A Compact Maple Leaf and Triangular Hybrid Fractal Shaped UWB Frequency Reconfigurable Antenna with Wide Continuous Tunable Band Notch

This paper presents a maple leaf (ML) and triangular hybrid fractal shaped monopole antenna with extended ultrawide band (UWB) frequency characteristics from 3.1 to 13.7 GHz. The proposed antenna exhibits a - 10 dB fractional bandwidth of 126% with the peak gain between 2.2 and 5.3 dBi within the frequency band of operation. Reconfigurable bandstop notch is achieved by using a varactor diode on inverted U-shaped slot created at the junction of the transmission line and ML-shaped antenna patch. By varying the capacitance of the varactor diode from 1.90 to 0.15 pF, different notch frequency bands from 3.37 to 8.22 GHz are obtained to suppress the unwanted frequency bands such as WLAN, WiMAX, ITU, and C-band. The evolutionary design steps and an equivalent lumped circuit model analysis of the proposed monopole antenna have been investigated. A comparative study of simulation, equivalent lumped circuit model and measured results is carried out to validate the proposed antenna's performances. The size of the proposed antenna is 0.23 lambda(g) x 0.18 lambda(g) where, lambda(g) is guided wavelength at the lowest cutoff frequency, 3.1 GHz.