Implementation of defected ground structure for microstrip filtenna design

A microstrip patch filtenna inspired by defected ground structure (DGS) is presented in this article. It uses modified split ring resonator and capacitance loaded strip as a radiating element. The presented structure is incorporated with a pair of double U-shaped DGS (DU-DGS) to obtain filtering characteristics. The width of DU-DGS plays a vital role in selecting attenuation poles of the filter as well as for the filtenna circuit. The separation distance between the DU-DGS also affects the resonant frequency of the structure. Both radiation and filtration can be performed through a single structure, otherwise known as filtenna. The physical size of the proposed filtenna in terms of guided wavelength is 2.465λg × 1.160λg × 0.116λg at 10.8 GHz, and is comparatively less to others reported, so is considered as a superior feature. The presented filtenna possesses impedance bandwidth of 700 and 1800 MHz at 10.8 and 16.6 GHz, which covers standards of X- and Ku-band, respectively. So, this can be referred to as dual band filtenna. The radiation pattern shows omnidirectionality in both E and H planes at resonance.