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Abstract-A spherical monopole antenna on the dielectric substrate is proposed for UWB applications. The antenna uses a combination of the conductor spherical antenna, the dielectric substrate and the ground plane under substrate. The simulated results demonstrate that the design structure covers the frequency range 4.6 GHz-10.6 GHz and more. The radius of sphere and the height of the antenna is R=5 mm, h=3.2 mm, respectively. In this paper, the effects of varying the dielectric constant, the radius of spherical, and the height are investigated. Good radiations are obtained over the wide bandwidth with an acceptable gain. Also, the input impedance of the proposed antenna is simulated by HFSS and demonstrated. Details of design structure are presented and studied.Index Terms-Spherical antennas, monopole antennas, UWB.

Abstract-In this paper a novel C-shaped Defected Ground Structure (DGS) on a microstrip line is proposed to provide a frequency rejection property with an improved Q factor at 2.4 GHz. Compared to the other DGS introduced structures in literature, the new structure has a simple and compact shape and its rejection characteristic is steeper at the stop band than the other reported structures. Different parameters of the DGS have been optimized for the best frequency response to reject the centre frequency. The proposed DGS is successfully designed and fabricated and the measured results are in a very good agreement with the simulated results.

Abstract-In this paper, a new compact dual band-reject C-shaped defected ground structure (DGS) for microstrip line is introduced. Using two units of the same shaped DGS with different dimensions, a dual band-stop filter is designed and implemented. Results show that there are two parallel resonance frequencies at 2.468 GHz and 6.629 GHz with a very high Q-factor. The frequency characteristics of the proposed filter could be controlled by adjusting the DGS parameters such as width and length of both C-shaped patterns. Also, the distance between the two DGS structure could be adjusted for the required frequency characteristics. The proposed DGS provides Q-factor of more than 50 with attenuation of at least 20 dB at the resonant frequencies. The new introduced DGS filter is successfully designed and fabricated and the measured results are in a very good agreement with those obtained by numerical investigation.Index Terms-Defected ground structure (DGS), dual bandreject filter, Q factor.