A compact planar slot antenna is proposed and developed for ultra - wideband Applications. This antenna has compact size of 23 x 18 x 1.2 mm. It is fabricated with FR4 substrate and it is fed by Coplanar Waveguide. The antenna operating range of 3.05 GHz to 12.91 GHz was observed from the simulation using Finite Element Method (FEM) and 3.11 GHz to 12.46 GHz were achieved from Method of Moments (MoM) based IE3D Electromagnetic solver. Experiment was conducted to verify the above frequency range and 3.08 GHz to 10.86 GHz was noted. The RBF neural network was also trained to validate the above result in terms of return loss of the proposed antenna. The antenna has stable Omni directional pattern in E-plane and bi-directional radiation pattern in H-plane. The group delay of the antenna is less than one nano second in operating bandwidth.

This paper presents the design of flexible trapezoidal radiating patch antenna array with FR4 substrate for onbody low frequency medical applications. The array resonates at 1.89 GHz with impedance bandwidth of 80 MHz and low return loss of -26.19 dB. The VSWR of 1.103 validate the activeness of the proposed antenna array having maximum surface current 133.1 (A/m) and directivity of 4.48 dBi. The antenna array exhibit the H-Field strength of 160.52 (A/m) and E-Field of 36093.4 (V/m) prove the radiation capability at low frequency on body application. These properties demonstrate the suitability of proposed array antenna for on body medical wireless applications.

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In this proposal new trapezoidal patch microstrip feed antenna array with ground defected by square shape is designed for detailed antenna parameter study in terms of return loss, VSWR, gain and radiation pattern for S band applications from 2 to 3 GHz. The bandwidth and radiation properties of four radiating element arranged in 2 x 2 array has been improved by defecting half of the ground by etching square shape opposite to the vertical feed point. 30 x 70 x 1.6 mm dimension structure has been fabricated in FR4 substrate for low cost applications and performance analyzed in three different planes. With comparison of four element array with full ground, the proposed array with defected ground has proved the improvement in behavior with return loss of -34.687 dB and ideally fit with VSWR of 1.038. Parametric study with feed length and substrate thickness has also been performed optimized decision of structure dimension. This study reveals that by reducing the substrate thickness and increasing the feed length, we can improve the performance of loss reduction. The front view has been simulated with full ground and defected ground for comparison and the compared results shows that the loss reduction of -22 dB has been achieved with VSWR value of 1.03 from 2.28 for defected ground structure. The designed structure has been simulated with CST software and the comparison of simulated results has conform that the proposed structure can be used for S band application like airport surveillance radars with wide bandwidth of 120 MHz and gain of 3.52 dBi. Comparison has been made between the proposed antenna array and the antennas available in literature with respect to bandwidth gain, reflection coefficient and defection type for better understanding.

In this paper, microstrip dual band antenna array with defected ground structure has been proposed for low frequency wearable on-body applications. The array has been simulated with Cotton, Polyimide, Polyester and Teflon (PTFE) flexible materials which are mostly used for biomedical applications. The performance of 2x2 trapezoidal patch array with partial ground, thin slot defection at center has been studied in terms of return loss, VSWR, power handling capability, radiation pattern and surface current distribution. All substrates exhibits acceptable fractional bandwidth below -10 dB and Cotton proves its superiority than other substrates with -20 dB and -48 dB return loss with 16.12% and 7.73% bandwidth at 1.24 GHz and 1.94 GHz respectively. The proper matching of array has been proved with VSWR value below 1.3 for all substrates. The observation of input port impedance shows that, Cotton array has good impedance matching nearly to 50 Ω and PTFE array has 100 Ω poor impedance matching. The proposed four flexible array exhibit omnidirectional pattern in H plane with 1.43 dBi gain and bidirectional pattern in E plane with 1.4 dBi gain which are support for ideal fitness of proposed flexible material array for medical applications.