Complementary metamaterial elements provide an effective permittivity and/or permeability for surface structures and/or waveguide structures. The complementary metamaterial resonant elements may include Babinet complements of "split ring resonator" (SRR) and "electric LC" (ELC) metamaterial elements. In some approaches, the complementary metamaterial elements are embedded in the bounding surfaces of planar waveguides, e.g. to implement waveguide based gradient index lenses for beam steering/focusing devices, antenna array feed structures, etc..

Metamaterials for surfaces and waveguides

The rectangular dielectric resonator antenna (DRA) centrally fed by a probe is investigated. Its operating mode is analogous to the TM011 mode of a cylindrical DRA. The DRA radiates like an electric monopole, generating omnidirectional linearly polarized (LP) fields. Based on this LP design, a novel omnidirectional circularly polarized (CP) DRA is studied for the first time. Slots are introduced to the sidewalls of the DRA, exciting a degenerate mode for the generation of CP fields. To demonstrate the idea, an omnidirectional CP DRA was designed for WLAN (2.4-2.48 GHz) applications. The reflection coefficient, axial ratio (AR), radiation pattern, and antenna gain are studied, and reasonable agreement between the measured and simulated results is observed.

Omnidirectional Linearly and Circularly Polarized Rectangular Dielectric Resonator Antennas

A wideband omnidirectional circularly polarized (CP) rectangular dielectric resonator antenna (DRA) is investigated in this communication. An inclined slot, loaded by a parasitic conducting strip, is fabricated on each sidewall of the DRA. The parasitic strips can excite a CP mode, which combines with the CP DRA mode to provide a wideband axial-ratio (AR) bandwidth of more than 25%. To fully utilize the increased AR bandwidth, the impedance bandwidth is also broadened by introducing a hollow cylinder at the center of the DRA. The hollow region is also used to accommodate a coaxial probe that excites the antenna. The reflection coefficient, AR, radiation pattern, antenna gain, and efficiency of the antenna are studied, and reasonable agreement between the measured and simulated results is observed. A parametric study was also carried out to characterize the proposed wideband CP omnidirectional antenna.

Wideband Omnidirectional Circularly Polarized Dielectric Resonator Antenna With Parasitic Strips

Operation principle and design approach of a novel planar end-fire circularly polarized (CP) complementary antenna is proposed. A vertically polarized printed magnetic dipole and a horizontally polarized printed dipole are combined on the same substrate, and a planar CP antenna with end-fire beam in parallel with its plane is thus designed. Prototype antennas centered at 5.80 GHz are then fabricated and measured to validate the operation principle and the design approach. The experimental prototype reported that the impedance bandwidth ( $20\text{log }\vert\text{S}_{11}\vert ) is about 1.90%, from 5.75 to 5.86 GHz and the 3-dB axial ratio (AR) bandwidth is about 14.48%, from 5.19 to 6.00 GHz. Therefore, the proposed design is applicable as a low-profile handheld reader antenna in radio-frequency identification (RFID) systems.

A Planar End-Fire Circularly Polarized Complementary Antenna With Beam in Parallel With Its Plane

A novel planar circularly polarized antenna with endfire radiation beam in parallel with the antenna substrate’s plane is proposed. The operation principle of the antenna is analyzed and design guidelines are laid down. Then, an optimized loop-aperture combined antenna is designed and demonstrated to exhibit an endfire beam in parallel with its plane within 5.74-5.88 GHz for $\vert{{\rm S}_{11}}\vert$ lower than $-10~\hbox{dB}$ and axial ratio smaller than 3 dB. The proposed antenna can be used as a low-profile, cost-effective, hand-held reader antenna for radio frequency identification systems .

Planar Endfire Circularly Polarized Antenna Using Combined Magnetic Dipoles

A circularly polarized omnidirectional antenna consisting of a vertical sleeve dipole and three pairs of tilted parasitic elements set around it is proposed. The antenna has a simple structure and no feeding network for radiating circular polarization. The authors describe the idea of the proposed antenna, some experimental approaches and the evaluation of the antenna by using the moment method.

A Circularly Polarized Omnidirectional Antenna

A circularly polarized omnidirectional antenna

A circularly polarized omnidirectional small helical antenna consisting of n-pairs of tilted half wavelength dipole antennas wound helically in the same direction is proposed The antenna has a simple structure and no feeding network such as a 90 degrees hybrid phase shifter or a split-sheath balun and a quarter wavelength transformer The paper describes the principle of the proposed antenna, and shows some experimental results and the analytical approaches by using a simple model<
 >

A circularly polarized omnidirectional small helical antenna

A reflector lens antenna consisting of an artificial dielectric

http://ieeexplore.ieee.org/iel3/1216/3116/00098195.pdf

Nozomu Hasebe

Papers

A Circularly Polarized Omnidirectional Antenna

A circularly polarized omnidirectional antenna

A circularly polarized omnidirectional small helical antenna

A reflector lens antenna consisting of an artificial dielectric

A small microstrip antenna consisting of a slot cut radiator and short pins