Dual‐band circularly polarized crossed‐dipole antenna with double split‐ring resonators and a defected ground structure

Abstract

A dual‐band cavity‐backed circularly polarized crossed‐dipole antenna with double split‐ring resonators (SRRs) is investigated in this paper. A pair of crossed dipoles connected by concentric ring‐delay lines is firstly designed as a circularly polarized (CP) antenna with only one CP mode. To extend the operation of the original design, a pair of the λ/4‐resonance SRRs are used to realize wider axial ratio bandwidth at higher band. At the same time, another pair of the λ/4‐resonance SRRs with larger dimension is adopted to obtain a lower frequency band, although the effect is not very satisfying. Then the cavity‐backed technology and a defected ground structure are both employed to improve the working bandwidth. The dual‐band CP antenna can be tuned into a wide bandwidth one by changing the dimensions of the larger SRRs. A good agreement between the simulated and measured results can be observed. The measured impedance bandwidths are 6.90% (3.36‐3.60 GHz) and 53.58% (4.40‐7.62 GHz). The measured 3‐dB AR bandwidth is 7.93% (3.39‐3.67 GHz) and 59.15% (4.08‐7.51 GHz).

Broadband crossed dipole circularly polarized antenna with parasitic round‐metal pillars

“…Besides, loading parasitic elements is also a very effective means for widening CP bandwidth of cross-dipole antennas. [11][12][13][14][15][16][17][18][19][20][21][22] These parasitic elements include double split-ring resonators (7.93%, 59.15%), 11 rotated-circular dipoles (41.3%), 12 asymmetrical cross-loop (53.4%), 13 asymmetric L-shaped strips (52.2%), 14 triangle-patches (58.9%), 15 four inverted L-shaped elements (83.5%), 16 a trapezoidal-dipole (63.4%), 17 dualsquare cavity ground (66.7%), 18 rotated grounded metal cuboids (86.4%), 19 shorted coupled pads (85.5%), 20 a slotbowtie cross-dipole (90.9%), 21 and four rotated metallic plates (106.1%). 22 Moreover, the CP bandwidth of the crossdipole antennas could be enhanced through combing the parasitic elements with modified dipoles.…”

Investigation of a defected ground structure inspired wideband printed monopole mobile antenna using characteristics mode analysis

“…This makes the antenna design more complex and requires precision, since antenna placement and its orientation can severely affect the signal diversity. Hence, in our study, a printed monopole antenna 18 with defected ground structures (DGS) 19–21 is utilized and expected to provide effective broadband matching, acceptable gain, and consistent radiation pattern in the designated operating bands. To achieve such type of trade‐offs from application point of view, a thorough analysis with its understanding to certain antenna parameters that affect the system performance is required, especially dealing with the compact multi‐resonant mobile antennas, that is, getting through the physics into simulation 22 .…”