Broadband printed circuit board folded dipole antenna

Compact low cost antennas with wideband performance are desired for a multitude of broadband and multifunction applications. At microwave frequencies, a small radiating element enables portable electronics with wireless connectivity. The antennas utilized in these systems are normally resonant radiators. However, resonant antennas usually have limited bandwidth due to their fast-varying radiation reactance near resonance. To extend the operating frequency of these antennas, it is desired to find a topology in which a low-loss reactive component can be introduced to compensate the antenna radiation reactance. A topology that offers this feature is the folded dipole. The behavior of the basic folded dipole has been investigated and analyzed exhaustively, and hence is not repeated. Rather, the paper focuses on an intuitive design procedure that yields an optimized wideband folded dipole design using low-cost printed circuit board. Antennas with 2:1 bandwidth were achieved using this procedure.