MT3620
Hardware User Guide
MediaTek Confidential
©
2020 MediaTek Inc.
Page 19 of 40
This document contains information that is proprietary to MediaTek Inc. Unauthorized reproduction or disclosure
of this information in whole or in part is strictly prohibited.
If full diversity is selected, the baseband software automatically drives the WF_ANTSEL0/1 pins
to control the external diverisity switch.
B
B
P
L
L
R
S
S
I
M
e
te
r
R
-cal
RC
-cal
SX
0
(3
~
4
G
H
z
)
L
P
F
5
G
T
R
X
T
R
S
W
Balun
R
F
D
IG
BG
WF_A_RFIO
WF_G_RF_ION
T
R
S
W
2
.4
G
T
R
X
Antenna
port
WF_G_RF_IOP
WF
_
A
N
T
S
E
L
0
WF
_
A
N
T
S
E
L
1
D
P
D
T
M
M
M
M
AG
C
ANT_ASSIGN
A
n
te
n
n
a
D
iv
e
rs
it
y
E
n
g
in
e
7.5.3
Antenna Placement Guidelines for Antenna Diversity
Radio signals rarely pass directly from one point in space to another. In reality, the signals are reflected
off walls etc. and will form multiple simultaneous paths between the two points. This results in points
in space where there are strong signals, and conversely, points where there are very weak signal, or nulls.
In the case of a device having a single antenna, if the antenna happens to be in a null, it may struggle or
even fail to reliably connect and transfer data.
Adopting the use of two antenna can help to overcome these problems. More specifically though, to gain
the full advantages of antenna diversity the two antennas need to be (a) physically separated by a
distance of at least a ¼ wavelength. At 2.4GHZ, a ¼ wavelength is approximately 3cm and at 5GHz,
approximately 1.5 cm. In addition, the polarization of the radio signals can be altered as they passes
through different mediums such as walls and doors. By placing the two antennas at 90’ to each other
maximises the likelihood that at least of the them will be correctly oriented to receive a strong signal.
This is illustrated in the following diagram.
