Search

This work portrays the design and analysis of an ingestible capsule multiple-input-multiple-output (MIMO) antenna for wireless capsule endoscopy (WCE) for animal husbandry. The proposed antenna element has a footprint of $0.18\lambda _{{0}}\,\,\times \,\,0.107\lambda _{{0}}\,\,\times \,\,0.002\lambda _{{0}}$ , which is transformed into a four-port MIMO antenna and bent into a cylindrical profile of 8.92 mm radius with dimensions of $0.184\lambda _{{0}}\,\,\times \,\,0.136\lambda _{{0}}\,\,\times \,\,0.002\lambda _{{0}}$ . The designed MIMO configuration consists of asymmetric extended fork-shaped radiators with U-slotted strips and meandered connected ground planes. The developed MIMO set is housed inside a polylactide (PLA) capsule that mimics a real-time pill camera. The capsule antenna operates at the Industrial, Scientific, and Medical (ISM) (2.45 GHz) and ultra-wideband (UWB) (3.1–10.6 GHz) frequencies. The link budget analysis and diversity metrics of the MIMO antenna are evaluated by embedding it inside the capsule. The MIMO bolus sensor antenna prototype is implanted in the skin mimicking gel and its impedance/radiation characteristics are studied. The estimated specific absorption rate (SAR) is found to be within the standard acceptable limits. Furthermore, machine learning approach is introduced for classification of animal type and early detection of animal medical illness, making it suitable for use in animal husbandry-capsule endoscopy, biomedical and biotelemetry applications due to its conformal and biocompatible nature.

The increased demand for automobile applications and connected-vehicles in the market has prompted much research into intelligent automotive antennas. Connected-vehicles are being used to change automotive technology and serve as a framework for a smart society. This paper presents a thirty-two-port hex‑polarized massive multiple-input-multiple-output (MIMO) antenna that operates at GPS, Wi-Fi, and ultra-wideband (UWB) frequencies. In the proposed MIMO antenna, thirty-two-unit cells are populated in 3D configuration, where eight-unit cells are arranged in the horizontal plane and twenty-four-unit cells are arranged in four different vertical planes. The unit cell, based on an isomorphic inverse approach, consists of a semi-circular radiator with integrated meandered slots and achieves a tri-band operation at 1.5 GHz, 2.4 GHz, and 3.1 to 11 GHz. The unit cell has a size of 20 mm × 20 mm and the developed MIMO architecture has dimensions of 85 mm × 85 mm. The peak gain of the proposed antenna is 3.85 dBi, and the efficiency is 89.5%. The MIMO antenna assembly exhibits a calculated Envelope Correlation Coefficient (ECC) using far-field, less than 0.1. The Total Active Reflection Coefficient (TARC) is found to be less than -10 dB and the difference of Mean Effective gain (MEG) is less than 1 dB. Also, Apparent Diversity Gain (ADG) and Effective Diversity Gain (EDG) by far-field method are found to be above 9 dB. Antenna assemblies like the one proposed, are filled in various layouts on 3D vehicular space to combat the diversity reception issues, catering to spatial and polarization needs. In order to substantially validate the designed MIMO antenna for vehicular applications, housing effects and on-car analysis have been studied.

This paper presents a miniaturized frequency selective surface (FSS) with stop band characteristics at the resonant frequency of 5.12 GHz. The unit cell size of the proposed FSS design is in the order of 0.095 λ×0.095 λ. The proposed unit cell is obtained by convoluting the arms of the basic swastika structure. The design provides fractional bandwidth of 9.0 % at the center frequency of 5.12 GHz in the 20 dB reference level of insertion loss. The symmetrical aspect of the design delivers identical response for both transverse electric (TE) and transverse magnetic (TM) modes thereby exhibiting polarization independent operation. The miniaturized design provides good angular independency for various incident angles. The dispersion analysis is done to substantiate the band stop operation of the convoluted swastika FSS. The proposed FSS is fabricated and its working is validated through measurements.

This paper presents the design of an Ultra‐wide band‐stop Frequency Selective Surface (FSS), the building block of which makes use of a modified Jerusalem cross loop structure. The proposed FSS unit cell has a coupled configuration with a modified Jerusalem cross loop on the top and a square loop on the rear side to operate over an ultra‐wide bandwidth. The proposed FSS design offers band‐stop characteristics over the entire UWB operating bandwidth extending from 2.95 to 12 GHz with a reference transmission loss of 10 dB. The proposed FSS unit cell has a miniaturized profile of 0.05λ˳ × 0.05λ˳ where the λ˳ corresponds to the free space wavelength at the lowest operating frequency. The rotational symmetry of the proposed FSS makes it polarization‐independent under both TE and TM modes of operation. Also, the proposed FSS exhibits a good angular stability response up to 60°. The prototype FSS is fabricated and the simulated results are validated using experimental measurements. Thus, the proposed FSS is a promising candidate for a multitude of applications such as spatial filtering (Bayatpur & Sarabandi, 2010, https://doi.org/10.1109/LMWC.2009.2038517), antenna gain enhancement (Chatterjee & Parui, 2016, https://doi.org/10.1109/TAP.2016.2552543), and electromagnetic shields (Chiu et al., 2008, https://doi.org/10.1109/TEMC.2008.2004560) operating over the UWB spectrum. This paper presents the design of an Ultra‐wide band‐stop Frequency Selective Surface (FSS)The proposed FSS design offers band‐stop characteristics over the entire UWB operating bandwidthThe proposed FSS is a promising candidate for a multitude of applications such as spatial filtering, antenna gain enhancement This paper presents the design of an Ultra‐wide band‐stop Frequency Selective Surface (FSS) The proposed FSS design offers band‐stop characteristics over the entire UWB operating bandwidth The proposed FSS is a promising candidate for a multitude of applications such as spatial filtering, antenna gain enhancement