Ch 001 Smart Ant Introd.pdf

7/21/2019 Ch 001 Smart Ant Introd.pdf

1/21

UNIVERSITTKARLSRUHE (TH)

Institut fr Hchstfrequenztechnikund Elektronik

by Werner Wiesbeck

Introduction to Smart Antennas

forBase Stations


2/21



Introduction to Smart Antennas Page 2 IHE UKA

Survey Smart Antennas

Subject pagesCh. 01 Smart Ant. Introd.ppt 20Ch. 02 Smart Ant. Feed Netw.ppt 26

Ch. 03.1 Lin. Ant. Arrays.ppt 27

Ch. 03.2 Cylindrical Arrays.ppt 28

Ch. 04 Diversity.ppt 27Ch. 04 Diversity Text

Ch. 05 SDMA, Pat. Synt.ppt 17

CH. 06 MIMO Literature

Ch. 06.1 MIMO CW.ppt 44


3/21




Smart Antennas, a Contribution?


4/21




Outline

The problem

The idea

Antennaslcircular arrays

lbi-conical antennalultra wide band antennas

Smart antenna systemslDiversity

lSFIR (spatial filtering for interference reduction)

lSDMA (space division multiple access)

lMIMO (multiple In-multiple Out)


5/21




Smart Antennas: Space Division Multiple Access(SDMA)

- directive beam

- users in different angularpositions can be servedin the same traffic channel


6/21




SDMA with Conformal Antennas


7/21




Smart Antennas: Spatial Filtering for InterferenceReduction (SFIR)

-directive beam

-different traffic

-channels for every user


8/21




Indoor-Applications

1

3

1

2

2

9

31

84

8

238

280

28

80

8 80

5 8

6 8

680

80

580

28

28

8 8 0 6 8 0

6

80

101

1 01

1 01

1 01

1 01

1 01

Bay AreaLocations

MapArt

RT E I F T A R EF r I nf rm t i n Pl l l

1- - 4-42 1; - 7-1 114 H ur FAX: - 7- 724


9/21




Smart Antennas: Spatial Filter Interference Reduction(SFIR) Jammer Suppression


10/21




Smart Antennas: Transmitter Follow Up


11/21




Adaptive Arrays for Smart Antennas

BeamformingNetwork

Beamforming

Control

Informationin the signal

Externalinformation

InformationProcessing

BeamformingAlgorithm

Signal

Weights

HardwareControl


12/21




ADC1

2ADC

N ADC

Analoge and Digital Beam-Forming

Analoge Beam-Forming

Digital Beam-Forming

phase shifter

beam-forming network

additional noise

loss of information

adaptive filter (AF)

simultaneous beams

SNR retained

no loss of informationy qi( )

wN

i

w2

i

w1

i

j

Nw

w2

j

w1

j

y qj( )

y qj( )

memory


13/21




Beam-forming with Conformal Antenna Arrays

Advantages of cylindrical arrays:

Increase the angular sector served by a single array

Gain is no function of scan angle

Elevation scanning is possible without a large array in z-direction

Integration in curved surfaces is possible

Why conformal antennas ?

General Cases

Planar

Multi-face Planar Arrays

Conformal Arrays (here: Cylindrical)


14/21




Conformal Antenna Principles

The gain of a conformal array is roughly the same gain as that for the projected planar array

The gain of a conformal array decreases as the directivity of the single element increases

The beam-width of conformal arrays is usually larger than that of the projected planar one

Conformal array analysis and synthesis depends on the elements used in the

array:

isotropic elements (theoretical sources)

azimuth omni-directional elements (usually dipoles)

directive elements

Additionally it depends on the part of the geometry used, like in the cylindrical

case:

m sector arrays

m complete arrays


15/21




Historical Background of Planar and Conformal Antennas

1994993992991990989988987986985

Conformal

Antennas

Multilayered Aperture

Coupled Antennas

Single Layered Aperture

Coupled Antennas

Single Layered Patch Antennas

Microstrip Technology


16/21




Optimization Principles for Beam-Forming of SmartAntennas

Iterative Least Mean Squares

Adaptive Array Theory (applies Array Kovarianz-Matrix)

Successive Projection (minimal correction of the aperture

distribution)

Genetic Algorithm

Simulated Annealing

......


17/21




Omnidirectional Pattern of a16x4 Circular X-BandArray

d

r

1

d = 0 05

0

r

= 2 2

r

1

= 2 8

0

-40

-30

-20

-10

0

0

30

12

0

150

18

0

210

240

270

300

330

f / deg

Horizontal plane

calculated measured


18/21




Pattern Synthesis for Sector Arrays with DirectionalSingle Elements, Projection Method

Array factor for directive elements:

Simplified (scalar) element pattern:

Projected position on the tangential plane:

Length of the projected array:

FGr = Inn= 0

N-1

fn(q,y) ej kasinqcos(y-nDy)+jn[ ]

fn

(q,y) = f (q,y- nDy)

L =2a sin N2

Dy

yn= a siny

n= a sin n Dy( )

y

y

Cn()=C1(-E)

element pattern

2a


19/21




- 5 0

- 4 0

- 3 0

- 2 0

- 1 0

0

4.3

Scatteringparameters/dB

4.7 5.1 5.5 5.9 6.3

frequency / GHz

S11

S12

S21

S22

Measured Scattering Parameters of the

8x Element Subarray

Layout of the

Used Antenna Element

Kapton

Rohacell HF 51

Ground PlaneRT/Duroid 5880

Rohacell HF 51

Reflector

8x1 Element Sub-ArrayOffset Slots, Corporate Feed, Sequential Feeding


20/21




O

180

+90

Magnitude/dB

- 4 5 +45

-135 +135

0

- 10

- 20

- 30

- 40

- 30

-20

- 10

0Co-Pol

X-Pol

O

180

+90

Magnitude/dB

- 45 +45

-135 +135

0

- 10

-20

-30

-40

-30

- 20

-10

0Co-Pol

X-Pol

Vertical Polarization H -Plane) Horizontal Polarization E -Plane)

8x1 Element Sub-ArrayOffset Slots, Corporate Feed, Sequential Feeding


21/21




Multiple In-Multiple Out (MIMO)

Efficient use of the 4-D communication space:

Spectrum Time Space

MIMO-Channel

transmitter space-time

processing

space-timeprocessing

receiver

Code

Documents

Ch 001 Smart Ant Introd.pdf