Bands-Spanned Radiation-Differentiated Antenna (BSRDA)

Bands-spanned radiation-differentiated antenna (BSRDA), with the ability of offering different radiation properties (polarization direction/radiation pattern) at different frequency bands, is urgently desired with the blooming of various wireless services. In this paper, a single-port BSRDA is proposed based on a single-layered patch antenna. The inner corner-truncated square patch is excited by a direct probe to provide broadside radiation at 3500 MHz, whereas the outer corner-truncated ring patch with four shorting posts and four notches is energized by the coupling to generate omnidirectional radiation at 2485 MHz. To verify the proposed design, a fully functional prototype was fabricated. Measured results show that 10-dB impedance bandwidths of 22 MHz and 273 MHz, peak gains of 1.98 dBi and 8.46 dBi at the two bands were obtained, respectively. Owing to the features of compact and simple structure, the proposed BSRDA is suitable for applications where multiple wireless services are demanded.