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A compact ultra-wideband planar monopole antenna with four notched bands is proposed. The antenna consists of a rectangular radiating patch with two bevels at lower edge and a modified ground plane with two bevels at upper edge. In order to realize multiple notch characteristics in the WiMAX band (3.3-3.7 GHz), the lower WLAN band (5.15-5.35 GHz), and higher WLAN band (5.725-5.875 GHz), three round shape slots are inserted in radiating patch. The fourth notch band in X-band downlink satellite communication band (7.1-7.76 GHz) is obtained by etching a pair of C-shaped slots in the ground. The proposed antenna exhibits a nearly omnidirectional radiation pattern in the H-plane, and a dipole-like radiation pattern in the E-plane for the for the entire pass band. The measured operating impedance bandwidth of proposed antenna ranges from 3.1 to more than 17 GHz having reflection coefficient magnitude less than -10 dB with four notched bands. The effects of each individual slot on band notch characteristics are also investigated. The measured gain of the proposed quad band notched antenna is relatively stable across the operating frequency band except notched bands and thereby making the proposed antenna suitable for practical UWB applications. Proposed antenna has a compact size of 30 9 26 mm 2 .

Abstract-A novel dual-band and dual-sense circularly polarized coplanar waveguide (CPW) fed planar antenna with an asymmetric rectangular slot is presented. An F-shaped feed line is protruded from the signal line into the slot. Circular polarization is obtained due to the F-shaped feed line and asymmetry in the slot. Axial ratio bandwidth is significantly enhanced by placing parasitic elements adjacent to the feedline. The antenna has a size of 63.5 × 55 mm 2 . The measured results agree well with simulation. The measured impedance bandwidths are 26.04% (1.57 GHz-2.04 GHz) for the lower band and 18.93% (2.87 GHz-3.47 GHz) for the upper band. The measured 3 dB axial ratio bandwidths of lower band and upper bands are 22.22% (1.6 GHz-2 GHz) and 10.53% (3.15 GHz-3.5 GHz), with respect to 1.8 GHz (RHCP) and 3.325 GHz (LHCP), respectively.