Overview

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

Save a snapshot of the schematic and paste it into your report.    ( P1 )

Double-click the "gear" icon in the upper right of the window to simulate.

The data plotting window and the following plot should appear.

Save the schematic as ampoip3freq100

Go to the new schematic, double click the Harmonic Balance, and note the frequencies. Reset them to 100 and 101 MHz. Double click the AC source and set the frequencies to the new frequencies. Rerun the simulation, and note the re-plotted data. Drop another plotting box in the visible area, and in the pop-up window:

Select DataSet -> Vout -> Add-> SpectrumdBm
Set PlotOptions -> xaxis -> 95-105 MHz,  y-axis -> -120 to -20 dBm.
You should get a new OIP3 spectrum around 100 MHz.

Save a snapshot of this new plot and turn it in. ( P2 )

Computing OIP3 in dBm from the new plot, what is the OIP3 at 100 MHz? (Q1 )

What is the third order intercept specification (TOI) of the amp (double-click the amp on the achematic)? (Q2 )

Based on your measurement, is TOI specified at the input or output of the amp in ADS? (Q3 )

Part 2

Start the software:

Next, select the design ami05T33aDiffAmp2.dsn, and double click that design file.

Double-click the schematic in the right half of the window, and the following schematic should appear.

Save a snapshot of the schematic WITH ANNOTATED DC BIAS POINTS and turn it in. (Use MenuBar::Simulate->AnnotateDCSolutions to get the DC voltages on the schematic.) ( P3 )

Double-click the "gear" icon in the upper right of the window to simulate.

The data plotting window and a plot similar to the following plot should appear.

WARNING.
The dBm reading in these plots are in error.
The value is 3 dB below the true value in dBm.

On the manual page for the dbm() function, it states: ... voltage is assumed to be a peak value. Using the dbm() function with rms will yield a result that is 3 dB too low unless the noise voltage is first converted to peak: noise_power = dbm(vout.noise * sqrt(2)); On the manual page for the vfc() function, it states: ... This measurement gives the RMS voltage value of one frequency-component of a harmonic balance waveform Hence, the three dB error.

To correct your OIP3 plots, you must double-click the dBm(xxx) on the plot, and mutliply by 1.414 (square root of 2). This is illustrated in the above plot.  A more safe method might be to multiply by 1.414 on the place in the schematic sheet where the variable is defiled, i.e., Voutlin=1.414*vfc(vout,0,{1,0}).

Save a snapshot of this corrected OIP3 plot and turn it in.  Hint: you shoud see -76.2 dBm IP3 level at -25 dBm input. ( P4 )

In the schematic, what is purpose of the BSIM3 item? (Q4 )

What is the frequency at which the OIP3 was measured? (Q5 )

What is the gain of the amplifier? (Q6 )

What is the output 1 dB compression point of the amplifier? (Q7 )

What is the the output third order intercept point of the amplifier? (Q8 )

Decreasing the dc current source from 20 to 5 mA, re-plot the OIP3 plot. Save a snapshot of  this single plot and turn it in. ( P5 )

After decreasing the dc current source to 5 mA, what is the output 1 dB compression point of the amplifier? (Q9)

After decreasing the dc current source to 5 mA, what is the output third order intercept point of the amplifier? (Q10)

After decreasing the dc current source to 5 mA, what is the threshold voltage, Vth, of the transistors in the differential amplifier? (Use MenuBar::Simulate->DataDeviceOpPoint to get the threshold voltage on the transistor.) (Q11)

If the current source is cut in half, how may dB do you expect the output power capability to decrease? (Q12) Hint: is the amplifier voltage or current going to clip first?

Part 3

• HFSS from linux
  
• In this part, you will construct a waveguide and measure its S-parameters and cutoff frequency
• Log into a linux termnal
  
• Run Mosaic::Engineering::Electrical::HFSS
• MenuBar::Project::InsertHFSSdesign as illustrated below
  

• MenuBar::HFSS::SolutionType::DrivenModal
• MenuBar::Modeler::Units select mm
• Next draw the waveguide as a box: MenuBar::Draw::Box  And at the bottom of the screen enter  x=0 y=0 z=0 mm, and  then type "enter "or "carriage return" then type dx=100 dy=22.9 dz=10.2 mm, and  then type "enter "or "carriage return"
• Alterntively, click the DrawBox tool icon (yellow arrow below), draw any box, click the "createBox" item (red arrow below), and edit the properties (blue arrow below) to set the Position=(0,0,0) and dimensions dx=100 dy=22.9 dz=10.2 mm as given above.
• Press the "fitAll" toolbar item (orange arrow below) to view the object.
  

when done it should look like:

• Save a snapshot of the waveguide as above and paste it into your report.    ( P6 )
• MenuBar::View::FitAll::AllViews
• MenuBar::Edit::Select::Object  then right-click the waveguide and AssignMaterial air
MenuBar::Edit::Select::Faces  then right-click the long waveguide top face,
then right-click nextBehind to get the bottom plate, then right-click assignBoundary Perfect-E
and repeat this for the long top face.
 In the same fashion assign the two long sidewalls as Perfect-E boundaries.

• Right-click the front face, and AssignExcitation::WavePort, set name=input1,
next, numberofmodes=1, click on the integration line field and select newline,
and draw a line from the center bottom of the port to the center top of the new port,
click next, donot renormalize, and finish.  Repeat this for the output port.


• Highlight the excitation ports in the ProjectManger pane (blue arrow below)
  
The ports and integration line should look like:

• The toolbar icons can be used to move the view (orange arrows above)
  
• Save a snapshot of the one port as above and paste it into your report.    ( P7 )
• MenuBar::HFSS::AnalysisSetup::AddSolutionSetup select General::
SolutionFrequency 20 GHz, click OK
• MenuBar::HFSS::AnalysisSetup::AddFrequencySweep and linear step sweep 6.0 to 16 GHz in 0.25 GHz steps, and SweepType=discreet
• Your analysis and sweep should appear in the ProjectManager pane (blue arrow below), where the sweep properties should appear when the Sweep item is highlighted
  
• MenuBar::File::Save
• MenuBar::HFSS::ValidationCheck  Everything should check
• MenuBar::HFSS::AnalyzeAll (red arrow above) to run the simulation and watch for errors at the bottom message areas (red arrows below)
  

• To see the results, run MenuBar::HFSS::Results::QuickReport S-parameters
to plot the results (you may need to click a minimize icon to show plots/reports hidden behind the top plot/report
Adjust you plot to go from -90 to 10 dBm and double click the lines and make the width=3
and right-click and remove s12 and s22
Your plot should look like:




• Make sure that the legend does not obscure any portion of your plotted curves (move it as above). 
  
• Save a snapshot of the S-parameters as above, and paste it into your report.    ( P8 )
• Based on the dimensions of the waveguide, what size waveguide is this (i.e., wr22,wr51,etc? (Q13) Hint http://en.wikipedia.org/wiki/Waveguide_(electromagnetism)
  
• What is the theoretical cutoff frequency of the lowest order mode for the waveguide? (Q14)

Part 5

• In this part, you will simulate a simple metamaterial, a type of split ring resonator (SRR)
  
• Download the HFSS file radioFall2012proj5ring4.hfss.zip and extract it to your hfss directory
  
• Open the file in HFSS, and you should see the design as follows:

• Save a snapshot of the design as above and paste it into your report.    ( P9 )

• Zoom in on the split ring (blue arrow below)
  
• Notice the lumped RLC sheet in the gap of the ring (red arrow below).  This behaves as a lumped component, a capacitor, in the gap.
  
• Select the lumped RLC in the ProjectManager pane (yellow arrow below)  and observe the capacitance value (yellow arrow below)
  

• Run the simulation
  
• When the simulation completes, select the first two results plots as illustrated below.
• Plot the relative permeability as shown (blue arrows below) by double-clicking XYplot1
• Plot the relativeS-parameters S11 and S21 as shown (red arrows below) by double-clicking "Sparameter"

• Note the frequency range where the relative permeability is negative (yellow arrow above).  This is the desied metamaterial behavior.
  

• Save a snapshot of the S-parameter plot as above, but with all scales/axes visible, and paste it into your report.    ( P10 )
• Save a snapshot of the relative permeability plot as above, but with all scales/axes visible, and paste it into your report.    ( P11 )
• From the capacitance value of the lumped RLC, and from the frequency of the resonance in the S-parameters, compute the inductance of the loop that resonates with the capacitance of the lumped RLC.  (Q15)
• Note, by right clicking results (in upper left pane of above figure near red arrow) and selecting output variables, you can see the formulas used to extract the mu and epsilon (generally these are approximations below),  See http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1210783 for details on the formulas:
• dd = .01  (length in meters of the physical region being characterized, typically the diameter of the ring)
  
• v1 = S(1,1)+S(2,1)
• v2 = S(2,1)-S(1,1)
• k0 = 6.28*Freq/3e8
• mur = 2/(cmplx(0,1)*k0*dd)*(1-v2)/(1+v2)
• epsr  = mur+2*cmplx(0,1)/(k0*dd)  
  
• epsr2 = 2/(cmplx(0,1)*k0*dd)*(1-v1)/(1+v1)   
• Note: above formulas should be used when de-embedding is up to within approx 1mm of edge of ring.  To see de-embedding, select Excitation in the upper left pane, select the waveport, right-click properties, and click the postprocessing tab.  When the waveport is selected, you should see an 3D arrow indicating how far the results are deembedded from the waveport.
  

Part 6

• Use an excel spreadsheet (amp3.xls) to calculate gain, Noise Figure, 1dB copmpression (P1dB), and output intercept pount (OIP3) of the following system.  Paste the spreadsheet results into your report (P12 20 points)
  Check some points by hand to prevent errors in using the spreadsheet.
• 
  
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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!!