Abstract:

In this paper, a novel design of a microstrip-fed compact monopole microstrip antenna with asymmetrically modified ground plane operating at ultra-wide band (UWB) frequency range is presented for microwave imaging applications.  The performance characteristics of the proposed antenna in terms of impedance bandwidth and return loss meet the ultra-wide band requirements. The design and simulation procedures of the proposed antenna are carried out using an electromagnetic simulation software based on the characteristic impedance for the transmission line model. The proposed antenna, with small size of 32 × 42 × 1.55 mm3 on an FR4 epoxy substrate with permittivity (εr) 4.4, is fabricated and validated through the simulations and measurements. It is demonstrated that the measured -10 dB bandwidth for return loss is from 2.08 to 7.4 GHz but after this frequency, the antenna operates with minimum 87.4% efficiency up to 10.6 GHz. The antenna exhibits acceptable UWB characteristics and the results show that the designed antenna is suitable for various microwave imaging applications operating at UWB. 

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