Circular Dipole Antenna for Mode 1 UWB Radio With Integrated Balun Utilizing a Flex-Rigid Structure

A fully integrated dipole antenna with balun for ultrawideband (UWB) radio utilizing a flexible and rigid printed circuit board is presented in this paper. The concept in this paper is to take advantage of the respective possibilities of the rigid and flexible parts. The balun utilizes broadside-coupled microstrips and is integrated in the rigid part of the printed circuit board, whereas the radiator is placed in the flexible part. The antenna with the balun covers the mode 1 UWB frequency-band 3.1-4.8 GHz (with margin) at voltage standing wave ratio (VSWR) <. Furthermore, good radiation characteristics and a linear phase response are observed with measurements.