User’s GuideHP 85052C Precision Calibration Kit

HEWLETTPACKARD

TRAININGVIDEOTAPE

USER’S PRODUCT NOTE PRODUCT NOTE CONNECTOR SERVICEGUIDE a510-5A 851 O-8A CARE CARD MANUAL

U s i n g t h e H P 85052CH P 85052c O p e r a t i n g a n d

Precision S e r v i c e M a n u a lCa l i b ra t i on K i t

HP 85052C Precision Calibration Kit Operating and Service Package

T A B L E O F C O N T E N T S

Chapter 1 Introduction to the Calibration KitCalibration Kit ComponentsAir Lines

O-2 GHz LoadsReflect StandardsIsolation StandardsPrecision AdaptersTools

5

Chapter 2 Performing a TRL 2-Port Measurement CalibrationElectrostatic DischargeClean and InspectCleaningUsing Connector GagesConfigure Port 1 and Port 2Install Test Port Return CablesInstall Precision AdaptersAir Line Frequency CoverageLoad Calibration Kit DefinitionMeasure Standards

When Stop Frequency is Greater than 7 GHzWhen Start Frequency is Less than 7 GHzWhen Start Frequency is Less than 2 GHz

Check the Calibration

11

Chapter 3 Noninsertable CalibrationsGeneral TheoryNoninsertable Device ConfigurationsAdapter Removal Calibration Procedure

Chapter 4 Other CalibrationsChanging Air Line Frequency RangeLowband Reflection Instead of

0 to 2 Loads or 2 to 7 LineLowband Reflection Procedure

26

28

3

I N T R 0 D U C T I 0 N

What’s in this Guide Th*IS guide describes how to use the HP 85052C calibration

Chapter 1

Chapter 2

Chapter 3

Chapter 4

User’s Video

Application Note

Service Manual

Before Proceeding. . .

kit with the HP 8510 vector network analyzer to performthe TRL 2-Port measurement calibration technique, andhow to evaluate the results of the calibration.This chapter introduces the components of the kit, anddescribes important connection techniques.In this chapter, detailed sequences describe how to set upthe network analyzer system, and use the kit to performthe 3.5 mm TRL ~-POX? Calibration procedure.Since many applications require measurement of devicesthat are not insertable, this chapter describes the theory ofand how to use the kit to perform the Adapter Removalprocedure for measurement of noninsertable devices.This chapter, entitled “Other Calibrations,” describes useof the network analyzer Modify Cal Kit function to redefinethe calibration kit and how to use the Lowband Reflectionoption.

This guide is supplemented by a video presentation thatshows how an experienced operator uses the calibration kitparts. If you have access to this tape, view it along with thismanual first.

Another supplement, Application Note 326, MicrowaveConnector Care, gives general principles of microwaveconnector care. With the exception of changing therecommended connector cleaning fluid from the previouslyrecommended liquid freon (a CFC) to isopropyl alcohol, thisconnector care manual will serve as an excellent startingpoint to become familiar with general requirements forachieving optimum results using this calibration kit.

Refer to the Service Manual for specifications, replaceableparts, and other pertinent information. Inside thecalibration kit box a quick reference card illustratesprocedures for connecting and disconnecting the air line.This memory aid is helpful to the operator who is familiarwith the kit and TRL 2-Port calibration theory.

The parts in this kit are delicate and must be handled withcare to avoid damage that would affect the accuracy of thecalibration. Check all test device connectors carefullybefore connecting to the TRL adapters.

HP 85052C Precision Calibration Kit

C H A P T E R O N E

Introduction to the Calibration Kit

The HP 85052C 3.5 mm Precision Calibration Kit isdesigned to be used in TRL 2-Port measurement calibra-tion as implemented in vector network analyzers. TRLstands for Thru-Reflect-Line, naming the main standardsused in the accuracy enhancement procedure.

TRL represents a family of calibration techniques thatmeasure various combinations of transmission lines andreflection standards to determine the 2-Port 12-term errorcoefficients. The specific calibration technique describedhere uses measurements of the zero-length thru connec-tion, identical reflection standards at each port, and one ormore transmission lines of appropriate impedance andlength for the frequency range. Both the TRL 2-PORT andthe Full 2-Port calibration types use the same accuracyenhancement mathematics to correct the measured data.TRL, as implemented with this calibration kit, brings con-venience, accuracy, and repeatability to the errorcorrection process because the typical TRL calibrationrequires fewer parts that are simpler to connect and -disconnect.

The 3.5 mm geometry connector is the most frequentlyused connector when frequency coverage up to 26.5GHz, reasonable commonality, and durability is desired.Well constructed connectors and transmission lines canwork up to 34 GHz. Metrology grade versions of this con-nector are used for high performance test ports and forcalibration standards. Whether the device uses SMA,SMA-compatible, or 3.5 mm, the HP 3.5 mm connectorsused on the HP test ports, adapters, cables, and calibrationstandards provide the most accurate and repeatable -solution.

All male connectors in this kit are HP precision with care-fully controlled dimensions. All female connectors are ofthe HP precision slotless (PSC-3.5) type. These connectorsare designed for long repeatability when used with appro-priate technique. This means careful inspection of the kitparts, familiarity with their use, and careful inspection ofthe Device Under Test (DUT) connectors. Refer to the“Specifications” chapter in the HP 85052C Service Man-ual, and the Technical Note included with this manual forspecific information about precision slotless connectors.

5

Calibration Kit Components

Air Lines

The HP 85052C 3.5 mm Precision Calibration Kit containscomponents useful for several different calibration tech-niques. The parts used for the TRL 2-Port calibration are:

l Longer precision air line for 2 to 7 GHzl Shorter precision air line for 7 to 32 GHzl Male and female short circuitsl Male and female fixed loads

Other parts included are:

l Three precision TRL adapters. Two adapter anti-rotation clampsl Calibration kit definition tapel Male and female open circuitsl Tools

Note the reference card in the box and the material list onthe bottom of the box.

These are precision air lines. Each one is always stored inits installation tool to help prevent damage and preservecleanliness.

The shorter air line is used for measurement calibrationover the 7 to 32 GHz frequency range. The longer air line isused for measurement calibration over the 2 to 7 GHzrange. Each air line is fully specified at all frequencieswithin its stated range.

7 - 3 2 LINE

II a’

2 - 7 L I N E

Line Standards - 7 to 32 GHz and 2 to 7 GHz Air Lines Installed in Tools with Storage Bottles

Polar Display Showing Phase Response of LongerAir Line Over 2 to 7 GHz Frequency Range

Polar Display Showing Phase Response of ShorterAir Line over 7 to 26.5 GHz Frequency Range

Air Lines Removed From installation Tools

Each air line consists of a separate outer conductor andcenter conductor and includes its own tool used forinstalling and removing the parts from the test port. Bothare insertable. Each has a male end and a female end. Themale end of the air line fits into the installation tool.

The parts may be removed for inspection, if necessary, butthe tool is always used to install the parts for calibration.Use extreme care in handling these parts. Use static dissi-pative finger sheaths, or “finger cots” to prevent contami-nation. Liquid or solid residue on the connector parts willdegrade performance. In particular, the inner conductorscan be easily deformed by squeezing. Do not use metallictweezers or other devices to pick up or hold the parts.

installing the Air Lines in installation Tools

0 to 2 GHz Loads Th’IS implementation of the TRL 2-Port calibration allowsmeasurement of the loads to determine the error coeffi-cients up to 2 GHz. Technically, the measurement istreated as an infinite-length transmission line whose inputreflection is the reference impedance, Z,.

Note: The male and female broadband loads aremanufactured to tolerances that assure equivalent responses,at least below 2 GHz. If one is damaged or otherwisebecomes defective, calibration erroriwill result.

0 to 2 GHz Loads -Male and Female Fixed Broadband Loads

Reflect Standards

Reflect Standards -Male and Female Short Circuits

Isolation Standards

isolation Standards -Male and Female Broadband Loads

Precision Adapters

In this TRL 2-Port calibration, the reflect standards areidentical short circuits with one connected to Port 1 andone to Port 2.

The male short circuit and the female short circuit aremanufactured to tolerances that assure equivalentresponses. If one is damaged or otherwise becomesdefective, calibration errors will result. Errors will alsoresult if the open circuits are used in the procedure insteadof the short circuits (unless the calibration kit standardassignment definition is changed).

The fixed loads used for the isolation part of the calibrationare the same broadband loads as used for the O-2 loadsmeasurement. Exact equivalent responses are not requiredfor this step.

Three precision adapters are included in this kit. Two arealways recommended for the 3.5 mm TRL 2-Portmeasurement calibration. All three can be used in theadapter removal calibration for measurement of nonin-sertable devices. Complete performance verificationassumes use of the precision adapters in this kit as the testports.

MALE to FEMALE MALE to MALE FEMALE to FEMALE

Precision TRL test port adapters

Recession Limits The female receptacle recession and the male pinrecession, along with other mechanical specifications ofPort 1 and Port 2, must be within limits to meet completemeasurement specifications. The precision adapterssupplied in this kit are manufactured to metrologystandards in order to obtain the best measurementaccuracy specifications. If other connectors than theseprecision adapters are used as the test ports, they must befully inspected. Using other than the highest qualityconnectors as the test ports will reduce accuracy andrepeatability as well as possibly damaging the calibrationstandards.

Precision Connectors For general use, any 3.5 mm precision slotless female con-nector can be used for the female test port. The 3.5 mmprecision male connector used on the male end of theseadapters is always required for measurements between7-32 GHz in order to connect the 7-32 GHz air line in thiskit. Any 3.5 mm precision male connector can be used atfrequencies less than 7 GHz.

hstdation Feature The precision adapter male connector has a special featureto allow installation of the 7-32 air line.

GAP

_L

t

l Grasp the knurled sleeve and move the nut to itsextended position by pulling on it.

This is the position used for measurement of the 7-32 GHzair line.

Extended Position

GAP

. Now move the sleeve forward and push the nut backinto its standard position.

This position is used to install the short air line, forconnecting the other calibration standards, and forconnecting the device under test.

Standard Position

9

/o ITorque Wrench

Tools At qor ue wrench and spanner wrench are included in thekit to loosen and tighten the connectors. The small torquewrench is used for the 3.5 mm nuts. The large torquewrench is used for the 20 mm nuts on the precisionadapters. It is included with the test set. The spannerwrench is used to hold the precision adapter while usingthe appropriate torque wrench to tighten the connection.

Also included is the hex wrench for tightening andloosening the adapter anti-rotation clamp securing screws.

Spanner Wrench

When making connections, turn the nut on the device,never turn the device itself. Turning the device will causeexcessive wear of both connector mating surfaces andcause debris to collect in the female receptacle.

Torque Wrench (not included) When making a connection:

Hex Wrench for AdapterAnti-Rotation Clamp

1. Carefully engage the male and female contacts, andthen tighten the nut by hand.

2. If necessary, use the spanner to hold one devicestationary against the direction of torque.

3. Hold the torque wrench with your thumb and indexfinger near the end of the handle.

4. Tighten the connection until the ball in the handlecrests on the cam (as the handle begins to “break”,releasing tension).

TIGHTEN WITHTORQUE WRENCH

HOLD WITHSPANNER WRENCH

It is not recommended or necessary to fully “break” thehandle of the torque wrench to reach the fully-specifiedtorque. As soon as the handle moves out of alignment, theconnection is properly torqued.

Reverse the above procedure to disconnect the connectors.

HANDLE BEGINS TO BREAK( C O R R E C T POINT T O S T O P)

HANDLE FULLY BROKEN TORQUING(NOT RECOMMENDED) DIRECTION

Using the Spanner and Torque Wrench Correct Torque Value

10

C H A I? T E R T W 0

Performing a TRL Z-PortMeasurement Calibration

This example describes use of the HP 3.5 mm precisioncalibration kit to measure an insertable device. When thetest device is insertable, the test ports can be connectedtogether to establish the Thru connection duringcalibration.

The procedure used for performing any measurementcalibration is as follows: .

1. Clean and inspect all connectors.2. Initiate measurement calibration procedure and

measure standards.3. Verify the calibration.4. Connect the device under test.

The rest of this section explains the above steps.

Electrostatic Discharge when you make connections to the network analyzer,either directly to the test set port or indirectly through acable that is connected to the test set port, protect theinstrument against electrostatic discharge (ESD). Alwayswear a grounding wrist strap connected to a conductivebench mat when working near sensitive equipment.

The human body almost always has some static charge.You are not usually aware of this charge because thehuman threshold for the perception of a static dischargeshock is about 30 kV. ESD as low as 60 volts can damagesensitive microcircuits.

Clean and Inspect The accuracy of error-corrected measurements using thenetwork analyzer depends upon the quality of themeasurement calibration. In turn, the quality of thecalibration depends on the condition and cleanliness of thetest ports and calibration standards, and the operator’s skillin making connections. Repeatability and accuracy areimproved by removing contaminants from mating surfacesduring cleaning.

Carefully inspect the following for cleanliness anddamage. Look for deformation of the male pin or thefemale receptacle, and for metallic and organic residue onthe mating surfaces.

l Test set test portsl Test port cablesl Precision adaptersl Calibration standardsl DUT Connectors

11

A low power magnifier, less than 6x, is adequate to inspectthe parts. Do not be concerned with minor defects such asscratches visible only with the magnifier; these willprobably not affect performance. If inspection showsmoisture, oil, or other residue, clean the parts.

When examining the female connector, look at the innercontact to see that the gripping fingers are not bent.

The greatest variable in the accuracy and repeatability forthese demanding measurements is the experience andattention to detail of the person actually making theconnections. Before going on, examine all parts carefully.

SPRING FORCES INNER

INSERTED MALE PIN

Detail of Precision Slotless Female Connector

Cleaning The parts must be clean in order to achieve best results.Use isopropyl alcohol, dry air or nitrogen, and lint-freeswabs to remove contaminants.

In general, do not force cleaning materials into connectorparts and do not immerse the part in cleaning fluids. Justmoisten the swab and wipe the surface lightly. To dry thepart, use a dry swab or light pressure from a dry air ornitrogen source.

Do not leave lint or particles of the swab in the connector.

If there is doubt about the condition of the connector, usethe connector gages to check the connector dimensions.The same care should be used for all connectors, especiallythe device under test.

12

Using Connector Gages

Before Connecting

Gaging is optional for the precision connectors in thiscalibration kit if the male and female center conductors areconcentric and do not show physical damage.

However, due to the large range of dimensions found onmost DUT connectors, the DUT connectors must always beinspected and gaged before connecting them to theprecision adapters. This is not usually a problem for theDUT female connectors, but may be a problem for DUTmale connectors, especially the economical SMA andSMA-compatible types.

BLACK %G( R E C E S S I O N)

RED PLUS SIGN(NOT USED)

LIMIT POINTER

DIAL INDICATOR

F E M A L E 3 . 5 m mCONNECTOR

GAGE

BLACK P L U SSIGN( P R O T R U S I O N )

RED MINUSSIGN( N O T U S E D)

GAGE INCREMENT0 . 0 0 0 1 I N C H

,r ’ ZERO SET KNOB

Connector Gage

13

Measurement Errors The gage measures the pin depth (recession) of theconnectors. If the pin depth to too far negative, errors willresult from excessive air gap in the connection.

Connector Damage If the pin depth is positive (protrusion), both matingconnectors will almost certainly be damaged.

Also, if the male pin diameter is greater than the maximum3.5 mm specification, it will cause permanent damage tothe female receptacle. If you try to measure the pin depthand the gage will not fit over the pin, it is an immediateindication that the pin is too large and must not beconnected to the precision adapters. The male pin of theDUT connector may fit into the gage and give a correctmeasurement, but still be slightly too large for theprecision adapter female receptacle.

Repair and Replacement In general, bent or deformed parts cannot be repaired inthe field. It is necessary to return the part to an HP servicecenter for repair or replacement. The air line center andouter conductors must be replaced as a set. Refer to thereplaceable parts chapter in the service manual suppliedwith the calibration kit for replacement part numbers andordering information.

--A- RECESSION

Cross Section of Female Connector Showing Recession limits

RECESSION _) j_

Cross Section of Male Connector Showing Recession Limits

14

Configure Port 1 and Port 2 several configurations are possible, depending upon thefrequency range, available cables, operator convenience,and DUT requirements. Following is an example hookupusing the two-cable set and two examples using a singlecable. The appropriate precision adapters are installed onthe ends of the cables and become Port 1 and Port 2.

TEST SETPORT 1 TEST PORT

ANTI-ROTATIONTEST SET

P O R T 2

I81 !~,!il ADAPTER

ANTI-ROTATION

PORT 1

PORT 1

PORT PORT1 2

Dual Cable Setup

P O R T 2

Single Cable, Port 1 Female

P O R T 2

Single Cable, Port 1 Male

15

Install Test Port Return Cables When all parts are ready for use, connect the test portextension cables. To connect a cable to the test set:

Loosen the test port anti-rotation clamp securing screwand slide the clamp over the cable far enough to provideaccess to the cable connector.

Connect the cable to the test port and tighten using thetorque wrench.

Slide the clamp toward the port, aligning it so that theflats on the clamp mate with flats around the test port.Tighten the clamp securing screw. This clamp keeps thecable from becoming loose from the test set connector.

Install Precision Adapters T o install the precision adapters and adapter anti-rotationclamp:

. Connect the adapter to the cable, tighten finger tight, andthen use the spanner and the torque wrench to achievethe final torque.

l Loosen the adapter anti-rotation clamp securing screwsand slide the clamp over the adapter. Align the clamp sothat it can grip both the cable connector body and theadapter body. Tighten the clamp securing screws. Thescrew tightening order is not important.

The adapter anti-rotation clamp assures that the TRLadapter does not become loose during calibration andmeasurement.

l Connect the second TRL adapter and its anti-rotationclamp to serve as Port 2.

PORT 1 P O R T 2

Two Cable Setup with AZ1 Components Connected

16

Air Line Frequency COVerage This illustration shows the frequency range covered by theair line and fixed loads for the Lines part of the TRL 2-Portcalibration procedure. If measuring over the entirefrequency range, measure the 7-32 Line first, then the 2-7Line, then the O-2 Loads. If measuring over a reducedfrequency range, only those standards for that frequencyrange need to be measured. For example, if you are testingover the 3-22 GHz range, only the 7-32 Line and the 2-7Line must be measured.

The standard label for the 2-7 Line would indicate that itsdata is valid only from 2 to 7 GHz. However, you maychoose to use data from the 2-7 Line down to the 1 GHz bysimply not measuring the O-2 Loads. If the O-2 Loads aremeasured after the 2-7 Line, the O-2 Loads data will replacedata from the 2-7 Line.

45 1 2 7 32MHZ GHz GHz GHz GHz

F1l-l i-l l-l

IrJl

Ll u u IIaEl-I

2 - 7 L I N E

m-m7 - 3 2 LINE

O - 2 L O A D S

Frequency Coverage for Line Part ofMeasurement Calibration

Load Calibration Kit Definition To begin measurement calibration, first load the calibrationkit definition from tape or disk.

Press:

TAPE/DISCSTORAGE is TAPE

LOADCAL KIT 1-2

CAL KIT 1FILE 1

When the calibration kit definition is loaded, the CAL 1softkey label will read 3.5 mm C. 1.

17

Measure Standards N ow perform the TRL 2-Port measurement calibrationprocedure using the HP 85052C 3.5 mm PrecisionCalibration Kit.

Note: The standards are measured in the order: Thru,Reflect, Line, Isolation in order to connect the loadstandards just once.

Press:

CALCAL 1TRL 2-PORT

l Connect the TRL male adapter (Port 1) to the TRL femaleadapter (Port 2).

l Press THRU. The HP 8510 makes six measurements; theyare S,,, S,,, S,,, S,,, and two specially redefined userparameters.

l Connect the Short circuit to Port 1.

. Press S,, REFLECT SHORT. S,, is measured.

S,, Reflect Short Standard

l Connect the Short circuit to Port 2.

l Press S,, REFLECT SHORT. S,, is measured.

l Press LINES.

S,, Reflect Short Standard

18

When Stop Frequency is Greater than 7 GHz If the stop frequency is greater than 7 GHz, install the 7-32GHz air line as follows:

l Move the Port 1 nut to its standard position and carefullyinsert the air line into the male connector using theinstallation tool.

Insert Air Line

l Squeeze the installation tool (closing the slot) to releasethe center conductor. Then pull the tool away from theconnector, leaving the outer and the center conductors inplace.

Sqeeze Tool to Release, then Pull

GOOD BAD

-IL- GAP

l Examine the outer and center conductors to see that theyare in place and concentric. If the center conductor is notcentered, use the installation tool to align it.

Check Concentricity

l Move the adapter nut to its extended position.

Extended Position with Air Line Installed

19

TURN n HOLD

. Carefully align and engage the Port 2 female contactwith the Port 1 male contact.

l Tighten finger tight, then use the spanner and torquewrenches to achieve the final torque.

Connect Port 2

l Press 7-32 LINE. The HP 8510 makes six measurements.All frequencies of the current range are measured, but onlydata from 7 to 32 GHz is used to compute error coefficients.

To remove the 7-32 GHz air line:

l Loosen the Port 1 nut, and then carefully move the Port 2adapter away.

Disconnect Port 2

l Move the adapter nut to its standard position.

Standard Position with Air Line Installed

l Examine the outer and center conductors to see that theyare in place.

l Carefully press the insertion tool onto the connector.

Connect the Insertion Tool

20

Hold the tool close to the connector without squeezingthe tool. Carefully pull the assembly away from theconnector.

Remove the 7-32 Line

. Check to see that both the inner and the outer conductorshave been removed and are secure in the installationtool.

If any part of the air line remains attached to the male port,first press the tool back onto the connector. Then, try towithdraw the tool and the air line parts again withoutclosing the slot.

If the air line center conductor remains with the femaleport, use the installation tool to remove it as follows:

Squeeze the tool and push it to engage the centerconductor.

Hold the tool close to the connector, squeeze the toolwithout closing the slot, and pull the assembly away.

Use your fingers to remove the center conductor from thetool.

Remove Center Conductorfrom Port 2 (if necessary)

l Carefully insert the center conductor back into theinstallation tool, male end first.

21

When Start Frequency is Less Than 7 GHz If the start frequency is less than 7 GHz, install the 2-7 GHzair line as follows:

TURN f\ HOLD

.

.

Move the Port 1 nut to its standard position. Carefullyinsert the air line outer conductor and center pin into themale connector using the installation tool.

Hold the air line outer conductor and tighten the Port 1nut finger tight. Use the torque wrench to achieve thefinal torque.

Connect the 2-7 Line

l Press the tool lightly to engage the center conductor.

Engage the Center Conductor

l Squeeze the tool to close the slot, then pull the tool awayfrom the connector, leaving the center conductor.

Remove the Tool

l Examine the outer and center conductors to see that theyare in place and concentric. If the center conductor is notcentered, use the tip of the installation tool to align it.

GOOD BAD

Check the Concentricity

l Move the air line nut back to expose the centerconductor. Carefully engage the Port 2 female contactwith the Port 1 male contact. Be patient making thisconnection because it is easy to move the centerconductor off center.

Move the Nut Back

22

l Move the nut forward to engage the threads, tightenfinger tight, then use the spanner and the torque wrenchto achieve the final torque.

Connect Port 2

. Press 2-7 LINE. The HP 8510 makes six measurements.All frequencies of the current range are measured, but onlydata from 1 GHz to 7 GHz is used to compute errorcoefficients.

To remove the 2-7 GHz air line:

l Loosen the air line nut and carefully move Port 2 awayfrom Port 1.

Disconnect Port 2

Engage the Tool

TURN f\ HOLD

l Insert the tool and lightly press it to engage the centerconductor.

l Loosen the adapter nut and then disconnect the outerconductor from the adapter. The center conductor will beremoved with the outer conductor.

Remove 2-7 Line

Note: It is important to be very careful to move Port 2 awayin a straight motion because the center conductor may stay inPort 2. If the center conductor remains with the female port,use the installation tool to remove it. Carefully insert thecenter conductor back into the insertion tool, male end first.

Remove the Center Conductorfrom Port 2 (if necessary)

23

When Start Frequency is Less than 2 GHz If the start frequency is less than 2 GHz, measure the O-2Loads as follows:

- ,r . - -..- -

l Connect a fixed load to Port 1 and a fixed load to Port 2.’ ..

l Press O-2 LOADS. The HP 8510 makes six measurements.All frequencies are measured, but only data up to 2 GHzare used. These measurements replace error coefficientsobtained from measurement of the 2-7 GHz air line below2 GHz. Leave the loads connected for the Isolation step.

Connect the O-2 Loads

l Press LINES DONE.

l Press ISOLATION.

If maximum transmission dynamic range is not required, skipthe isolation part of the calibration by pressing OMITISOLATION and then ISOLATION DONE.

Or, to obtain maximum transmission dynamic range,perform the isolation part of the calibration as follows:. Connect a fixed load to Port 1 and a fixed load to Port 2.. Increase the AVERAGING FACTOR for the isolation

measurement to at least 128. Then press FWD. ISOL’NISOL’N STD. S,, is measured.

.

.

.

Press REV. ISOL’N ISOL’N STD. S,, is measured.

Press ISOLATION DONE. You may wish to reduce theaveraging factor for measurement of the device under test.

Press SAVE TRL 2-PORT.

Fomard and Reverse isolation Standards

When the computation of error coefficients is complete, pressCAL SET 1 (or any other cal set). Error coefficients derivedfrom measurement of the TRL standards are computed andsaved, and then 2-Port correction is turned on.

Carefully inspect the connectors on the device under testand measure their center conductor pin depth beforeconnecting the device under test to the system. Device-under-test connectors with incorrect pin size, pin depth,or pin alignment can damage the test port adapters.

24

Check the Calibration A good first check of the calibration is to measure thetransmission and reflection characteristics of the longer airline. Connect the air line between Port 1 and Port 2 andview the Szl magnitude and phase and the S,, magnitude.The air line should exhibit low insertion loss and linearphase. The S,, should be constant over the entirefrequency range.

2-7 Line with Short Circuit

>

2-7 Line S,, Magnitude and Phase

For a second check, connect the 2-7 Line to Port 1, thenconnect the Short circuit to the end of the air line, and viewthe reflection response.

Select:

SD O M A I NTIME BAND PASS

View the S,, response. Use the marker to measure theresponses at 0 seconds (a rough measure of effectivedirectivity) and the mismatch at twice the length of the airline (a rough measure of effective source match). The traceshould appear as shown below. If not, the calibration hasnot been performed correctly or the calibration devices aredefective.

START -50.0 PI

*TOP 400.0 PI

Plot of Time Band Pass with Shorted Air Line

25

C H A P T E R T H R E E

Noninsertable Devices

Noninsertable Device Configurations

General Theory The o owing sequence describes the adapter removalf 11method of calibration for measurement of a noninsertabledevice. This procedure is the most complete and effectivecalibration procedure for measurement of noninsertabledevices. Although this technique does require two separate2-Port calibrations, it remains the only traceable methodfor minimizing the uncertainty in this measurement. Thethree precision adapters in this calibration kit provide theparts required to make the process relatively easy.

Detailed information about the adapter removalcalibration is contained in HP Product Note 8510-13,available from your local HP Sales Office.

The previous calibration sequence assumed that the deviceunder test is insertable; it has a male connector on one portand a female connector on the other port. Thus, themeasurement system can be calibrated and then the testdevice inserted without changing the system test portconnectors.

However, the majority of devices used in microwavesystems are noninsertable. Of interest here are deviceshaving either both male or both female 3.5 mm connectorson Port 1 and Port 2.

Female to Female If the device you are measuring has two female connectors,_. . . _ -.your setup would look like the hgure on the left. ‘1 hefemale-to-female precision adapter is substituted for thedevice under test to accomplish this calibration.

Male to Male If the device you are measuring has two male connectors,your setup would look like the figure on the left. The male-to-male precision adapter is substituted for the deviceunder test to accomplish this calibration.

Male-Male Dmice Under Test

26

Adapter RemovalCalibration Procedure

Create Cal Set for Port 1

Port 2 Cal Srt

Create Cal Set for Port 2

Port 2 Cal Set

Adapter Removal Mathematics

Renmr the Adapter and Cormect the DUT

First create the Port 1 calibration set by performing the TRL2-Port calibration between Port 1 and the adapter. Keepthe adapter connected to Port 2 during the entireprocedure. Save the calibration in Cal Set 1.

Next create the Port 2 calibration set by performing theTRL 2-Port calibration between Port 2 and the adapter.Keep the adapter connected to Port 1 during the entireprocedure. Save the calibration in Cal Set 2.

The Adapter Removal function mathematically combinesthe Port 1 cal set with the Port 2 cal set to produce a thirdcal set having the effects of the adapter removed. Theresulting cal set is as if Port 1 and Port 2 could be connectedtogether.

When the two calibrations have been saved, proceed withthe adapter removal sequence as follows:

Press:

CALMORE

MODIFY CAL SETADAPTER REMOVAL

Press CAL SET for PORT 1, then CAL SET 1.

Press CAL SET for PORT 2, then CAL SET 2.

Press ADAPTER 3.5 mm C.l. This specifies thecalibration kit that includes the length specification for theprecision adapter.

Press MODIFY & SAVE, then CAL SET 3.

The new calibration set is computed and stored. 2-Portcorrection is turned on.

Now remove the third adapter and connect the device undertest.

The display should now show an accurate S-parametermeasurement of the device.

27

28

C H A P T E R

Other Calibrations

F 0 U R

Changing the Air Line of your application requires a frequency range slightly

Frequency Range beyond the standard frequency range of one of theprecision air lines, you may extend the frequency range ofone of the air lines in order to accomplish the calibration byconnecting only one of the air lines.

The error coefficients are determined with best accuracywhen the Thru and the Line phase response is separated byt 90 degrees at corresponding frequencies. When thetransmission phase response of a line standard is the sameor gets very close to zero or 180 degrees of the Thrustandard at the same frequency, the result becomes lesscertain. The correct result cannot be determined when thephase response is exactly equal or 180 degrees apart. Thisis why a particular length air line covers a specificfrequency range.

To evaluate the phase response, first do a simple transmis-sion frequency response calibration using the Thrustandard (Port 1 connected directly to Port 2), thenmeasure the S,, phase of the air line. The standard air linefrequency specifications provide for greater than 20degrees separation.

Experiment with this by using the Modify Cal Kit functionto change the Minimum Frequency or MaximumFrequency specification for the air line, and thenperforming the TRL 2-Port calibration procedure. Withcorrection on, trace noise on the error-corrected trace mayincrease at the points where the phase of the air line usedfor calibration approaches the phase of the thru, oftenshowing large discontinuities at the point where the phaseof both standards is identical or separated by 180 degrees.

If this error is acceptable in your measurement, change thestandard label for the air line and save the redefined cal kiton tape for later use. If the error is not acceptable, reloadthe standard cal kit definition.

Lowband Reflection instead Of The Lowband Reflection part of the TRL 2-Port procedure

O-2 Loads or 2-7 Line is optional. If used, error coefficients obtained by thisprocedure replaces measurements of the O-2 loads.

For this calibration kit, the lowband reflection part of thecalibration is typically not used because measurement ofthe O-2 Loads provides better accuracy (given that theloads are in good condition and repeatable).

If you do not select LOWBAND REFLECTION, the errorcoefficients obtained from measurement of the TRLstandards are used over the complete current frequencyrange. If you do select LOWBAND REFLECTION, errorcoefficients obtained from these additional calibration stepswill be used up to 2 GHz.

In actual measurement applications, the Lowband Reflectionoption will not produce greater accuracy than using the O-2Loads. If you are uncertain, it is relatively simple to comparemeasurement results using the different techniques.

Lowband Reflection Procedure Selecting the Lowband Reflection part of the procedureguides you through these additional steps to measure anopen circuit, short circuit, and fixed load at Port 1 and anopen circuit, short circuit, and fixed load at Port 2. So, if thestart frequency is less than 2 GHz and you wish to use theopen/short/load technique for calibration below 2 GHz,then after measuring the Thru, Reflect, Isolation and Linestandards and before pressing SAVE TRL 2-PORT, performthe following lowband reflection sequence.

Measure Thru, Reflect, Isolation, and Line standards. If thestart frequency is less than 2 GHz, press LOWBANDREFLECTION.

l Press LOWBAND REFLECT’N

l Connect the Short circuit to Port 1 and then press(S,,): SHORT.

. Connect the Open circuit to Port 1 and then press(S,,): OPEN.

l Connect the Fixed Load to Port 1 and then press(S,,): LOAD.

l Connect the Short circuit to Port 2 and then press(S,,): SHORT.

l Connect the Open circuit to Port 2 and then press(S,,): OPEN.

. Connect the fixed load to Port 2 and then press(S,,): LOAD.

l Press REFLECT’N DONE.

l Press SAVE TRL 2-PORT, and then CAL SET 1, (or anyother cal set).

When SAVE is pressed, error coefficients from measurementof the Open, Short, and Load are used for frequencies below 2GHz; and coefficients from measurement of the Thru, Reflectand Line are used for frequencies above 2 GHz.

29

u!! HEWLETTPACKARD

Customer Order Number85052-90059Printed in USA April 1995