Raghunath Subhanrao Bhadade

Bio: Raghunath Subhanrao Bhadade is an academic researcher from College of Engineering, Pune. The author has contributed to research in topics: Microstrip & MIMO. The author has an hindex of 2, co-authored 4 publications receiving 7 citations. Previous affiliations of Raghunath Subhanrao Bhadade include Massachusetts Institute of Technology.

“Circularly polarized 4 × 4 MIMO antenna for WLAN applications”

Abstract: A circularly polarized (CP) 4 × 4 MIMO antenna with low mutual coupling is proposed to operate at 2.4 GHz WLAN band (IEEE 802.11b/g/n/ax) applications. The proposed design consists of four CP penta...

High Gain Circularly Polarized Pentagonal Microstrip for Massive MIMO Base Station

Abstract: In this paper we propose a circularly polarized pentagonal microstrip antenna on a suspended substrate with coaxial probe feed and five loaded slits for Massive MIMO BS Antenna applications. Massive Multiple-Input Multiple-Output (MIMO) is one of the key component to be incorporated in the 5G cellular systems. The proposed antenna is successfully simulated using HFSS 13.0, fabricated on a FR-4 substrate and measured. The proposed antenna exhibits a much higher gain of 6.17dB, improved impedance bandwidth of 171.9 MHz (Return loss, S11= -10dB) , axial ratio bandwidth (< 3dB) of 135 MHz , patch area of 1775 mm2 , and also yields return loss better than -15 dB around the center frequency of 2.45 GHz (ISM Band). Measured characteristics of the antenna are in good agreement with the simulated results.

Real-time Decoding of Satellite Signals

Abstract: Satellite is a common term these days and a tremendous amount of work is conducted in space and technology. The proposed system briefs about the decoding of live satellite signals with help of a mini ground station using USRPB200 Software Defined Radio (SDR), RTL SDR mini and a self-designed V-shaped Antenna. The objective of the proposed system includes decoding the satellite signals in the Ultra High Frequency(UHF) and Very High Frequency (VHF) bands with their respective implementations in the GNU Radio environment. Signals from International Space Station (ISS), Meteor Satellites, and National Oceanic and Atmospheric Administration (NOAA), are captured during multiple passes to study in detail and explore how communication exactly happens. The proposed system also sheds light on the hardware and software used while decoding the signals, the mini-ground station, the different challenges faced during the process, and the solutions to overcome the same.

Tri-band Dual Polarized 2 × 2 MIMO Antenna for Wireless Communications

Abstract: A dual polarized (DP) 2 × 2 MIMO antenna with high gain and isolation is proposed for WLAN band (IEEE 802.11a/b/g/n) and C-band (spectrum sharing) applications. The proposed MIMO antenna design consists of two DP pentagonal microstrip elements. A slot on a ground is introduced to escalation the isolation among two antennas. The measured frequency bands extend from 2.43 to 2.54 GHz, 4.05 to 4.13 GHz and 5.22 to 5.37 GHz with VSWR <2. The achieved isolation between two ports is more than 30 dB. The measured peak gains at 2.45 GHz, 4.09 GHz and 5.29 GHz resonant frequencies are 7.95 dBd, 3.39 dBd and 4.18 dBd, respectively. The RT druid 5880 substrate is used for fabricating the MIMO antenna. Measured results agree with the simulation ones. The diversity performances in terms of diversity gain (DG), efficiency, and envelope correlation coefficient (ECC) have also been reported. The proposed MIMO antenna is tested using Wi-Fi router.

Low-Profile and Closely Spaced Four-Element MIMO Antenna for Wireless Body Area Networks

Abstract: A compact four-element multiple-input multiple output (MIMO) antenna is proposed for medical applications operating at a 2.4 GHz ISM band. The proposed MIMO design occupies an overall volume of 26 mm × 26 mm × 0.8 mm. This antenna exhibits a good impedance matching at the operating frequency of the ISM band, whose performance attributes include: isolation around 25 dB, envelope correlation coefficient (ECC) less than 0.02, average channel capacity loss (CCL) less than 0.3 bits/s/Hz and diversity gain (DG) of around 10 dB. The average peak realized gain of the four-element MIMO antenna is 2.4 dBi with more than 77 % radiation efficiency at the frequency of interest (ISM 2.4 GHz). The compact volume and adequate bandwidth, as well as the good achieved gain, make this antenna a strong candidate for bio-medical wearable applications.

Design of dual band four port circularly polarized MIMO DRA for WLAN/WiMAX applications

Abstract: This article presents a circularly polarized 4-port Multiple Inputs Multiple Outputs dielectric resonator-based antenna with two resonating bands for WLAN (5.0 GHz) and WiMAX (3.5 GHz) applications...

Designed Circularly Polarized Two-Port Microstrip MIMO Antenna for WLAN Applications

Abstract: The proposed work describes a corner square-cut square-patch multiple-input multiple-output (MIMO) antenna with reduced mutual coupling for circular polarization (CP). A two-port MIMO-CP antenna was designed and operated at 5.6 GHz for wireless local area network (WLAN) applications. The dimensions of the MIMO-CP antenna were 22.5×50mm2(0.43λ0×0.933λ0) and the FR4 substrate height was 1.6 mm. Between the two-elements, the edge-to-edge distance was 12.2 mm (0.227 λ0), where λ0 was the free space wavelength at 5.6 GHz. A slot was created in the middle of the ground in the proposed MIMO antenna to reduce mutual coupling and improve CP. The ground slot improves impedance matching and provides a better S-parameter and axial ratio (AR), according to the antenna results. According to the simulated results, the proposed antenna bandwidth of 5.23–6.42 GHz (21.4%) for S11 were <−10 dB, isolation was −37 dB with a peak gain of 6 dB and AR ≤3 dB from 5.37 to 5.72 GHz (6.25%). The proposed antennas are simple to fabricate, have low profiles, are inexpensive, have good isolation, and are CP. The diversity gain (DG) and envelop correlation coefficient (ECC) results are better in the simulated frequency band. A MIMO-CP antenna geometry prototype is built and measured for comparison, yielding good results when compared to the simulated and measured results. The MIMO-CP antenna, as designed, is suitable for WLAN applications.

Dual Polarized, Multiband Four-Port Decagon Shaped Flexible MIMO Antenna for Next Generation Wireless Applications

Abstract: A compact, dual polarized, multiband four-port flexible Multiple Input Multiple Output (MIMO) antennae with the connected ground and high isolation is designed with computation and experimental measurement studies. All four monopole radiators are embedded decagon-shaped flexible FR-4 substrate with an outer radius of 10 mm in order to accomplish circularly polarized (CP) radiations, bandwidth enhancement, and compact size of only 45×38×0.2 mm ³ (0.375λ × 0.316λ × 0.0016λ, at lowest resonating frequency 2.5GHz). The interconnected ground structure is loaded with an Interlaced Lozenge Structure (ILS) to suppress the surface wave radiations resulting in low mutual coupling between the radiators. The proposed MIMO antenna demonstrates measured 10-dB impedance bandwidths of 9.63% (2.37–2.61 GHz), 28.79% (3.30–4.41 GHz), and 16.91% (4.98–5.90 GHz) in the LTE 38/40, Sub-6 GHz 5G NR n77/n78, WLAN and Wi-Fi bands, respectively. Furthermore, broad 3-dB Axial Ratio Bandwidth (ARBW) of 28.79% (3.30–4.41 GHz) with gain greater than 4 dBi and efficiency above 80% are achieved. Finally, the bending analysis of the proposed flexible MIMO antenna along the X- and Y- directions shows good performances in terms of scattering parameters, 3 dB ARBW, and MIMO diversity parameters.

Design of Quad-Port Ultra-Wideband Multiple-Input-Multiple-Output Antenna with Wide Axial-Ratio Bandwidth.

Abstract: This article presents a compact, planar, quad-port ultra-wideband (UWB) multiple-input–multiple-output (MIMO) antenna with wide axial ratio bandwidth (ARBW). The proposed MIMO design consists of four identical square-shaped antenna elements, where each element is made up of a circular slotted ground plane and feed by a 50 Ω microstrip line. The circular polarization is achieved using a protruding hexagonal stub from the ground plane. The four elements of the MIMO antenna are placed orthogonally to each other to obtain high inter-element isolation. FR-4 dielectric substrate of size 45 × 45 × 1.6 mm3 is used for the antenna prototype, and a good agreement is noticed among the simulated and experimental results. The proposed MIMO antenna shows 3-dB ARBW of 52% (3.8–6.5 GHz) and impedance bandwidth (S11 ≤ −10 dB) of 144% (2.2–13.5 GHz).