Open AccessBandwidth and radiation specifications enhancement of monopole antennas loaded with split ring resonators
Author(s) -
AlibakhshiKenari Mohammad,
NaserMoghadasi Mohammad,
Sadeghzadeh R.A.
Publication year - 2015
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2015.0172
Subject(s) - physics , directional antenna , magnetic monopole , monopole antenna , electrical length , split ring resonator , bandwidth (computing) , resonator , resonance (particle physics) , helical antenna , optics , random wire antenna , dipole antenna , biconical antenna , antenna (radio) , slot antenna , acoustics , antenna efficiency , electrical engineering , telecommunications , computer science , engineering , atomic physics , quantum mechanics
New broadband antennas loaded with split ring resonators (SRR) are proposed and investigated. The results illustrate that by loading the conventional monopole antennas with an asymmetrical meander lines SRR, a lower resonance frequency mode can be excited. The dimensions of the SRR have been selected to provide a resonance close the resonance of the monopole antennas. The results illustrate that when both resonance coincide the antennas bandwidths and radiation properties can be enhanced. The length and width of the antennas are 25 × 10 − 2 λ 0 × 11 × 10 − 2 λ 0 and 25 × 10 − 2 λ 0 × 21 × 10 − 2 λ 0 at 4 GHz for monopole antennas, and 29 × 10 − 2 λ 0 × 21 × 10 − 2 λ 0 at 2.9 GHz for both monopole antennas loaded with SRR. For antennas without SRR loading, maximum of measured gains and efficiencies are 3.6 dBi and 78.5% for F‐antenna, and 3.9 dBi and 80.2% for T‐antenna, hence they appear at 5 GHz. For antennas with SRR loading, these parameters are 4 dBi and 81.2% for F‐antenna, and 4.4 dBi and ∼83% for T‐antenna, which appeared at 6 GHz. By implementing the meander lines SRR as a matching load on the monopole antennas, the resulted antennas cover the measured frequency bandwidths of 2.9–6.41 GHz and 2.6–6.6 GHz (75.4 and ∼87% fractional bandwidths), which are ∼2.4 and 2.11 times more than monopole antennas with an approximately same in size.