Design of a compact dualband quasi‐isotropic antenna

A dualband quasi‐isotropic antenna is presented. It is based on the split‐ring‐resonators (SRRs), which provide a quasi‐isotropic radiation pattern with an electrically small size. For the dualband operation, the SRRs are placed orthogonally to reduce the mutual coupling between the elements. A folded dipole structure is applied to the SRR, therefore, the input impedance at each band can be easily tuned. Both simulated and measured results are presented. The results show dualband operation (792 and 1124 MHz), high efficiency (higher than 86 and 85.5%), compact size ( ka = 0.47 at 792 MHz), moderate gain deviation (4.42 and 5.76 dB) with simple direct feed.