Miniaturized Multiband Antenna with Pattern Diversity

By combining the concept of multiband antennas with the use of annular sectors, a design framework to realize compact antennas capable of operating in three frequency bands and exhibiting pattern diversity is demonstrated. The antenna includes two separately fed sectors loaded with rectangular slots, and a parasitic scatterer for mutual coupling suppression. The antenna operates at f₁=2.4 GHz, f₂=3.76 GHz, and f₃=5.15 GHz, with 0.26 × 0.26 × 0.01 λ³ (w.r.t. f₁, electrical size k a=0.83). Full-wave simulations demonstrate that the antenna can achieve radiation efficiency > 25% in each band, where more than 10 beam states with linear and elliptical polarization are synthesized. Due to its miniaturization, multiband pattern diversity, and efficiency characteristics, the design is considered to be a promising solution to enhance the performance of emerging on-/in-body medical applications.