RF and mm-Wave Research by 9PoxGNrD


									RF and mm-Wave Research

 Ali Niknejad, Robert Brodersen,
    Jan Rabaey, Robert Meyer

   University of California at Berkeley
Presentation Outline

    Research Focus
    60 GHz Update
    Universal Radio
    Ultra Wideband LNA
    Summary
              Research Focus Areas

   Universal Radio                           60 GHz WLAN


      Dynamic Radio                          Gb/s Data Rates
Multistandard Operability              Multi-Antenna Architecture
   Broad/Multi band                         Sub-100nm CMOS
   Short/Long Range
                                   WLAN at 17/24 GHz
UWB              Cognizant Radio
60 GHz Transceiver Update

     Chinh Doan, Sohrab Emami,
     Brian Limketkai, David Sobel,
   Patrick McElwee, Mounir Bohsali,
      Sayf Alalusi, Hanching Fuh
     FCC Unlicensed Spectrum at 60 GHz
 A key motivation for this project: there is 5 GHz of unlicensed
  bandwidth available at 60 GHz, with numerous, obvious
  advantages and applications
 But path loss is high at 60
  GHz due to propagation loss
  and small capture area of an
  antenna element
 Antenna capture area 100 x
  smaller compared to 5 GHz
                                            D1 D2   
                                                    2         2
          Pr Ae1 Ae 2                  Pr
              2 2                                  
          Pt  R                       Pt (4 R ) 2
          60 GHz Wireless LAN System

                       10-100 m

   Objective: Enable a fully-integrated low-cost Gb/s data
    communication using 60 GHz band.
   Approach: Employ emerging, standard CMOS and SiGe
    technology for the radio building blocks. Exploit antenna
    array for improved gain and resilience.
           Applications and Impact
   Our Goal: Wireless LAN networks operating at data rates
    100 X faster than today (1 Gb/s)
   This research will also enable CMOS and SiGe
    technology as a low-cost small footprint alternative to
    many microwave and mm-wave systems (100 X cost
   Examples:
      Anti-collision radar for automobiles

      Short-range high-throughput data communication
       (wireless USB)
      Point-to-point Gb/s wireless data network links

   Advance state of the art in modeling and simulation of
    CMOS and SiGe microwave and mm-wave systems

                  Challenges and Solution
   Major Challenges:
      High path loss at 60 GHz (relative to 5 GHz)

      Silicon substrate is lossy – high Q passive elements difficult to realize

      CMOS building blocks at 60 GHz

      Need new design methodology for CMOS mm-wave

      Low power baseband architecture for Gbps communication

   Solution:
      CMOS technology is inexpensive and constantly shrinking and operating

       at higher speeds – multiple transceivers can be integrated in a single chip
      Antenna elements are small enough to allow integration into package

      Beam forming can improve antenna gain, spatial diversity offers

       resilience to multi-path fading
      Due to spatial power combining, individual PAs need to deliver only ~

       50 mW
       Performance Goals
                              Gain                20 dB
                              Noise Figure        8 dB
                              Power               100 mW

                              Power               50 mW
                              Output Power        0 dBm

                              Gain                20 dB
                              Efficiency          15%
                              Power               15 dBm

            Frequency of Operation
         Current Status     18 Months             EoP
CMOS        20 GHz            40 GHz             60 GHz
SiGe        30 GHz                      60 GHz
CMOS Active and Passive

       Sohrab Emami
        Chinh Doan
             mm-Wave BSIM Modeling

   Compact model with extrinsic
   DC I-V curve matching
   Small-signal S-params fitting
   Large-signal verification

   Challenges:
        Starting with a sample which is
         between typical and fast
        Millimeter-wave large-signal
        Noise
        3-terminal modeling
           Model Extraction: Small-Signal

   Extensive on-wafer S-parameter
    measurement to 65 GHz over a
    wide bias range
   Parasitic component values
    extracted using a hybrid
    optimization algorithm in Agilent
   The broadband accuracy of the
    model verifies that using lumped
    parasitics is suitable well into the
    mm-wave region.
        Transistor Design and Modeling
   Transistor layout
       Multi-fingered transistors
       Close substrate contacts
       Minimize source/drain
       CPW input/output
   Transistor modeling
       Lumped small-signal
       Broadband accuracy up to
        65 GHz

                     MSG @ 60 GHz = 6.3 dB
                     U @ 60 GHz = 8.6 dB
Large-Signal Verification

            Harmonics power measurement
                Class AB operation
                Large-Signal amplification at
                 60 GHz
                  Transmission Lines

   Transmission line types:
       CPW: high inductance, requires bridges
       Microstrip: shields from substrate, low inductance
   Capable of realizing precise small reactances
   Inherently scalable, broadband models
        ADS and HFSS Passive Models
   ADS Passive Models
       Simple electrical models
       Scalable (in length)
       Fast simulation time
       Allows use of optimizers
   HFSS Passive Models
       Accurate broadband
        prediction of reactance and
       Comparison of arbitrary
       Visualization of EM fields

         Both models provide good broadband accuracy!
            60-GHz Amplifier Design

   3-stage cascode amplifier design
   Cascode transistors improve isolation, stability
   Input/output matching networks designed to match 50 Ω
   Broadband design to account for process variation
   Designed using only measured components
         60-GHz Amplifier Simulation

   Passband gain = 11 dB
   Input/output return loss > 20 dB
   Power dissipation = 54 mW
Performance of Single-Gate Mixer
60-GHz LNA and Dual-Gate Mixer
        40 GHz 2:1 Injection-locked divider

   Oscillators at 60 GHz have already
    been demonstrated at ISSCC
   Key challenge is to build a VCO in a
    synthesizer loop
   One alternative is a LO doubler to
    ease divider power requirement
   Another option is a injenction locked
   Resonator-based frequency divider
       20 GHz oscillator core
       2nd harmonic in core locks onto injected
  Injection-locked Divider Layout

               Output buffer      Pierce oscillator
                                  CPW used for
                                  800 MHz
                                   locking range at
                                   –3 dBm injected
 Injected                          signal power
Signal path

       Oscillator core
      20 GHz Fully Integrated CMOS PA

                                                               50 
                       30 pH                         373 fF
                                  1.6 pF

                        2.2 mm
                        0.13 m
                                                 54 pH         224 pH

                        2.2 mm
                        0.13 m

   Multistage matching network               Power supply = 1.5V
   Power out ~ 100 mW                        Matching network IL = 2.73 dB
   Drain efficiency ~ 20%                    Qind ~ 10, Qcap ~ 30
   Power gain hard to simulate
             20 GHz CMOS PA Layout


  Gate                               Inductors

  Input                              Output

  GSG                                GSG

Power NFET                            MIM
 Cascode                              Caps
    Milestones and Progress Report
   Present Status:
        Measurement facilities at BWRC upgraded to allow active/passive measurements
         up to 60 GHz
        CMOS test chips measured and analyzed
        Optimal layout of CMOS transistors verified
        30 GHz 7HP SiGe Receiver (taped out in 6/03)
        60 GHz LNA/Mixer Designed and Fabricated (tape out in 11/03, 12/03)
        ISSCC Invited Talk on 60 GHz CMOS

   Future:
      Measure Nov/Dec CMOS Circuits

      Design and fabricate 60 GHz CMOS front-end blocks

      Measure 30 GHz SiGe blocks and receiver

      Demonstrate 20 GHz active antenna array and CMOS PA
    Universal Radio

        Axel Berny, Gang Liu
Zhiming Deng, Nuntachai Poobuapheun
Challenges for RF Radio Design

             Simultaneous need for low noise and
              good linearity
             Receive a weak signal in the presence of
              strong interferer
             Strong signal exercises amp linearity
             Reciprocal mixing causes VCO noise to
              limit performance
      High External Component Count
             DCS/PCS                        BPF: PCS

                                            BPF: DCS
                                 RX         BPF: GSM

                                            LPF: PCS/DCS   Isolator   Coupler

                        Diode/Switch   TX   LPF: GSM       Isolator   Coupler

   Current trends in academia and industry have reduced component count
    at RF and IF
   The Low-IF, Direct-Conversion, and Wideband IF radio architectures
    eliminate (reduce) external IF filters
   Systems still heavily dependent on external components on the front end:
    SAW filters, switches, directional couplers, matching networks, pin
    diode, diplexers …
   Many of these components are expensive (high Q) and narrowband
                                Multiplicity of Standards
                                                                                                                          Cellular voice: GSM,
                                                                                                                           CDMA, W-CDMA, CDMA-
          Image Reject

                                RF Mixer
                                           Channel Select              IF IQ Mixers                    Baseband
                                                                                                                           2000, AMPS, TDMA…
                                                                                                             ADC   I

      LNA 1             LNA 2              IF         AGC
                                                                                                                          Same standard over multiple
                                                                                                                           frequency bands (4-5 GSM
                                           IF Gain and AGC


              LC Tank
                         RF Synthesizer                      IF Tank       IF PLL     IF Synthesizer                       bands exist today)
                                                                                                                          Data: 802.11b, 802.11a,
                                                                                                                           Bluetooth, 3G
                                                                                                                          A typical handheld computer
                                                                                                                           or laptop should be
                                                                                                                           compatible with all of the
                                                                                                                           above standards
                                                                                                                          Today a typical cellular
                                                                                                                           receiver has 3-4 radio front-
                                                                                                                           ends … this approach does
                                                                                                                           not scale!
        Dynamic Operation
                               High power consumption due
                                to simultaneous requirement
                                of high linearity in RF front-
                                end and low noise operation
                               The conflicting requirements
                                occur since the linearity of
                                the RF front-end is exercised
                                by a strong interferer while
                                trying to detect a weak signal

 The worst case scenario is a rare event. Don’t be
 A dynamic transceiver can schedule gain/power of the
  front-end for optimal performance
              Universal Dynamic Radio

   High dynamic range broadband
    front end and high speed ADC             MEMs resonators / filters

   Eliminate high-Q front-end                                           ADC

    filtering, employ integrated
    MEMS filtering instead


   Design parallel or broadband
    amplifiers to cover major bands           Tank

    around 1 GHz, 2 GHz, 5 GHz, etc.
   Require dynamic operation to
    reduce power
   Employ broadband matching,
    filtering, and amplification
    (e.g. 500 MHz – 3 GHz)
Broadband VCO for Universal
   Frquency Synthesizer

          Axel Berny
         Zhiming Deng
        Universal Receiver Front End

   Goals
       A multi-standard dynamically operated LNA and Mixer
       A low-power fully-integrated multi-standard Frequency Synthesizer
       A wideband low-phase-noise VCO

   Proposed Specifications
       Frequency range: 800MHz ~ 2.5GHz (cover all the cellular phone
        standards and 802.11b standard)
       LNA: S21 ~ 15dB, NF < 4dB
       Reference frequency: ~ 20MHz
       Frequency resolution: ~ 2.5kHz
       Phase noise: < -116dBc/Hz at 600kHz
       Settling time: < 150us
                  Broadband LNA
   Two Stage input matching Architecture

                           • Two-Stage input matching improves
                           the bandwidth by a factor of 2-3.

                           • Use cascode devices to improve

                           • Quality of passive devices determine
                           the noise figure of the input stage.
   Preliminary Results-LNA

                    - At 15mA bias current, the
                    LNA can operate from 0.7-
                    2.5 GHz with acceptable

                    - At 1.9 GHz, bias current
                    can be adjusted to control
                    the power consumption and
                    performance of the LNA.

15mA      1.9 GHz
Synthesizer PLL Simulink Model

      Type-I, Order-2, Sigma-Delta Fractional-N PLL

       Model Simulation Result: Frequency Settling
Broadband VCO with Switch Caps


                                                    2C                2C

                                                    C                 C




            A0                   A1                      A3
  1x                   2x             ...   8x

       A0                   A1                     A3

 Broadband VCO Layout
                        A 1.8 GHz LC VCO
                        1.3 GHz Tuning Range
                        Mixed-signal Amplitude
VCO                     0.18µm CMOS
                        phase noise of –104.7dBc/Hz at
         Peak Det.       a 100kHz
         & Comp.
                        3.2mA from a 1.5V supply

          Amplitude Calibration Loop

   Analog amplitude feedback introduces noise
   Digital feedback loop can be run once at start-up
                            Measured Tuning Range

                            Kvcomax= 270MHz/V


Frequency (GHz)





                        0          0.3          0.6               0.9   1.2   1.5
                                                      Vtune (V)
                                 Measured Phase Noise

                                   fo = 2.4GHz, 2.6mW
                                      fo = 1.8GHz, 4.8mW
                        -80              fo = 1.2GHz, 10mW
Phase Noise (dBc/Hz)






                             4                   5                                6        7
                          10                10                               10       10
                                                     Frequency Offset (Hz)
Calibration Loop in Action
                                      Importance of Calibration
                             12.0                                                                                                  -94

                                                             Pd - calibrated                                                       -96
                                                             Pd - uncalibrated
                                                             PN@100k - uncalibrated
                                                             PN@100k - calibrated

                                                                                                                                          Phase Noise @ 100kHz offset (dBc/Hz)
    Power Dissipation (mW)


                              6.0                                                                                                  -104





                              0.0                                                                                                  -114
                                    1.2E+09   1.4E+09      1.6E+09               1.8E+09   2.0E+09     2.2E+09        2.4E+09
                                                                          Frequency (Hz)

                  Phase noise at 100kHz offset from the carrier and core power dissipation vs. frequency, for calibrated and uncalibrated VCO.
          TX: Class A/F Dual Mode PA
   Design a power amplifier which meets requirements called
    by the next generation wireless communication standards
    while providing backward compatibility with existing
       Integration: fully integrated without any off chip components
       Long talk time: maintain high efficiency over entire output range
       High data rate: amplitude modulation requires high linearity
                                         Class-F tuning

      Distributive Active Transformer


       1:1          1:1          1:1          1:1

             Vin1         Vin2         Vin3         Vin4

   Power combining major challenge of PA design
   Caltech work has shown that “DAT” is promising candidate
    for fully integrated power combining and matching
   Low loss transmission lines form 1:1 transformers
   Distributed nature allows power/efficiency control
3-10 GHz UWB LNA

Andrea Bevilacqua and Ali Niknejad
   to be presented at ISSCC ‘04
         UWB RF Radio Architecture

   System architecture for next generation UWB system hotly
   Regardless of choice of architecture, there is a need to
    amplify the signals at the front-end
                Broadband LNA Design

   Distributed amps are “easy”
    solution but consume too much
   Absorb transistor parasitics into
    3-section Chebychev filter
   Shunt peaking helps extend
LNA Layout
Reduce Parasitics in TW Process
    Measured Small Signal Performance

   Input/output matching better than -10 dB over 3-10 GHz band
   Power gain of 10 dB with good reverse isolation
   TW connection helps gain at HF at expense of isolation
Variation Over 6 Measured Parts
Measured Inductor Quality Factor
           Noise Measurement Setup

   Measured de-embedded noise figure as low as 4 dB
   Attenuation of input filter adds dB-for-dB
   Average NF in band 5.5 dB
   TW connection has slightly higher noise
   NF matches simulations when induced gate noise is included
Measured Large Signal Performance

   IIP3 measured at -6.7 dBm
   IIP2 measured at 0 dBm
Comparison to Other Broadband Amps
   CMOS technology has been demonstrated to be effective for
    microwave and mm-wave applications
   Modeling layout-dependent parasitics of integral importance at
    mm-wave frequencies
   Enhanced lumped models based on BSIM IV-CV core capable
    of predicting large signal and small signal behavior at 60 GHz
   The ingredients for a 60 GHz TX/RX at hand. The low power
    implementation of an LNA, mixer, VCO, and PA are next
   Universal radio can simplify radio design and reduce time to
   Dynamic LNA/mixer/VCO operation allows power savings with
    acceptable reduction of performance
   Broadband LNA topology good alternative to distributed
    amplifier design

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