Integration Guide

4
Antennas
The nRF9160 module supports multiple cellular frequency bands as listed in Bands of operation on page
5. As the electrical size of the antenna sets fundamental limits for antenna bandwidth, it is recommended
to select an antenna supporting only the operational bands of the final device and optimize the antenna
performance at frequencies in question. The smaller the electrical size, the narrower the reachable
bandwidth and the lower the radiation efficiency.
If wide bandwidth and small physical size is required from the final device, antenna tuners may be
advantageous: antenna input matching can be optimized for the frequency of operation at a time. It is also
possible to design the antenna to have tunable resonant frequency. Antenna suppliers and design houses
provide solutions for size limited antennas. The nRF9160 module provides control for external antenna
tuners. For more information, see nWP033 - nRF9160 Antenna and RF Interface Guidelines.
Note: The nRF9160 module has been certified only with the antenna solution presented in
Reference circuitry on page 17. However, it is possible to use other antenna types and models
with nRF9160. Adequate testing and regulator certifications are always required from the final
device regardless of antenna selection.
4.1 Antenna interface
The nRF9160 module has a single-ended 50 Ω antenna port where the antenna solution shall be
connected. nRF9160 is evaluated with a 50 Ω antenna load. To ensure good overall RF performance,
antenna impedance and the characteristic impedance of the transmission line (i.e. cable) connecting the
antenna and antenna port must be 50 Ω. Impedance mismatch may lead to performance degradation.
Maximum antenna VSWR 2:1 is recommended but VSWR 3:1 can still be accepted in the final device.
Respective minimum return loss values are 9.5 dB and 6.0 dB.
The length of the transmission line from the antenna to the nRF9160 antenna port should be kept as
short as possible to minimize losses, as this loss is directly deteriorating the module’s transmitted and
received power. Additionally, low-loss matching circuit between the antenna and the nRF9160 antenna
port is recommended to minimize loss caused by antenna and PCB routing mismatch. Reserving space
from device manufacturer's application board for matching components (e.g. π-circuit) is recommended.
This is because, for example, catalog antennas are typically tuned on reference board and differences
to device mechanics may impact antenna impedance. It is also possible that device mechanics change
during the development phase of the final device, and these modifications may impact antenna
performance. Matching components can be used to compensate the impact of mechanics change to
antenna impedance, and thus it may not be mandatory to modify the antenna itself.
The nRF9160 module has an internal ESD circuit in the antenna port, but additional ESD components at
device manufacturer's application board may be used. The design of the ESD circuit shall be such that the
impact on RF frequencies is negligible.
Note: ESD filtering may be necessary for some active components that can be used at antenna
path. Such components can be, for example, RF switches and antenna tuners. For further ESD
requirements, see the RF switch and antenna tuner datasheets.
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