Design and measurement of a planar dual-band antenna for the Tyndall Multiradio wireless sensing platform

A planar, dual-band, Electrically Small Antenna, operating at the 433 MHz and 868 MHz ISM bands is reported, designed for the WSN Tyndall Multiradio (s-Mote) platform. It is a meandered IFA, fed by a CPW and its planar form makes it easily integrated on PCB along with the rest of the circuitry. A dual-band balun was employed to allow accurate characterization of the antenna by canceling the unbalanced behavior of the feed RF coaxial cable that causes a backwards flow of current on the shield of the coaxial cable which disturbs the measurement. Measured and simulated data are in close agreement showing Return Loss greater than 10 dB at both frequency bands. Simulated radiation patterns for the elevation and azimuthal planes with dipole-like characteristics are also included and compared with measurements followed by a discussion on the measurement setup.