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Anil Kumar Pandey
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Application Design Scope and Objective
This flow demonstrates the usage of multiple technologies based on different PDKs , LTCC, Packaging, 3DConnector and RF board defined in separate libraries along with ADS standard libraries to realize the completedesign transceiver layout for EM simulation.
The transceiver system that has been designed consists ofmainly Seven major technologies:1. SPDT : Based on not-linear demo kit2. LNA : Based on non-linear MT kit3. Power Amplifier : X-parameter file of MMIC power
amplifier4. LTCC BPF : 3 pole low pass filter based on 6 layer LTCC
technology5. Connector from EMPro as OA library : 3D SMA
Connecter modeled in EMPro6. QFN Package : Standard QFN package for LNA and SPDT
switch packaging7. Antenna : single layer C-band microstrip patch antenna
The LNA and SPDT are designed using two different PDKs having different technologies defined in two separatelibraries whereas as Antenna and PA are designed using ADS standard libraries. Layer stack and material propertiesin these two PDKs are same but naming of components and color code is different. LTCC Low pass filter is designusing LTCC technology . The complete transceiver circuit is realized in layout using side by side nested technology .FEM simulation is carried out without active components in layout for complete system. The design is thensimulated for S-Parameter in schematic with EM model along with active components .
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Transceiver and it’s Applications
PA
LNA
T/R Module
SW
PA
LNA
T/R Module
SW
PA
LNA
T/R Module
SW
PhaseShifter
PhaseShifter
Antenna Linear Array
PD
Antenna Linear Array
Antenna Linear ArrayPhaseShifter
PD
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A transceiver is a device comprising both a transmitter and a receiver which arecombined and share common circuitry or a single housing. When no circuitry iscommon between transmit and receive functions, the device is a transmitter-receiver
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Transmit/Receive chain at C-Band (5 GHz)
Technologies:
AntennaPA LNA SPDT
PDK1
MMICs
PDK2
BPF
LTCC Microstrip
LNA
PA
SPDT Switch
BPF
Receiver
Transmitter
Switch Control
AntennaTransceiver
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Transceiver System: Cross section view
PackagedPower Amp
PTH
DC LinesMicrostrip Ground Plane
Patch Antenna
MMIC
LNA Filip Chip
QFN Package
MMIC
SPDT Filip Chip
QFN Package
LTCC LPF
SMA Connector
MMIC LNA
PA
MMIC SPDT
LTCC LPF
Backside Microstrip Patch
Antenna
SMA ConnectorDC Bias lines
Transceiver System Design in ADS
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Transceiver Design flow in ADS
Component specifications
Choice of topology – Choice of the active device
Active device characterization-DC IV – bias point
Tuning / optimization / design centering
Designing with Foundry / DK elements Re Optimization
Linear simulation for insertion loss and isolation
Generation of Layout (LVS feature)
Schematic generation
Linear simulation for insertion loss and isolation.
Transient /Envelop simulation
Incorporate pre-simulated PA data file as database component
Design of C-band microstrip antenna on Alumina
Prepare Antenna for nested Technology
RF board design with all components as nested technology
Optimization and RF board for better performance
FEM- Simulation of complete RF board
Circuit simulation of complete Transceivers in schematic along wit h active components
MMIC Chip Design (LNA & SPDT)
Layout Design EM sim
EM co-simulation with FETs
Tuning / optimization / design centering
Using Stacked nested technology for Chip + Package
EM simulation of Package + MMIC Chip
EM co-simulation of Package + MMIC Chip along with FETs
Design of Bandpass filter in schematic
Realization of BPF in layout using LTCC technology
Prepare LTCC BPF for nested Technology
LTCC BPF design
Microstrip Antenna Design
PA Design
RF board with Side by Side MTM
Complete Systems with Connector
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Board
Chip
ModuleDesign Components
1. SPDT : Based on not-linear demo kit2. LNA : Based on non-linear MT kit3. Power Amplifier : X-parameter file of MMIC power amplifier4. LTCC BPF : 3 pole low pass filter based on 6 layer LTCC technology5. Connector from EMPro as OA library : 3D SMA Connecter
modeled in EMPro6. QFN Package : Standard QFN package for LNA and SPDT switch
packaging7. Antenna : single layer C-band microstrip patch antenna
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• Total 12 equivalent layer board• 7 different technologies• 2 stack up + 4 side by side technologies• EMPro design as OA lib component• 3 different layout units
mm ( millimeter)
mil
um
Side by Side MTM Substrate
MMIC SPDT Substrate
MMIC LNA Substrate
SPDT + Package SubstrateLNA + Package Substrate
Antenna Substrate
LTCC LPF
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Low-noise amplifiers (LNAs) are critical for extracting signals fromnoise in communications receivers. The Non-Linear ‘MT’ versionof MMIC demo kit contains MESFETs with non-linear modelswhich can be used as basic LNA elements. In designing the LNA,the first step is to decide which profile provides the bestcombination of features and performance. The next step is tochoose device size. Device size will affect the LNA's bandwidth,DC power consumption, noise figure, and nonlinear performance.Here First LNA has been realized using ideal component isschematic then with demo kit components. From schematicdesign , a layout design is created for EM simulation. LAN isintegrated with QFN package using stacked nested technology.
MMIC LNA DesignTechnology-1
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LNA – EM Cosimulation
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LNA on QFN Package : EM simulation dataFEM Solver: DM64 ( RHEL5, 64, 72 GB box)
Simulation Time 21 min
Max Process Size 15.960 GB
Max Unknowns 1.52 million
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Single-Pole-Double-Throw (SPDT) switches are widely used inTransmit/Receive applications. MMIC SPDT switch has been designedusing standard series-shunt configuration . The Non-Linear MMIC demokit contains MESFETs with non-linear models which can be used as basicswitching elements. SPDT switch has one input and two output arms. RFpower is guided into one of the arms by switching ON the required armand switching OFF the other arm.
Ideally, no power should be detected in the OFF arm. However, due tothe parasitic and coupling effects, RF power leaks into the OFF arm. Theleaked power is grounded by placing a shunt MESFET in ON state asshown in the following figure
This reduces the power detected in the OFF arm and thus improves the isolation.
RF-IN
RF-OUT1
RF-OUT2
FET
RF-IN
RF-OUT1
RF-OUT2
FET
ON
ONOFF
OFF
MMIC SPDT Switch DesignTechnology-2
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MMIC SPDT Switch Circuit and EM Cosimulation
SPDT switch is design first using Ideal lumped elements. RF flows from Source to Drain when Gate is at 0 volt.Hence series FETs have input and output at Source and Drain respectively. Single DC bias is used to connect allON devices and another single DC bias is used to connect all OFF devices. After verifying the basic switchaction, idle components are replaced with MMIC demo-kit components in layout . Schematic circuit with demokit components are generated with option ‘Schematic > Generate/Update Schematic’ .
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SPDT + Package EM Cosimulation dataFEM Solver: DM64 ( RHEL5, 64, 72 GB box)
Simulation Time 1 hour 6 min
Max Process Size 30.2 GB
Max Unknowns 2.71 million
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LTCC LPF Filter
Low Temperature Co-fired Ceramic (LTCC) is a multi-layer ceramic technology, which processes theability to embed the passive elements, such as resistors, capacitors and inductors into a ceramicinterconnect package while the active elements are mounted in the top layer. Up to 50 layers canbe constructed.
In the design a 3 pole low pass filter up to 6 GHz has been designed by using spiralinductor and capacitor. The technology used in this example is LTCC. The basiccomponents spiral inductor and capacitor been designed with parameterized value. Filter has been optimize by varying parameters that changes value of L and C.
Technology-3
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Microstrip Patch Antenna Design along with Via Transition
Antenna with LTCC Filter
Antenna Gain Pattern
Technology-4
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QFN Package CharacterizationTechnology-5
This is QFN package that uses standardpackaging substrate configuration. QFNpackage is characterized with a simplebondwire connection
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SMA- Connector Simulation in EMPro
SMA Connector simulation in ADS schematic taking EMPro look-a-like components
Technology-6
SMA connector is modeled in EMPro andimported in ADS as OA librarycomponents.
SMA Connector for RF inand RF out of Transceivermodule.
Filed propagation
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RF Board CharacterizationInterspacing between traces are critical to get good return loss and low insertion loss. This analysis is carried out by simulating complete RF board with EM solver then visualizing field coupling between nearby traces. Spacing is optimize to minimize interspace coupling
Technology-7
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Project Breakup : Discontinuity into consideration
FEM Solver is not able to handle completeproblem due to memory limitation ( 70 GHz ).Divided problem in 3 segments takingdiscontinuity points into consideration.
FEM Solver: DM64 ( RHEL5, 64, 72 GB box)
Simulation Time 7 hour 6 min
Max Process Size 45 GB
Max Unknowns 4.3 million
Solver DM64 (order-1)
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Complete System : Ideal Components
First complete transceiver systemperformance has been simulated by placingall complements modeled with schematiccomponents. The LNA and SPDT aredesigned using two different PDKs havingdifferent technologies defined in twoseparate libraries whereas as for PA X-parameter simulated file and for antenna S-parameter simulated file have been taken.The complete transceiver circuit is thencreated with and without using the Modulesubstrate. The design is then simulated forS-Parameter.
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Complete System : EM Co-Simulation for LNA+SPDTD Module Level
SPDT Switch Chip +QFN Package : EM Co-simulation model
LNA Chip + QFNPackage : EM Co-simulation model
Result are close to circuitsimulation . EM-Co simulationtakes care of all loss andcoupling simulation effect
Chip
Module
Chip
Module
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Complete System : EM Co-Simulation RF Board Level
Result are matching withcircuit simulation butthere is around 6dBpower loss from poweramplifier to antenna EM-Co simulation takes careof all loss and couplingeffect in simulation
Chip
Module
RF Board
Complete transceiver design issimulated using EM simulated look-a-like component and active circuit inschematic
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Complete System : EM Co-Simulation RF Board Level
SPDT
LNA
Antenna
LTCC -LPF
PA
RF-IN RF-OUT
This is schematic simulation of transceiver alongwith radiating antenna and active components.Here PA is in ON state while LNA is in OFF state.Simulation data of PA is showing good return loss at5.23 GHz. This combined two look-a-likecomponents, Antenna + LPF and LNA+SPDT switch .PA is modeled from pre-simulated X-parameter file.
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An
tenn
a Linear A
rray
PhaseShifter
PD
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PhaseShifter
PD
Phase
Shifter
PD
PhaseShifter
PD
Antenna ArrayT/R modulePSPD
Active Phased Array using MTM - Transceiver
T/R modules are used in Active phasedarray antennas as transmit and receivedevice.
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Complete Project Setup in ADS
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Simulation Result of Complete System
Circuit simulation setup in ADS
Return loss at Poweramplifier ( ON) . Thissupply power to 1:8 lineararray system using 1:1Power divider
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Simulation Results
Design name Parameters Specification
MMIC- SPDT Switch
Frequency range DC to 20 GHz
Insertion loss < 1 dB
I/O Return loss < -15 dB
Isolation > 30 dB
MMIC - LNA
Input Power Range
Noise Figure 4.01 dB at 5.08 GHz
Stability Factor 1.43 at 5.08 GHz
Power AmplifierGain ~ 12 dB in T/R system
PA Efficiency
LTCC- LPFPass bandwidth Up to 5.6 GHz
I/O Return Loss < -15 dB
Antenna
Frequency range 5 – 5.3 GHz ( 300 MHz )
Polarization Linear Polarization
Gain 7 dB
Transceiver SystemSupply Voltage Single Bias Supply Operation (3 V)
Overall I/O Return Loss < -20 dB
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Conclusion
Side by Side Multi Technology has been demonstrated for designof complete Transceiver System . This flow also demonstrated
– The usage of multiple technologies based on different PDKs , LTCC,Packaging, 3D Connector and RF board defined in separate librariesalong with ADS standard libraries to realize the complete designtransceiver layout for EM simulation.
– Multi-level hierarchy support
– Multi-Technology vertical stack up
– Full FEM simulation of entire layout including MMICs
– EMPro design as library component
– Use EM simulation to find coupling problem in multichip system and RF board
– Application of transceiver system for active phased array system
