Intermodulation Distortion Mitigation in Microwave Amplifiers and Frequency Converters

Transcription

1 Intermodulation Distortion Mitigation in Microwave Amplifiers and Frequency Converters Carlos Saavedra Professor of Electrical Engineering Queen s University Kingston, Ontario K7L 3N6 30 January 2017

2 Outline Concepts/Review Broadband GaN power amplifier with distortion cancellation Stand-alone distortion cancelling cell Distortion cancellation techniques for mixers C. Saavedra, Queen s University 2 30 January 2017

3 ω 1 ω 2 ω 1 ω 2 ω amplifier ω ω 1 ω 2 ω Ideally: [A 1 cos(! 1 t)+a 2 cos(! 2 t)] 3 [A = +3A 2 1 cos(! 1A 2 cos 2 (! 1 t)+a 1 t)cos(! 2 cos(! 2 t)+ 2 t)] 3 = +3A 2 1A 2 cos 2 (! 1 t)cos(! 2 t)+ 3A 1 A 2 2 cos(! 1 t)cos 2 3A (! 2 t)+ 1 A 2 2 cos(! 1 t)cos 2 (! 2 t)+ x i (t) 3 rd order IMD x i (t) ω 1 ω h i (t) h i (t) x(t) NX y(t) = a n x n (t) n=1 h o (t) ω 1 ω 2 x(t) NX y(t) = a n x n (t) n=1 ω 1 ω h 2 ω o 1 (t) ω 2 ω 2ω1 ω 2 2ω 2 ω 1 ω 2 2ω1 1 ω 2 2ω 2 ω 1 C. Saavedra, Queen s University 3 30 January 2017 y o (t) y o (t) 2ω ω ω 1 ω 2

4 P out (dbm) OIP3 IP3 OP 1dB IP 1dB IIP3 P in (dbm) 4

5 X Power series model x i (t) Passive network x(t) X Nonlinear/ Memoryless y(t) Passive network y o (t) X x i (t) x(t) X NX a n x n (t) n=1 y(t) H i (!) H o (!) y o (t) 5

6 H f (!) X x i (t) NX NX a n x n (t) n=1 y o (t) 6

7 Derivative superposition [1,2] This method to mitigate IMD relies on modeling the FET drain current as a power series: i ds = NX g mn vgs n n=1 g mn I DS n!@v n GS i da M A M B i db Copyright 2005, IEEE with permission [2] 7

8 HFET f T doublers [3] i o i o v in (t) T1 T2 v in (t) T1 X T2 X Z in = R i1 +R i2 g m gm1 R i2 + 1! 2 C gs1 C gs2 j! C gs1 C gs2 Z in = R i1 + R i j! C gs1 C gs2 h 21 = 1+j2f/f T (jf/f T ) 2 h 21 = 2f T jf 8

9 1-6 GHz, 2-Watt GaN baseline amplifier 9

10 measured measured 10

11 measured measured 11

12 Distortion-cancelling GaN amplifier 12

13 recall the approximation, i ds = NX g mn vgs n n=1 g mn I DS n!@v n GS 13

14 Measured Gain Simulated Gain Gain (db) Frequency (GHz) OIP3 (dbm) measured at 1 GHz DADC PA DC PA Baseline PA Output Power (dbm) 14

15 measured A. M. El-Gabaly, D. Stewart and C. E. Saavedra, "2-Watt Broadband GaN Power Amplifier RFIC using the ft Doubling Technique and Digitally-Assisted Distortion Cancellation'', IEEE Transactions on Microwave Theory and Techniques, vol. 61, no. 1, pp ,

16 Stand-alone Distortion Cancelling Cell

17 17

18 Z 0 2Z 0 Z 0 λ/4 Z 0 power coupler auxiliary FET phase shifter 18

19 General purpose amp: CSA , Celeritek Auxiliary FET: NE34018, NEC GaAs HFET Auxiliary amp: ABP1200, Wenteq Corp. Varactors: SMV LF, Skyworks Substrate: RO3010, er =

20 Wen Li and C. E. Saavedra, "A Stand-Alone Distortion-Cancelling Cell for Microwave Amplifiers", IEEE Microwave and Wireless Components Letters, vol. 23, no. 4, pp ,

21 Mixers

22 22

23 VDD RL RL Vbias Vbias M5 Vout1 Vout2 M6 M7 M8 M9 M10 VLO_p VLO_p VLO_n VRF_p M1a M1 M2 M2a VRF_n NF = 15.9 db! M. Wang, Shan He, C. E. Saavedra, "+14 db Improvement in the IIP3 of a CMOS Active Mixer Through Distortion Cancellation", C. Saavedra, IEEE Queen s MTT-S International UniversityWireless Symposium, Beijing, China, April January 2017

24 Switched Gm mixer [4] VDD load I B g mv RF I B 1 2 g mv RF V RF+ (t) V RF- (t) VDD LO switch (½ circuit) 24

25 V DD V DD IF amp V IF (t) V RF+ (t) L G /2 L G /2 V RF+ (t) L G VDD V RF- (t) VDD V LO+ (t) C B C B V LO- (t) I BG I BG 25

26 IF output stage

27 Experimental results 27

28 Experimental results 28

29 Experimental results 29

30 A. M. El-Gabaly, H. Li and C. E. Saavedra, "A Decade-Bandwidth Low-Noise Mixer RFIC with a Distortion-Cancelling Output Amplifier", IEEE Symposium on Radio Frequency Integration, Taipei, Taiwan, 2016.

31 Acknowledgments National Research Council Natural Sciences and Engineering Research Council of Canada CMC Microsystems

32 References [1] D. R. Webster and D. G. Haigh, "Low-distortion MMIC power amplifier using a new form of derivative superposition," in IEEE Trans. Microwave Theory and Techniques, vol. 49, no. 2, pp , Feb [2] V. Aparin and L. E. Larson, "Modified derivative superposition method for linearizing FET low-noise amplifiers," in IEEE Transactions on Microwave Theory and Techniques, vol. 53, no. 2, pp , Feb [3] K. Krishnamurthy, R. Vetury, S. Keller, U. Mishra, M. J. W. Rodwell and S. I. Long, "Broadband GaAs MESFET and GaN HEMT resistive feedback power amplifiers," in IEEE Journal of Solid-State Circuits, vol. 35, no. 9, pp , Sept [4] E. Klumperink, S. Lowsma, G. Wienk, B. Nauta, A CMOS Switched Transconductro Mixer IEEE J. Solid- State Circuits, v. 39, n. 8, [5] A. M. El-Gabaly, D. Stewart and C. E. Saavedra, "2-Watt Broadband GaN Power Amplifier RFIC using the ft Doubling Technique and Digitally-Assisted Distortion Cancellation'', IEEE Transactions on Microwave Theory and Techniques, vol. 61, no. 1, pp , [6] Wen Li and C. E. Saavedra, "A Stand-Alone Distortion-Cancelling Cell for Microwave Amplifiers", IEEE Microwave and Wireless Components Letters, vol. 23, no. 4, pp , [7] M. Wang, Shan He, C. E. Saavedra, "+14 db Improvement in the IIP3 of a CMOS Active Mixer Through Distortion Cancellation", IEEE MTT-S International Wireless Symposium, Beijing, China, April [8] A. M. El-Gabaly, H. Li and C. E. Saavedra, "A Decade-Bandwidth Low-Noise Mixer RFIC with a Distortion- Cancelling Output Amplifier", IEEE Symposium on Radio Frequency Integration, Taipei, Taiwan,

33 Q & A 33