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In this paper, a CPW fed UWB planar monopole Butterfly's-wing shaped antenna with reconfigurable band notch characteristics is presented, tested and fabricated in the beginning three eelliptical patches are used to construct the antenna, then three elliptical slots have been created to improve the performance of the antenna. By using suitable varactor diodes in suitable positions in the slots a notch frequency can be obtained. The notch frequency of the antenna can be controlled by varying the varactor diodes' capacitance that varied from 0.2 to 1.4 pf and frequency tunability can be achieved without modifying the basic antenna geometry. The proposed antenna is suitable for downlink band notching applications in C-band satellite (3.6–4.2 GHz). Finite element method FEM is used to simulate the proposed structures using HFSS. A prototype of the proposed antenna using three capacitor elements is fabricated and S11 is measured. Three 0.5 pf single capacitor element are used instead of the varactor diodes which are not available in the laboratory and the measured S11 is compared with the simulated results. Very good agreement has been obtained between them. The proposed antenna without and with capacitors yield directive patterns in the E-plane and omnidirectional patterns in H-plane. Also the gain is suppressed in the notch frequency. [ABSTRACT FROM AUTHOR]

Heart shaped reconfigurable band notched UWB microstrip line fed monopole antenna using two mushrooms like electromagnetic band gaps (EBGs) loaded by two varactor diodes has been developed, examined and fabricated. The effect of EBG dimensions, on the notch frequency, was first examined. A notched frequency of 5.3 GHz is obtained when two square EBGs with rectangular slits are used with length equal 7.5 mm and gap, g = 0.5 mm. The EBGs is loaded by a varactor diode to achieve re-configurability. The notch frequency covers WiMAX when varactor capacitance C = 0.7 pF and covers WLAN when C = 0.1pF. Also, the notch can be easily eliminated by decreasing the capacitance below 0.1 pF. A prototype of the proposed antenna using single capacitor elements with capacitances 0.6 pF is fabricated and S11 is measured. Notch frequency at 4 GHz is obtained in both simulated and measured antenna structures. The antenna with EBG has a directive radiation pattern in E-plane and omnidirectional pattern in H-plane. Also, the gain is suppressed in the notched frequencies. The group delay is nearly stable in the UWB frequency range, except at the notch frequencies, which is distorted sharply. FEM and FIT are hired to simulate the proposed antenna structure using HFSS and CST respectively. Very good agreement between both results has been obtained. [ABSTRACT FROM AUTHOR]

In this paper, a new flower-shaped microstrip line feed reconfigurable band-notched UWB monopole antenna using single varactor diode is introduced and fabricated. Different notch frequencies can be obtained using different capacitance values. The effect of changing the varactor position is also examined. The flower shape is first optimized to obtain UWB characteristics. Then, a slot is made in the microstrip line to be loaded later with a single varactor diode. A wide range of notch frequencies can be obtained using this simple configuration which covers most of the narrow band coexistence systems. The notch frequency can be lower by increasing the capacitance value. The notch frequency covers the WLAN band when C = 0.8 pF and covers the WiMAX band when the capacitance is changed to 0.7 pF for the same antenna configuration and varactor position. Two prototypes of the proposed antenna using two different single capacitor elements with capacitances 0.6 pF and 1.5 pF are fabricated, and their reflection characteristics are measured and compared with the simulated ones. Notch frequencies at 6.1GHz and 4.3 GHz are obtained respectively in both simulated and measured antenna structures. The proposed antenna has a directive radiation pattern in E-plane and omnidirectional pattern in Hplane. Also, the gain is suppressed in the notched frequencies. The group delay is nearly stable in the UWB frequency range with very little variations, but it is distorted sharply at the notch frequencies. So, the proposed antenna is a good candidate for the modern UWB systems. [ABSTRACT FROM AUTHOR]