© Agilent Technologies 2013 Aerospace & Defense Symposium 2013 Optimizing On-Wafer Noise Figure Measurements to 67 GHz David Ballo, Agilent Technologies.

© Agilent Technologies 2013 Aerospace & Defense Symposium 2 Agenda Overview of PNA-X Noise Figure Noise Receiver Characterization Extending Accuracy To Probe Tips Considerations for the 50 to 67 GHz Band

© Agilent Technologies 2013 Aerospace & Defense Symposium 3 © Agilent Technologies 2013 Aerospace & Defense Symposium Noise Figure Review Noise factor (F, linear) and noise figure (NF, dB) are Very useful and industry-accepted figures of merit that characterize how much noise an amplifier or converter adds Defined in terms of SNR degradation: Noise factor (F, linear) and noise figure (NF, dB) are Very useful and industry-accepted figures of merit that characterize how much noise an amplifier or converter adds Defined in terms of SNR degradation: F = (S o /N o ) (S i /N i ) = (N o ) (G x N i ) NF (dB) = 10 x log (F) DUT S o /N o S i /N i Gain Not the same as phase noise! Test system is assumed to be exactly 50 ohms

© Agilent Technologies 2013 Aerospace & Defense Symposium 4 Agilent’s Noise Figure Legacy 340A 1958 8970 1980 PSA with NF 2002 ESA with NF 2003 PNA-X with 26.5 GHz NF 2007 MXA, EXA with NF 2007 8560/90 with NF 1995 85120 1999 NFA 2000 Over 50 years of Leadership! PXA with NF and noise-floor extension 2009 NEW! Now to 50 GHz!

© Agilent Technologies 2013 Aerospace & Defense Symposium 5 © Agilent Technologies 2013 Aerospace & Defense Symposium Comparison of PNA-X to NFA and SAs NFA and spectrum analyzers use the Y-factor method Uses noise source with specified “excess noise ratio” (ENR) Measures noise figure and gain of DUT PNA-X uses the cold source method Gain and noise power measured separately, without a noise source Allows many measurements to be made with a single connection to the DUT Advanced error correction using an impedance tuner yields highest measurement accuracy Source impedance Noise source 346C 10 MHz – 26.5 GHz +28V Diode off  T cold Diode on  T hot

© Agilent Technologies 2013 Aerospace & Defense Symposium 6 © Agilent Technologies 2013 Aerospace & Defense Symposium Graphical Representation of Noise Power P in (cold) P out (cold) P in (hot) P out (hot) Noise added by amplifier Noise Power In Noise Power Out DUT Slope = amplifier gain VNA

© Agilent Technologies 2013 Aerospace & Defense Symposium 7 Y-Factor Accuracy Degrades for On-Wafer Test Noise source  Good accuracy On-wafer multi-instrument (ATE) environment Noise source  Degraded accuracy Noise source On-wafer environment  Degraded accuracy PNA-X provides highest accuracy in all situations

© Agilent Technologies 2013 Aerospace & Defense Symposium 8 PNA-X Noise Figure Measurement Option 029 Application: Measure key amplifier or converter parameters including noise figure up to 67 GHz with a single set of connections ECal module used as an impedance tuner to remove the effects of imperfect system source match Performance: Achieve the highest measurement accuracy of any solution on the market Speed: Typically 4 to 10 times faster than the NFA

© Agilent Technologies 2013 Aerospace & Defense Symposium 9 © Agilent Technologies 2013 Aerospace & Defense Symposium PNA-X’s Unique Source-Corrected Technique PNA-X varies source match around 50 ohms using an ECal module With resulting impedance/noise-figure pairs and vector-error terms, very accurate 50-ohm noise figure can be calculated Each impedance state is measured versus frequency Noise figure at 50 ohms (Z 1, F 1 ), (Z 2, F 2 ), … Z’s measured during cal F’s measured with DUT frequency

© Agilent Technologies 2013 Aerospace & Defense Symposium 10 © Agilent Technologies 2013 Aerospace & Defense Symposium PNA-X’s Scalar Noise Calibration Assumes the system source match is 50 ohms Eliminates need for an impedance tuner Provides good accuracy with 3 to 6 dB attenuator at end of input test cable Advantages: –Faster (one noise-power sweep versus four to seven for full vector cal) –Less expensive (ECal tuner not used) Assume system source match is exactly 50 ohms

© Agilent Technologies 2013 Aerospace & Defense Symposium 11 Example Measurements of Unmatched Device PNA-X method using source correction Noise source: SNS 4002A (14 dB ENR) Under-sampled data Y-factor method (High ENR noise source) 401 points Narrowband data

© Agilent Technologies 2013 Aerospace & Defense Symposium 12 New PNA-X Noise Hardware Option 029 adds 43.5/50 GHz noise receiver Option 029 adds 50 GHz noise receiver 43.5/50 GHz PNA-X 67 GHz PNA-X Built-in tuner eliminates need for extra ECal Standard receiver available for 50 – 67 GHz

© Agilent Technologies 2013 Aerospace & Defense Symposium 13 System Noise Figure 50 GHz (Measured on N5247A 67 GHz PNA-X) Standard receiver: port 2 coupler reversed Standard receiver Low-noise receiver, high-gain setting 17 dB 29 dB Specification

© Agilent Technologies 2013 Aerospace & Defense Symposium 16 Characterizing Noise Receivers Noise contribution of the noise receiver must be known and subtracted from raw measurements to provide corrected noise figure of the DUT Measured noise power affected by receiver gain, bandwidth, noise figure More gain means higher noise power Wider bandwidth (the B in kTB) means higher noise power Gain and bandwidth can be measured separately, or together as one product Noise source method measures gain-bandwidth product directly by applying a known amount of excess noise from a noise source Noise source 346C 10 MHz – 26.5 GHz Bandwidth (B) Gain (G)

© Agilent Technologies 2013 Aerospace & Defense Symposium 17 Power-Meter-Based Noise Receiver Characterization PNA-X power-meter calibration method measures gain and bandwidth separately Power meter is used to calibrate a source, which in turn is used to calibrate the noise receiver gain For each frequency point, the noise bandwidth filter is swept to measure the receiver’s response Response is then integrated to calculate equivalent noise bandwidth Equivalent receiver noise bandwidth

© Agilent Technologies 2013 Aerospace & Defense Symposium 18 Noise Calibration User Interface For low-noise receiver, choose between a power meter or a noise source for receiver characterization* Cal steps are essentially the same for either choice: connect noise-receiver standard, through, S-parameter standard(s) Standard NA receiver calibration still requires a power sensor, since noise source ENR is not sufficient to overcome internal noise *When using a power meter for calibration, only 0.8, 2, and 4 MHz noise bandwidths are available (8 and 24 MHz bandwidths require noise source) Noise channel cal Cal All Channels

© Agilent Technologies 2013 Aerospace & Defense Symposium 19 Accuracy of Power Meter Noise Receiver Cal Power-meter-based calibration offers the same or better accuracy as that obtained from using a noise source Between 45 and 50 GHz, power-meter-based calibration does not suffer jitter degradation due to noise source ENR roll-off Power-meter-based measurement uncertainty is likely to be a bit better compared to using an off-the-shelf noise source comparable to using an NPL-calibrated noise source

© Agilent Technologies 2013 Aerospace & Defense Symposium 20 Comparison of Noise Source and Power Meter Calibrations on an Agilent 83050A 50 GHz Amplifier 201 pts, 4 MHz noise BW, 50 noise avgs, 7 imped, sweep time 00:02:22 0.5 dB Noise figure S-parameters

© Agilent Technologies 2013 Aerospace & Defense Symposium 21 Comparing Noise Receiver Cal Methods Calibration Method AdvantagesDisadvantages Power sensor Often easier to find up to 50 GHz No loss of accuracy > 45 GHz Calibration and measurement times are longer since 8 and 24 MHz noise BWs are unavailable Noise source Fastest calibrations and measurements High familiarity with NF users May be hard to obtain Low ENR > 45 GHz lowers accuracy due to increased measurement jitter Noise BWNoise sourcePower meter 4 MHz9.312.8 24 MHz1.2N/A 50 noise averages, 201 points 50 MHz – 50 GHz, 201 points, 7 impedance states 10.8 x Calibration time (min) 7.3 x Noise bandwidth, MHz

© Agilent Technologies 2013 Aerospace & Defense Symposium 22 © Agilent Technologies 2013 Aerospace & Defense Symposium Noise Figure Uncertainty Calculator Version 2 Includes noise-source- and power-meter-based calibrations Includes vector and scalar calibration Shows uncertainty contributors and potential compression issues Available at www.agilent.com/find/nfcalc

© Agilent Technologies 2013 Aerospace & Defense Symposium 24 © Agilent Technologies 2013 Aerospace & Defense Symposium On-Wafer Noise Figure Calibration Two fundamental approaches: Use Calibration Wizard (or Cal All Channels) to combine coaxial and on-wafer calibration Calibrate completely with coaxial standards and de-embed wafer probes (s2p files for probes can be obtained from PNA macro)

© Agilent Technologies 2013 Aerospace & Defense Symposium 25 1-port cal (remove adapter after cal) 2 Calibrating On-Wafer Using Cal Wizard 1 2-port TRL cal with extra impedances 3 Noise figure calibration wizard automatically embeds probe loss to noise-characterization data to move noise-cal reference plane to 2-port-cal reference plane Use noise source or power meter for receiver characterization

© Agilent Technologies 2013 Aerospace & Defense Symposium 26 © Agilent Technologies 2013 Aerospace & Defense Symposium Receiver Noise Parameter Characterization Receiver noise parameters are measured during calibration to ensure the right amount of receiver noise is subtracted from measurements, based on DUT’s S22 (output match of DUT provides noise receiver source match) Receiver noise power measured with different source impedances at port 2 Fastest and easiest approach is to use an ECal module –Receiver noise “pulling” can be done in the step where the 1-port parameters are measured at the noise-source calibration plane –Noise source is always connected to port 2, so no problem to do noise pull –Power sensor is connected to port 1, so can’t perform receiver noise pull –When using power sensor, need extra TRL standards (short or open, offset open) Noise calibration plane

© Agilent Technologies 2013 Aerospace & Defense Symposium 27 Calibrating On-Wafer Using De-embedding 1 Two 1-port coaxial cals or one 2-port coaxial cal Obtain s2p files for probes (done once) Two 1-port on-wafer cals or one 2-port on-wafer cal 2 Use noise source or power meter for receiver characterization Perform coaxial noise calibration Use ECal or mechanical calibration kit 3 Use fixture feature to de-embed s2p files of probes from measured data Measurement

© Agilent Technologies 2013 Aerospace & Defense Symposium 28 © Agilent Technologies 2013 Aerospace & Defense Symposium Cable Loss at Port 2 When using a noise source, it is best to connect directly to port 2 If direct connection is not possible, port 2 cable should have low loss If loss of port 2 cable is too high, it may preclude use of noise source due to lack of excess noise above ~45 GHz (use power meter)

© Agilent Technologies 2013 Aerospace & Defense Symposium 31 © Agilent Technologies 2013 Aerospace & Defense Symposium Potential Limitations of Internal Tuner On-wafer measurements are typically on un-matched devices that are very sensitive to source match Additional loss of cables and probes collapses spread of impedances presented to DUT Vector-noise-calibration algorithm can have difficultly finding correct solution in some setups Tuner impedances, 50 GHz Tuner impedances, 1 GHz

© Agilent Technologies 2013 Aerospace & Defense Symposium 32 Setup Using External Tuner Test port 1 R1 Test port 2 R2 A B rear panel OUT 2 Source 1 OUT 1 Pulse modulator Source 2 (standard) OUT 1OUT 2 Pulse modulator J12J6J5J7J2J1J4J3 50 dB RF2 OUT RF1 OUT LO OUT Signal combiner Noise receivers 10 MHz - 6 GHz 6 - 50 GHz Tuner Source 2 Output 1 Source 2 Output 2 To receivers LO External ECal Input bias

© Agilent Technologies 2013 Aerospace & Defense Symposium 33 Setup Using External Tuner, Bias Tee, Coupler Test port 1 R1 Test port 2 R2 A B rear panel OUT 2 Source 1 OUT 1 Pulse modulator Source 2 (standard) OUT 1OUT 2 Pulse modulator J12J6J5J7J2J1J4J3 50 dB RF2 OUT RF1 OUT LO OUT Signal combiner Noise receivers 10 MHz - 6 GHz 6 - 50 GHz Tuner Source 2 Output 1 Source 2 Output 2 To receivers LO External ECal Input bias

© Agilent Technologies 2013 Aerospace & Defense Symposium 34 On-Wafer Setup 1 With External Components Vector noise calibration using external tuner, bias tee, and coupler ECal module used as tuner Bias tee Test coupler 5 dB Vector noise calibration using external tuner and bias tee Input bias

© Agilent Technologies 2013 Aerospace & Defense Symposium 37 © Agilent Technologies 2013 Aerospace & Defense Symposium Noise Figure to 67 GHz Low-noise receivers work up to 50 GHz Standard receivers can be used between 50 and 67 GHz Standard receivers lack Internal LNAs, so NF is significantly degraded compared to noise receiver Filters in front of mixer to reject out-of-band noise To low band noise receiver (.01 – 6 GHz) Diode level detector 6 – 12 GHz 12 – 26 GHz 26 – 50 GHz Noise input Filter bank for third-harmonic- conversion rejection LO input Low band LO output IF output LNA chain 15 dB Noise receiver mixer Limiter LO RFIF Low-noise receiver (high band)

© Agilent Technologies 2013 Aerospace & Defense Symposium 38 Gain Considerations for 50 – 67 GHz Band System noise figure of N5247A standard receiver In dB, DUT gain + DUT noise figure + preamplifier gain should be > ~45 dB Conditions: Load on port 2 Port 2 coupler reversed

© Agilent Technologies 2013 Aerospace & Defense Symposium 39 Setup Using External Preamplifier, Tuner Port 2 coupler in reversed position Test port 1 R1 Test port 2 R2 A B rear panel OUT 2 Source 1 OUT 1 Pulse modulator Source 2 (standard) OUT 1OUT 2 Pulse modulator J12J6J5J7J2J1J4J3 50 dB RF2 OUT RF1 OUT LO OUT Signal combiner Noise receivers 10 MHz - 6 GHz 6 - 50 GHz Tuner Source 2 Output 1 Source 2 Output 2 To receivers LO SOURCE OUT CPLR THRU SOURCE OUT CPLR THRU CPLR ARM RCVR B IN

© Agilent Technologies 2013 Aerospace & Defense Symposium 40 © Agilent Technologies 2013 Aerospace & Defense Symposium Considerations for High-Gain Setups With lots of gain in test setup, one must take extra care to set port powers low enough so as to not compress the preamplifier or PNA-X receiver during calibration and subsequent measurements Port 1 power matters for thru measurements Port 2 power matters for S22 open/short measurements For scalar-noise calibration, port 1 coupler can be reversed to improve S11 measurements (extra loss in source path precludes vector-noise calibration) Increase port power as much as possible for power-meter calibration step Use channel averaging to lower S-parameter trace noise

© Agilent Technologies 2013 Aerospace & Defense Symposium 41 Harmonic Mixing With Standard PNA-X Receivers PNA-X uses 3 rd -harmonic mixing > 26.5 GHz Conversion efficiency around fundamental is much higher than efficiency at 3 rd harmonic f LO fundamentalLO 3 rd harmonic A Broadband noise from DUT IF filter response ADC PNA-X receiver LO

© Agilent Technologies 2013 Aerospace & Defense Symposium 42 Noise Figure Example Using Standard Receiver with 50 GHz PNA-X NF of broadband DUT NF of filtered DUT S21 of filtered DUTS21 of broadband DUT Note: Measurements done with PNA-X port 2 coupler was reversed

© Agilent Technologies 2013 Aerospace & Defense Symposium 43 For Fundamental Mixing, Filtering Removes Noise At LO Third-Harmonic Frequency f LO fundamentalLO 3 rd harmonic A ADC PNA-X receiver LO Noise around third harmonic frequency is eliminated LPF or BPF

© Agilent Technologies 2013 Aerospace & Defense Symposium 44 For Third-Harmonic Mixing, Filtering Removes Noise At LO Fundamental Frequency ADC PNA-X receiver LO f LO fundamentalLO 3 rd harmonic A Noise around fundamental frequency is eliminated HPF or BPF LO 5 th harmonic Two V281A (WR-15) waveguide-to-coax adapters in series make an excellent ~50 GHz highpass filter

© Agilent Technologies 2013 Aerospace & Defense Symposium 45 © Agilent Technologies 2013 Aerospace & Defense Symposium Summary PNA-X extends source-corrected noise figure measurements to 50 GHz, while maintaining industry’s highest measurement accuracy New hardware option includes built-in 50 GHz low-noise receiver and impedance tuner Standard receivers extend measurements up to 67 GHz, typically with an external preamplifier and filter Characterize noise receivers using a power meter or noise source Accurate on-wafer measurements of sensitive devices can use alternative setups for effective vector-noise-correction Noise source 346C 10 MHz – 26.5 GHz

© Agilent Technologies 2013 Aerospace & Defense Symposium 47 Noise Parameters (New for A.09.80) Noise parameters available to show how well LNA was designed Noise parameters only valid with vector-noise correction Accurate for nominally matched devices only Maury Microwave is the recommended supplier for general- purpose noise-parameter solutions Internal impedance tuner states (10 GHz)

© Agilent Technologies 2013 Aerospace & Defense Symposium 50 © Agilent Technologies 2013 Aerospace & Defense Symposium Troubleshooting NF Measurements When reporting issues, include: Model and option numbers Firmware version Instrument state, if possible (save in hold mode to preserve traces) Information about DUT (gain, NF, converter block diagram…) Detailed setup description (e.g. on-wafer, long cables, sources…) Calibration conditions (e.g. power levels, DUT connectors, cal standards…) Show plots of NF, S21 or SC21, DUTRNPI, SYSRNPI (with 50 termination)

© Agilent Technologies 2013 Aerospace & Defense Symposium 51 © Agilent Technologies 2013 Aerospace & Defense Symposium Troubleshooting NF Measurements, Continued Calibration issues Look at uncalibrated measurement to see if calibration is bad “Unable to orient ECal”: make sure proper module is defined as tuner “Cannot achieve target power”: too much loss in test system Noise source Use correct ENR values for noise source Make sure noise source is connected to 28 volt BNC Use noise source with recent calibration or verify ENR values with power-meter cal Comparing to NFA: different noise sources will give different answers NF has lots of trace noise: use 10 noise averages with noise receiver and 346C. Use more averages for 346A. Use more averages to overcome test set loss. On wafer: need to define extra reflection standard for receiver noise pull

© Agilent Technologies 2013 Aerospace & Defense Symposium 52 © Agilent Technologies 2013 Aerospace & Defense Symposium Troubleshooting NF Measurements, Continued Power meter issues Unleveled errors: asking for too much power for given source attenuator (use Cal All instead) Use correct sensor cal factors Make sure loss table is off Don’t measure at or near noise floor of sensor (typically -35 dBm for thermocouple sensors) – use Cal All instead Gain issues Compare S-parameters in noise channel with standard channel (if S-parameters are wrong, noise figure will be wrong too) Avoid DUT compression (compressing DUT causes NF to appear worse) For high-gain DUTs, uncouple and set reverse power >> input power to get clean S22 and S12 measurements or use Cal All

© Agilent Technologies 2013 Aerospace & Defense Symposium 53 © Agilent Technologies 2013 Aerospace & Defense Symposium Troubleshooting NF Measurements, Continued Option 028 (standard receivers) Use adequate noise averaging (100 minimum) Need enough system gain (30 dB to 20 GHz, 40 dB to 50 GHz, 45 dB to 67 GHz) Filter away noise at (3*Fc) or (Fc/3) and in some cases, (5*Fc/3) Measure filter across complete range of instrument, not just range of measurement (don’t assume out-of-band responses stay down) Filter at output of external LNA Avoid compressing external LNA Avoid compressing or overloading NA receiver (Reversing port 2 coupler lowers compression point by 15 dB) Make sure narrowband-IF path is not used

© Agilent Technologies 2013 Aerospace & Defense Symposium 54 © Agilent Technologies 2013 Aerospace & Defense Symposium Troubleshooting NF Measurements, Continued NF for Converters Add filter to DUT output to suppress LO feed-through Not enough LO power (mixer starved) Use filter or attenuator on LO signal to minimize LO noise contribution DSB or SSB converter (PNA-X not matching Y-factor method) Make sure time bases of external signal generators are tied to 10 MHz reference General issues Spikes in measurements are usually caused by radiated or conducted interference (use screen room to eliminate radiated interference; use batteries to eliminate conducted interference) Amplifiers with AGC must be held at fixed gain

© Agilent Technologies 2013 Aerospace & Defense Symposium 55 4-Port 13.5/26.5 GHz PNA-X Options 419, 423, 029 C R3 Test port 1 R1 Test port 4 R4 A D Rear panel Pulse generators 1 2 3 4 Source 1 OUT 1OUT 2 Pulse modulator Source 2 OUT 1OUT 2 Pulse modulator Test port 2 R2 B Noise receivers 10 MHz - 3 GHz 3 – 13.5/ 26.5 GHz To receivers LO +28V Test port 3 Signal combiner +-+- Impedance tuner for noise figure measurements J9J10J11J8J7J2J1J4J3 35 dB 65 dB J6J5 RF OUT LO OUT RABCD IF inputs RF jumpers Receiver Mechanical switch

© Agilent Technologies 2013 Aerospace & Defense Symposium 56 4-Port 43.5/50 GHz PNA-X Options 419, 423, 029 C R3 Test port 1 R1 Test port 4 R4 A D Rear panel Pulse generators 1 2 3 4 Source 1 OUT 1OUT 2 Pulse modulator Source 2 OUT 1OUT 2 Pulse modulator Test port 2 R2 B Noise receivers 10 MHz - 6 GHz 6 - 50 GHz To receivers LO +28V Test port 3 Signal combiner +-+- J9J10J11J8J7J2J1J4J3 35 dB 60 dB J6J5 RF OUT LO OUT RF jumpers Receiver Mechanical switch RABCD IF inputs 60 dB Tuner

© Agilent Technologies 2013 Aerospace & Defense Symposium 57 4-Port 67 GHz PNA-X Options 419, 423, 029 Test port 3 C R3 Test port 1 R1 Test port 4 R4 Test port 2 R2 A D B To receivers LO Pulse generators Rear panel 1 2 3 4 OUT 2 Source 1 OUT 1 Pulse modulator Source 2 (standard) OUT 1OUT 2 Pulse modulator J12J6J5J7J2J1J4J3 50 dB RF2 OUT RF1 OUT LO OUT Signal combiner RABCD IF inputs Noise receivers 10 MHz - 6 GHz 6 - 50 GHz Tuner RF jumpers Receiver Mechanical switch

© Agilent Technologies 2013 Aerospace & Defense Symposium 2013 Optimizing On-Wafer Noise Figure Measurements to 67 GHz David Ballo, Agilent Technologies.

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© Agilent Technologies 2013 Aerospace & Defense Symposium 2013 Optimizing On-Wafer Noise Figure Measurements to 67 GHz David Ballo, Agilent Technologies.

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