Flexible and Beam Steerable Planar UWB Quasi-Yagi Antenna for WBAN

Abstract

An Ultra-Wide Band (UWB) Quasi Yagi antenna with beam steering property is reported in this paper for Wireless Body Area Network (WBAN) application. The proposed antenna has a driver dipole, micro-strip line to slot-line transition and four parasitic strips printed on a very thin substrate of thickness 0.2 mm. The coplanar strip-line (CPS) is used to connect the driver dipole to the slot-line. The proposed antenna has an improved bandwidth of 7.4 GHz along with unidirectional radiation pattern. The parasitic strips act as directors to attain high gain of 7.8 dBi with better directionality. The flexible and compact geometry with footprint of 34 mm × 30 mm makes the antenna suitable for body worn devices. Further to improve the communication between the sensor and the cluster node in WBAN, design of two element antenna array with footprint of 34 mm x 52.3 mm, is constructed to achieve beam steering and the performance metrics are evaluated. The proposed flexible antenna offers large gain and high impedance bandwidth simultaneously. The prototype of the simulated antenna is fabricated and the simulation results are validated using experimental measurements. The measurement and simulation results are found in good agreement.