 is a ground line made of a metal circuit pattern. A coordinate system is established with the direction of the coaxiality of the first rectangular part 1 and the second rectangular part 2 as the y-axis. Then the x-axis is the width direction of the first rectangular part 1 and the second rectangular part 2. The width of both rectangular parts is greater than or equal to the width of the needle tip 4, and the length of the second rectangular part 2 is at least twice the length of the first rectangular part 1.

[0040] The open circuit standard 10 includes a short circuit standard 9, and a section is cut out between the first rectangular portion 1 and the second rectangular portion 2 of the short circuit standard 9 to disconnect the two and form an open circuit.

[0041] The load standard component 11 includes an open circuit standard component 10, and a thin film resistor 5 is provided at the break point of the open circuit standard component 10 to connect the open circuit.

[0042] The through standard component 12 has a third rectangular portion 6 and a fourth rectangular portion 7 arranged coaxially along the Y-axis. The third rectangular portion 6 is a signal line made of a metal circuit pattern, and the fourth rectangular portion 7 is a ground line made of a metal circuit pattern. There is a gap between the two, and the gap width is such that the impedance of the through standard component 12 is equal to 50 ohms.

[0043] The first rectangular portion 1 and the second rectangular portion 2 have different widths. The dielectric substrate 14 is made of alumina ceramic, and the metal circuit pattern is made of gold.

[0044] In the load standard component 11, the thin film resistor 5 is coaxially arranged with the connected first rectangular portion 1 and second rectangular portion 2, and the thin film resistor 5 is made of TaN material with a resistance of 50 ohms.

[0045] The present invention also includes a verification circuit 13;

[0046] The verification circuit 13 includes a through standard component 12, and a resistor circuit 8 is provided at the end of its fourth rectangular portion 7 away from the third rectangular portion 6, the length of which in the x-axis direction is measured by a time delay. t delay It is expressed and calculated using the following formula;

[0047]

[0048] In the formula, l For the total length of the straight-through standard part 12, c The speed of light in a vacuum. ε r is the relative permittivity.

[0049] In this invention, the distance of the gap in the through-type standard component 12 can be calculated using formulas or simulation. Currently, the theoretical calculation of asymmetric coplanar waveguides is still quite complex; relevant literature can be consulted. A simpler method is to use simulation software to perform simulation, adjusting the port impedance by adjusting the gap width of the metal circuit, with a step size of 1µm, simulating the impedance of the through-type standard component 12 up to 50 ohms.

[0050] Example 2: See Figures 1a to 7d Using the above method, our dielectric substrate 14 is an alumina ceramic circuit board, and short-circuit standard 9, open-circuit standard 10, load standard 11, through standard 12 and verification circuit 13 are fabricated on the dielectric substrate 14. The verification circuit 13 is a through test line with a delay of 40ps.

[0051] This invention uses a GS probe or SG probe with a pin pitch of 150µm for calibration, and then connects it to the verification circuit 13 to measure its S-parameters. The measured results are as follows: Figures 7a-7d We define the two ends of verification circuit 13 as port one and port two, respectively. Parameter S11 is the return loss of port one of verification circuit 13, parameter S22 is the return loss of port two of verification circuit 13; parameter S12 is the insertion loss from port one to port two of verification circuit 13, and parameter S21 is the insertion loss from port two to port one of verification circuit 13. Figures 7a-7b As can be seen, its calibration effect is within the 10MHz-40GHz range, with a return loss of less than -20dB. Figures 7c-7dAs can be seen, the insertion loss is less than 0.5 dB, exhibiting good through-pass performance, indicating high calibration accuracy. This invention can be fully applied to practical testing.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An asymmetric coplanar waveguide calibration component for connecting the probe of a vector analyzer and calibrating the parameters of the vector analyzer, comprising a short-circuit standard, an open-circuit standard, a load standard, and a through-circuit standard fabricated on a dielectric substrate, characterized in that: The probe is a GS probe or an SG probe, and one probe includes two tips; The short-circuit standard component includes a first rectangular part and a second rectangular part arranged coaxially. The first rectangular part is a signal line made of a metal circuit pattern, and the second rectangular part is a ground line made of a metal circuit pattern. A coordinate system is established with the coaxial direction of the first rectangular part and the second rectangular part as the y-axis. Then the x-axis is the width direction of the first rectangular part and the second rectangular part. The width of both rectangular parts is greater than or equal to the width of the pin tip, and the length of the second rectangular part is at least twice the length of the first rectangular part. The open circuit standard component includes a short circuit standard component, and a section is cut out between the first rectangular portion and the second rectangular portion of the short circuit standard component to disconnect the two and form an open circuit. The load standard component includes an open-circuit standard component, and a thin-film resistor is provided at the break point of the open-circuit standard component to connect the open circuit. The through standard component has a third rectangular portion and a fourth rectangular portion arranged coaxially along the Y-axis. The third rectangular portion is a signal line made of a metal circuit pattern, and the fourth rectangular portion is a ground line made of a metal circuit pattern. There is a gap between the two, and the gap width is such that the impedance of the through standard component is equal to 50 ohms. It also includes a verification circuit, which comprises a through standard component and a resistor circuit disposed at the end of its fourth rectangular portion away from the third rectangular portion, the length of which in the x-axis direction is measured by a time delay. t delay It is expressed and calculated using the following formula; ， In the formula, l The total length of the through standard part, c The speed of light in a vacuum. ε r is the relative permittivity.

2. The asymmetric coplanar waveguide calibration component according to claim 1, characterized in that: The first rectangular portion and the second rectangular portion have different widths. The dielectric substrate is made of alumina ceramic, and the metal circuit pattern is made of gold.

3. The asymmetric coplanar waveguide calibration component according to claim 1, characterized in that: In the load standard component, the thin film resistor is coaxially arranged with the connected first rectangular portion and second rectangular portion, and the thin film resistor is made of TaN material with a resistance of 50 ohms.

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