Self-Mixing Amplifier for CW Sensors

Transcription

1 Self-Mixing Amplifier for CW Sensors Master thesis presentation Congying Chen Supervisor: Prof. Dr.-Ing. Klaus Solbach Department of Electrical Engineering and Information Technology Microwave and RF Technology

2 Contents Motivation 10 MHz Single Stage Amplifier Analysis Design and Measurement of 10 GHz Self-Mixing Amplifier Conclusion Congying Chen 2

3 Motivation Background Nonlinear Fundamentals Mixer Fundamentals Congying Chen 3

4 Motivation - Background CW Sensor Traditional transmitter and receiver designs Congying Chen 4

5 Motivation - Background New concept Congying Chen 5

6 Motivation Nonlinear Fundamentals Nonlinear network analysis v a out 0 = a = v 0 out + a (0) 1 v in + a 2 v 2 in + a 3 v 3 in + K a 1 = dv dv out in v in =0 a 2 = d 2 v dv out 2 in v in =0 a 3 = d 3 v dv out 3 in v in =0 If vin =V0 cosω0 t, the output voltage is = (a0 + a 2 V0 ) + (a1 V0 + a3 V0 )cosω 0 t + a 2 V0 cos2ω t +K vout 0 Congying Chen 6

7 Motivation Nonlinear Fundamentals Voltage gain (retained to the third order) 1 db-compression Point G = a v a 3 V 2 0 Congying Chen 7

8 Motivation Mixer Fundamentals Down conversion Conversion Loss Variation of FET Output Conductance f L IF c = f RF - f LO P = 10log P RF IF > 0dB g(t) = g gncosnωlo t n=1 Congying Chen 8

9 Motivation Mixer Fundamentals Drain current i(t) = g(t) v = V RF [g RF 0 (t) cosω = V RF RF [g 0 t + 2 g n= 1 cosω n RF t + 2 [cosn(ω RF n= 1 g n + nω cosnω LO LO t cosω ) t + cosn(ω RF RF t] nω LO ) t]] Congying Chen 9

10 10 MHz Single Stage Amplifier Analysis Simulation Measurement Congying Chen 10

11 10 MHz Single Stage Amplifier Analysis Simulation Circuit Design Congying Chen 11

12 10 MHz Single Stage Amplifier Analysis Simulation Amplifier output Conductance G Congying Chen 12

13 10 MHz Single Stage Amplifier Analysis Simulation Mixer Characteristics Z IF Congying Chen 13

14 10 MHz Single Stage Amplifier Analysis Simulation Mixer Characteristics Congying Chen 14

15 10 MHz Single Stage Amplifier Analysis Measurement Methods of Measurement Spectrum Analyzer Oscilloscope P P Z out out IF Pout [dbm] = 10log 1mW u50rms = 50 Ω u 0 = 50 Ω -50 Ω u 50 2 Congying Chen 15

16 10 MHz Single Stage Amplifier Analysis Measurement Measurement with a Spectrum Analyzer Unit LO, RF and IF signal [dbm] Conversion Loss [db] RF signal IF signal LO signal Conversion Loss IF signal Conversion Loss IF signal Conversion Loss IF signal Conversion Loss Congying Chen 16

17 10 MHz Single Stage Amplifier Analysis Measurement Measurement with an Oscilloscope LO Signal [dbm] RF Signal [dbm] -10 Open[mV] 50Ω [mv] Impedance[Ω] Output Power[dBm] Congying Chen 17

18 10 MHz Single Stage Amplifier Analysis Measurement Measurement of the Amplifier Output Conductance (RF Input Conductance) Input Power[dBm] v_in[mv] v_out[mv] v_out_50ω [mv] Z[Ω] G[mS] *10^ *10^ *10^ *10^ *10^ *10^ *10^ Congying Chen 18

19 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation Measurement Congying Chen 19

20 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation Transistor Selection & Operating Point Bias network Design Congying Chen 20

21 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation Stability Analysis (1- S K = Δ = S 11 S S22 2 S S -S S Δ < 1 2 ) > 1 Congying Chen 21

22 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation Input and output matching and Overall Amplifier G Congying Chen 22

23 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation Input and output matching and Overall Amplifier Congying Chen 23

24 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation Input and output matching and Overall Amplifier Congying Chen 24

25 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation Input and output matching and Overall Amplifier Congying Chen 25

26 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation RF Input Conductance Congying Chen 26

27 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation 1 db Compression Point Congying Chen 27

28 Design and Measurement of 10 GHz Self-Mixing Amplifier Design and Simulation IF Signal Congying Chen 28

29 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Implementation Congying Chen 29

30 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Measurement of the S Parameters Congying Chen 30

31 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Measurement of 1 dbm-compression Point Input Power[dBm] Output Power[dBm] Congying Chen 31

32 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Measurement of the Mixer Conversion Loss L = 100 mh C 2 = 1.5 μf C 2 > 1 2πf IF Congying Chen 32

33 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Mixer Products (Spectrum Analyzer) RF Signal [dbm] IF Signal [dbm] LO Signal[dBm] Conversion Loss[dB] IF Signal [dbm] Conversion Loss[dB] IF Signal [dbm] Conversion Loss[dB] Congying Chen 33

34 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Mixer Products (Spectrum Analyzer) P RF = -10dBm Congying Chen 34

35 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Mixer Products (Oscilloscope) without C 2 LO Signal [dbm] RF Signal [dbm] -10 Open[mV] 50Ω[mV] Impedance[Ω] Output Power[dBm] Congying Chen 35

36 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Mixer Products (Oscilloscope) with C 2 LO Signal [dbm] RF Signal [dbm] -10 Open[mV] 50Ω [mv] Impedance[Ω] Output Power[dBm] Congying Chen 36

37 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Calculation of Impedance in Imagine Part Impedance[Ω] Measured without Impedance[Ω] Measured with Impedance[Ω] of C C2 C Congying Chen 37

38 Design and Measurement of 10 GHz Self-Mixing Amplifier Measurement Conversion Loss LO Signal[dBm] Conversion Loss[dB] Congying Chen 38

39 Conclusion Larger LO Signal Larger Output Signal Lower Output Impedance The LO Signal depends on 1 db-compression point Feasibility of Self-Mixing Amplifier Congying Chen 39

40 Thank You for Your Attention