Ritesh Kumar Badhai

Abstract: A printed symmetric co-planar waveguide (CPW)-fed on-body monopole antenna is proposed for use on human arm body phantoms in medical diagnosis applications. The advantages of the presented antenna over other on-body antennas include low profile, miniaturization, wide bandwidth, and lower reflection coefficient, with good peak gain and better impedance matching with the human phantom. The optimized antenna had dimensions of $$0.020\lambda _{0}\,\times \,0.015\lambda _{0}\,\times \,0.0013\lambda _{0}$$ (where $$\lambda _{0}$$ is the wavelength in air of the lowest operating frequency). It covers almost all bands used in wireless body area network (WBAN) applications, including Medical Implant Communication Service (MICS, 402–405 MHz), Wireless Medical Telemetry Service (WMTS, 420–1430 MHz), Medical-BAN (2.36–2.4 GHz) as well as industrial, scientific, and medical (ISM, 2.4–2.485 GHz). The fractional impedance bandwidth was simulated to be 170 % (0.25–3.05 GHz) in free space and 168 % (0.32–3.67 GHz) in the presence of a multilayer tissue model. The fractional impedance bandwidth was measured to be 162 % in free space and 161 % in the presence of a human arm body phantom.

Abstract: This article presents the design of a printed bow–tie slot monopole antenna for landmine detection. The characteristics of antenna are obtained for coplanar waveguide feed bow–tie slot monopole configuration for several cases. The proposed antenna exhibits a bandwidth of 340 MHz with a reduced area of around 76% with respect to rectangular and circular patch antennas. Finally, a prototype model of reduced size bow–tie slot monopole antenna is fabricated and tested for Ground penetration radar application. The experimental results are compared with simulation results and are found to be in good agreement. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 122–125, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24872

Abstract: A compact asymmetric coplanar strip fed Sinc shaped monopole antenna suitable for multifrequency operations is proposed for portable wireless devices. The proposed Sinc shaped monopole antenna with truncated half ground plane operates at three frequency bands, 2110–2380, 4180–4600, and 5200–5678 MHz, showing fractional impedance bandwidths of 12, 9, and 8.8%, respectively, suitable for Universal Mobile Telecommunications System, Long Term Evolution handheld devices, Worldwide Interoperability for Microwave Access, Wireless Local Area Network, Hyperlan-2, and aeronautical navigation applications. Proposed antenna shows a dual mode of polarization. Finally a prototype model is developed for a typical configuration and the simulated results are validated experimentally.

Abstract: In this paper a modified compact CPW fed printed monopole antenna is presented. Modified double circular shaped monopole antennas with different type of feedings are proposed to achieve directional radiation characteristics and high front to back lobe ratio (F/B) for various applications. The proposed antenna covers the ultra-wideband (3.3 GHz–10.6 GHz) and a part of the license free super wideband (10.6 GHz–20 GHz) and it can be used to meet the vast range of wireless applications. For different directional radiation characteristics the proposed antenna can be used for some specific applications such as terrestrial communication like satcom applications, biomedical applications like tumor detection, imaging applications, stroke diagnosis system, and point to point communication etc. The proposed antenna prototypes exhibit good impedance matching for the proposed band of operation. The parametric study is performed to achieve the optimized performance of the antenna. The overall antenna size of the proposed antenna is 42×50×1.57 mm3. The proposed prototypes are designed and simulated using HFSS. The finally designed antenna offers good impedance bandwidth, well directive radiation characteristics, good gain and efficiency.

Abstract: A tapered feed circular monopole super ultra-wideband (UWB) printed antenna is proposed in this paper. The antenna consists of circular patch with tapered feed by 50 ohm microstrip line. The feed given to the antenna is tapered which helps in improving the UWB antenna performance. The volume of the proposed antenna is 50 × 40 × 1.6 mm3 including the patch, substrate and the ground plane. The associated 10 dB impedance bandwidth is from 1.48 GHz to 35 GHz. The return loss (S 11 <-10dB), radiation pattern and the gain shows in good agreement with the bandwidth. ANSYS HFSS version 15 commercial software has been used to design, simulate and to optimize the antenna performance. The substrate used for antenna design is FR-4 having thickness 1.6 mm, dielectric constant 4.4 and loss tangent 0.02. The radiation pattern, gain plot, returns loss and group delay has been investigated in this paper.

Abstract: In this article, a novel design for the modified bow-tie slot antenna with a rectangular tuning stub for 2.4/5.2/5.8 GHz triple-band applications is presented. The prototype consists of a modified bow-tie slot, the strip line in the bow-tie slot, and the rectangular tuning stub for the feeding. The simulation results showed that the impedance matching of the proposed modified bow-tie slot antenna was greatly affected by the feed gap and the strip line in the bow-tie slot. The experiment results indicate that the impedance bandwidth (return loss: −10 dB definition) of the proposed antenna was about 1.405 GHz for the 2.4 GHz band and 1.305 GHz for the 5 GHz band. The radiation patterns and gains in the experiment results are also presented and discussed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:126–130, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25647

Abstract: For the non-destructive sounding of the sub-surface for a large range of applications, a coplanar waveguide-fed bowtie slot antenna operating in a wide frequency band [0.4;1.5] GHz has been designed. The main originality of our work is the extension of the operating frequency band of the uniplanar bowtie slot antenna to frequencies lower than 800 MHz. The shape and the dimensions of the antenna have been optimised in the presence of a soil using numerical simulations based on the finite difference time domain approach. For the characterisation of the sub-surface, a transmission link comprising a pair of bowtie slot antennas that are moved along the soil surface has been studied in details to obtain the system performance in the frequency and time domains. First experimental results have been obtained on a sandy soil in the frequency domain using a vector network analyser. The experimental data have been analysed and compared with simulations results.

Abstract: In recent years, the interest in the Internet of Things (IoT) has been growing because this technology bridges the gap between the physical and virtual world, by connecting different objects and people through communication networks, in order to improve the quality of life. New IoT wearable devices require new types of antennas with unique shapes, made on unconventional substrates, which can be unobtrusively integrated into clothes and accessories. In this paper, we propose a fully textile dual-band logo antenna integrated with a reflector for application in IoT wearable devices. The proposed antenna’s radiating elements have been shaped to mimic the logo of South-West University “Neofit Rilski” for an unobtrusive integration in accessories. A reflector has been mounted on the opposite side of the textile substrate to reduce the radiation from the wearable antenna and improve its robustness against the loading effect from nearby objects. Two antenna prototypes were fabricated and tested in free space as well as on three different objects (human body, notebook, and laptop). Moreover, in the two frequency ranges of interest a radiation efficiency of 25–38% and 62–90% was achieved. Moreover, due to the reflector, the maximum local specific-absorption rate, which averaged over 10 g mass in the human-body phantom, was found to be equal to 0.5182 W/kg at 2.4 GHz and 0.16379 W/kg at 5.47 GHz. Additionally, the results from the performed measurement-campaign collecting received the signal-strength indicator and packet loss for an off-body scenario in real-world use, demonstrating that the backpack-integrated antenna prototype can form high-quality off-body communication channels.

Abstract: A novel planar monopole antenna with dual-band circularly polarisation (CP) is presented here. The antenna consists of a modified L-shaped monopole, an inverted-L strip, and a modified ground. The utilisation of the modified L-shaped monopole not only generates dual-band operation, but also excites CP radiation in the lower band. In order to achieve CP in the upper band, a parasitic inverted-L strip is added on the top plane of the substrate and a modified ground is designed. The proposed antenna has been fabricated and tested, the measured -10 dB reflection coefficient bandwidths are 370 MHz (2.38-2.85 GHz) in the lower band and 2330 MHz (4.05-6.38 GHz) in the upper band. The measured corresponding 3 dB axial ratio (AR) bandwidths are 610 MHz (2.39-3 GHz) and 850 MHz (5.15-6 GHz), respectively. The overlapped -10 dB reflection coefficient and AR bandwidths can totally cover the WLAN bands, Wi-Fi bands, Bluetooth band, and partly cover the WiMAX bands. The proposed antenna owns bidirectional radiation characteristic and reasonable gain at both the lower band and the upper band.

Abstract: Bio-telemetry is an advanced area of research that enables the transmission of biomedical parameters from human body to external monitoring device. Wearable antennas showing robust performa...