Ultra-wide band measurement bridge

Patent metadata

Field	Value
Publication number	US-9823284-B2
Application number	US-201314398418-A
Country	US
Kind code	B2
Filing date	May 3, 2013
Priority date	May 3, 2012
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A measuring bridge ( 1 ) provides a first matching pad ( 2 ), a second matching pad ( 3 ) and a third matching pad ( 4 ), wherein all matching pads ( 2, 3, 4 ) comprise at least three resistors ( 2 1 , 2 2 , 2 3 , 3 1 , 3 2 , 3 3 , 4 1 , 4 2 , 4 3 ) which are arranged in a T-structure. A second resistor ( 3 2 ) of the second matching pad ( 3 ) is connected to a second resistor ( 2 2 ) of the first matching pad ( 2 ), and a third resistor ( 4 3 ) of the third matching pad ( 4 ) is connected to a third resistor ( 2 3 ) of the first matching pad ( 2 ). A second resistor ( 4 2 ) of the third matching pad ( 4 ) can be connected to a device under test ( 7 ). A third resistor ( 3 3 ) of the second matching pad ( 3 ) can be connected to a calibration standard ( 5 ), and a first resistor ( 3 1 , 4 1 ) of the second and the third matching pad ( 3, 4 ) are connected in each case to a signal input of an element ( 11 ) which suppresses a common-mode component on its two signal inputs.

First claim

The invention claimed is:

1. A measuring bridge comprising:
a first matching pad;
a second matching pad; and
a third matching pad,
wherein all matching pads comprise at least three resistors, which are arranged in a T-structure,
wherein a second resistor of the second matching pad is connected to a second resistor of the first matching pad and a third resistor of the third matching pad is connected to a third resistor of the first matching pad,
wherein a second resistor of the third matching pad is configured to be connected to a device under test,
wherein a first resistor of the second and the third matching pad are connected to two signal inputs of an element which suppresses a common-mode component on its two signal inputs, and
wherein the measuring bridge comprises a bias unit which is connected to the second resistor of the third matching pad.

2. The measuring bridge according to claim 1 ,
wherein a third resistor of the second matching pad is configured to be connected to a calibration standard.

3. The measuring bridge according to claim 2 ,
wherein the element is a balun or a differential amplifier.

4. The measuring bridge according to claim 1 , wherein a first resistor of a first matching pad is configured to be connected to a signal generator and/or wherein a second resistor of the first matching pad is combined with a second resistor of the second matching pad to form a first equivalent resistor and/or wherein a third resistor of the first matching pad is combined with a third resistor of the third matching pad to form a second equivalent resistor.

5. The measuring bridge according to claim 1 , wherein the resistors of the first, second and third matching pads are embodied as thin-film resistors on a substrate, and/or wherein the substrate is a ceramic or quartz substrate.

6. The measuring bridge according to claim 4 ,
wherein the calibration standard is formed by at least one thin-film resistor on the substrate and/or wherein a conductor track which connects the at least one calibration standard embodied as a thin-film resistor to the second matching pad provides a V-shaped recess at its end facing towards the calibration standard, which reduces a capacitive scattering field, and/or wherein the measuring bridge provides a first connector, via which the second matching pad is configured to be connected to a separate calibration standard, and
wherein the first connector provides the same electrical properties as a second connector which connects the third matching pad to the device under test.

7. The measuring bridge according to claim 2 , wherein the measuring bridge comprises a dummy-bias unit which is connected to the third resistor of the second matching pad and wherein the dummy-bias unit is constructed in the same manner as the bias unit, so that the measuring bridge is symmetrical.

8. A balun comprising:
a first portion,
wherein the first portion comprises a substrate on the upper side of which a first signal line and at least one second signal line are guided, and on the lower side of which a thin-film resistor layer is embodied beneath the signal lines,
wherein the thin-film resistor layer provides a DGS structure which splits the thin-film resistor layer into two mutually separate thin-film resistor layers,
wherein the width of the DGS structure is matched to the substrate material used and the frequency range to be covered, and
wherein the DGS structure is embodied directly between the first signal line and the at least one second signal line.

9. The balun according to claim 8 ,
wherein the balun comprises a second portion,
wherein the second portion provides a coaxial line, of which the inner conductor is connected to the first signal line and of which the outer conductor is connected at a first end of the coaxial line to the second signal line, and
wherein at least one first ferrite surrounds the coaxial line.

10. The balun according to claim 8 ,
wherein the first signal line and the second signal line are arranged close to one another and/or that the substrate is a ceramic or quartz substrate.

11. The balun according to claim 8 ,
wherein the DGS structure is embodied directly between the two signal lines on the lower side of the substrate.

12. The balun according to claim 9 ,
wherein the outer conductor of the coaxial line is connected at a second end to the reference ground and/or wherein the balun provides a compensation line, of which the first end is connected to the first signal line and/or wherein the compensation line is a wire.

13. The balun according to claim 12 ,
wherein the compensation line together with the coaxial line is surrounded by the at least one first ferrite or that the compensation line is surrounded by at least one further ferrite,
wherein the at least one further ferrite provides the same properties as the at least one first ferrite and/or wherein a second end of the compensation line is connected to the reference ground.

14. The balun according to claim 12 ,
wherein the end of the coaxial line which is distant from the first portion of the balun is connected to a first cup core,
wherein the first cup core comprises a coaxial line coiled within a ferrite or wherein the coaxial line is coiled within the first cup core and/or wherein the compensation line is connected to a second cup core,
wherein the second cup core comprises a line coiled within a ferrite, or wherein the compensation line is coiled within a second cup core and
wherein the second cup core provides the same electrical properties as the first cup core.

15. The measuring bridge according to claim 1 , wherein a balun according to any one of claims 8 to 14 is inserted into the measuring bridge as a common-mode suppressing element.

Assignees

• Rohde & Schwarz

Inventors

• Sterns Michael
• Leibfritz Martin

Classifications

• H01P5/12

  Coupling devices having more than two ports (H01P5/04 takes precedence) · CPC title

• G01R27/06 Primary

  Measuring reflection coefficients; Measuring standing-wave ratio · CPC title

• G01R27/32

  in circuits having distributed constants {, e.g. having very long conductors or involving high frequencies} · CPC title

• G01R27/04 Primary

  in circuits having distributed constants {, e.g. having very long conductors or involving high frequencies} · CPC title

• G01R27/28

  Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response (in line transmission systems H04B3/46) · CPC title