A wideband isotropic radiated planar antenna using sequential rotated l-shaped monopoles

In this communication, we have proposed a compact planar antenna for isotropic radiation pattern in a wide operating band. The proposed antenna consists of four sequential rotated L-shaped monopoles that are fed by a compact uniform sequential-phase (SP) feeding network with equal amplitude and incremental 90$^\circ phase delay. Based on the rotated field method, a full spatial coverage with gain deviation less than 6 dB is achieved in a wide operating band from 2.3 to 2.61 GHz, also with well-impedance matching. A prototype of the proposed antenna has been built and tested. The measured results, including the reflection coefficient, gain, and radiation patterns, are analyzed and compared with the simulated results.