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Design and Measurement of a Differential Printed Antenna for a Wireless Sensor Network Node

Pires, N. ; Parra, T. ; Skrivervik, A. K. ; Moreira, A. A.

IEEE Antennas and Wireless Propagation Letters Vol. 16, Nº 1, pp. 2228 - 2231, May, 2017.

ISSN (print): 1536-1225
ISSN (online):

Scimago Journal Ranking: 1,05 (in 2017)

Digital Object Identifier: 10.1109/LAWP.2017.2708742

This letter presents the design and measurement of an antenna integrated into an agricultural sensor network node oper- ating on the 2.4-GHz ISM band using the ZigBee protocol stack. The novel structure, coined bowtie-shaped folded dipole (BSFD), has a differential 100 Ω input impedance matching a particular con- troller widely used in wireless sensor network (WSN) applications. This letter also presents a survey of existing WSN antennas to which the proposed design compares favorably. The challenges of testing a differential antenna using conventional single-ended equipment are addressed regarding antenna impedance and radiation pattern measurements. The differential antenna input impedance was con- firmed with four different test setups using a conventional vector network analyzer. The radiation pattern of the proposed antenna was measured in-prototype resorting to a spectrum analyzer. The measured patterns show that the proposed antenna has a maximum received power over 4 dB compared to two early versions of the WSN node that used commercial off-the-shelf antenna solutions. The performance was also confirmed in a field test where a BSFD- equipped prototype achieved close to a 300-m range, tripling that typical for ZigBee applications.