sub harmonic mixer design with ansoft designer
TRANSCRIPT
Subharmonic Mixer Design With
Ansoft Designer
Subharmonic Mixer Design With
Ansoft Designer
Tony DonisiAnsoft Road ShowAutumn, 2002
Presentation #9
Circuit And Systems Designs Are Growing More Complex
Ansoft Designer Can be used to reduce design cost and speed time-to-market for even the most challenging RF/microwave designs.
Ansoft DesignerAnsoft Designer Can be used to reduce design cost and speed time-to-market for even the most challenging RF/microwave designs.
Unique TechnologySolver on demand
CosimulationVisualization
Unique TechnologySolver on demand
CosimulationVisualization Tight Integration
Circuit, System
and Planar EM
Tight IntegrationCircuit, System
and Planar EM
Advanced CapabilitiesTransient Analysis
Load Pull3D plotting
Integrated 2D layoutIntegrated 3D layout
Advanced CapabilitiesTransient Analysis
Load Pull3D plotting
Integrated 2D layoutIntegrated 3D layout
AnsoftDesigner
AnsoftAnsoftDesignerDesigner
Circuit• Linear• Harmonic balance• Transient• Load Pull• Modulation analysis• VCO Design and analysis
Circuit• Linear• Harmonic balance• Transient• Load Pull• Modulation analysis• VCO Design and analysis
System• Frequency domain and convolution engine• BER• Modulation
System• Frequency domain and convolution engine• BER• Modulation
Planar EM• SVD FastSolve technology• Thick 3D metal• Edge Meshing• Triangular mesh• Variable thickness and εr• Advanced visualization
Planar EM• SVD FastSolve technology• Thick 3D metal• Edge Meshing• Triangular mesh• Variable thickness and εr• Advanced visualization
Overview
w Introductionw Theory w Designw Simulationw Resultsw Conclusion
Subharmonic mixers provide a design challenge due to:
• Higher frequencies• Higher order mixer products• Intricate geometries• Device modeling
Subharmonic mixers provide a design challenge due to:
• Higher frequencies• Higher order mixer products• Intricate geometries• Device modeling
Subharmonic Mixer
w Advantagesw Low frequency LOw Inherent 2LO rejectionw LO easily filtered
w Disadvantagesw Higher order spursw Higher conversion loss
RF LO 2LO
2LO - RF 2LO + RFLO
RF
Frequency
Power
Uses even harmonics of the LO for its conversion products
For a “standard” mixer, the product of interest is LO ± RF.
For a subharmonic mixer, 2LO ± RF is the desired signal.
Uses even harmonics of the LO for its conversion products
For a “standard” mixer, the product of interest is LO ± RF.
For a subharmonic mixer, 2LO ± RF is the desired signal.
nLO ± mRF
Mixer Characteristics
w LO at 14GHz w RF at 28.1GHzw Output at 100mhz w 5mil thick Alumina
w Flip-Chip surface mount antiparallel diode pair
w Spiral inductors for IFw Low-Q on Alumina
Mixer Design
LO Filter Design
OutputMatching
LOMatching
RFMatching
IF Filter Design
Stubs and matching
3D Planar Modeling of Vias, coupled lines, and “non-standard microstrip structures3D Planar Modeling of Vias, coupled lines, and “non-standard microstrip structures
Diode Characterization
Subharmonic Mixer Diodes
w Subharmonic mixers us antiparallel diode pairsw These mixers produce most of their power at “odd”“odd” products
of the input signalsw Even products are rejected due to the I-V characteristicsw m + n odd
w Attenuation of even harmonics is determined by diode “balance”
w Diode “match” is criticalw “Antiparallel” diode pairs are manufactured by many
companiesw Diodes come from the adjacent areas of the wafer so the
characteristics match very wellw Ideal for MMICSw SMT, Beamlead and flipchip versionsw Spice parameters available
Diode CharacterizationDiode Characterization
Diode CharacterizationDiode Characterization
Diode I-V Characteristics
V
I
V
I
Harmonic Mixer
Subharmonic Mixer
Harmonic mixers use single diodes or FETs, having familiar I-V characteristics
Subarmonic mixers use antiparalleldiodes, giving the I-V characteristics shown
Designer Component With Netlist Equivalent
DIODES:@ID_a %0 %1 *RS(RS=@RS) *CJ0(CJ0=@CJ0) *VJ(VJ=@VJ) *TJ(TJ=@TJ) *TNOM(TNOM=@TNOM) *XTI(XTI=@XTI) *EG(EG=@EG) *M(M=@M) *AREA(AREA=@AREA) *T(T=@T) *IS(IS=@IS) *N(N=@N) *FC(FC=@FC) *BV(BV=@BV) *IBV(IBV=@IBV) *IMAX(IMAX=@IMAX) *GC1(GC1=@GC1) *GC2(GC2=@GC2) *GC3(GC3=@GC3) *MOD(MOD=@MOD) *NOISE(NOISE=@NOISE) *FCP(FCP=@FCP) *KF(KF=@KF) *AF(AF=@AF) *SN(SN=@SN) *HARM(HARM=@HARM) *ISR(ISR=@ISR) *NR(NR=@NR) *NBV(NBV=@NBV) *NBVL(NBVL=@NBVL) *IBVL(IBVL=@IBVL) *IKF(IKF=@IKF) *TBV1(TBV1=@TBV1) *TBV2(TBV2=@TBV2) *TRS1(TRS1=@TRS1) *TRS2(TRS2=@TRS2) *TIKF(TIKF=@TIKF) *VDT0(VDT0=@VDT0)
DIODES:@ID_a %0 %1 *RS(RS=@RS) *CJ0(CJ0=@CJ0) *VJ(VJ=@VJ) *TJ(TJ=@TJ) *TNOM(TNOM=@TNOM) *XTI(XTI=@XTI) *EG(EG=@EG) *M(M=@M) *AREA(AREA=@AREA) *T(T=@T) *IS(IS=@IS) *N(N=@N) *FC(FC=@FC) *BV(BV=@BV) *IBV(IBV=@IBV) *IMAX(IMAX=@IMAX) *GC1(GC1=@GC1) *GC2(GC2=@GC2) *GC3(GC3=@GC3) *MOD(MOD=@MOD) *NOISE(NOISE=@NOISE) *FCP(FCP=@FCP) *KF(KF=@KF) *AF(AF=@AF) *SN(SN=@SN) *HARM(HARM=@HARM) *ISR(ISR=@ISR) *NR(NR=@NR) *NBV(NBV=@NBV) *NBVL(NBVL=@NBVL) *IBVL(IBVL=@IBVL) *IKF(IKF=@IKF) *TBV1(TBV1=@TBV1) *TBV2(TBV2=@TBV2) *TRS1(TRS1=@TRS1) *TRS2(TRS2=@TRS2) *TIKF(TIKF=@TIKF) *VDT0(VDT0=@VDT0)
Diode CharacterizationDiode Characterization
Diode Footprint
Diode CharacterizationDiode Characterization
Diode Schematic
Frequency Input at 14GHz, 2f located at 28GHz
Object: Used Designers advanced visualization capabilities to gain greater insight into diode electrical performance
Object: Used Designers advanced visualization capabilities to gain greater insight into diode electrical performance
Diode CharacterizationDiode Characterization
Sweep Setups
Diode CharacterizationDiode Characterization
3D Parameter Plot
Variation with Junction
Capacitance and Series Resistance
Variation with Junction
Capacitance and Series Resistance
Diode CharacterizationDiode Characterization
Amplitude of 2f Product Vs. Parameter Variation
“Ideal” Spectral
Response
“Ideal” Spectral
Response
Variation with Junction
Capacitance
Variation with Junction
Capacitance
Variation with Forward Voltage
Variation with Forward Voltage
Variation with Series
Resistance
Variation with Series
Resistance
Diode CharacterizationDiode Characterization
Mixer Design: LO filter
LO Filter DesignLO Filter Design
LO filter Real Time Tuning
LO Filter DesignLO Filter Design
Mixer Design: LO filter Results
LO Filter DesignLO Filter Design
“Custom” MCPL
This implementation will “ease” the transition from one coupler section to the next.
This implementation will “ease” the transition from one coupler section to the next.
LO Filter DesignLO Filter Design
Filter Co-Simulation Results
CoSimulation ResultsCircuit ResultsCoSimulation ResultsCircuit Results
LO Filter DesignLO Filter Design
Other Solver on DemandPossible Topologies
Designer planar EM does not have the “draw on grid” restriction. Ensemble meshes based on geometry you specify, not some pre-defined grid.
Designer planar EM does not have the “draw on grid” restriction. Ensemble meshes based on geometry you specify, not some pre-defined grid.
LO Filter DesignLO Filter Design
• Tees• Tapers• Y-Junctions• Any other topology!
• Tees• Tapers• Y-Junctions• Any other topology!
Triangle based meshing assures an accurate simulation.
Triangle based meshing assures an accurate simulation.
Stub Analysis
14GHz Stub 82.5mil Long, 3.3mil wide42GHz Stub 27.0mil Long, 2.9mil wide
14GHz Stub 82.5mil Long, 3.3mil wide42GHz Stub 27.0mil Long, 2.9mil wide
Tuning StubsTuning Stubs
Shorted Stub
Tuning StubsTuning Stubs
Designer’s Co-Simulation allows users to define their own custom 2D and 3D vias.• No restrictions on layers or geometry• No more “guesswork
Designer’s Co-Simulation allows users to define their own custom 2D and 3D vias.• No restrictions on layers or geometry• No more “guesswork
Low Pass Filter
IF FilterIF Filter
Assembling the circuit
w Stubs at key locationsw Reflect power back into diodesw Proper phasew Passed parametersw Tuning (real time)
w SMT or chip capacitorw Flip-Chip Diodew LO filter geometryw Grounded stub for DC return
Subharmonic MixerSubharmonic Mixer
Subharmonic Mixer Schematic & Layout
Subharmonic MixerSubharmonic Mixer
Subharmonic Mixer 3D Layout
Subharmonic MixerSubharmonic Mixer
This mixer can be directly inserted into another circuit, or even a system level circuit, to provide accurate system simulation. Designer’s system tool automatically extracts the necessary parameters from this circuit for use in the system simulation
This mixer can be directly inserted into another circuit, or even a system level circuit, to provide accurate system simulation. Designer’s system tool automatically extracts the necessary parameters from this circuit for use in the system simulation
Output Power Vs LO Input Power
Subharmonic MixerSubharmonic Mixer
RF Power = -20dBmRF Power = -20dBm
Output Power Vs RF Input Power
Subharmonic MixerSubharmonic Mixer
Harmonic Output
Output Power Vs RF Frequency
Subharmonic MixerSubharmonic Mixer
IF Power Vs Frequency and Parameter W5t Variation
Subharmonic MixerSubharmonic Mixer
IF Power Vs W1 and L1 Variation2 Dimensional Plot
Subharmonic MixerSubharmonic Mixer
IF Power Vs W1 and L1 Variation3 Dimensional Plot
Subharmonic MixerSubharmonic Mixer
Conclusion
w Subharmonic mixer design illustrated Designer’s advantagesw More accurate simulations w No restrictions on geometric modelsw Higher frequenciesw Higher order mixer productsw Intricate geometriesw Device modeling
w Solver on demandw Cosimulationw Visualization
Designer’s flexibility as a completely integrated circuit, system and planar tool has been demonstrated.
Designer’s flexibility as a completely integrated circuit, system and planar tool has been demonstrated.