Microwave Circuits and Metamaterials

Project 7

Overview

Remain in same project groups for the semester.

The objective of this project is to measure third-order nonlinearities and OIP3 in the lab.

NOTE: Use the Project Report Template and keep answers to questions on consecutive sheets of paper with all plots at the end.

IN NO CASE may code or files be exchanged between students, and each student must answer the questions themselves and do their own plots, NO COPYING of any sort! Nevertheless, students are encouraged to collaborate in the lab session.

Only turn in requested plots ( Pxx ) and requested answers to questions ( Qxx ).

Part 1

In this part, third-order nonlinearities are measured in the lab.
Two different test stations are set up in the lab, each station with different equipment and a different amplifier to be measured

Test Setup/Station 1

The test setup for test station 1 is shown below
The top instrument is an Agilent N1996A spectrum analyzer
The bottom instrument is an Agilent E4438C Vector Signal Generator

First, connect the cable directly from the signal generator into the spectrum analyzer to check the frequencies and power levels of the two input signal frequencies. (The Agilent E4438C Vector Signal Generator is capable of internally creating 2 signals.)
Second, set the signal generator for -25 dBm, such that you observe two frequencies at 199.5 and 200.5 MHz, each one at a power level of -24 dBm (24 dB below 1 milliwatt) on the spectrum analyzer (red arrow below)
If the signals are already present on the spectrum analyzer screen, only minor adjustments should be needed. If the instructor is not available, you may need to refer to the detailed setup instructions at the end of this document
Make sure that the signal generator is set for -25 dBm
Then, you should observe a spectrum similar to the following

Press "Marker" and "PeakSearch" to set a marker on the left spectral line (red arrow above)
The power level should be approximately -29 dBm at 199.5 MHz,
Record this power level, Pin in dBm, and frequency (199.5 MHz) of the left peak (red arrow above). The power level that you record here will be the input power level (Pin) to the amplifier that you will measure later ( Q1 )
Make sure that the marker readout is visible, and you can clearly see the power level and frequency of the peak at the red arrow above, then take a photograph for your report ( P1 )
Connect the MAR-1 amplifier as shown below, with the spectrum analyzer connected to the output and with the signal generator connected to the input and 10Vdc power (red=positive, black=negative)

Recheck to make sure that the signal generator is set for -25 dBm
You should observe an output spectrum similar to the following

Make sure that the marker readout is visible, and you can clearly see the power level and frequency of the peak at the red arrow above, then take a photograph for your report ( P2 )
Record the power level, Pout in dBm, and frequency (199.5 MHz) of the fundamental input frequency left peak (yellow arrow above). The power level that you record here will be the output power level (Pout) of the amplifier at the fundamental frequency ( Q2 )
The gain of the amplifier is Pout-Pin, where Pout is from question Q2 and Pin is from question Q1. What is the gain in dB? ( Q3 )
The two third-order distortion frequencies are clearly seen at the left and right of the original input frequencies.
Record the power level, P3 in dBm, and frequency (198.5 MHz) of the left peak (red arrow above). ( Q4 )
Compute the output third-order intercept point OIP3 from the formula in class: OIP3=Pout + (Pout-P3)/2. ( Q5 )

As discussed in class, if you increase the input power levels by 10 dB, the third order distortion should increase by 30 dB
Increase the input level from -25 dBm to -15 dBm, and you should see increased distortion similar to the following

Make sure that the marker readout is visible, and make sure that you can clearly see the power level and frequency of the peak at the yellow arrow above, then take a photograph for your report ( P3 )
Record the power level, P3 in dBm, and frequency (198.5 MHz) of the left peak (yellow arrow above). ( Q6 )
How many dB did the level increase from Q4 to Q6? ( Q7 )

You should not need to use the following equipment setup information
Detailed instrument setup instructions, if instructor is not available

First ask the instructor to assist, since minor adjustments are often all that is needed
Otherwise:
For the Agilent E4438C Vector Signal Generator to create a 2-tone signal for measurement of OIP3.

Press “Preset.”
Press “Frequency” 200 MHz.
Press Mode>More>Multitone>InitializeTable, and select NumberTones=2, FreqSpacing=1MHz, Phase=Fixed, Seed=fixed.
Press “Mod” on, press “RF” on.
Press “Amplitude” -20 dBm, “Frequency” 200 MHz, and Mode>more>multitone>mutitoneOn and ApplyMultitone

For the Agilent N1996A spectrum analyzer

Press “Frequency”=200MHz, “span”=10MHz, “Amplitude”=10dBm.
You should see two tones at 199.5 and 200.5 MHz from the signal generator.
Press “Marker,” and “PeakSearch,” and Marker>more Add a second marker

Test Setup/Station 2

The test setup for test station 2 is shown below
The top instrument is an Agilent E4402B spectrum analyzer
The bottom instruments are a pair of Racal-Dana signal generators

First, connect the cable directly from the output of the signal-combiner (connecting the two signal generators) into the spectrum analyzer to check the frequencies and power levels of the two input signal frequencies.
Note the signal-combiner in the photo above is used to add the outputs of the 2 signal generators
Second, set the 2 signal generatorsfor -20 dBm on the dials. This requires the dials below the meters to be set to -20 dBm and the vernier dial adjusted for the meter to read "0" on the red scale as below:

You shuld observe two frequencies at 199.5 and 200.5 MHz, each one at a power level of -24 dBm (24 dB below 1 milliwatt) on the spectrum analyzer (red arrow below).
If the signals are already present on the spectrum analyzer screen, only minor adjustments should be needed. If the instructor is not available, you may need to refer to the detailed setup instructions at the end of this document
Make sure that the signal generator is set for -20 dBm, as in the picture above
Then you should observe a spectrum similar to the following

Press "Marker" and "PeakSearch" to set a marker on the left spectral line (red arrow above)
The power level should be approximately -24 dBm at 199.5 MHz,
Record this power level, Pin in dBm, and frequency (199.5 MHz) of the left peak (red arrow above). The power level that you record here will be the input power level (Pin) to the amplifier that you will measure later( Q8 )
Make sure that the marker readout is visible, and you can clearly see the power level and frequency of the peak at the red arrow above, then take a photograph for your report ( P4 )
Connect the ERA-5 as shown below, with the spectrum analyzer connected to the output and with the signal generator connected to the input and 10Vdc power (red=positive, black=negative)

See the photo above for use of the signal-combiner to sum the outputs of the 2 signal generators
Recheck to make sure that the signal generator is set for -20 dBm
You should observe an output spectrum similar to the following

Make sure that the reference level on this spectrum analyzer is set to 20 dBm (yellow circle above)
Make sure that the marker readout is visible, and you can clearly see the power level and frequency of the peak at the red arrow above, then take a photograph for your report ( P5 )
Record the power level, Pout in dBm, and frequency (199.5 MHz) of the fundamental input frequency left peak (yellow arrow above). The power level that you record here will be the output power level (Pout) of the amplifier at the fundamental frequency ( Q9 )
The gain of the amplifier is Pout-Pin, where Pout is from question Q9 and Pin is from question Q8. What is the gain in dB? ( Q10 )
The two third-order distortion frequencies are clearly seen at the left and right of the original input frequencies.
Record the power level, P3 in dBm, and frequency (198.5 MHz) of the left peak (red arrow above). ( Q11 )
Compute the output third-order intercept point OIP3 from the formula in class: OIP3=Pout + (Pout-P3)/2. ( Q12 )
As discussed in class, if you increase the input power levels by 10 dB, the third order distortion should increase by 30 dB
Increase the input level from -20 dBm on the racal-dana generator's dial to -10 dBm, and you should see increased distortion similar to the following

Make sure that the marker readout is visible, and make sure that you can clearly see the power level and frequency of the peak at the yellow arrow above, then take a photograph for your report ( P6 )
Record the power level, P3 in dBm, and frequency (198.5 MHz) of the left peak (yellow arrow above). ( Q13 )
How many dB did the level increase from Q11 to Q13? ( Q14 )

You should not need to use the following equipment setup information
Detailed instrument setup instructions, if instructor is not available

First ask the instructor to assist, since minor adjustments are often all that is needed
Otherwise:
For the Racal-Dana generators, see the photographs and instructions above
See the photo above for use of the signal-combiner to sum the outputs of the 2 signal generators
For the Agilent E4402B spectrum analyzer

Press “Frequency”=200MHz, “span”=10MHz, “Amplitude”=10dBm.
You should see two tones at 199.5 and 200.5 MHz from the signal generator.
Press “Marker,” and “PeakSearch,” and Marker>more Add a second marker

Report

NOTE ReportTemplate: Use the Project Report Template and keep answers to questions on consecutive sheets of paper with all plots at the end.

Do not add extraneous pages or put explanations on separate pages unless specifically directed to do so. The instructor will not read extraneous pages!

Only turn in requested plots (Pxx ) and requested answers to questions (Qxx ). All plots must be labeled P1, P2, etc. and all questions must be numbered Q1, Q2, etc. YOU MUST ADD CAPTIONS AND FIGURE NUMBERS TO ALL FIGURES!!

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