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Antenna Engineering
MIMO System
2MIMO Antenna
Wireless standards and MIMO
3MIMO Antenna
SISO and Multipath Fading
4MIMO Antenna
Multiple Antennas improves Signal Quality
5MIMO Antenna
Multiple Antennas improve capacity
6MIMO Antenna
Antenna Polarization
7MIMO Antenna
Cross Polarization
8MIMO Antenna
Correlation coefficient
9MIMO Antenna
Mean Effective Gain
10MIMO Antenna
MEG Ratio
11MIMO Antenna
MIMO antenna design parameters
Low envelope correlation between antennasLow envelope correlation can result from having sets of antenna patterns that are diverse in the spatial, phase and polarization senses. In order words, if all antenna patterns are "looking" in different directions or in different ways(phase/polarization) one has low correlation.
Large individual antenna mean effective gain (MEG)MEG refers to the gain of an antenna in particular environment relative to some reference antenna (e.g. isotropic radiator). In order words, it is a measure of how well an antenna receives power for a particular scattering environment.
All antennas with roughly the same mean effective gainThe MEG of each antenna needs to be roughly the same for a balanced system
Low total array reflection coefficient (TARC)Antennas radiate simultaneously and must have minimal crosstalk pairs
12MIMO Antenna
2x2 MIMO Antenna Design
The typical antenna specification for 2x2 MIMO has the following goals;
Number of independent antenna ports: 2
Radiation efficiency : As high as possible
Gain balanced ratio (ratio of the gain at each antenna port) : As high as possible, approaching 1
Correlation coefficient (envelope correlation coefficient between the two antenna ports) : As low as possible, approaching 0
13MIMO Antenna
Diversity Gain
14MIMO Antenna
Correlation in free space
15MIMO Antenna
Correlation with Scattering object
16MIMO Antenna
Correlation over distance
17MIMO Antenna
Diversity Gain
18MIMO Antenna
Antenna placement (2-antenna array)
19MIMO Antenna
Single Antenna Design (f=2.6GHz)
20MIMO Antenna
Placement Investigation (s-parameters)
21MIMO Antenna
Mutual coupling (2-1)
22MIMO Antenna
Mutual coupling (2-2)
23MIMO Antenna
Mutual coupling (2-3)
24MIMO Antenna
Mutual coupling comparison
25MIMO Antenna
Correlation coefficient comparison
26MIMO Antenna
MIMO Antenna Design
27MIMO Antenna
MIMO Antenna Design
28MIMO Antenna
MIMO Antenna Design
29MIMO Antenna
MIMO Antenna Design
30MIMO Antenna
MIMO Antenna Design
31MIMO Antenna
LTE handset antenna design
32MIMO Antenna
LTE handset antenna design
33MIMO Antenna
LTE handset antenna design
VSWR: <2:1 Efficiency:
30-40%
CC: >0.8Coupling:
-4dB
Patterns almost
identical
34MIMO Antenna
LTE handset antenna design
35MIMO Antenna
LTE handset antenna design
VSWR <2.2:1
Isolation:
<-13 dB
Efficiency 50-58%
CC: <0.35
Significantly different patterns results in low envelope correlation
coefficient36MIMO Antenna
Ex) MIMO Antenna Design
Ground Surface Current and Isolation
37MIMO Antenna
Antenna surface
current distribution
Type A antenna current
-9dB isolation
Type B antenna current
-11dB isolation
Preferable positionActually position only is not enough
Ex) MIMO Antenna Design
MIMO Antenna 38
Type 1
Type 2
Ex) MIMO Antenna Design
Current distribution with slot on the ground
MIMO Antenna 39
Open endShort end
Current magnitude
Current suppressed
Current inducing coupling
Ex) MIMO Antenna Design
1/4 slot on PDA ground size
MIMO Antenna 40
30db suppression
Ex) MIMO Antenna Design
MIMO Antenna 41
Ex) MIMO Antenna Design
MIMO Antenna 42
1.Without slot
2.With 2.4GHz only
3.With 5.2GHz only
4.With dual slot
Ex) MIMO Antenna Design
MIMO Antenna 43