In this paper, a new method of improving cross-polarization (XP) performance on a wideband microstrip antenna is proposed, by adopting a defected ground structure (DGS). This F-slot shaped defected ground structure (F-DGS) exhibits considerable improvement in terms of XP properties, broad boresight angular suppression, and impedance bandwidth (S11 < -10 dB). Lower than -26 dB XP level is achieved over 206˚ angular range, while the impedance bandwidth is broadened to 15.5%. Both wideband rectangular patches with and without F-DGS have been fabricated and experimented.
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