Autonomous Cars: Radar, Lidar, Stereo Cameras · Infineon RRN7745P & RTN7735P eWLB Fan-out Package - 77GHz Radar Dies The radar receiver die is packaged in an eWLB (embedded Wafer

Autonomous Cars:Radar, Lidar, Stereo Cameras

1 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala

CAMERAS FOR AUTONOMOUS DRIVING


Role of Cameras in Automotives

� Camera module market ~$25B in 2015, expected to double by 2025 (Yole)� Machine Vision integration with multiple sensors for ADAS and partial

autonomous driving� Disadvantages of cameras

• Environmental conditions can introduce problems• Difficulty in detecting non- illuminated and varying lighting conditions• Computer vision limitations for reliable detection


CMOS image sensors for Automotive are quite different from Consumer Electronics

Source: Yole

� Improved Low light sensitivity by larger pixel size� Lower resolution (it’s not about Mega pixels)� Fast response time (significantly faster than smartphone cameras

� Packaging Differences• Embedded logic in image sensor package• Ceramic packages for higher functional safety requirements


Challenges� Fast image acquisition� Stereo camera for depth and distance of the object in image plane� High resolution AND high speed

• Resolution: greater than 1k x 1k pixels, aim for 4k x 4k• Frame rate: 60 fps and higher for shorter reaction time

� Zoom into image area for a greater detail � Efficient image processing for real-time analysis� Wider field of view than radar or laser systems


Cameras in Current Cars (Bosch)

� Bosch‘s mono and stereo camera system: smallest currently available in the market. Has a 50-degree horizontal field of view for 50m distance.

Bosch’s stereo camera system


Cameras in Current Cars (Panasonic)

� Stacked CMOS imaging chip and processing electronics in one package� Compact enough to fit within rearview mirror assembly or behind the windshield� Low cost high resolution cameras, but limited speed� High speed cameras limited resolution� Circuits for efficient image processing for real-time analysis� Can be implemented with multiple units for stereo vision

Panasonic CMOS 34227 Sensor


Prior Work at GT: 1st CIS DEMONSTRATOR on LOW COST 3D GLASS PACKAGE

� 100um Thin Glass Substrate

� Wafer Level Camera on Top Side

� Thin Logic Emulator IC on bottom side

� Solder reflow at chip level

� Passed initial tests at Georgia Tech

� <1mm total thickness (3x reduction from

PWB integration)

� 10x higher I/Os for integrating multiple

sensors, logic, memory etc.


Thermal Control Using Glass Package� Glass limits lateral thermal spreading by design� Junction temperatures can be reduced by vertical copper vias� Heating of image sensor with IC stacking or silicon interposers

Without copper With copper

Glass

38C 58C 48C 50C

49.1C 49.4C 49.1C 49.4C

Silicon10mm x 10mm Test Chipon Glass or Si Interposer


RADAR


Why RADAR in NAE?

• Above functions Require radar sensors due to their robustness in varying environmental conditions like rain, dust, or sunlight

(J. Hasch, "Driving towards 2020: Automotive radar technology trends," Microwaves for Intelligent Mobility (ICMIM), 2015 IEEE MTT-S International Conference on, Heidelberg, 2015, pp. 1-4.)

Roadmap for driver assistance functions

• Short, Medium and Long Range RADAR Modules

Critical to Fully Autonomous Driving

11IEEE-CPMT Workshop – Autonomous Cars

Automotive RADAR – Brief Intro

• Basic Architecture and Requirements- Frequency Modulated Continuous Wave (FMCW) Doppler Radar- 76 GHz – 81 GHz- Severe Environment Conditions- Long Term Reliability

Many challenges to device and design !!

TxRx

fr

Freq

uenc

y

fb

fd

fb fd

fr

Transmit FMCW Signal76-81 GHz

Compare Received Signal with Transmitted Signal to Extract

Distance and Velocity

PROF. JOHN CRESSLER


Automotive RADAR Evolution

1999 Mercedes-Benz • First manufacturer to use radar

for autonomous cruise control (ACC) system in S-class

Active Components Evolution

Pack

agin

g Ev

olut

ion

GaAs Technology

• Discrete semiconductor components ÆMMIC blocks or even complete

transceiver circuits

Silicon-based SiGe technology• Improved RF performance at high freq.• Destined to be the mainstream

semiconductor technology millimeter-wave

(J. Hasch, E. Topak, R. Schnabel, T. Zwick, R. Weigel and C. Waldschmidt, "Millimeter-Wave Technology for Automotive Radar Sensors in the 77 GHz Frequency Band," in IEEE Transactions on Microwave Theory and Techniques, vol. 60, no. 3, pp. 845-860, March 2012.)

Chip on board wire bonding

Flip chip mounting on substrate

eWLB (embedded wafer level

BGA) package

Evolution of SiGe Device Technology

Courtesy of P. Chevalier


Challenges in Automotive RADARPackage Challenges

� Low losses and reflections chip to substrateTransition

� Thermal dissipation� High Reliability� Low cost

• Generation of sufficient output power at high frequency

• LNA demonstration

Device Challenges

• No LNA: High NF → Low SNR → Lowmaximum detecting range of system

77GHz 4-channel automotive radar transceiver chip specification

(H. P. Forstner et al., "A 77GHz 4-channel automotive radar transceiver in SiGe," Radio Frequency Integrated Circuits Symposium, 2008. RFIC 2008. IEEE, Atlanta, GA, 2008, pp. 233-236. )


Status of Automotive RADAR Products

Bosch LRR3 Sensor• SiGe MMICs instead of Gunn oscillators and discrete mixer diodes • Size and package complexity reduction

Bosch LRR3 SensorBosch LRR2 Sensor


Latest Automotive RADAR Products

Bosch Mid Range Radar (MRR) Sensor• Frequency band 76-77 GHz• Distance range up to 160 meters • Integrates two electronic boards and STMicroelectronics devices• RF board with Hybrid PTFE/FR4 substrate and equipped with planar antennas• Infineon 77GHZ SiGe Monolithic Microwave Integrated Circuits (MMIC) used as High-Freqency

transmitter and receiver


Recent Automotive RADAR Packaging Technologies Infineon RRN7745P & RTN7735P eWLB Fan-out Package - 77GHz Radar Dies

The radar receiver die is packaged in an eWLB (embeddedWafer Level BGA) package, Fan-Out technology fromInfineon.

Back view

Die3mm x 3mm

Package cross-section


Proposed High Linearity Low Noise RX

Block Diagram

�One of the first Radar modules to integrate LNA in front end

�Leading Edge SiGe Receiver9 Employ Advanced SiGe Node

9 Use Novel Circuit Design

9 Incorporate High Gain High Linearity

LNA

� Current Design Phase

9 LNA layout modificationPROF. JOHN CRESSLER


Proposed High-Linearity LNA

9 IBM 9HP 90nm technology9 3 cascaded cascode stages9 Fully differential to improve CMRR9 Input transformer balun:

- Provide RF ESD protection and differential signal

9 Inter-stage matching with transformers9 Variable gain

- Improve input P1dB

Area: 0.6mm x 1 mmVCC: 2.5V

IN

OUT

VCC

VB1_13

VB2_13

VB1_2

VB2_2

GND

GND

GND

PROF. JOHN CRESSLER


LNA Initial Design and Simulation� Transistor Sizing: 6um, 8um, 10um Simulation Results

S-param

NF

P1dB

Gain 17.3 dBNF 6.221 dB3dB Freq 56GHz-94GHzDC Power 91.5 mWInput P1dB -14.5 dBm

PROF. JOHN CRESSLER

IEEE-CPMT Workshop – Autonomous CarsSlide 20

CONFIDENTIAL

GT Program Focus� The research objective is to design and demonstrate an ultra miniaturized low cost

integrated 77GHz radar & high speed camera module applying the most advancedpanel-level glass fan-out (PGFO) packaging technologies to the following parameters:

77 GHz Radar Chip

Processor

Image sensor

Antenna Incident light

Glass

Cover glass

Active area Camera ModuleRadar Module

Properties Objectives Prior Art

Integrated Module

Package type GFO FO-WLP/ CeramicCost <1x 1.2x

Reliability AEC Q100 Grade 1 AEC Q100 Grade 3Thickness < 300 um > 500 um

RadarNoise Figure 6-7 dB > 20 dB

Gain 15 dB < 15 dBAntennas Integrated in package Integrated in PCB

CameraData Rate ~ 1 Gbps <1 Gb/s

Response time < 1 ms >1 ms


LIDAR


Why Lidar for Automotive ?

� Cameras and radar cannot ensure 100 % safety� Radars provide no object detection� Cameras depend on environmental conditions.� Lidar enables high precision detection in real time � Time of Flight lasers in Lidar are the most accurate for real time and

long range detection.


Basics of Lidar

Fired Laser Pulses

Reflected Laser Pulses

Starting a timer when the pulse goes out and stopping by the reflected pulse


Challenges

� Cost reduction (see figure)� Miniaturization for easy integration in car body� High aperture angle – number of channels � Reliability by application of solid state lidar


Lidar Products

� Velodyne lidar system VLP-16• Range: 100 m, • Power consumption: ~8 W, • Weight: 830 grams, • Footprint:~Ø103 mm x 72 mm,• 16 channels, ~300,000

points/sec, • 360° horizontal field of view,

30° vertical field• Accuracy: +/- 3 cm (typical)• Rotating mirror inside

assembly,• Laser: Class 1 – 903 nm

wavelength


Lidar Products

� Quanergy Solid-state LIDAR system• Field of view is 120 degrees both horizontally and vertically. • The minimum range is 10 cm, and the maximum range is at least

150 m at 8 percent reflectivity. • At 100 meters, the distance accuracy is +/- 5 cm, and the

minimum spot size is just 9 cm.

Small (9 cm x 6 cm x 6 cm), no moving parts


Solid State Lidar

� Uses an optical phased array as a transmitter (no micro mirrors), which steers laser pulses by shifting the phase.

Documents

Autonomous Cars: Radar, Lidar, Stereo Cameras · Infineon RRN7745P & RTN7735P eWLB Fan-out Package - 77GHz Radar Dies The radar receiver die is packaged in an eWLB (embedded Wafer