The present invention features a dual-band meander line loaded antenna "MLA" that operates in a loop mode for a first frequency band and utilizes capacitive tuning to adjust the monopole resonant frequency for a second frequency band. In one embodiment orthogonal MLA elements (130, 140) are equipped with one or more capacitive flaps (136, 146) to lower the monopole resonant frequency of the structure. By offset-tuning the MLA elements (130, 140) and properly feeding RF signals, the inventive antenna exhibits vertically polarized operation at a first operating frequency and circular polarization at a second operating frequency. A typical use for the inventive antenna is for a dual-purpose cellular phone and GPS antenna. In cellular phone mode, the antenna operates at approximately 845 MHz with vertical polarization while simultaneously operating with circular polarization as at 1.5 GHz for GPS services.
展开▼
