RF Front End Radio Design Simulations and Specifications

RF Front End Radio Design. Simulations and Specifications Hemish Parikh Advisor: Prof. William R. Michalson

RF Front End Receiver Design - Outline • • Overview System parameters Specifications System Analysis System Parameter relations System Simulations in ADS Roadmap Questions 12/7/2020 2

RF Front End Receiver Design - Overview You are Here 12/7/2020 3

RF Front End Receiver Design - Overview Possible Front End Models • Model 1: Direct RF Sampling Today’s Focus • Model 2: Direct Down Conversion 12/7/2020 4

RF Front End Receiver Design – System Parameters • • • System Gain (G) System Noise Figure (NF) Input 3 rd Order Intercept Point (IIP 3) Receiver Sensitivity (Rx-Sens) Receiver Spurious Free Dynamic Range (SFDR) • Inter Modulation Distortion (IMD) 12/7/2020 5

RF Front End Receiver Design - Specifications Component Identification RF MICRO DEVICES ANALOG DEVICES RF-2361 AD-8367 COMTELCO ANALOG DEVICES PEXW-400 AD-8343 MURATA 415 -465 MHz 0 -50 MHz VECTRON VARI-L OSC-1 B 0 -10 MHz VCO 190 -445 T ANALOG DEVICES 12/7/2020 ADF-4112 6

RF Front End Receiver Design - Specifications - LNA • RFMD – 2361 – – 12/7/2020 Low Noise Figure (NF): 1. 9 d. B Gain (G): 20 d. B Input 3 rd order intercept point (IIP 3): 6 d. Bm Max input RF level: +10 d. Bm 7

RF Front End Receiver Design - Specifications - AGC • AD 8367: – Variable Gain: -2. 5 d. B to 42. 5 d. B – NF ? ? ? – IIP 3 ? ? ? 12/7/2020 8

RF Front End Receiver Design - Specifications – Mixer (1) LO+RF LO-RF RF LO • • • IM Products Big role in overall system performance Mixing is just frequency shifting Produces LO+RF and LO-RF Produces Unwanted Inter Modulation Distortion (IMD) IM products: (M*LO + N*RF) and (M*LO - N*RF) Good Mixer or a Bad Mixer !!!!!? ? 12/7/2020 9

RF Front End Receiver Design - Specifications – Mixer (2) Good Mixer Low Noise Figure (< 15 d. B) Good Port Isolation (~ 50 d. Bm) 12/7/2020 High IP 3 ( > 15 d. B) High Conversion Gain LO drive level (application dependent) 10

RF Front End Receiver Design - Specifications – Mixer (3) • AD 8343: – – NF: 11 d. B Gain: 7. 1 d. B IIP 3: 20 d. Bm LO drive level: -10 d. Bm 12/7/2020 11

RF Front End Receiver Design - Specifications – Mixer (4) LO = 400 MHz 12/7/2020 12

RF Front End Receiver Design - Specifications - TCXO / VCO • Vectron TCXO: – Frequency: 10 MHz – Stability: 2. 5 ppm – Mechanical Trip: +/- 3 ppm 12/7/2020 • Vari-L VCO: – Tuning Range: 400 to 500 MHz – Tuning Sensitivity: 15 MHz/V 13

RF Front End Receiver Design - Specifications – PLL (1) • ADF 4113: – Programmable counters: P, B, A, R 12/7/2020 14

RF Front End Receiver Design – Analysis System Gain G 1= -2 d. B G 2= 20 d. B G 3= 7. 1 d. B G 4= -2 d. B G(d. B) = G 1+G 2+G 3+G 4 P_in = G + P_out 12/7/2020 BPF LNA MIXER LPF P_in (d. Bm) -40 -42 -22 -14. 9 Gain (d. B) -2 20 7. 1 -2 Cumulative Gain -2 18 25. 1 23. 1 P_out (d. Bm) -42 -22 -14. 9 -12. 9 15

RF Front End Receiver Design – Analysis System Noise Figure (1) Noise Sources System Noise Thermal Noise Figure quantifies how noisy the system is Reference Max allowed NF: Noise Figure is WCDMA: 9 d. B Noise Factor in d. B Cellular: 10 d. B PCS: 6. 8 d. B System noisy due to losses in GOAL: Design receiver circuit, solid state devices. with lowest NF !!!!!! 12/7/2020 16

RF Front End Receiver Design – Analysis System Noise Figure (2) Critical G 1= -2 d. B G 2= 20 d. B G 3= 7. 1 d. B G 4= -2 d. B NF 1=2 d. B NF 2=1. 9 d. B NF 4=11 d. B NF 5= 2 d. B Noise Figure of Cascaded System 12/7/2020 BPF LNA MIXER LPF NF (d. B) 2 1. 9 11 2 Cumulative NF (d. B) 2 3. 9 4. 21 4. 22 17

RF Front End Receiver Design – Analysis System Input IP 3 (1) Third Order products: 2 f 1+f 2, 2 f 1 -f 2, 2 f 2+f 1, 2 f 2 f 1, where f 1 and f 2 are two inputs. IP 3 is a measure of system linearity. Point where the desired signal and the 3 rd order distortion have equal magnitudes. 12/7/2020 Problem: Relatively large magnitude and difficult to filter Reference Min allowed IIP 3: Cellular: -13 d. Bm PCS: -11. 425 d. Bm 18

RF Front End Receiver Design – Analysis System Input IP 3 (2) G 1= -2 d. B IIP 1= d. Bm G 2=20 d. B IIP 2= 6 d. Bm G 3=7. 1 d. B G 4= -2 d. B IIP 3=20 d. Bm IIP 4= d. Bm Critical 12/7/2020 19

RF Front End Receiver Design – Analysis Receiver Sensitivity (1) • Rx. Sens quantifies the receivers ability to respond to weak signal. SNR_min = 12 d. B (Assume) BW = 50 MHz A/D Input Rx. Sens = Noise Floor + 10 log(BW) + SNR_min + Noise Figure 12/7/2020 Rx. Sens = -174 + 77 + 12 + 4. 22 = -80. 78 d. Bm Significantly reduces 20 The Rx. Sens

RF Front End Receiver Design – Analysis Receiver Sensitivity (2) 12/7/2020 As BW increases, sensitivity becomes poor 21

RF Front End Receiver Design – Analysis Receiver Sensitivity (3) 12/7/2020 22

RF Front End Receiver Design – Analysis Receiver Spurious Free Dynamic Range • High DR means Receiver can operate over wide range of input power levels. – Receiver’s Output starts to saturate if the Input is above the range – Below DR, the noise dominates. SFDR = 0. 66 (IIP 3 – Rx. Sens) = 0. 66 (1. 1 + 80. 78) 12/7/2020 = 54. 6 d. B 23

RF Front End Receiver Design – Analysis AGC Issues • Max AGC Gain: – Lowest NF – Lowest IIP 3 12/7/2020 • Min AGC Gain: – High IIP 3 – High NF • Poor Dynamic Range: 25 d. B 24

RF Front End Receiver Design – Parameters Relations System Parameters Relations Higher IP 3 Maximize Rx. Sens Bandwidth Dependent 12/7/2020 Maximize DR Application Dependent Minimize NF 25

RF Front End Receiver Design - Simulations ADS simulations for Gain (1) 12/7/2020 26

RF Front End Receiver Design - Simulations ADS simulations for Gain (2) Swapped 12/7/2020 27

RF Front End Receiver Design - Simulations ADS simulations for NF(1) 12/7/2020 28

RF Front End Receiver Design - Simulations ADS simulations for NF(2) Swapped 12/7/2020 29

RF Front End Receiver Design - Simulations ADS simulations for IMD (1) 12/7/2020 30

RF Front End Receiver Design - Simulations ADS simulations for IMD (2) 12/7/2020 31

RF Front End Receiver Design - Simulations ADS simulations for IMD (3) 12/7/2020 32

RF Front End Receiver Design - Simulations ADS simulations for SFDR Rx Signal Level = -25 d. Bm SFDR ~= 50 d. B SFDR 12/7/2020 33

RF Front End Receiver Design - Simulations 12/7/2020 34

RF Front End Receiver Design Roadmap • • ADS with Matlab ADS with Instruments Set-up Evaluation board Migrate to 2. 4 GHz 12/7/2020 35

RF Front End Receiver Design ? 12/7/2020 36