Probe and method for examining electrical characteristics of devices

• US 20010017549A1
• Filed: 12/20/2000
• Published: 08/30/2001
• Est. Priority Date: 02/25/2000
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Inoue, Akira, Katoh, Takayuki, Iwamoto, Naofumi, Aso, Takeshi, Suetsugu, Takumi
• Granted Patent: US 6,617,864 B2
• Time in Patent Office: Days
• US Class Current: 324/754
• CPC Class Codes: G01R 1/06733 Geometry aspects G01R1/06727 takes precedence
• CPC Class Codes: G01R 1/06766 Input circuits therefor
• CPC Class Codes: G01R 1/06772 High frequency probes

Abstract

Provided is a probe whose characteristic impedance can be accurately adjusted to the desired value with the production of a small number of prototypes. The probe includes a first line provided with a signal terminal to be connected to a signal electrode of a circuit to be measured and at least one first region which is connected to the signal terminal and to which one end of a chip capacitor is connected, a second line which is connected to a terminal that belongs to the first line and is located opposite to the connecting end and provided with a junction to be connected to the measuring instrument at the remaining terminal and an impedance matched to the characteristic impedance of the measuring instrument, a ground conductor provided with a ground terminal to be connected to the ground electrode of the circuit to be measured and at least one second region which is connected to the ground terminal and on which the remaining terminal of the chip capacitor is mounted in one-to-one correspondence with the first region. The impedance of the probe viewed from the circuit to be measured is provided by a chip capacitor mounted in specified positions within the first region and the second region.

Claims

1. A probe for a high-frequency signal used for an electric test in a high-frequency band of a circuit to be measured, the probe comprising:

a signal terminal to be connected to a signal electrode of the circuit to be measured;

a first line that has a specified impedance, one end connected to the signal terminal and at least one first region to which one end of a chip capacitor is connected;

a second line that is connected to a terminal opposite to the end of the first line connected to the signal terminal and has a junction to be connected to a measuring instrument for executing the electric test at a remaining terminal and an impedance matched to a characteristic impedance of the measuring instrument;

a ground terminal to be connected to the ground electrode of the circuit to be measured; and

a ground conductor that is connected to the ground terminal and has at least one second region to which a remaining terminal of the chip capacitor is connected in one-to-one correspondence with the first region, wherein

a chip capacitor of a specified capacitance value that is mounted in specified positions within the first region and the second region so that an impedance of the probe viewed from the circuit to be measured has a desired value.

2. A probe for a high-frequency signal as claimed in

claim 1

, wherein

the ground conductor is formed on an insulating substrate having a back surface ground conductor and provided with a plurality of via holes connected to the back surface ground conductor, and

an interval between each of the via holes and the signal terminal and an interval between via holes are each not greater than one fourth of a wavelength λ

of the high-frequency signal inputted to the signal terminal.

3. A probe for a high-frequency signal as claimed in

claim 1

, wherein

a specified chip inductor is inserted in the first line.

4. A probe for a high-frequency signal as claimed in

claim 1

, wherein

a line that is branched from the ground conductor as the second region is provided, the chip capacitor is connected across the branched line and the first region, and an LC resonance circuit constructed of the branched line and the chip capacitor resonates with a higher harmonic of a multiple of the frequency of the signal inputted to the signal terminal.

5. A probe for a high-frequency signal as claimed in

claim 1

, further comprising:

a high-impedance branch line that is branched from the vicinity of the signal terminal of the first line and has a terminal for detecting a potential of the signal terminal.

6. A probe for a high-frequency signal as claimed in

claim 1

, further comprising:

an isolator that has impedance characteristics corresponding to the frequency of the input signal between the first line and the second line, the impedance characteristics being identical to that of the isolator provided in the output section of the circuit to be measured.

7. A probe for a high-frequency signal as claimed in

claim 1

, further comprising:

a conductor that is connected to the ground conductor and shields electromagnetic waves by covering the first line and the second line with interposition of a specified gap.

8. A method for examining electric characteristics of devices, comprises providing a prove for a high-frequency signal used for an electric test in a high-frequency band of a circuit to be measured, the probe includes

a signal terminal to be connected to a signal electrode of the circuit to be measured;

a first line that has a specified impedance, one end connected to the signal terminal and at least one first region to which one end of a chip capacitor is connected;

a second line that is connected to a terminal opposite to the end of the first line connected to the signal terminal and has a junction to be connected to a measuring instrument for executing the electric test at a remaining terminal and an impedance matched to a characteristic impedance of the measuring instrument,

a ground terminal to be connected to the ground electrode of the circuit to be measured; and

a ground conductor that is connected to the ground terminal and has at least one second region to which a remaining terminal of the chip capacitor is connected in one-to-one correspondence with the first region, wherein

a chip capacitor of a specified capacitance value that is mounted in specified positions within the first region and the second region so that an impedance of the probe viewed from the circuit to be measured has a desired value.

9. A method as claimed in

claim 8

, wherein

the ground conductor is formed on an insulating substrate having a back surface ground conductor and provided with a plurality of via holes connected to the back surface ground conductor, and

an interval between each of the via holes and the signal terminal and an interval between via holes are each not greater than one fourth of a wavelength λ

of the high-frequency signal inputted to the signal terminal.

10. A method as claimed in

claim 8

, wherein the probe further includes

a specified chip inductor is inserted in the first line.

11. A method as claimed in

claim 8

, wherein the probe further includes

a line that is branched from the ground conductor as the second region is provided, the chip capacitor is connected across the branched line and the first region, and an LC resonance circuit constructed of the branched line and the chip capacitor resonates with a higher harmonic of a multiple of the frequency of the signal inputted to the signal terminal.

12. A method as claimed in

claim 8

, wherein the probe further includes

a high-impedance branch line that is branched from the vicinity of the signal terminal of the first line and has a terminal for detecting a potential of the signal terminal.

13. A method as claimed in

claim 8

, wherein the probe further includes

an isolator that has impedance characteristics corresponding to the frequency of the input signal between the first line and the second line, the impedance characteristics being identical to that of the isolator provided in the output section of the circuit to be measured.

14. A method as claimed in

claim 8

, wherein the probe further includes

a conductor that is connected to the ground conductor and shields electromagnetic waves by covering the first line and the second line with interposition of a specified gap.