Wideband jean antenna with bending structure for microwave imaging applications

Abstract

In this paper, a wideband jean antenna with bending structure for flexible microwave imaging applications is presented. Coplanar waveguide (CPW) feeding structure with Koch shape ground slotted technique has been implemented for widening the bandwidth. The design evolution process of the proposed antenna is started from a simple CPW-fed monopole antenna to bending circumstance. The proposed antennas under normal condition, bending circumstance and as well as on-arm bending effect are simulated and optimized using CST microwave studio software and fabricated; also tested so as to validate the results. Under normal condition, the antenna provides measured bandwidth of 4500 MHz (1.5-6 GHz) in the case of |S11|≤−10 dB while 4360 MHz (1.44-5.8 GHz) for the measured bandwidth under bending circumstance is obtained. Also, there is a slight degradation on the reflection coefficient of the antenna under on-arm bending so that measured bandwidth became narrower with operating frequency of 3800 MHz (2.2-6 GHz). The measured gain of the antenna fluctuates between 2.5-5.6 dBi and 1.5-2.8 dBi with quasi-omnidirectional pattern within the expected frequency band for normal and bending condition, respectively. The proposed antenna provides a good performance in terms of its reflection coefficient and radiation characteristics. Therefore, due to insensitiveness to bending and body effect, the proposed antenna has become good candidate for microwave imaging applications.