Pratik Mevada - Academia.edu (original) (raw)

Papers by Pratik Mevada

IEEE Transactions on Antennas and Propagation, 2022

International Journal of RF and Microwave Computer-Aided Engineering, 2022

Iete Journal of Research, 2021

This paper presents the design of common aperture dual band dual linearly polarized microstrip ar... more This paper presents the design of common aperture dual band dual linearly polarized microstrip array antenna, working at L and S-band for airborne synthetic aperture radar (SAR). The antenna has be...

2019 IEEE Indian Conference on Antennas and Propogation (InCAP), 2019

This paper demonstrates X-band periodically loaded meandered coplanar waveguide (CPW) structure b... more This paper demonstrates X-band periodically loaded meandered coplanar waveguide (CPW) structure based phase shifter built on Barium Strontium Titanate (BST: BaxSr1-x TiO3) ferroelectric substrate. CPW line has been loaded with 29 nos. interdigital capacitors (IDC) whose capacitance is varied with application of bias voltage, due to ferroelectric property of BST material. Design of IDC loaded meandered CPW line with integrated bias tee and DC blocking mechanism has been presented and analyzed using 2.5D electromagnetic solver. 800 phase shift and 4.8dB insertion loss at 10.5GHz for voltage range of 0-400V has been achieved in simulation. Scanning performance of 4 elements linear array has also been analyzed for maximum 800 phase shift. Designed phase shifter has been developed using 0.5μm thick BST layer with Ba0.6Sr0.4TiO3 composition has been realized using SolGel technique.

2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, 2020

This paper presents the analysis of phased array antenna where elements are clustered using Pinwh... more This paper presents the analysis of phased array antenna where elements are clustered using Pinwheel type aperiodic tiling pattern, to improve side lobe level (SLL). Parametric analysis has been carried out to select optimum subsection of Pinwheel pattern for clustering of array which is excited with required phased excitation to achieve 10° and 20° beam scan. Worst SLL in 3D radiation pattern of an array with Pinwheel clustering is improved by 3.8dB and 6.6dB for 10° and 20° beam scan respectively. Moreover, no. of TRMs has also been reduced by 68% while maintaining significantly low SLL.

This paper demonstrates the scan blindness removal in C-band multilayer microstrip phased array a... more This paper demonstrates the scan blindness removal in C-band multilayer microstrip phased array antenna using uniplanar compact electromagnetic bandgap (UC-EBG) structure. Unit cell approach has been adopted to compute electromagnetic band-stop range of UC-EBG structure. The proposed design of UC-EBG structure shows electromagnetic bandgap of 4.6 GHz to 5.3 GHz. 16 elements linear aperture coupled microstrip array antenna embedded with UC-EBG structure has been designed, developed and tested. The active reflection coefficient (ARC) of linear array antenna has been measured to detect scan blindness and its removal. Scan blindness removal has also been demonstrated by far field characterization of linear array antenna in scanning mode. It has been established that, scan blindness appearing at 200-220 scan angles, in absence of UC-EBG structure, can be removed by embedding UC-EBG structure between array elements. The full wave simulations of UC-EBG structure and antenna structures have...

- In this paper, the design and development of dual linearly polarized stacked patch antenna for ... more - In this paper, the design and development of dual linearly polarized stacked patch antenna for GNSS Reflectometry (GNSS-R) application is presented. The stacked microstrip patch antenna with proximity coupled feed configuration is used in this design. This type of antenna can be used as a nadir looking antenna in the receiver of GNSS Reflectometry. The antenna has been developed and measured. The antenna is having measured 10 dB return loss bandwidth of 118 MHz (7.5%) and peak gain of 8 dBi at center frequency 1.575 GHz for both linear polarization. The antenna is also analyzed with the Zenith looking antenna and mutual coupling between these two antennas is better than 50 dB. This antenna is used for GNSS Reflectometry application.

This paper investigates effect of various types of aperture tapering on grating lobe level (GLL) ... more This paper investigates effect of various types of aperture tapering on grating lobe level (GLL) of array antenna. Formulation of farfield pattern computation of array antenna with sub-array for required scan angle is discussed. Study has been performed for S-band 16 elements coaxial fed microstrip array antenna, excited with 2 elements sub-arrays. Symmetric linear aperture tapering, symmetric raised cosine type aperture tapering and (cos + sin) type asymmetric aperture tapering is applied on array elements and the farfield patterns and its parameters including grating lobe is computed and studied for 100 beam scan. The presented study is applicable to any size of array antenna and its conclusions can be generalized to design array antennas.

This paper presents the design and development of broadband power divider, which equally divides ... more This paper presents the design and development of broadband power divider, which equally divides power from the Standard (WR-51) air filled waveguide to non-standard dielectric (Teflon) filled waveguides. The design uses Y-Junction and T-junction interconnection and a novel way to reduce the reflection at the dielectric-air interface for better S-parameter performance. The non-standard waveguide has dimensions of a (broad-wall) = 9 mm and b (narrow-wall) = 4.5mm. The simulated and measured S-parameter performance of the power divider has been presented. The design is simulated using the High Frequency structure simulator (HFSS). The power divider can be used for dielectric filled waveguide fed antenna like slotted waveguide antenna.

This paper presents the design of broadband planar slotted waveguide array (SWA) antenna, excited... more This paper presents the design of broadband planar slotted waveguide array (SWA) antenna, excited with novel waveguide feeder network which also functions as broadband impedance matching network. A 4 x 12 narrowband longitudinal shunt slotted waveguide array working at X-band, is designed and integrated with 1:4 waveguide feeder network which offers the broadband impedance matching. Design of such broadband SWA antenna requires computation and matching of active parameters at SWA antenna ports and waveguide output ports. Active reflection coefficients and active normalized admittances have been computed using simulated S-parameters of SWA antenna and waveguide feeder network. Simulation of proposed antenna has been executed using 3D electromagnetic simulator. Prototype of 4 x 12 broadband SWA antenna is also developed and characterized to validate its performance. 6.3% bandwidth of S11 < -17dB and 24.2dBi boresight gain at 9.6GHz have been achieved in measurement. Comparison of s...

This paper demonstrates frequency agile inset fed microstrip patch antenna built on Barium Stront... more This paper demonstrates frequency agile inset fed microstrip patch antenna built on Barium Strontium Titanate (BST: BaxSriXTiO3) ferroelectric substrate. Concept and design methodology of X-band frequency agile microstrip patch antenna monolithically integrated with coplanar capacitor, bias tee and DC block capacitor are discussed. Antenna design is carried out on 0.5 m thick Ba0.6Sr0.4TiO3 hosted by 1mm Quartz substrate. C-V characterization of this BST film is also performed and presented. Microstrip antenna on BST film has been realized using SolGel method and it shows 50MHz frequency tunability during measurement for bias voltage variation from OV to 154V The gain and pattern purity of the antenna is maintained over this bandwidth.

Emerging Waveguide Technology, Aug 1, 2018

This chapter describes the design and development of broadband slotted waveguide array (SWA) ante... more This chapter describes the design and development of broadband slotted waveguide array (SWA) antenna. Conventional SWA antenna offers a few percentages of bandwidth, which can be enhanced using proposed novel differential feeding technique which electrically divides large resonating SWA into wideband subarrays by creating virtual shorts. This chapter discusses concepts to achieve broadband nature of SWA antennas, design, development, and characterization of edge fed slotted waveguide array antenna, coupling slot fed SWA antenna, and high efficiency broadband slotted waveguide array. The developed SWA antennas are characterized and their measured results are presented. The developed prototype of proposed SWA antenna demonstrates measured return loss better than −17 dB over 7.6% bandwidth and achieves 90.2% antenna efficiency. This chapter also briefs about planar broadband SWA antenna and its prototype development and characterization.

Lecture Notes in Electrical Engineering, 2019

Code Division Multiple Access (CDMA) based onboard adaptive digital beamforming (DBF) system is p... more Code Division Multiple Access (CDMA) based onboard adaptive digital beamforming (DBF) system is proposed and implemented on hardware. It is essentially required for Tracking, Telemetry and Tele-command (TTC) operations of multiple moving users (LEO) simultaneously through GEO stationary Data Relay Satellite System (DRSS). CDMA based multiple access scheme is proposed on S-band to provide services to multiple users simultaneously on same frequency and to meet power spectral density requirements on the ground. CDMA based adaptive DBF hardware for S-band nine elements axial mode helix antenna array is developed and performance of system is demonstrated in radiation mode conditions. New signal acquisition scheme based on processing of signal received through wide-receive beam using single antenna element is proposed and implemented on hardware. New scheme to generate reference signal by tracking carrier phase and code phase of incoming signal independently from adaptive DBF module is al...

2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting

This paper presents the analysis of the multifaceted reflectarray (RFA) antenna for spatial bandw... more This paper presents the analysis of the multifaceted reflectarray (RFA) antenna for spatial bandwidth improvement. Geometries of faceted RFA have been designed by segmenting the phase correcting surface in tilted 3-panel and 5-panel configurations. Phase distribution over RFA surface and directivity variation with frequency have been computed using Geometric Optics (GO) based technique and achieved 6.5% and 7.4% 1-dB gain bandwidth in case of 3-panel and 5-panel faceted RFA, respectively as compared to a flat RFA having 1.8% 1-dB gain bandwidth.

Journal of Electromagnetic Waves and Applications

Progress In Electromagnetics Research Letters

This paper discusses the design of a 6-m Cassegrain optics based multiband reflector antenna inte... more This paper discusses the design of a 6-m Cassegrain optics based multiband reflector antenna integrated with beam waveguide (BWG) optics, which consists of an ellipsoidal mirror and three plane mirrors. The presented antenna has been simulated, and 75.8% and 76.8% aperture efficiencies have been achieved at 0.225 THz and 0.338 THz, respectively. The initial design parameters of elements of BWG network are computed using fundamental Gaussian beam parameters. The simulated results of the antenna including aperture efficiency have been presented and discussed in detail. The antenna has been designed for the ground based THz telescope for radio astronomy.

2018 IEEE Indian Conference on Antennas and Propogation (InCAP)

IET Microwaves, Antennas & Propagation

Ferroelectrics Letters Section, 2016

Earth Observing Missions and Sensors: Development, Implementation, and Characterization IV, 2016