RF Circuit Synthesis for Physical Wireless Design

Transcription

1 RF Circuit Synthesis for Physical Wireless Design

2 Overview Subjects Review Of Common Design Tasks Break Down And Dissect Design Task Review Non-Synthesis Methods Show A Better Way To Solve Complex Design Challenges Audience Designers Tasked With Rapid Development Of System Components

3 RF Wireless Community WIFI CABLE COMM DEVICES CELLULAR Wireless Devices RFID GOVERMENT SATELLITE INSTRUMENTS NAVIGATION

4 System Architecture Starting from a system level view Assemblies of component units constitute a system The component parameters are generated by system requirements Made up of one or more Amplifier Mixer Filters: Microwave and Passive Lumped Couplers/splitters Oscillators etc. We start by breaking down tasks to individual modules Design of one or more require unique skills

5 Component Design Tasks Today s Focus is on Four Design Tasks Microwave Filter Design Lumped Passive Filter Design Signal Control Elements Matching for Optimum Power Transfer

6 Non Synthesis Techniques The Non-Synthesis Method Experience is required to choose topology, equivalent circuits and strategy for failed performance Links to physical realization is a manual process Select Topology And Components Conversion to micro-strip, slab-line, strip-line etc. Does not guarantee optimum design Optimize Response Best performance, Component count, Size, Materials Matching tools are limited i.e. Smith chart Strategy? NO Met Goals Time and Resource Consuming NO YES Strategy? Hours, days, or even weeks to complete Missed deadlines To Manufacture YES Met Goals Convert To Physical Format Board Turns Build Device Test Device NO EM Solver? YES YES Met Goals NO

7 Microwave Filter Design Task 2.4 GHz WiFi Front End Microwave Filter System Specifications / Goals Frequency MHz Insertion Loss- -2dB Shape- Butterworth Order- 3

8 Microwave Filter Design Task MFILTER- A Better Way Start With Filter Type Shape Low-pass, High-pass, Band-pass, Band-reject Shape Butterworth, Chebyshev, Bessel etc. Subtype Eight physical formats

9 Microwave Filter Design Task Which topology is best? Distributed Filters Exhibit Recurring Band Pass Where and how many is a function of filter type COMB filters have control over the band where response is repeated Filter Size varies Cost-COMB requires a capacitor for each resonator We have selected a Hairpin Design for this demonstration

10 Microwave Filter Design Task Settings Select Z0, Order, Start-Stop frequencies Select Resonator Zo Select Tapped / Coupled

11 Microwave Filter Design Task Advanced-TLINE automatically converts to a physical form including discontinuities, bends, chamfers, and steps

12 Microwave Filter Design Task Synthesized Hairpin Filter Advanced TLINE Hairpin Filter with Modeled Microstrip Loss and Dispersion

13 Microwave Filter Design Task Using Built-in Optimizer Fine tune for the discontinuities, bends, loss, dispersion effects etc.

14 Microwave Filter Design Task Using Monte Carlo Determine Effect of Loss Tan Effect of etching tolerance e.g. spacing Effect of Er

15 Microwave Filter Design Task Layout Filter Perform EM Simulation Export To Manufacturer Test Completed Filter

16 Microwave Filter Design Task Measure Filter TESTLINK Compare to Simulation Measured EM Modeled

17 Microwave Filter Design Task Performance Summary Center Frequency 2450 MHz 2390 MHz Bandwidth 200 MHz 260 MHz Insertion Loss 2 db 3.2 db $ Cost? ~$0.50 Note: Know your substrate material especially ER and Loss Tan

18 Microwave Filter Design Task Link data to SPECTRASYS behavioral model Po=1.2 db NF=0.1dB

19 Microwave Filter Design Task MFILTER- A better way Classical synthesis shapes Butterworth, Chebyshev, Elliptical etc. Multiple topologies Instant schematic and graphical updates Coupled or Tapped input Multiple physical realizations e.g. stripline, microstrip, inverted microstrip etc. via Advanced T-Line Automatic compensation of vias, grounds, steps, and T-Junctions Direct link to layout and EM simulation engine Monte Carlo, Yield and what If analysis Measurement of Device via TESTLINK

20 Lumped Filter Design Task 70 MHz IF Filter System Specifications / Goals Frequency MHz Insertion Loss- 0.5dB? Shape- Butterworth Order- 14?

21 Lumped Filter Design Task PASSIVE FILTER - A Better Way Start With Filter Type Shape Low-pass, High-pass, Band-pass, Band-reject Shape Butterworth, Chebyshev, Bessel, Elliptical etc. Subtype Eight physical formats Some Formats Lend Themselves Better to Wide or Narrow Responses Note: Changes in schematic and graph when parameters are changed is Instantaneous

22 Lumped Filter Design Task Which Shape And Subtype To Pick? Component Count Response BW, Group Delay Out Of Band Response Symmetry, Roll Off Ease of Manufacture Common Inductance or Capacitance Balanced Circuit at a Buttons Click!

23 Lumped Filter Design Task Multiple Filter Shapes Butterworth Chebyshev Bessel Singly Terminated For Diplexers etc.

24 Lumped Filter Design Task Settings Input / Output Resistance Not limited to 50 ohms or symmetrical impedances! Cutoff Frequencies Filter Order Specify Cutoff Attenuation Common L or C for some filter types

25 Lumped Filter Design Task Response of Synthesized Shunt C Coupled Filter Shunt C Coupled filter results in common inductor Five Sections Chosen

26 Lumped Filter Design Task Using Standard Values Results in Shifted Response Tune Standard Values for best results Original vs. standard values

27 Lumped Filter Design Task Replacing Ideal Std Values with Manufacturers S-data Increased insertion loss due to finite Q s of components Be Mindful of SRF and Qs of Manufacturer s Components and The Frequency range of their data Original vs. S-data values

28 Lumped Filter Design Task Perform Layout and EM Simulation

29 Lumped Filter Design Task EM simulation with S-Data Parts Use Co-Simulation to Fine Tune Standard Valued S-Data Only a single EM simulation is required since copper pattern is invariant Filter with S-data specified parts EM Filter with S-data specified parts

30 Lumped Filter Design Task Comparison of Original Synthesized Filter Use Monte Carlo for Yield and Manufacturability

31 Lumped Filter Design Task Pad and Dielectric Effects More prominent at higher frequencies, 500MHz Filter example shown H=59mil Er= 3.9, 4.5, 4.9 H=30mil H=10mil

32 Lumped Filter Design Task Pad and Dielectric Effects More prominent at higher frequencies Co-Simulation feature is used to re-tune filter EM results in shift due to pad effects Std value tuning brings filter back EM std values L=39 Ca=5.6 Cb=3.9 Cc=18 Ccd=3.6 EM std values otpz L=39 Ca=3.3 Cb=2.4 Cc=7.5 Ccd=2.4

33 Lumped Filter Design Task Performance Summary Center Frequency Bandwidth 70 MHz 68.1 Std Pts 20 MHz 17.3 Std Pts 67 MHz 17 MHz Sections 14 5 Insertion Loss 0.5 db 3.9 db $ Cost? ~$2.90 (16x$0.15) Note: Know your substrate material especially ER and LossTan

34 Lumped Filter Design Task Link data to SPECTRASYS behavioral model When S-Parameter File is Substituted For Behavioral Model In System Simulator Note: 3db Additional Loss And Increase In Spur Level (below noise floor) And An Increase Of 0.11dB In Noise Figure

35 Lumped Filter Design Task PASSIVE FILTER- A better way Classical synthesis shapes Butterworth, Chebyshev, Bessel, Singly Terminated etc. Multiple topologies Instant schematic and graphical updates Single or Balance types Direct link to layout and EM simulation engine Co-Simulation aides final optimization Monte Carlo and Yield analysis Measurement of Device via TESTLINK

36 Signal Control Design Task What is Signal Control? Distribution And Control Of Power Through The Use Of Couplers, Splitters, Dividers, Attenuators, Baluns Where Is It Used? Power Monitoring, Amplifiers, Mixers, Power Combining, Beam Forming

37 Signal Control Design Task Signal Control Elements Splitters Single or Multi-section, 0 deg, 180 deg Couplers Lange, Backward Wave, Lumped Power Dividers Distributed, Lumped Balun Attenuators

38 Signal Control Design Task SIGNAL CONTROL, a better way! Topology Selection of over 43 topologies Splitters Couplers Power Dividers Baluns Attenuators

39 Signal Control Design Task Settings Selection of: Impedance Coupling Factor Upper/Lower cutoff Number of Sections Number of Outputs Optimization Goals I/O line lengths

40 Signal Control Design Task Instant Realization Dynamic Schematic and Graphs

41 Signal Control Design Task Options Create a Layout Use Advanced TLINE to Convert to Physical Format

42 Signal Control Design Task Options Manufacturing Process Select Physical Form Switch between any of the processes (e.g. ideal to microstrip, stripline to microstrip etc.) Accounts for discontinuities, corners, steps etc. Uses selectable substrate definition

43 Signal Control Design Task Conversion to Microstrip Causes Shift Shift due to non-ideal models, losses, dispersion etc. Re-optimize element parameters to specifications Shift due to Microstrip

44 Signal Control Design Task Layout Is Created By Checking Box in Options Tab EM Simulation Is Performed To Verify Design Goals

45 Signal Control Design Task EM Simulation Shows Difference In Isolation Between Output Ports EMPOWER s Ability To Co-Simulate Allows The Tuning Of Isolation Resistor For Optimum Isolation Optimum R= 91 ohms instead of 100 ohms

46 Signal Control Design Task SIGNAL CONTROL- A better way Over 43 Topologies Splitters, Couplers, Baluns, Attenuators 0 deg, 90 deg, 180 deg types Multiple outputs, Multiple stages Instant schematic and graphical updates Optimization of final process Direct link to layout and EM simulation engine Co-Simulation aides final optimization Monte Carlo and Yield analysis Measurement of Device via TESTLINK Link data to SPECTRASYS behavioral model

47 Matching Design Task Where is Matching used? At Almost Every Interface Between Connected Components Minimize Power Loss Between Entities

48 Matching Design Task Front End Receiver Amp Parameters Frequency Range 2200 MHz to 2600 MHz Gain 30dB Noise Figure 3dB Match Nominal 50 Ohm Input/Output P1dB +10dBm PSAT 13dBm TOI 20dBm

49 Matching Design Task Complex Matching Issues Simultaneous Matching For Noise Figure, Input/Output, and Interstage Difficult Using Manual Techniques, Especially For Conditionally Stable Device NE52418 Selected Part Meets Our Gain And Noise Figure Needs

50 Matching Design Task Conditionally Stable Simultaneous Input/Output Match Is Not Possible Good News, Noise Figure Meets Our Goal With 50 Ohm Input

51 Matching Design Task MATCH A Better Way Ideal For Complex Multistage Matching Real Or Complex Terminations File Based Complex Data For Terminations / Devices Multitude Of Available Matching Structures Lumped And Or Distributed

52 Matching Design Task Nominal Goals Met With Interstage Matching Sections

53 Matching Design Task Matching Network Incorporated Into Design Use Advance TLINE Converts To Physical Process Includes Steps, Discontinuities, Vias, etc.

54 Matching Design Task Monte Carlo Analysis Matching <100% Yield, Determine Effect On System Or End User Gain And NF 100% Yield

55 Matching Design Task Optimize Circuit For Response And Match Measure Pertinent Parameters Frequency Range 2.2 GHz-2.6 GHz Gain 30dB +/-.5 db Noise Figure 1.06 db Match <-15dB? P1dB 0 dbm (10 dbm)? TOI 18.6 dbm (20 dbm)? PSAT 10.4 dbm (13 dbm)

56 Matching Design Task Replacing Behavioral Model With Design No Significant Change In Spur Or Harmonic Content Noise Figure Improved by 2dB

57 Matching Design Task MATCH- A better way Multiple matching networks and topologies Mix and match between distributed and lumped networks Match to real, complex and S/Y/Z files Broadband matching, Multi-stage matching Instant schematic and graphical updates Direct link to layout and EM simulation engine Co-Simulation aides final optimization Monte Carlo and Yield analysis Link Data To SPECTRASYS Behavioral Model

58 Summary Reviewed Of Common Design Tasks Reviewed Non-Synthesis Methods Showed A Better Way To Solve Complex Design Challenges Synthesis Incorporating Standard Values Substituted Measured S-Data For Accuracy Optimized Performance Layout And EM Simulation For Verification Exported Data For Incorporation Into Higher Level Design We Showed A Comprehensive Set Of Tools, In a Common Environment For Rapid Development, Improving Time To Market With Fewer Re- Designs

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