Miniaturized integrated folded helical antennas

Abstract

This paper presents a folding scheme to address fundamental issues of planar electrically small resonant antennas with small radiation resistance, high Q factor, and narrow bandwidth. Two printed folded helical antennas are investigated as examples of small antennas for GSM1800/1900 bands. Dramatic bandwidth enhancements of as much as 66% and 163% are found, respectively, for folded helical dipole and its monopole version over their non-folded counterparts. The proposed folding method facilitates integrated antenna miniaturization with self resonance, sufficient bandwidth, and self impedance matching.