Dual-band Dual-mode Antenna Research Articles

Compact low profile 5.8 GHz MPA for on-body applications

A compact microstrip patch antenna (MPA) with a T shape monopole technique is designed, simulated, and measured. By using fire retardant material (FR-4) as a substrate with a low profile, the proposed antenna is designed and simulated to be used for on-body biomedical applications. A center frequency of 5.78 is achieved with a gain of 11.78 dB and a matching impedance of -47.47 dB. A 1.48 W/Kg (10 gm) as a specific absorption rate (SAR) is achieved and 29.69 dB front to back ratio with a bandwidth of 3.376 GHz. The antenna was examined in free space as well as on-body using CST-MW software. The proposed antenna is fabricated and examined. Finally, a comparison is done among simulated results, measured results, and the dual-band dual-mode antenna. The proposed antenna overcomes the latter work in terms of small size, high matching impedance, high front to back ratio, and operating bandwidth.

Compact Dual-Band Dual-Mode Antenna With Omni-/Unidirectional Radiation Characteristics

A novel dual-band dual-mode antenna that operates at 2.45/5.8 GHz is proposed in this letter. The antenna exhibits linearly polarized omnidirectional radiation in the low band, and circularly polarized broadside radiation in the high band. To improve the 3 dB axial-ratio (AR) bandwidth, both truncated patches and a sequential rotation technique are combined together in the antenna design. The omnidirectional radiation in the low band is achieved by exciting four open-ended slots etched in the ground plane for the first time. The four slots form a magnetic-dipole-like current distribution along the edge of the ground plane, resulting in omnidirectional radiation. The low- and high-band operations are seamlessly integrated into a common design, sharing the same structure. This work provides a novel approach for improving the versatility of a radio frequency front-end subsystem without increasing footprint. The proposed antenna is prototyped and measured, showing good results in terms of impedance/AR bandwidths, isolation, radiation, and polarization.