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This paper presents compact UWB cylindrical dielectric resonator antenna with reconfigurable band notch capability using single varactor diode. Theoretical results are achieved for the design with the range of frequencies 4-10.6 GHz. Using single varactor diode, different notch frequencies can be obtained using different capacitance values. The effect of changing the varactor position is also examined. A Wide range of notch frequencies can be achieved using this simple configuration, which covers most of coexisted narrow band systems. The notch frequency can be lower by increasing the capacitance value. Finite Element Method (FEM) and Finite Integration Technique (FIT) are hired to simulate the proposed antenna structure using HFSS and CST MWS respectively. The notch frequency covers the WLAN band when C=0.9 pF and covers the WiMAX band when the capacitance is changed to 0.8 pF for the same antenna configuration and varactor position. The antenna with DRA has a directive radiation pattern in E-plane and omnidirectional pattern in H-plane. Also, the gain is suppressed in the notched frequency. The group delay is nearly stable in the UWB frequency range, except at the notch frequencies.

In this paper, CPW-Fed ultra wideband (UWB) planar monopole antenna (PMA) loaded by double elliptical split ring resonators (ESRRs) for double band-notch characteristics is introduced and examined. Two different ESRRs with different dimensions are printed in the antenna backside to notch two different frequencies. The ESRRs are also rotated and the corresponding return loss effect is examined.  Different notch frequencies can be obtained by varying the ESRRs, dimensions. Two single SRRs are used to notch two frequencies instead of using dual SRR pairs. Two notch frequencies at 5.2 GHz and 6.9 GHz has been obtained to notch WLAN and C-band wireless applications, respectively. A directive radiation pattern in E-plane and omnidirectional radiation patterns in the H-plane could be observed. Also the gain is suppressed in the notch frequencies. The group delay is nearly stable in the UWB frequency range, except at the notch frequencies, which is distorted sharply. So, the proposed antenna is a good candidate for the modern UWB systems. Finite element method FEM and finite integration technique FIT are used to simulate the proposed structures through the usage of Ansys HFSS and CST MWS. Very good agreement between both results has been obtained.

In this paper, the effect of changing the structure of split ring resonator SRR from circular to elliptical shape is presented and tested. The theoretical analysis of circular SRR (CSRR) is tested and its results are compared with the simulated ones. Comparison between both configurations is introduced. The new elliptical SRR (ESRR) can be adapted to operate in multi range of frequencies. The effect of gap position in ESRR resonant is also examined. When both gaps are moved but still aligned, the resonant frequency still the same. But when single gap is moved only the resonant frequency the resonant frequency in changed to reach its maximum value when both gaps are in the same position. Frequency tunability can be offered by loading a single variable capacitor between ESRR metallic rings.  The resonant frequency of the ESRR can be controlled by varying the capacitance of the varactor diode. Finite element method FEM is used to simulate the proposed structures using HFSS.