Active–Passive Reconfigurable Antenna Covering 70–7200 MHz Bandwidth

This communication presents an active-passive reconfigurable antenna with 70–7200 MHz bandwidth for multiple wireless services. The active-passive reconfiguration is achieved by reusing a properly designed monopole antenna with the active-passive reconfigurable matching circuit, which is composed of a passive path and an active path. The passive path guarantees an inherent bandwidth of 923–7200 MHz for higher frequencies. The active path, achieved by a transistor biased in its ohmic region, ensures the impedance matching within 70–1200 MHz for lower frequencies. The path selection is facilitated by the cooperated design among the transistor, the p-i-n diodes, and their own bias circuits. Therefore, the proposed active-passive reconfigurable antenna achieves a total bandwidth spanning from 70 to 7200 MHz with a reflection coefficient consistently below −10 dB and validated by experiments. Such wideband performance exhibits the exciting potential for multiple-standard signal sensing to support increasing wireless services with a single antenna configuration.