A compact UWB antenna with dynamically switchable band-notched characteristic using broadband rectenna and DC-DC booster

In this article, a dynamically switchable ultra-wideband (UWB) planar monopole antenna employing defected ground structure (DGS) with a folded stepped impedance resonator (SIR) that can operate as either a UWB mode or the single band-notched mode is introduced. The UWB monopole antenna contains a novel whirligig-shaped radiating patch and a chambered conductor as a partial ground plane. The switchable UWB antenna uses one PIN diode as switching elements in the DGS-SIR structure without any biasing network. When the state of diode is OFF, the planar monopole antenna changes to the UWB mode, and when the diode is turned ON, a frequency notch is created at 5–6 GHz. The state of diode is set to the “ON” state dynamically in the presence of a 5–6 GHz RF signal that is detected by using a wireless power management unit (PMU) that contains a broadband rectenna and a DC-DC passive booster. The rectenna consists of a novel cypress-shaped monopole antenna as a signal receiving part and two sub-rectifiers which are connected to a 3 dB branch-line coupler with a grounded isolation port. The antenna switches from UWB to single band-notched when an RF input signal (≥8.5 dBm) in the 5.25 GHz is sensed by the RF PMU with a conversion efficiency of 26% and DC output voltage of 0.36 V, and it fades immediately in real time when the external RF signal is eliminated. In the three-tone signals, the efficiency and input signal improvements are about 10% and −5.5 dBm in the low-power levels, especially, and so develop and enhance the performance of the dynamic reconfigurability.