A True Differential Millimeter Wave System with Port Power Control. Presented by: Suren Singh

Transcription

1 A True Differential Millimeter Wave System with Port Power Control Presented by: Suren Singh

2 Agenda Need for True Differential and RF Power Control Vector Network Analyzer RF Port Power Control Port Power Control At Millimeter Wave Frequencies True Mode Stimulus Measurements True differential at Millimeter wave Network Analyzers Module # Page 2

3 Need for True Differential and RF Power Control Millimeter Wave Component Test On-wafer Devices (Existing) Characterization of on-wafer components Wireless HDMI (Emerging) 60 GHz CMOS Differential Devices Measurement Standards (Emerging) Waveguide standards definitions for Calibration > 110 GHz Automotive (Existing) 77 GHz collision prevention systems Intelligent Cruise Control HD Disc Player )))))))))))))))))))) Module # Page 3

4 Need for True Differential and RF Power Control Materials and Imaging Free space material measurements. Security Imaging Systems Corrosion Detection Bio-fuel (Emerging) Antenna and Bio-Science Antenna Characterization (Sub) mm-wave interferometer for astrophysics (Emerging) Atacama Large Millimeter Array (ALMA) (NRAO, ESO, IRAM) Deep Space Radio Astronomy (Expanding) Bio-science (2-3 THZ) (Emerging) Module # Page 4

5 Current Solutions Current Status Power Control Use of existing measurement systems. Designing own control systems. Current Status True Differential Implementation of own solutions. Use of Baluns for Differential Measurements. Additional external hardware to measure power. Simply not measure Module # Page 5

6 Output Power (dbm) Requirements for Millimeter Wave Power Control Ensure that the DUT is in linear region Maintain high power for best dynamic range measurements Prevent Device Damage Gain Compression AM-to-PM conversion Saturated Output Power Compression region Linear region (slope = small-signal gain) Input Power (dbm) Module # Page 6

7 Basic Power Control Techniques G P out Open Loop Attenuator control P out G P out G SLOPE TEMP SET SET Closed Loop Multi Variable Closed Loop Single Variable Module # Page 7

8 Open Loop Attenuator Control Network Analysis G Signal Separation Module Source Module P out Test Port Cost effective simple technique. Mechanical / solid state attenuation. Range limited by attenuator, but larger steps. Power accuracy limited by gain, attenuator, directivity etc.. Requires calibration at every setting. Limited applications. Limited to a fixed power setting. No power sweep capability. R Pout T f ( Gain, Attenuation, Directivity, Freq...) Module # Page 8

9 Closed Loop ALC Network Analysis G Signal Separation Module Test Port SLOPE TEMP R T SET Source Module Pout f ( Gain, Attenuation, Directivity, Freq...) Currently most accurate method. Use of a feedback control techniques. Active control provided by the integrating amplifier. Compensation of other factors, slope, temperature Range is a function of the square law of the detection. Broadband detector limits minimum power setting. Single calibration across the power range Module # Page 9

10 PNA-X Offers Premier Network Analysis Performance The N5242A forms the Engine for Agilent s next generation of Millimeter Wave solutions. 2- and 4-port versions Built-in second source and internal combiner for fast, convenient measurement setups Unrivaled flexibility and configurability Internal modulators and pulse generators for fast, simplified pulse measurements High accuracy noise figure measurements using Agilent s unique source-correction method Enables full millimeter wave Port Power control Allows us to support True mode at millimeter wave frequency. Module # Page 10

11 PNA-X RF Port Power Control Open Loop Receiver Leveling Internal Module # Page 11

12 PNA-X Open loop G Signal Separation Module Test Port SLOPE TEMP R T SET Source Module Network Analyzer Power Meter HPIB Power Sensor Source Power Calibration Module # Page 12

13 PNA-X Internal Levelling G Signal Separation Module Test Port SLOPE TEMP R T SET Source Module Network Analyzer Power Meter HPIB Power Sensor Source Power Calibration Module # Page 13

14 PNA-X Receiver Levelling G Signal Separation Module Test Port SLOPE TEMP R T SET Source Module Firmware Correction Network Analyzer HPIB Power Sensor Power Meter Source Power Calibration Module # Page 14

15 Comparison of the Internal, Open and Receiver Internal Levelling Open Loop Levelling Receiver Levelling Module # Page 15

16 Agilent s Latest Millimeter Wave Solution With the N5262A and N5261A Test set provides the most complete set of Millimeter Wave Measurements at the widest Frequency 2- and 4-port versions True Differential measurements using a 4 port test set. Internal modulators and pulse generators for fast, simplified pulse measurements Supports waveguide bands starting at 50 GHz to 0.5 THz Full millimeter wave port power control. Unrivaled flexibility and configurability Module # Page 16

17 Millimeter Wave Systems Block Diagram Source 2 LO Source 1 OUT 1 OUT 2 OUT 1 OUT 2 To receivers R1 A R2 B Test port 2 RF INPUT Waveguide Test Port REF RECEIVER LO DRIVE TEST RECEIVER Module # Page 17

18 Millimeter Wave Power Level Control - Attenuator Module # Page 18

19 Millimeter Wave Power Level Control - Receiver Source 2 LO Source 1 OUT 1 OUT 2 OUT 1 OUT 2 To receivers R1 A R2 B Test port 2 RF INPUT Waveguide Test Port REF RECEIVER LO DRIVE TEST RECEIVER Module # Page 19

20 Source Power Calibration Receiver Calibration PNA-X RF OUT Set at Max Power W Band Power Sensor Set PNA-X Source for max port power Measure the Receiver power over frequency. Measure the port power with a Power sensor over the Frequency R1 PNA-X REF RECEIVER Max. Power Table Receiver Calibration Recevier Power RF Drive Power Module # Page 20

21 Pout(dBm) Source Power Calibration P in Vs P out PNA-X RF OUT Step the PNA-X Source from maximum down to the minimum. Measure the Receiver power over frequency. Generate the P in vs. P out Table. P in VS P out Table R P in vs P out Pin(dBm) Module # Page 21

22 Source Power Calibration Receiver Calibration Module # Page 22

23 Source Power Calibration P in Vs P out Module # Page 23

24 Source Power Calibration Establish Accuracy Module # Page 24

25 Performance - Power Level Setting Error < 0.1 dbm Module # Page 25

26 Performance Power Sweep of 40 to 50 dbm Module # Page 26

27 Source Power Calibration Beyond 110 GHz Requires a max port power Table. Used to generate the Receiver Calibration Generates the PNA-X Source Calibration Create a Max Power File Erickson Calorimeter Module # Page 27

28 Differential Device - Measurement Alternatives Result 2-port VNA Measure Single-ended S-parameters To VNA DUT To VNA 2-port VNA Measure Single-ended S-parameters with Baluns To VNA DUT To VNA 4-port VNA Measure Multiport S-parameters S11 S21 S31 S41 S12 S22 S32 S42 S13 S23 S33 S43 S14 S24 S34 S44 To VNA To VNA DUT To VNA To VNA Calculate Mixed-mode S-parameter S S S S DD11 DD21 CD11 CD 21 S S S S DD12 DD22 CD12 CD 22 S S S S DC11 DC21 CC11 CC 21 S S S S DC12 DC22 CC12 CC 22 Module # Page 28

29 Measurements with Single-ended Stimulus Apply a single one-port drive at a time Repeat 4-times, one for each port For each application, measure the 4 output signals Thus, we get four raw S-parameters for each stimulus From these raw measurements, and an error-correction (which contains the source, load match, etc of the VNA) we compute the corrected S-parameters Finally, mixed-mode S-parameters are calculated from the corrected S- parameters Module # Page 29

30 Integrated True-mode Stimulus Application: itmsa (Option 460) Differential (180 outof-phase) Common (in-phase) 3 4 itmsa enables fast and accurate balanced device characterization under real operating conditions, and adds to the portfolio of PNA-X capabilities, further solidifying PNA-X s role as a great solution for active-device test. 1 2 With a 4-port PNA-X Millimeter System, you can Apply DUT/VNA mismatch-corrected truedifferential or true-common-mode stimulus in forward, reverse or both directions. Precisely control amplitude and phase offsets. Make fully-error-corrected balanced measurements on balanced-input and balanced-output as well as one port single-ended and one port balanced devices. Module #

31 Now Consider a True-Mode Drive Apply real-world stimulus to balanced devices Apply a differential signal at the input, then the output; then apply a common mode signal at the input, and the output. From these 4 measurements, you can compute all the S-parameters. True-mode stimulus Differential (180 0 out-of-phase) Common (in-phase) Module # Page 31

32 How do we create True-Mode signals: Start with a dual-source VNA Module # Page 32

33 We can precisely control the phase of each source Using Agilent proprietary Fractional-N Synthesizer Custom ICs 50 MHz Ref Module # Page 33

34 Now that we can control phase, how do we determine the right phase to set? R1 LO R3 OUT 1 Source OUT 2 Source 1 OUT 2 OUT 1 2 R4 R2 Ctl A C D B Tes t por t 1 RF Sw ALC Split Tes t por t 3 ALC Isolators IF Sw Tes t por t 4 ALC RF Sw P1 P2 (4) (8) P3 P4 Ctl Pwr Tes t port 2 (4) First, Do a 4-port Q-SOLT Calibration at the Reference Plane Module # Page 34

35 From the two-port terms of Ports 1 and 3 we can compute the relative phase of Ports 1 vs. 3 Note that the a1/a3 signal depends upon the DUT a1 F1 a1 S31 b3 R3/F3 b3 P1 D1 Port 1 M1 S11 DUT Port 3 S33 M3 D3 P3 b1 R1/F1 b1 S13 a3 F3 a3 a1/a3 ( a1 R1 b1 M1 - a1 M1 D1 ) R1 ( a3 R3 b3 M3 - a3 M3 D3 ) T1 Module # Page 35

36 Device Mismatch can cause a True-Mode error Suppose the source puts out a perfect differential signal DUT Module # Page 36

37 Device Mismatch can cause a True-Mode error The DUT will reflect some signal. Since the ports aren t identical, the reflection will be different from each port DUT Module # Page 37

38 Device Mismatch can cause a True-Mode error The source will re-reflect some signal back to the DUT DUT Module # Page 38

39 Device Mismatch can cause a True-Mode error Phase Shifted DUT Amplitude Error And the final signal at the DUT will no longer be true differential Module # Page 39

40 Phase Error (Deg) DUT/VNA Mismatch Can Cause a True-Mode Error The final signal at the DUT will no longer be true-differential. Source Mismatch DUT Mismatch Phase after mismatch calibration Amplitude Error 10 5 Phase without mismatch correction Phase Shifted Frequency (Hz) itmsa accounts for the DUT/VNA mismatch errors and precisely adjusts amplitude and phase of two signals at the reference plane. Module # Page 40

41 Phase Error after Adjustments Port 2 Note that R2/R4,2 is an unique parameter in true-mode channel that shows the phase difference between a pair of ports in balanced port 2 where it has differential stimulus on the balanced port 2. (180 degree phase offset is applied to show the trace around 0 degree) Module # Page 41

42 Measurements with True-mode Stimulus Apply a common-mode signal at an input balanced port and measure responses at all four ports Apply a differential signal at the same port and measure responses at all ports Repeat for an output balanced port From these 4 measurements, you can compute all the corrected S- parameters Finally, mixed-mode S-parameters are calculated from the corrected S- parameters 1 2 Module # Page 42

43 Single-ended vs. True-mode Measurements Calibration is no different. Measurement setups are the same. One click to turn on true-mode. Results, can be the same or may be different in nonlinear operation (or large signal response). Module # Page 43

44 Arbitrary Amplitude and Phase Offset f Understanding device responses to unbalanced stimulus helps; Optimize input matching circuit and maximize performance Potentially specify the device performance better f Module # Page 44

45 Power or Gain Source Phase Offset : The reference signal (P in ) sees the Phase offset! Sdd21 = P out (diff)/p in (diff) P out (diff) P in (diff) 0 Phase Offset 360 Phase offset of 20 deg applied to Port 3 Source a Module # Page 45

46 Power or Gain As a Fixture: The reference signal (P in ) does not see the Phase offset! As a Fixture changes the signal to the DUT but NOT the reference signal Sdd21 = P out (diff)/p in (diff) P in (diff) P out (diff) 0 Phase Offset 360 Only Agilent supports this mode. Module # Page 46

47 Gain (db) Stimulus Phase Sweep - Fully Characterize DUT Phase Offset (degree) Module # Page 47

48 When Stimulus on DUT Output Port Is a Problem Forward or reverse true-mode helps; Prevent damages on DUT if its output port is sensitive to RF signal. Maintain accuracy with best possible S-parameter error correction and DUT/VNA mismatch-corrected true-mode stimulus. Note that Reverse True Mode becomes active when SE-BAL topology is selected. Module # Page 48

49 Gain (db) Summary How itmsa Can Help DUT/VNA mismatch -corrected stimulus Arbitrary phase/ amplitude offset Fwd/Rev true-mode measurements Better measurements Better simulation Know DUT better Spec it better Faster verification Fewer samples Phase Offset (degree) Shortest time to market Gaining market share Lowest design cost Module # Page 49

50 Thank You Module # Page 50