RM310 NXP Semiconductors, RM310 Datasheet - Page 13

• Manufacturer Part Number: RM310
• Description: Ht Rm 310 Hitag Tm Mini Reader Module
• Manufacturer: NXP Semiconductors

HT RM310
8. In order to achieve a satisfactory reading distance, the quality factor of the antenna coil (for
9. By knowing R
10. After having checked the antenna voltage as described in point 9, connect your antenna to the
Attention:
The above measures must not differ from the antenna design instructions of Chapter 2.4.
Htrm310.doc/HS
non-metal environment) should be approximately Q = 40.
The quality factor of the coil is calculated as follows:
can be calculated. It is very important to calculate the antenna voltage before connecting the
antenna to the HT RM310 module to avoid damage. If the calculated value of Û
Û
The resistor has to be placed as shown in Chapter 2.4.6.
HT RM310 module and measure the read/write distances with your transponders. Should the
read/write distances not meet your expectations, the following points should be considered:
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The size of the antenna and the size of the transponder have to be in a defined ratio (between
4 and 1).
That means if you increase the antenna beyond a certain size, the maximum read/write dis-
tances will decrease when using the same transponder.
The optimal shape of the antenna coil is a circle, while the performance of a square shaped
coil is much better than that of a rectangular one (with the same circumference).
In order to achieve better read/write distances the quality factor of the antenna coil should
be increased, but must not be higher than Q=40. This can be attained with the following
measures:
All conducting material has to be removed from the antenna environment.
A thicker wire can be used for the coil.
Ferrite can be placed behind the antenna coil to concentrate the field.
Extension of the antenna area.
Also with a different number of turns better results can be achieved.
=32 Vp, a resistor R
s
and the dropping resistor (R
e
must be used to protect the receiver input.
Q
Page 13 of 41
Rev. 2.3
R
S
L
i
= 22 ) the current Î and the antenna voltage Û
2
R
S
f L
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is higher than
02-10-1998
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