IFM Efector 190 ANT820 Manual

Short instructions
RFID-UHF-Antenna
Mid Range
ANT820
704979 / 00 01 / 2012
UK

RFID-UHF-Antennas
2
Inhalt
1 Preliminary note � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 3
2 General safety notes� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 3
3 Product description� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 4
3�1 Low range antennas� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 4
3�2 Mid range antennas � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 4
3�3 Wide range antennas � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 5
3�4 Antenna type according to read range and transponder shape � � � � � � � � � 6
4 Technical Data � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 8
5 Reader output power � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �11
6 Compliance with standards� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 12
7 Installation / Attachment � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 14
8 Typical applications� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 16
9 Technical appendix � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 17
9�1 Antenna gain � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 17
9�2 ERP: Effective radiated power � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 18
9�3 Examples – antennas – input power � � � � � � � � � � � � � � � � � � � � � � � � � � � � 18
10 Abbreviations � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 19

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1 Preliminary note
Read this document before use to familiarise yourself with operating conditions,
installation and operation� Keep the document during the entire duration of use of
the device�
Adhere to the safety instructions�
2 General safety notes
Before starting installation work or replacing the unit, the accompanying applica-
tion notes must be read carefully and the content understood�
The detailed information in the data sheets and in these application notes must be
complied with carefully during installation and operation!
The installation team must be properly qualified and familiar with the safety regula-
tions applicable in the country concerned�
Connection, installation and maintenance work, as well as all other work on the
unit, may only be carried out by properly qualified and trained employees� The unit
may only be used for the purpose intended by the manufacturer�
Unauthorized changes to the unit and the use of spare parts and peripheral
devices which are not sold or recommended by the manufacturer can result in
fires,electric shocks and injuries� Such actions therefore result in exclusion of liabil-
ity and make the manufacturer’s guarantee (warranty) null and void�
The version of the manufacturer’s guarantee (warranty) applies which was valid
at the time of purchase� We accept no liability for unsuitable manual or automatic
adjustments made to the unit parameters and inappropriate use of the unit�
Repairs may only be undertaken by authorised personnel� Opening or attempting
to repair the unit makes all guarantee/warranty claims null and void� Improper work
on the unit may jeopardise electrical safety�
The manufacturer is not liable for accidents caused by the user opening the unit!
When carrying out work on the unit, the valid safety regulations must be complied
with�

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3 Product description
The ifm electronic antenna range includes a variety of UHF reader antennas,
which can fulfil the requirements of almost all RFID applications� The antennas are
divided into three product lines according to read range: low range, mid range and
wide range antennas�
3.1 Low range antennas
With dimensions of 90 x 63 mm, the low range antennas have a high field concen-
tration in the near-field, with significantly reduced antenna gain in the far-field� With
these properties, the antennas achieve writing/reading results at ranges of up to
10 cm with a typical selectivity of 5 cm�
Low range antennas are available in Low Range (ANT810/ANT910) and Ultra Low
Range (ANT805)� The ultra low range antenna was designed to read dipole tags
(far-field tags) at an extremely limited distance� These antennas can also activate
loop tags (“near-field tags”) up to 3 cm� The Low range antenna was developed for
larger ranges and is particularly suited to near-field tags� The antenna allocation
according to read range and transponder shape is outlined in Chapter 3�4�
Figure: ANT810 / ANT910 Low Range Antenna Figure: ANT805 Ultra Low Range Antenna
3.2 Mid range antennas
The mid range antenna ANT820 was developed for applications in the area
between near-field and far-field� Particular importance was placed on creating a
compact construction to enable integration into environments with limited space�
Read ranges of over 2 m are still possible even with dimensions of 156 x 126 mm�
The mid range antenna also offers increased selectivity at lower reading distances
compared with conventional antennas� This antenna design is therefore also suit-
able for use in the so-called transition area with a variety of transponder types�

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Figure: ANT820 Mid Range Antenna
3.3 Wide range antennas
For traditional wide-range applications with read ranges of over 10 m, ifm elec-
tronic offers a wide range antenna model characterised by a half width of 70°
(ANT830)� The circular polarization usually required for UHF applications has been
significantly improved compared with other antennas available on the market� For
the so-called axis ratio, which is used as a characteristic value for circular polariza-
tion, the new model achieves typical values of 1 dB� If specified at all, the usual
value on the market lies at around 3 dB�
The improved circularity
leads to a significant reduc-
tion in the dependence of
the reading results on the
position or alignment of the
transponder� Great impor-
tance was also placed on
the front-to-back ratio of the
antennas to reduce the influ-
ence of the close (assembly)
environment on the antenna
properties�All antennas have
an extremely high protec-
tion class which guarantees
problemfree use in any
environment�
Figure: ANT830 Wide Range Antenna

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3.4 Antenna type according to read range and transponder shape
Antenna type Read range Tag type
Loop tag Hybrid Dipole tag
ANT805
ANT810
ANT910
0-10 cm
ANT820
10-30 cm
30-100 cm
> 100 cm
ANT830
10-30 cm
30-200 cm
> 200 cm
The correct combination of reader antenna and transponder is essential for every
RFID application� The correct selection ensures a high read rate and reliable op-
eration of the system�
The low range (ANT810/ANT910) and ultra low range antennas (ANT805) can
read loop, hybrid and dipole transponders up to 10 cm and offer a very good de-
fined read range�
The mid range antenna (ANT820) can activate loop transponders up to 30 cm,
hybrid up to 100 cm and dipole transponders up to several meters�
The wide range antenna (ANT830) is designed for typical far-field dipole tran-
sponders with read ranges of over 10 m, but it can also read the near-field and
hybrid transponders at a short distance�

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The typical read ranges of the presented antennas can be seen in the following
figure�
2m
4m
6m
8m
10m
ANT830 70° 33 ERP
ANT820 100° 27 ERP
ANT805/ANT810
0 2m
4m 2m 4m
Figure: Read ranges of the RFID-UHF-Antennas
To achieve the best reading and writing results, we recommend operating
the ifm UHF RFID reader antennas exclusively with UHF readers from ifm
electronic�

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4 Technical Data
Typ Nr� ANT820
Frequency range MHz 865-870
Antenna gain dBic 4
Polarisation Right-hand circular (RHC)
VSWR < 1,3 : 1
Impedance Ω50
Front-to-back ratio cm > 10
Max� radiated power
(ETSI EN 302 208) W ERP 0,5
Far-field divergence ° 100
Connection TNC socket
Protection class IP 67
Weight g 320
Dimensions (W x H x D) mm 156 x 126 x 36
Material Antenna cover: Polymer-Blend
Installation Four through holes Ø 4�2 mm for M4 screws
Temperature range Storage temperature: -40° C – +85° C
Ambient temperature: -20° C – +55°C
The antenna ANT820 is right-hand circular polarised and has a typical antenna
gain of 4 dBic� In the figure “Circular antenna gain against frequency for the
ANT820” the circular gain is plotted against frequency� The operating range of the
antenna is shown in grey� Outside the operating range the gain of the antenna
ANT820 drops off� Due to this drop off, interference from other systems is mini-
mised, as is interference to other systems� The figure “Directional characteristic of
the ANT820 (RHC)” shows the righthand circular directional characteristic of the
ANT820� The half power beam width is approx� 100° and the front-to-back ratio is
>10 dB� The axial ratio (AR) of the ANT820 is significantly less than 2 dB for the
major part of the upper hemisphere (θ = ± 90°). The matching against frequency is
below -18 dB in the working range of the antenna� The 10 dB bandwidth is greater
than 20 MHz� The figures relate to a reflection-free environment� For real environ-
ments with reflections, there may be variations from the values shown here (on
this topic see chapter 7 Installation / Attachment)�

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Gain [dB]
Frequency [MHz]
Figure: Circular antenna gain against frequency
Figure: Directional characteristic in azimuth (RHC)

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S-Parameters [dB]
Frequenz [MHz]
Figure: Matching S11

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5 Reader output power
The maximum output power for the reader is defined by the ETSI standard EN 302
208-1 V1�2�1 (dated April 2008)� It is defined by the antenna gain, the half power
beam width and the cable attenuation on the reader - antenna connection�
For antennas with a half power beam width of up to 70° a power of
PERP,max = 2 W ERP (Effective Radiated Power) is allowed. For other half power
beam widths the power is limited to PERP,max = 0,5 W ERP.
The ERP is converted in accordance with EN 302 208-1 into output power PC at
the reader as follows:
PC,max = PERP,max - GIC + 5,15 + CL
For the antenna ANT820 the following maximum output power is then obtained:
PC,max = 27 dBm - 4 dBic + 5,15 + 0 dB = 28,15 dBm = 0,653 W
Where:
PC,max: refers to the maximum output power of the reader in dBm,
PERP,max: refers to the maximum effective radiated power of the antenna in dBm,
GIC: refers to the circular antenna gain in dBic,
CL: the cable loss in dB (here assumed to be 0 dB)

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6 Compliance with standards
As RFID systems are radio installations, they fall under the European Commission
directive 1999/5/EC (Radio Equipment and Telecommunications Terminal Equip-
ment R&TTE)�
A series of harmonised standards are in place to prove conformity with the basic
requirements of this directive, which are published in the official journal of the
European Union�
The ifm antenna ANT820 is a passive antenna structure� It is therefore the system
integrator who is responsible for ensuring compliance with the standards – i�e� the
person who combines the individual components of an RFID system with each
other, in particular the reader and antennas� We therefore strongly recommend
acquiring these standards�
Two important standards in relation to antennas are (with no claim of complete-
ness) EN 302208 and EN 50364: The first deals with frequency spectrum issues
and limits the maximum radiated power, while the EN 50364 addresses the limits
regarding exposure of people to electromagnetic fields�
In accordance with EN 50364, compliance is achieved if the defined limit values
of the electrical and magnetic field strength are not exceeded at a distance of 20
cm around the antennas� On compliance with the maximum antenna input power
specified in the standard EN 302208, the electrical and magnetic field strength
from the antenna ANT820 are below the defined limits at a distance of 20 cm�
Compliance with the standards is therefore ensured�
As the antenna ANT820 can be used for special applications also with a read
range of less than 20 cm, numerical calculations have also been made on the
specific absorption rate (SAR)� The calculated SAR values are compared with the
basic limit values of EN 50364 – separated according to professional exposure
and exposure to the general public, as well as local exposure to head and body or
the extremities� The assumptions made here (such as the operating mode of the
RFID system and properties of the human skin) guarantee a conservative estima-
tion of the exposure (worst case scenario)�
The calculation was also carried out for the most sensitive constellation, i�e� for the
event that members of the general public are permanently located in close proxim-
ity to the antenna with head and body� If the distance between the person and the
antenna is less than 3 cm, with the ANT820 it is ensured the rate remains below
the maximum SAR allowed with an antenna input power of up to 0�34 W (25�31
dBm)� In all other cases the ANT820 can be operated using the maximum radiated
power specified in the data sheet of 0�5 W ERP (27 W ERP) or an antenna input
power of 0�653 W (28�15 dBm)�

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The table below shows the maximum input powers with which the antenna can be
supplied to ensure that the basic limit values for the SAR are not exceeded� A dif-
ference is made here between the different types of exposure�
Maximum input power ANT805 Distance
person - antenna
< 3 cm
Distance
person - antenna
≥ 3 cm
General public
Limit values head and body 2 W/kg
Pein = 340 mW
(25,31 dBm)
Pein = 653 mW
(28,15 dBm)
General public
Limit values local limbs 4 W/kg
Professional exposure
Limit values head and body 10 W/kg
Limit values local limbs 20 W/kg
Pein = 653 mW
(28,15 dBm)
Table: The maximum input powers

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7 Installation / Attachment
To achieve the maximum range with the antenna, there must not be any interfering
objects between the antenna and the tag to be read� The function of the antenna is
affected by the type of fixing and the surrounding materials� For optimum antenna
behaviour there should not be any conducting objects in the vicinity of the antenna�
The following dimensions are given as adequate distances:
The distance to large metal surfaces and to the ground should be at least 70 cm
(see Figure 1)�
If it is not possible to avoid mounting in front of a metallic surface, a mounting
support can be used that establishes a distance of exactly 12 cm between the rear
wall of the antenna and the metal surface (see Figure 2)�
In case of direct mounting on a metallic surface (e� g� a plate as part of a mount-
ing support), the metal plate should be square and have dimensions that do not
exceed 16 x 16 cm (see Figure 3)�
Other objects such as, e�g�, containers with liquids in the immediate vicinity affect
the functionality of the antenna�
If these recommended distances cannot be met due to the local situation, the
antenna characteristics will change such that it will be necessary to re-assess the
antenna in this special installation situation�
1 2
Minimum spacing on all sides: 70 cm
3

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The cable should be laid vertical (see figure below right) away from the antenna
and should be laid direct� The cable length is to be selected as short as possible to
minimise cable losses� Cable loops around the antenna or laying the cable in front
of the antenna (see figure below left) are to be avoided�
X

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8 Typical applications
●Logistics applications on attachment to industrial trucks
●Conveyor system applications
●Gate applications for article identification
●Bulk tag and single tag applications
●Access systems (e�g� ski lift, control systems for travel tickets and admission
tickets)
When using the antennas, comply with the relevant valid regulations in your
country and any standards and guidelines valid specifically for the area or
place of use�

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9 Technical appendix
9.1 Antenna gain
The gain is the ratio between the radiated power density in the main radiation di-
rection for the antenna in question and a reference antenna with the same supply
power�
Reference antennas are isotropic radiators or λ/2 – dipole
Frequent logarithmic tasks:
- dBi: linear gain based on isotropic radiator
- dBd: linear gain based on dipole
- dBic: circular gain based on isotropic radiator

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The isotropic radiator is a loss-free point radiator with an even spherical radiation
pattern in all directions� Its power density is distributed evenly over a sphere with a
surface of 4π²r, where r is the radius of the sphere.
The gain of the λ/2 – dipole is 1.64 and the power density it produces is 1.64 times
greater than the power density from the isotropic radiator�
An example antenna with a gain of 6 dBi achieves a power density 6 dB greater
than that of the isotropic radiator� If the gain of this antenna is referred to the gain
of the λ/2 dipole, the gain in dBb is obtained:
6 dBi – 2.15 dBi = 3.85 dBd
The circular polarized gain (dBic) is also 3 dB greater than the gain in dBi�
9.2 ERP: Effective radiated power
Product of the power supplied to a transmitter antenna multiplied by its gain rela-
tive to a λ/2 dipole.
EIRP: Equivalent Isotropically Radiated Power
Product of the power supplied to a transmitter antenna and its gain relative to the
isotropic radiator�
With UHF-RFID, the maximum ERP is specified by law� When using antennas with
a high gain, the reader power must be reduced accordingly� This means that the
read range doesn’t increase with the antenna gain – the width of the read range is
merely changed�
ERP [dBm] = Pin [dBm] + G [dBd]
EIRP [dBm] = Pin [dBm] + G [dBi]
EIRP = ERP * 1,64
EIRP [dBm] = ERP [dBm] + 2,15 dB
9.3 Examples – antennas – input power
Europe: ERP power is limited according to EN 302208 to 2 W (33 dBm)�
An antenna has a gain of 8�5 dBic
dBic converted to dBi:
8.5 dBic = 8.5 - 3 = 5.5 dBi
dBi converted into dBd:
5.5 dBi = 5.5 - 2.15 = 3.35 dBd
Antenna input power: 33 dBm - 3.35 dBd = 29.65 dBm (0.922 W)

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USA: EIRP power is limited according to FCC Part 15 to 4 W (36 dBm)�
1� Antenna gain smaller or equal to 6 dBi
Antenna input power is equal to 30 dBm (1 W)
2� Antenna gain larger than 6 dBi (e�g� 7 dBi)
Antenna input power must be reduced: 36 dBm – 7 dBi = 29 dBm (0.794 W)
10 Abbreviations
Abbreviations used in this application notes:
DIN German Institute for Standardisation
EIFF Effective Isotropic Field Factor, shows the field isolation of far-field to near-field standard-
ised to an isotropic radiator�
EIRP Equivalent Isotropically radiated power
EN European Standard
ERP Effective Radiated Power
RFID Radio Frequency Identification
SAR Specific Absorption Rate
UHF Ultra High Frequency