very-near-field solutions for far-field...

Very-Near-Field Solutions

for

Far-Field Problems

Agenda

Corporate Information

Introduction to Very-Near-Field

Very-Near-Field Implementation

EMxpert Validation

What About Far-Field?

EMxpert Demonstration

Customer Case Studies

Conclusion

Corporate Introduction

An Established Company

Very-near-field magnetic measurements expert

– Unique patented products for RF/MW and EMS/EMI

Private Canadian corporation since 1989

– Worldwide coverage

Recognized innovative products

A Leader

World Leading Developer of Visual Real-Time

EM and RF Test Solutions

Antenna and PCB Designers

Product Integration and Verification Engineers

Diagnostic Tool

Pre-Compliance Not Compliance

Chamber on your Desktop

EMxpert

– EMC/EMI diagnostic tool enabling designers to rapidly diagnose and solve EM problems in a single design cycle in their own lab environment

RFxpert

– APM tool enabling engineers to quickly evaluate and optimize their designs with real-time antenna performance characterization at their desk

Fundamentals

High-density planar antenna array

High-speed electronic switching

Very near-field measurements

Far-field predictions

Real-time real-fast

No chamber

Far-Field / Near-Field / Very-Near-Field

Introduction to Very-Near-Field

What is Far-Field?

d

d

What is Near-Field?

Anything not in the far-field

Stay out of the reactive region!

d

What is Very-Near-Field?

C.A.Balanis – Antenna Theory : Analysis and Design 3rd Ed.

More Realistic Approximation

For a case of D = 1 m

Reactive region can extend beyond the measurement distance of EMC test

Situation for many EMC problems – No radiating near-field

for low frequencies

J.C.Bolomey - Engineering Applications of the Modulated Scatterer Technique

Far-Field Measurements

Far-field site far away and demanding a large area

Open-air-test-site (OATS) avoids reflections

Difficult nowadays because of EM noise pollution

Image: www.noiseblog.com

Far-Field Measurements cont.

Controlled environment

Anechoic or semi-anechoic chamber

Image: www.geosig.com

Near-Field Measurements

Near-field scanning for antenna measurement

Very-Near-Field Measurements

Origin of all emissions

– Insight into root causes

Size limited to DUT size

Extrapolate far-field from very-near-field

A Better One

Very-Near-Field Implementation

EMxpert

Real-time measurements ( <1 sec)

Compact tabletop instrument

Cost effective solution

Powerful Scanner

1218 probes in a 29 x 42 array – 2436 loops in X

Antennas – Sensitive down to -135 dBm

– Inefficient for EMI isolation

– Broadband

• 50 kHz to 4 GHz

• 150 kHz to 8 GHz

3.75mm resolution

Scan area 21.8cm x 31.6cm

Isolated case for safe testing

System Configuration

External Trigger

USB LAN/USB

Control RF

EMSCAN Scanner

Spectrum Analyzer

EMSCAN Adapter

EMSCAN Application

Spectral Scan

Spatial Scan

Modes of Operation

Benefits of Very-Near-Field Testing

Real-Time

Changes in real-time – Intermittent events

– Functional testing

A/B Comparison

Obsolescence management

Production unit versus gold standard

Conducted Immunity Insights

Injected signal path

Component susceptibility

Common Mode

How signals couple onto connectors creating common mode problems

Effectiveness of Filters

Effectiveness of Shielding

Simulation

EMxpert Validation

Simulation

EMC Analysis for a PCB mounted switching regulator using Electromagnetic Simulator

Mitsuharu Umekawa

EDA Application Engineering

Electronic Measurement Group

Agilent Technologies

Microwave Workshop and Exhibition

December 1st , 2011

Simulation

Validation of ADS Momentum simulation models

EMC Toyo corporation (EMSCAN Representative)

Tokyo, Japan

November 1, 2011

What about Far-Field?

Pre-compliance Testing

Relative

Virtual

Predictive

Correlation between VNF and FF

Relative Testing

Case Study

PCBs containing split planes on ground plane fail EMI requirements more often than those without

Measured at DVT Solutions in Calgary Canada

Case Study Parameters

Impact of Open-Ended Micro-Strip Line Designs

– Very-Near-Field Levels Analysis

• Effects of joining split planes at discrete locations with simple short along ground plane split

• Effects of placing 470pF chip capacitors between split planes at discrete locations along ground plane split

– Far-Field Levels Verification

• Changes in the far-field levels from ground plane split with shorts and chip capacitors between split planes

Test PCBs

Test Case 2 Ground Plane

c/w Split

Test Case 1 Ground Plane

w/o Split

Test Cases 3 - 7 Split Plane

c/w Modifications

Case 1: Micro-strip Line

Case 2: Ground Split

Cases 3 to 4: Shorting Jumper

Test Case 4 Edge

Test Case 3 Center

Cases 5 to 7: Chip Capacitors

C (pF)

Frequency (MHz)

Z (Ohm)

470 220 1.54

470 780 0.43

1410 220 0.51

1410 780 0.14

Test Case 5 1 x 470pF in Center

Test Case 6 1 x 470pF at Edge

Test Case 7 3 x 470pF in Center

Very-Near-Field Setup of EMxpert

Very-Near-Field Measurements 220 MHz Spatial Scan

Very-Near-Field Effects of Split

Solid Ground Split Ground

Shorting Jumper

Solid Ground

Split Ground

Jumper Center

Jumper Edge

Capacitor

Solid Ground

470pF Center

1410pF Center

470pF Edge

220 MHz Analysis

Analysis of current distributions with uniformity being prioritized over actual level

– Case 3 Jumper centre

– Case 7 Three capacitors centre

– Case 5 Single capacitor centre

– Case 6 Single capacitor edge (no mitigation)

– Case 4 Jumper edge (no mitigation)

Very-Near-Field Measurements 780 MHz Spatial Scan

Very-Near-Field Effects of split

Solid Ground Split Ground

Shorting Jumper

Solid Ground

Split Ground

Jumper Center

Jumper Edge

Capacitor

Solid Ground

470pF Center

1410pF Center

470pF Edge

780 MHz Analysis

Visualization of hot spots for quick identification of mitigation techniques from best to worst

– Case 7 Three capacitors centre

– Case 5 Single capacitor centre

– Case 3 Jumper centre

– Case 6 Single capacitor edge

– Case 4 Jumper edge

Very-Near-Field Conclusion

3-capacitor centre preferred as solution across all bands

Chamber Far-Field Measurements

Far-Field Measurements

Frequency

(MHz)

Microstrip

Line

(dBuV/m)

Split

(dBuV/m)

Split+Jumper

(dBuV/m)

Split+470pF

(dBuV/m)

Split+1.41nF

(dBuV/m)

Test Case 1 Test Case 2

Test Case 3

Test Case 4

Test Case 5 Test Case 6 Test Case 7

Label Full Ground Split Center Edge One Cap

Center

One Cap

Edge

Three Cap

Center

220 MHz 27.2 56.2 24.3 53.5 48.4 40.2 34.1

780 MHz 35.1 59.4 53.3 62.8 49.4 68.0 49.3

Far-Field Conclusions

3-capacitor centre or jumper centre preferred

Depending on the frequency of higher concern

Summary of VNF and FF

Case 220MHz FF Level

220MHz FF order

220MHz NF order

780MHz FF level

780MHz FF order

780MHz NF order

Full Ground 27.2 - 35.1 -

Split Ground 56.2 - 59.4 -

Jumper Centre 24.3 1 1 53.3 3 3

Jumper Edge 53.5 5 5 62.8 4 5

470pF Centre 48.4 4 3 49.4 2 2

470pF Edge 40.2 3 4 68.0 5 4

1410pF Centre 34.1 2 2 49.3 1 1

VNF Correlation with FF

High correlation between very-near-field and far field results when fault type taken into account

Purely looking at very-near-field emission levels without considering distribution can be misleading

– Spatial results are critical

Can be used for system testing with Golden Sample

– A/B comparison

Test Duration for all 7 Test Cases

EMxpert

– 1 ¾ hours for 2 frequencies

Automated probe

– 21 hours for 2 frequencies

Chamber

– 28 hours for 2 frequencies

Virtual Chamber

Virtual Chamber Testing

Far-field measurements without chamber or OATS – Testing as long as in a chamber or OATS

Systematic very-near-field and far-field measurements – Ambient noise

– Cable noise

– DUT emissions

Caveat is constant ambient noise

Virtual Chamber Testing

Device Emission: Shows up in near-field scan and far-field position scans but not in far-field ambient

Device Emission at an Ambient Frequency: Shows as ambient in the far-field ambient scan and as a marked peak in the near-field scan; suspected to be a legitimate peak that happens to occur very close to an ambient signal

Suspected Device Emission: Signal that is not in the far-field ambient or near-field device scan but appears in the position scans; it is a suspected cable emission

Ambient Frequency: A signal that shows up in the far-field ambient scan and nowhere else

Predictive Application

Far-Field Prediction

Software to predict Open Area Test Site (OATS) or free space radiated EMI of PCB

– Compensated EMxpert very-near-field data

– PCB structure and design models

Absorber mat 2 mm

PCB Modelling

PCB usually consists of ASICs, plane splits, traces, loops and slots

ASIC key source of EM radiations – Source is nothing but switching noise generated by ASIC

Traces, loops, plane splits and slots enhances radiation – Efficient antennas

Model assigned to PCB design with out-of-10 weighing factor – Individual weighing factor closely represents physical design of

PCB

Model Attributes

Single Source ASIC Split Loop Slot Trace

Nominal 5 5 4 3 3

Multiple Sources ASIC Split Loop Slot Trace

Balanced 2 2 2 2

Mixed 3 4 1

Digital 5 2 2 1

High Density 8

Methodology

VNF FF

EMxpert Export Correct Import Model Transform

10 to 30 minutes

Far-Field Prediction

World’s fastest pre-compliance

– FCC/ANSI, CISPR and user-defined limit lines

Demonstration

Demonstration

Customer Case Studies

NFC Testing

Spectral/Spatial Motorola RAZR LTE

Amp [-122.7 to -80.2 dBm] Freq [1574.000 to 1576.000 MHz]

Resolution Bandw idth: 300.0 Hz

Attenuator Value: 0 dB

Scanner Module: ISM-L4G-Xi-M7, 29 X 42

Date: 12/7/2012 2:01:44 PM

Frequency(MHz) Auto

1576.001575.001574.00

Am

plitu

de(dB

m) A

uto

-80.0

-81.0

-82.0

-83.0

-84.0

-85.0

-86.0

-87.0

-88.0

-89.0

-90.0

-91.0

-92.0

-93.0

-94.0

-95.0

-96.0

-97.0

GPS Interference Testing

Customer Burn-In Tests Case Study Medical Industry

PCB with Pre-Programmed Tests

Wi-Fi module

High speed RAM

HDD

Microcontroller

HDD Tests

Noise from the HDD is being coupled on to the Wi-Fi antenna cable.

HDD Tests with Ferrite

One solution is a ferrite place on the antenna cable.

RAM Tests

Burn-in test of the RAM shows coupling to HDD and Wi-Fi cable.

Customer SERDES Case Study Automotive Industry

Objectives

Quantify the EMI emissions profile by comparing half-duplex deserializer (SERDES) to next generation full-duplex design

Determine whether full-duplex design impacts EMI profile and, if so, quantify the difference

Results courtesy of National Semiconductor / Texas Instruments

Test Method

Design team placed original half-duplex board on the EMxpert scanner to generate a baseline measurement.

Powered the device under test (DUT) and activated the scan

Test Results

Baseline results

Full-duplex results

Conclusion

No spikes and very similar peak emissions

Better EMI profile (more blue in the spatial scan)

No appreciable change occurred in full-duplex mode – Implementation of the full-duplex feature with no additional mitigation measures.

Design team conducted the scans on the EMxpert system in their offices

Results in minutes

To test the new design in a third party chamber would have required that an engineer travel to an off-site test facility for the better part of a day

Customer SSCG Case Study Automotive Industry

Objective

Generate compelling and quantified evidence to present to automotive industry customers that SSCG feature reduces EMI emissions .

Results courtesy of National Semiconductor / Texas Instruments

Test Setup

Place device under test (DUT) on the EMxpert scanner with SSCG turned “OFF”, power and capture emissions profile

To demonstrate the effectiveness of the feature, run identical test, but with SSCG function turned “ON.”

Test Results

SSCG OFF

SSCG ON

Conclusion

The design team was able to compare 4 different methods to implement SSCG

They were able to carefully compare results that rather dramatically highlighted the benefit of the SSCG feature

Feature drastically reduces overall electromagnetic radiation

Whenever the customer support team presented the above comparison, it universally resulted in a customer response of “Wow”!

Reason: Automotive engineers’ biggest challenge is reducing EMI Any features that reduce EMI result in faster time-to-market, less shielding, and lower costs

Conclusion

Summary

Advantages

– Continuous peak hold scan for spurious events

– Real-time view of emission sources and currents

– Fast pre-compliance regulatory data

– Low acquisition cost and zero operational cost

Benefits

– Test time reduction > 100 x

– Rapid design iteration, prototyping & optimization

– Reduced chamber investment or third party testing

– Cost effective preparation to compliance

Business Case

In a single product life cycle, avoiding one board re-spin and retest can save $$$

Third party testing – 8 hours driving

– Night in a hotel

– $3000 for chamber time

– 4 days for debugging

Exciting Value Proposition

Substantially Reduce Project Development Costs

Dramatically Increase Designer Productivity

Significantly Accelerate Time-to-Market

1 Hour in a Chamber or 1 Second with EMSCAN?

EMxpert – Magic Goggles

www.emscan.com

Thank You