Apparatus, system, and method for improved calibration and measurement of differential devices

Abstract

An apparatus, system and method for facilitating the calibration and measurement of differential devices by a variety of laboratory fixtures. An adapter is used to transition the connection of standard coaxial interfaces to a hermaphroditic differential interface while compensating for discontinuities on impedance at the connection. The adapter includes a transition region with conductors and shield dimensions that compensate for the discontinuity in impedance. The adapter has pin and socket inputs so that a mated pair of the adapters provides an insertable device for test and measurement on a four port vector network analyzer.

1 . An adapter for converting single-ended coaxial signals to differential signals, comprising: 
 at least two coaxial interfaces for coupling to a coaxial device;    a first signal conductor for transmitting signals through the adapter;    a second signal conductor for transmitting signals through the adapter;    a shield conductor;    a transition region for providing a transition between coaxial and differential transmission environments and maintaining a uniform differential impedance through the transition; and    a differential interface for coupling to a differential device.    
   
   
       2 . The adapter of  claim 1 , wherein the transition region includes the first signal conductor, the second signal conductor and the shield conductor, having dimensions providing uniform differential impedance.  
   
   
       3 . The adapter of  claim 1 , wherein the transition region includes a coupling device for connecting a first portion of the first signal conductor to a second portion of the first signal conductor and connecting a first portion of the second signal conductor to a second portion of the second signal conductor.  
   
   
       4 . The adapter of  claim 1 , wherein in the transition region, a first portion of the first signal conductor is spliced together with a second portion of the first signal conductor and a first portion of the second signal conductor is spliced together with a second portion of the second signal conductor.  
   
   
       5 . The adapter of  claim 1 , wherein the differential interface includes an air space between the first conductor and the second conductor.  
   
   
       6 . The adapter of  claim 1 , wherein the at least two coaxial interfaces are standard precision coaxial interfaces.  
   
   
       7 . The adapter of  claim 6 , wherein the diameter of the at least two coaxial interfaces is selected from the group consisting of 1.0 millimeter, 1.85 millimeters, 2.4 millimeters, 3.5 millimeters or 7 millimeters.  
   
   
       8 . The adapter of  claim 1 , wherein a center axis of each of the at least two coaxial interfaces is situated at an angle between 0 and 90 degrees from the center axis of the differential interface.  
   
   
       9 . The adapter of  claim 1 , wherein the differential interface further comprises a mating member for mating to another device for measurement with a 4-port vector network analyzer.  
   
   
       10 . The adapter of  claim 1 , wherein said transition region further includes a dielectric support structure at or near the transition between the coaxial and differential transmission environments.  
   
   
       11 . The adapter of  claim 1 , wherein the diameter and dimensions of the first conductor and second conductor vary within the transition region.  
   
   
       12 . The adapter of  claim 1 , further comprising dielectric beads for supporting the first signal conductor and the second signal conductor.  
   
   
       13 . The adapter of  claim 1 , wherein a center axis of each of the at least two coaxial interfaces is situated at an angle of 10-degrees from the center axis of the differential interface.  
   
   
       14 . An interface apparatus for connecting a differential device to an adapter for converting single-ended coaxial signals to differential signals, comprising: 
 a first differential signal conductor;    a second differential signal conductor; and    a shield conductor,    wherein the diameter of the shield conductor is substantially equal to four times the diameter of the first differential signal conductor.    
   
   
       15 . The interface apparatus of  claim 14 , wherein a center axis of the first differential signal conductor and a center axis of the second differential signal conductor are each situated at a substantially equal distance between an inner surface of the shield conductor and a center axis of the shield conductor.  
   
   
       16 . The interface apparatus of  claim 14 , wherein the first differential signal conductor is situated at a distance substantially equal to half of the diameter of the shield conductor from the second differential signal conductor.  
   
   
       17 . The interface apparatus of  claim 14 , wherein the first conductor and second conductor are each situated at a distance substantially equal to one quarter of the diameter of the shield conductor from an inner surface of the shield conductor.  
   
   
       18 . The interface apparatus of  claim 14 , further comprising contacts that include a male contact and a female contact.  
   
   
       19 . The interface apparatus of  claim 14 , further comprising contacts that are the same sex.  
   
   
       20 . The interface apparatus of  claim 14 , further comprising hermaphroditic pin and socket contacts allowing mating with a differential device regardless of the sex of the contacts of the differential device.  
   
   
       21 . The interface apparatus of  claim 14 , further comprising an alignment hole and an alignment pin providing correct alignment of a mated pair of adapters.  
   
   
       22 . The interface apparatus of  claim 14 , wherein the alignment pin is longer than a connecting plug of the differential interface to provide protection for the connecting plug.  
   
   
       23 . The interface apparatus of  claim 14 , wherein the interface apparatus has a 4 millimeter outer diameter.  
   
   
       24 . An apparatus for converting a single-ended signal of a first device having a coaxial interface to a differential signal of a second device having a differential interface while maintaining uniform differential impedance at a connection between coaxial and differential environments, wherein said first device is a testing device and said second device is a device under test.  
   
   
       25 . A system for converting from single-ended coaxial signals to differential signals, comprising: 
 a single-ended coaxial device;    an adapter with at least two coaxial interfaces for coupling to the single-ended coaxial device;    at least two signal conductors for transmitting signals through the adapter;    a transition region within the adapter for providing a transition between coaxial and differential transmission environments and maintaining a uniform differential impedance through the transition; and    a differential interface on one end of the adapter for coupling to a differential device.    
   
   
       26 . The system of  claim 25 , wherein the transition region includes the at least two signal conductors and a shield conductor, the dimensions of which provide the uniform differential impedance.  
   
   
       27 . The system of  claim 25 , wherein the transition region includes a coupling device for connecting a first portion of one of the at least two signal conductors to a second portion of the one of the at least two signal conductors and connecting a first portion of the second of the at least two signal conductors to a second portion of the second of the at least two signal conductors.  
   
   
       28 . The system of  claim 25 , wherein the transition region includes a first portion of one of the at least two signal conductors spliced together with a second portion of the one of the at least two signal conductors and a first portion of a second of the at least two signal conductors spliced together with a second portion of the second of the at least two signal conductors.  
   
   
       29 . The system of  claim 25 , wherein the differential interface includes an air space between the first conductor and the second conductor.  
   
   
       30 . The system of  claim 25 , wherein the at least two coaxial interfaces are standard precision coaxial interfaces.  
   
   
       31 . The system of  claim 30 , wherein the diameter of the at least two coaxial interfaces is selected from the group consisting of 1.0 millimeter, 1.85 millimeters, 2.4 millimeters, 3.5 millimeters or 7 millimeters.  
   
   
       32 . The system of  claim 25 , wherein a center axis of each of the at least two coaxial interfaces is situated at an angle between  0  and  90  degrees from the center axis of the differential interface.  
   
   
       33 . The system of  claim 25 , wherein the differential interface further comprises a mating member for mating to another device for measurement with a 4-port vector network analyzer.  
   
   
       34 . The system of  claim 25 , wherein said transition region further includes a dielectric support structure at or near the transition between the coaxial and differential transmission environments.  
   
   
       35 . The system of  claim 25 , wherein the diameter and dimensions of the first conductor and second conductor vary within the transition region.  
   
   
       36 . The system of  claim 25 , further comprising dielectric beads for supporting the first signal conductor and the second signal conductor.  
   
   
       37 . The system of  claim 25 , wherein the differential interface has a 4 millimeter outer diameter with hermaphroditic pin and socket signal contacts.  
   
   
       38 . A method for converting from single-ended coaxial signals to differential signals, comprising: 
 coupling at least two coaxial transmission lines from a first device to at least two coaxial interfaces of an adapter;    providing a connection within said adapter between coaxial and differential transmission environments;    compensating for differential impedance discontinuity at the connection using a transition region of said adapter; and    coupling a differential interface of said adapter to a differential device.    
   
   
       39 . The method of  claim 38 , further comprising varying the dimensions of signal conductors and a shield conductor within said transition region to compensate for differential impedance discontinuity at the connection.  
   
   
       40 . The method of  claim 38 , further comprising converging the at least two coaxial interfaces at a  10  degree angle to form at least one differential line inside the adapter.  
   
   
       41 . The method of  claim 38 , further comprising mating the adapter at the differential interface with another device for measurement with a 4-port vector network analyzer.  
   
   
       42 . The method of  claim 38 , further comprising supporting signal conductors at the transition region at or near said connection using a dielectric support structure.  
   
   
       43 . The method of  claim 38 , further comprising supporting signal conductors in the coaxial interfaces using dielectric beads.  
   
   
       44 . A method for converting from single-ended coaxial signals to differential signals by providing a connection between coaxial and differential transmission environments that compensates for differential impedance discontinuity at a connection between coaxial and differential environments, wherein said compensation is achieved prior to connection to a device under test.  
   
   
       45 . An insertable test device, comprising: 
 a first adapter having a first differential interface; and    a second adapter having a second differential interface, wherein each of the first adapter and second adapter includes at least two coaxial interfaces for coupling to a coaxial device, a first signal conductor for transmitting signals through the adapter, a second signal conductor for transmitting signals through the adapter, a shield conductor, and a transition region for providing a transition between coaxial and differential transmission environments and maintaining a uniform differential impedance through the transition; and the first adapter and the second adapter are mated at the first differential interface and the second differential interface.