A series-fed printed-bowtie antenna with broadband characteristics and end-fire radiation

A novel series-fed printed antenna comprising a bowtie radiator, a V-shaped dipole director, and a planar-type Marchand balun is investigated. On the basis of careful design and optimization, this antenna features a very broad bandwidth. Measured results show that the prototype antenna possesses an operating bandwidth of 47.7% (for the 10dB return-loss criterion), an end-fire radiation pattern with a front-to-back ratio greater than 13dB, and cross-polarization radiation less than -14dB across the frequency band of interest. The property of low mutual coupling between two antennas printed on the same substrate or stacked in the vertical direction can also be observed.