Dr P K Jain | IT BHU (original) (raw)

Papers by Dr P K Jain

The Journal of Physical Chemistry C, 2007

International Journal of Electronics, 1999

A cylindrical waveguide, provided with wedge-shaped metal vanes projecting radially inward from t... more A cylindrical waveguide, provided with wedge-shaped metal vanes projecting radially inward from the wall of the guide, excited in the transverse electric (TE) mode, was analysed. The analysis was carried out considering the angular harmonics generated by the angular positioning ...

IETE Technical Review, 1993

ABSTRACT The analytical approaches developed by the authors to the problem of a helical slow-wave... more ABSTRACT The analytical approaches developed by the authors to the problem of a helical slow-wave structure of a travelling-wave tube (TWT) are reviewed. Models developed take into account the effects of the finite thickness of the helix, the discrete dielectric support bars/rods for the helix, the proximity of a metal envelope, the finite resistivities of the metallic parts and attenuator coating on helix supports. The analysis is effective in studying the anisotropic, the inhomogeneous and the distributed-attenuator loading of the helix each of which has a relevance to broadhanding a TWT for electronic warfare applications.

2007 Joint 32nd International Conference on Infrared and Millimeter Waves and the 15th International Conference on Terahertz Electronics, 2007

In the present communication, authors analyzed eigen-frequency and ohmic quality factor of cylind... more In the present communication, authors analyzed eigen-frequency and ohmic quality factor of cylindrical cavity resonator, operating in azimuthally symmetrical mode (TE03), for potential application in gyrotron oscillators. Eigen-frequency and ohmic quality factor has been calculated analytically, the results have been validated with the results obtained from MAGIC simulation software. Ohmic quality factor obtained for tapered cavity have been used to study the effect of structure dimensions like length of mid-section of the cavity, input taper angle and output taper angle. It is found that the ohmic quality factor increases with decrease of the length of mid-section and input taper angle, and with the increase of output taper angle. Out of input and output taper angles, the later was found more sensitive controlling parameter for the ohmic quality factor as well as for ohmic wall losses. Furthermore, the vector fields have been plotted for the mid-section of the cavity to help achieve optimum device operation.

IEEE Transactions on Electron Devices, 1988

ABSTRACT

International Journal of Infrared and Millimeter Waves, 2000

The gyro-TWT in a cylindrical waveguide of linearly-tapered cross section was analyzed for the ga... more The gyro-TWT in a cylindrical waveguide of linearly-tapered cross section was analyzed for the gain-frequency response, using the Pierce-type gain equation. The taper in the waveguide cross section was adjusted for wide device bandwidths, either by changing the taper angle, while keeping the interaction length to be constant, or by changing the interaction length, while keeping the initial and final

Microwave and Optical Technology Letters, 2000

d s 0.5d in Eqs. 26 ᎐ 29 2 and the convergence and accuracy features were found to be essentially... more d s 0.5d in Eqs. 26 ᎐ 29 2 and the convergence and accuracy features were found to be essentially the same. V. CONCLUSIONS A simple algorithm that allows an inexpensive and accurate computation of leaky-wave poles for grounded inhomogeneous dielectric slabs has been presented. The proposed method relies on a rigorous derivation of the relevant TREs, which are solved using an efficient Pade-approximant-based root-finding procedure in the complex plane. Numerical simulations, involving single-and two-layer profiles, show that the proposed method is attractive in terms of accuracy, computational budget, and implementation ease. Worthwhile extensions, presently under investigation, in-Ž. volve bi anisotropic layers and cylindrical geometries.

International Journal of Infrared and Millimeter Waves, 2007

In the method of tapering the cross section of the interaction structure for broadbanding a gyro-... more In the method of tapering the cross section of the interaction structure for broadbanding a gyro-TWT, the different portions of the interaction length of the taperedcross-section waveguide become effective for different frequency ranges if the magnetic field and beam parameters are profiled to maintain the condition of electron cyclotron resonance throughout the interaction length. In the present paper, the study of profiling the magnetic field and beam parameters in steps of the stepped analytical model of a double-tapered discloaded circular waveguide was made throughout the steps of the model. In the observed profile, the magnetic flux density in a typical step relative to its value in first-step decreases from first-step (gun-end) to end-step (collector-end) of the model considering the up-tapering schemes, in which structure parameters increase from gun-end to collector-end. Also, the transverse beam velocity in a typical step relative to its value in first-step decreases from gunend to collector-end. However, the Larmor radius in a typical step relative to its value in firststep as well as the hollow-beam radius in a typical step relative to its value in first-step, both increase from gun-end to collector-end in the model considering the up-tapering schemes.

Journal of Electromagnetic Waves and Applications, 1998

Journal of Fusion Energy, 2013

A three dimensional particle-in-cell code MAGIC-3D has been used to study the output performance ... more A three dimensional particle-in-cell code MAGIC-3D has been used to study the output performance improvement of a relativistic magnetron through simultaneous use of electric priming and magnetic field perturbation techniques. The side resonators of the resonant structure have been loaded symmetrically at angle of 120°with low-loss annular shaped dielectric to implement the electric field priming alternating with metal rods to perturb the RF magnetic field. All the simulations have been performed on the well known A6 relativistic magnetron for 2p-mode of operation. The results indicate that single 2p-mode operation with 30 % reduction in startup time and 12 % improvement in radiated output power can be achieved through electric priming by loading the RF resonators with annular shaped low-loss dielectric and magnetic field perturbation with 3-metal rods.

2006 7th International Symposium on Antennas, Propagation & EM Theory, 2006

... Vishal Kesari*, PK Jain, and BN Basu Centre of Research in Microwave Tubes, Department of Ele... more ... Vishal Kesari*, PK Jain, and BN Basu Centre of Research in Microwave Tubes, Department of Electronics Engineering, Institute of Technology Banaras Hindu University, Varanasi - 221 005, India, *vishal kesarigrediffmail.com ... [2] MV Kartikeyan, CT Iatrou and M. Thumm, "A ...

IEEE Transactions on Electron Devices, 1987

A helix, supported by a number of longitudinal dielectric support rods of circular cross section ... more A helix, supported by a number of longitudinal dielectric support rods of circular cross section enclosed in a glassldielectric tube envelope, is field analyzed for dispersion characteristics, treating the support rods as a continuous homogeneous dielectric of an effective permittivity suitably interpreted in terms of the support parameters. Measurements are made on two typical structures in two different frequency ban& for dispersion characteristics. The experimental observations agree very closely with the theoretical prediction when the effect of the finiteness of the helix-wire thickness is taken into consideration in the analysis. A calculation of interaction impedance adds a relevance to the problem.

Applied Optics, 2020

A magnetically tunable metasurface comprising meta-atoms with InSb-patched, InAs-patched, and unp... more A magnetically tunable metasurface comprising meta-atoms with InSb-patched, InAs-patched, and unpatched pixels was simulated using commercial software to maximize the absorption of normally incident radiation in the terahertz spectral regime, with the patches decorating the illuminated face of a gold-backed polyimide substrate. Maximum absorptance of 0.99 and minimum absorptance of 0.95 can be obtained in 0.14–0.23-THz-wide bands in the 2–4-THz spectral regime, with an average tuning rate of and 0.24-THz dynamic range when the controlling magnetostatic field is aligned parallel to the incident electric field. The use of both InSb and InAs patches is much superior to the use of patches of only one of those materials. The design can be adapted for neighboring spectral regimes by exploiting the scale invariance of the Maxwell equations.

Journal of Electromagnetic Waves and Applications, 2000

ABSTRACT The analysis of a lossless helical slow-wave structure (SWS) using equivalent circuit ap... more ABSTRACT The analysis of a lossless helical slow-wave structure (SWS) using equivalent circuit approach, reported elsewhere, had been carried out for the fundamental mode only. This is essentially used to predict the transmission line parameters. Moreover, in the analysis the effect of permittivity on the radial propagation constant has not been considered. The radial propagation constant was considered to be same over the different structure regions. In this paper, the analysis has been developed for the space-harmonic modes considering different radial propagation constant over different structure regions. Due to it, the present analysis becomes more general, accurate and capable of dealing with a wide range of structure parameters. The dispersion relation developed here in terms of the equivalent line parameters for a lossless structure, namely, shunt capacitance per unit length and series inductance per unit length for the space-harmonic modes, as a special case, passes on to those obtained earlier by considering same radial propagation constants over different structure regions and for the fundamental mode. Besides the dispersion characteristics, characteristics impedance has also been predicted in terms of line parameters. The results presented here in terms of the structure parameters can be used

IEE Proceedings H Microwaves, Antennas and Propagation

... R. Verma, RK Gupta, L. Kumar and SN Joshi are wlth Central Electronics Engineering Research I... more ... R. Verma, RK Gupta, L. Kumar and SN Joshi are wlth Central Electronics Engineering Research Institute (CEERI), Pilani, 333031, India PK Jain and B N ... of obtaining the tape-model results for a arbitrarily loaded helix suggested in this paper is highly simplified in the ...

This paper in detail presents the analytical study of modulating cavity of Reltron.It has three d... more This paper in detail presents the analytical study of modulating cavity of Reltron.It has three different modes, i.e.,0, π/2 and π in accordance with their electric field patterns. Equivalent circuit analysis is done to get the better understanding of the electron beam modulator. To validate the theoretical analysis,CST Microwave Studio is used for cold test simulation.

IETE Technical Review, 2002

The cold as well as hot dispersion relation for a gyro-TWT employing a cylindrical waveguide load... more The cold as well as hot dispersion relation for a gyro-TWT employing a cylindrical waveguide loaded with a dielectric lining on its wall was obtained. An improved approach was given where the effect of dielectric loading was incorporated in the deduction of the hot dispersion relation rather than in an earlier approximate approach where the effect had been considered only in the deduction of the cold dispersion relation. The hot dispersion relation was used to obtain Pierce-type gain expression. The dielectric lining with optimally chosen permittivity and thickness values provided an improvement with respect to the gain as well as bandwidth of the device as compared to a dielectric-free, unloaded device. The gain-frequency responses predicted by the approximate and improved approaches differed more as the permittivity and the thickness of the dielectric lining increased, though the other relevant device parameters like the optimum beam position for maximum gain did not appreciably differ.

2009 International Conference on Emerging Trends in Electronic and Photonic Devices & Systems, 2009

... Experiment S Umamaheswara Reddy, P. Raja Ramana Rao, Bhanu Naidu, and Lalit Kumar Microwave T... more ... Experiment S Umamaheswara Reddy, P. Raja Ramana Rao, Bhanu Naidu, and Lalit Kumar Microwave Tube Research and Development Centre, Bharat Electronics Complex, Jalahalli PK Jain Department of Electronics Engineering, Banaras Hindu University, Varanasi, India ...

2011 IEEE Applied Electromagnetics Conference (AEMC), 2011

ABSTRACT

Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2012

ABSTRACT In this study, composite powder (MEC1031C) was modified with the addition of 0.4 wt.% La... more ABSTRACT In this study, composite powder (MEC1031C) was modified with the addition of 0.4 wt.% La2O3. The effects of La2O3 addition on microstructure, formation of new phases, and microhardness were studied. The La2O3 addition refines the microstructure, forms new phases, and increases microhardness of high-velocity oxy-fuel (HVOF) coatings. The erosive wear behaviours of HVOF-sprayed coatings were investigated by response surface methodology. To investigate and develop the erosive wear model of unmodified (without La2O3) and modified (La2O3 addition) HVOF-sprayed coatings, four factors, velocity (V), impact angle (A), temperature (T), and feed rate (F), with each factor at three levels, were used. Analysis of variance was carried out to determine the significant factors and interactions. Investigation showed that the velocity, temperature, and feed rate were the main significant factors, while velocity–feed rate was the main significant interaction. Thus, an erosive wear model was developed in terms of main factors and their significant interactions. The validity of the model was evaluated by conducting experiments under different wear conditions. A comparison of modelled and experimental results showed 5–11 per cent error. The modified (La2O3 addition) HVOF-sprayed coating showed high erosive wear resistance compared to unmodified coating. This is due to the increase in hardness of the modified coating.

The Journal of Physical Chemistry C, 2007

International Journal of Electronics, 1999

A cylindrical waveguide, provided with wedge-shaped metal vanes projecting radially inward from t... more A cylindrical waveguide, provided with wedge-shaped metal vanes projecting radially inward from the wall of the guide, excited in the transverse electric (TE) mode, was analysed. The analysis was carried out considering the angular harmonics generated by the angular positioning ...

IETE Technical Review, 1993

ABSTRACT The analytical approaches developed by the authors to the problem of a helical slow-wave... more ABSTRACT The analytical approaches developed by the authors to the problem of a helical slow-wave structure of a travelling-wave tube (TWT) are reviewed. Models developed take into account the effects of the finite thickness of the helix, the discrete dielectric support bars/rods for the helix, the proximity of a metal envelope, the finite resistivities of the metallic parts and attenuator coating on helix supports. The analysis is effective in studying the anisotropic, the inhomogeneous and the distributed-attenuator loading of the helix each of which has a relevance to broadhanding a TWT for electronic warfare applications.

2007 Joint 32nd International Conference on Infrared and Millimeter Waves and the 15th International Conference on Terahertz Electronics, 2007

In the present communication, authors analyzed eigen-frequency and ohmic quality factor of cylind... more In the present communication, authors analyzed eigen-frequency and ohmic quality factor of cylindrical cavity resonator, operating in azimuthally symmetrical mode (TE03), for potential application in gyrotron oscillators. Eigen-frequency and ohmic quality factor has been calculated analytically, the results have been validated with the results obtained from MAGIC simulation software. Ohmic quality factor obtained for tapered cavity have been used to study the effect of structure dimensions like length of mid-section of the cavity, input taper angle and output taper angle. It is found that the ohmic quality factor increases with decrease of the length of mid-section and input taper angle, and with the increase of output taper angle. Out of input and output taper angles, the later was found more sensitive controlling parameter for the ohmic quality factor as well as for ohmic wall losses. Furthermore, the vector fields have been plotted for the mid-section of the cavity to help achieve optimum device operation.

IEEE Transactions on Electron Devices, 1988

ABSTRACT

International Journal of Infrared and Millimeter Waves, 2000

The gyro-TWT in a cylindrical waveguide of linearly-tapered cross section was analyzed for the ga... more The gyro-TWT in a cylindrical waveguide of linearly-tapered cross section was analyzed for the gain-frequency response, using the Pierce-type gain equation. The taper in the waveguide cross section was adjusted for wide device bandwidths, either by changing the taper angle, while keeping the interaction length to be constant, or by changing the interaction length, while keeping the initial and final

Microwave and Optical Technology Letters, 2000

d s 0.5d in Eqs. 26 ᎐ 29 2 and the convergence and accuracy features were found to be essentially... more d s 0.5d in Eqs. 26 ᎐ 29 2 and the convergence and accuracy features were found to be essentially the same. V. CONCLUSIONS A simple algorithm that allows an inexpensive and accurate computation of leaky-wave poles for grounded inhomogeneous dielectric slabs has been presented. The proposed method relies on a rigorous derivation of the relevant TREs, which are solved using an efficient Pade-approximant-based root-finding procedure in the complex plane. Numerical simulations, involving single-and two-layer profiles, show that the proposed method is attractive in terms of accuracy, computational budget, and implementation ease. Worthwhile extensions, presently under investigation, in-Ž. volve bi anisotropic layers and cylindrical geometries.

International Journal of Infrared and Millimeter Waves, 2007

In the method of tapering the cross section of the interaction structure for broadbanding a gyro-... more In the method of tapering the cross section of the interaction structure for broadbanding a gyro-TWT, the different portions of the interaction length of the taperedcross-section waveguide become effective for different frequency ranges if the magnetic field and beam parameters are profiled to maintain the condition of electron cyclotron resonance throughout the interaction length. In the present paper, the study of profiling the magnetic field and beam parameters in steps of the stepped analytical model of a double-tapered discloaded circular waveguide was made throughout the steps of the model. In the observed profile, the magnetic flux density in a typical step relative to its value in first-step decreases from first-step (gun-end) to end-step (collector-end) of the model considering the up-tapering schemes, in which structure parameters increase from gun-end to collector-end. Also, the transverse beam velocity in a typical step relative to its value in first-step decreases from gunend to collector-end. However, the Larmor radius in a typical step relative to its value in firststep as well as the hollow-beam radius in a typical step relative to its value in first-step, both increase from gun-end to collector-end in the model considering the up-tapering schemes.

Journal of Electromagnetic Waves and Applications, 1998

Journal of Fusion Energy, 2013

A three dimensional particle-in-cell code MAGIC-3D has been used to study the output performance ... more A three dimensional particle-in-cell code MAGIC-3D has been used to study the output performance improvement of a relativistic magnetron through simultaneous use of electric priming and magnetic field perturbation techniques. The side resonators of the resonant structure have been loaded symmetrically at angle of 120°with low-loss annular shaped dielectric to implement the electric field priming alternating with metal rods to perturb the RF magnetic field. All the simulations have been performed on the well known A6 relativistic magnetron for 2p-mode of operation. The results indicate that single 2p-mode operation with 30 % reduction in startup time and 12 % improvement in radiated output power can be achieved through electric priming by loading the RF resonators with annular shaped low-loss dielectric and magnetic field perturbation with 3-metal rods.

2006 7th International Symposium on Antennas, Propagation & EM Theory, 2006

... Vishal Kesari*, PK Jain, and BN Basu Centre of Research in Microwave Tubes, Department of Ele... more ... Vishal Kesari*, PK Jain, and BN Basu Centre of Research in Microwave Tubes, Department of Electronics Engineering, Institute of Technology Banaras Hindu University, Varanasi - 221 005, India, *vishal kesarigrediffmail.com ... [2] MV Kartikeyan, CT Iatrou and M. Thumm, "A ...

IEEE Transactions on Electron Devices, 1987

A helix, supported by a number of longitudinal dielectric support rods of circular cross section ... more A helix, supported by a number of longitudinal dielectric support rods of circular cross section enclosed in a glassldielectric tube envelope, is field analyzed for dispersion characteristics, treating the support rods as a continuous homogeneous dielectric of an effective permittivity suitably interpreted in terms of the support parameters. Measurements are made on two typical structures in two different frequency ban& for dispersion characteristics. The experimental observations agree very closely with the theoretical prediction when the effect of the finiteness of the helix-wire thickness is taken into consideration in the analysis. A calculation of interaction impedance adds a relevance to the problem.

Applied Optics, 2020

A magnetically tunable metasurface comprising meta-atoms with InSb-patched, InAs-patched, and unp... more A magnetically tunable metasurface comprising meta-atoms with InSb-patched, InAs-patched, and unpatched pixels was simulated using commercial software to maximize the absorption of normally incident radiation in the terahertz spectral regime, with the patches decorating the illuminated face of a gold-backed polyimide substrate. Maximum absorptance of 0.99 and minimum absorptance of 0.95 can be obtained in 0.14–0.23-THz-wide bands in the 2–4-THz spectral regime, with an average tuning rate of and 0.24-THz dynamic range when the controlling magnetostatic field is aligned parallel to the incident electric field. The use of both InSb and InAs patches is much superior to the use of patches of only one of those materials. The design can be adapted for neighboring spectral regimes by exploiting the scale invariance of the Maxwell equations.

Journal of Electromagnetic Waves and Applications, 2000

ABSTRACT The analysis of a lossless helical slow-wave structure (SWS) using equivalent circuit ap... more ABSTRACT The analysis of a lossless helical slow-wave structure (SWS) using equivalent circuit approach, reported elsewhere, had been carried out for the fundamental mode only. This is essentially used to predict the transmission line parameters. Moreover, in the analysis the effect of permittivity on the radial propagation constant has not been considered. The radial propagation constant was considered to be same over the different structure regions. In this paper, the analysis has been developed for the space-harmonic modes considering different radial propagation constant over different structure regions. Due to it, the present analysis becomes more general, accurate and capable of dealing with a wide range of structure parameters. The dispersion relation developed here in terms of the equivalent line parameters for a lossless structure, namely, shunt capacitance per unit length and series inductance per unit length for the space-harmonic modes, as a special case, passes on to those obtained earlier by considering same radial propagation constants over different structure regions and for the fundamental mode. Besides the dispersion characteristics, characteristics impedance has also been predicted in terms of line parameters. The results presented here in terms of the structure parameters can be used

IEE Proceedings H Microwaves, Antennas and Propagation

... R. Verma, RK Gupta, L. Kumar and SN Joshi are wlth Central Electronics Engineering Research I... more ... R. Verma, RK Gupta, L. Kumar and SN Joshi are wlth Central Electronics Engineering Research Institute (CEERI), Pilani, 333031, India PK Jain and B N ... of obtaining the tape-model results for a arbitrarily loaded helix suggested in this paper is highly simplified in the ...

This paper in detail presents the analytical study of modulating cavity of Reltron.It has three d... more This paper in detail presents the analytical study of modulating cavity of Reltron.It has three different modes, i.e.,0, π/2 and π in accordance with their electric field patterns. Equivalent circuit analysis is done to get the better understanding of the electron beam modulator. To validate the theoretical analysis,CST Microwave Studio is used for cold test simulation.

IETE Technical Review, 2002

The cold as well as hot dispersion relation for a gyro-TWT employing a cylindrical waveguide load... more The cold as well as hot dispersion relation for a gyro-TWT employing a cylindrical waveguide loaded with a dielectric lining on its wall was obtained. An improved approach was given where the effect of dielectric loading was incorporated in the deduction of the hot dispersion relation rather than in an earlier approximate approach where the effect had been considered only in the deduction of the cold dispersion relation. The hot dispersion relation was used to obtain Pierce-type gain expression. The dielectric lining with optimally chosen permittivity and thickness values provided an improvement with respect to the gain as well as bandwidth of the device as compared to a dielectric-free, unloaded device. The gain-frequency responses predicted by the approximate and improved approaches differed more as the permittivity and the thickness of the dielectric lining increased, though the other relevant device parameters like the optimum beam position for maximum gain did not appreciably differ.

2009 International Conference on Emerging Trends in Electronic and Photonic Devices & Systems, 2009

... Experiment S Umamaheswara Reddy, P. Raja Ramana Rao, Bhanu Naidu, and Lalit Kumar Microwave T... more ... Experiment S Umamaheswara Reddy, P. Raja Ramana Rao, Bhanu Naidu, and Lalit Kumar Microwave Tube Research and Development Centre, Bharat Electronics Complex, Jalahalli PK Jain Department of Electronics Engineering, Banaras Hindu University, Varanasi, India ...

2011 IEEE Applied Electromagnetics Conference (AEMC), 2011

ABSTRACT

Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2012

ABSTRACT In this study, composite powder (MEC1031C) was modified with the addition of 0.4 wt.% La... more ABSTRACT In this study, composite powder (MEC1031C) was modified with the addition of 0.4 wt.% La2O3. The effects of La2O3 addition on microstructure, formation of new phases, and microhardness were studied. The La2O3 addition refines the microstructure, forms new phases, and increases microhardness of high-velocity oxy-fuel (HVOF) coatings. The erosive wear behaviours of HVOF-sprayed coatings were investigated by response surface methodology. To investigate and develop the erosive wear model of unmodified (without La2O3) and modified (La2O3 addition) HVOF-sprayed coatings, four factors, velocity (V), impact angle (A), temperature (T), and feed rate (F), with each factor at three levels, were used. Analysis of variance was carried out to determine the significant factors and interactions. Investigation showed that the velocity, temperature, and feed rate were the main significant factors, while velocity–feed rate was the main significant interaction. Thus, an erosive wear model was developed in terms of main factors and their significant interactions. The validity of the model was evaluated by conducting experiments under different wear conditions. A comparison of modelled and experimental results showed 5–11 per cent error. The modified (La2O3 addition) HVOF-sprayed coating showed high erosive wear resistance compared to unmodified coating. This is due to the increase in hardness of the modified coating.