This paper presents a framework for human detection using an ultra-wideband (UWB) radar system and proposes a novel UWB radar antenna design with double-winding structures for radar applications. The proposed antenna achieves high gain and bandwidth, overcoming the shortcomings of Vivaldi antennas, which are the preferred antennas for radar applications. In the proposed novel design, winding structures are incorporated nearer to the main resonator, which suppresses harmonic distortion and enhances the radar detection process. The proposed antenna is designed to cover a frequency range from 6 GHz to 10.5 GHz. The design is analyzed for different design configurations with and without winding structures. However, the dual-side winding structure configuration achieves better performance than the single-side winding structure. The proposed design achieves a maximum bandwidth of 2.09 GHz in the dual-side winding structure configuration, which is a remarkable achievement for radar and precise locating applications. The proposed design achieves improved return loss performance greater than -10 dB in all operating frequencies and voltage standing wave ratios equal to 1 with improved gain and directivity.

This article proposes a flexible ultra-wideband (UWB) antenna for wearable electronics and biomedical applications. The antenna presented for this work is fabricated on a Kapton polyimide (PI) substrate, and the operating frequency ranges from 2.4 GHz to 7.1 GHz. The footprint of the proposed antenna is 35 × 45 mm with an elliptical radiating element fed by coplanar waveguide (CPW), which achieves improved impedance matching characteristics. The choice of substrate, design constraints, fabrication process, and bending test of the proposed flexible UWB antenna are explained in detail in this paper. A comparative study on the choice of substrate is performed and the Kapton PI is chosen as the substrate material, which makes the antenna less susceptible to degradation in antenna performance that arises due to bending effects. The measurement and simulated results of the fabricated antenna show a good degree of agreement. The return loss performance of the proposed antenna is greater than -10 dB in all the operating bands with improved gain and directivity. The flexible nature with multiple frequency bands of operation and good bending performance makes the proposed antenna appropriate for wearable electronic and biomedical applications.

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