– 1 –Revised 3/12/2018
Product Description
The Linx VDP Series antenna is a highly versatile
antenna, offering high performance in a wide range
of applications as well as an industrial ruggedness
at a commercial price point. These durable, low
profile, IP67, UV, and extended temperature rated
robust antennas mount to non-conductive surfaces
with an integrated PSA adhesive patch and have
a vertical cable egress. With two meters of low
loss cable, the VDP Series antenna can be located
remotely from the radio and positioned for optimal
performance. The VDP Series offers a very rugged
solution at a fraction of the cost of competitive
options.
The dual-band VDP Series supports the 868MHz
and the 915MHz bands, covering the most popular
global sub-GHz unlicensed bands in a single,
compact antenna. This makes it ideal for products
that are sold into different regions worldwide using
popular sub-GHz technologies, such as LoRa,
SigFox, 802.15.4 and proprietary systems. It is
easily customized with different cable lengths and
connectors for volume orders. Contact Linx for
details.
Features
• Dual-band (863–873MHz and 902–928MHz)
• Fully weatherized - UV protected, IP67, wide
temperature range
• Low Loss cable for better RF performance at
higher frequency bands
• Center-fed from the end
• Omni-directional pattern
• Durable & unobtrusive
• SMA or RP-SMA connector
Ordering Information
ANT-8/9-VDP-2000-SMA (with SMA connector)
ANT-8/9-VDP-2000-RPS (with RP-SMA connector)
Electrical Specications
Center Frequency: Band 1: 868MHz
Band 2: 915MHz
Recom. Freq. Range: Band 1: 863–873MHz
Band 2: 902–928MHz
Bandwidth: Band 1: 10MHz
Band 2: 26MHz
Wavelength: ½-wave
VSWR: ≤1.9 typical
Peak Gain: Band 1: 4.3dBi
Band 2: 3.5dBi
Impedance: 50-ohms
Max Power: 10W
Cable: 2m Low Loss RG-174/U
Connection: SMA or RP-SMA
Oper. Temp. Range: –40°C to +85°C
UV Resistance: UL 2556 section 4.2.8.5
or equivalent
ANT-8/9-VDP-2000-ccc
Data Sheet
22.0 mm
(0.87”)
115.0 mm
(4.53”)
126.0 mm
(4.96”)
6.3 mm
(0.25”)
5.0 mm
(0.20”)
7.5 mm
(0.30”)
8.8 mm
(0.35”)
– 2 –ANT-8/9-VDP-2000-ccc Data Sheet
3:1
2:1
1:1
800MHz 900MHz 1000MHz
VSWR
25%
11%
0%
Reflected Power
1.4581.159
VSWR Graph
What is VSWR?
The Voltage Standing Wave Ratio (VSWR) is a measurement of how well an antenna is matched to a source
impedance, typically 50-ohms. It is calculated by measuring the voltage wave that is headed toward the load
versus the voltage wave that is reflected back from the load. A perfect match has a VSWR of 1:1. The higher
the first number, the worse the match, and the more inefficient the system. Since a perfect match cannot
ever be obtained, some benchmark for performance needs to be set. In the case of antenna VSWR, this
is usually 2:1. At this point, 88.9% of the energy sent to the antenna by the transmitter is radiated into free
space and 11.1% is either reflected back into the source or lost as heat on the structure of the antenna. In
the other direction, 88.9% of the energy recovered by the antenna is transferred into the receiver. As a side
note, since the “:1” is always implied, many data sheets will remove it and just display the first number.
How to Read a VSWR Graph
VSWR is usually displayed graphically versus frequency. The lowest point on the graph is the antenna’s
operational center frequency. In most cases, this is different than the designed center frequency due to
fabrication tolerances. The VSWR at that point denotes how close to 50-ohms the antenna gets. Linx
specifies the recommended bandwidth as the range where the typical antenna VSWR is less than 2:1.
– 3 –ANT-8/9-VDP-2000-ccc Data Sheet
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XZ-Plane Gain YZ-Plane Gain XY-Plane Gain
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XZ-Plane Gain YZ-Plane Gain XY-Plane Gain
860 - 870MHz
900 - 930MHz
XZ-Plane Gain YZ-Plane Gain XY-Plane Gain
860MHz
870MHz
900MHz
920MHz
930MHz
– 4 –
Copyright © 2018 Linx Technologies
159 Ort Lane, Merlin, OR 97532
Phone: +1 541 471 6256
Fax: +1 541 471 6251
www.linxtechnologies.com ANT-8/9-VDP-2000-ccc Data Sheet
About Gain Plots
The true measure of the effectiveness of an antenna in any given application is determined by the gain
and radiation pattern measurement. For antennas gain is typically measured relative to a perfect (isotropic)
radiator having the same source power as the antenna under test, the units of gain in this case will be
decibels isotropic (dBi). The radiation pattern is a graphical representation of signal strength measured at
fixed distance from the antenna.
Gain when applied to antennas is a measure of how the antenna radiates and focuses energy into free
space. Much like a flashlight focuses light from a bulb in a specific direction, antennas focus RF energy into
specific directions. Gain in this sense refers to an increase in energy in one direction over others.
It should also be understood that gain is not “free”, gain above 0dBi in one
direction means that there must be less gain in another direction. Pictorially
this can be pictured as shown in the figures to the right. The orange pattern
represents the radiation pattern for a perfect dipole antenna, which is shaped
like a donut. The pattern for an omnidirectional antenna with gain is shown in
blue. The gain antenna is able to work with a device located further from the
center along the axis of the pattern, but not with devices closer to the
center when they are off the axis – the donut has been squished.
Gain is also related to the overall physical size of the antenna, as well as
surrounding materials. As the geometry of the antenna is reduced below the effective wavelength (considered
an electrically small antenna) the gain decreases. Also, the relative distance between an electrically small
antenna and its associated ground impacts antenna gain.