Srikanta Pal Electromagnetics Scientist

Major Scientific Contributions to Radio Astronomy and Wireless Communication (of PAL)

  • World’s Largest Radio Telescope, GBT, US: Professor Pal solved an open scientific research problem on signal interference with giant Green Bank Telescope (110M diameter) at National Radio Astronomy Observatory in US. NRAO wanted to eradicate strong satellite digital audio radio signals (Sirius and XM) of various LEO satellites overloading the correlator digitizer in the front end of GBT, thereby stopping rotation of the telescope. The goal was to reduce these SDARS signals in the downstream signal processing paths to enhance observation range of the GBT. To meet this requirement, Dr. Pal, had developed two miniaturised bandstop filters based on novel elliptical designs on thin film based High Temperature Superconductors (HTS), in the University of Birmingham (U.K.).  These filters have extremely sharp 50 dB notch at the frequency of the very strong Sirius and XM satellite signals at 2.33 GHz with very low attenuation loss below 2.31 and above 2.35 GHz. Astronomers in NRAO, after installation of these filters in GBT S-band receiver front end are now able to use the telescope in 1.73 – 2.60 GHz (S-band) which they could not do since telescope’s inception. NRAO were extremely pleased to achieve excellent results (one order better rejection) for wideband pulsar observations and flashed this research news. The work is reported: IEEE Microwave and Wireless component letters, Vol. 22, No. 5, pp. 236-238, May 2012. University of Birmingham conferred upon him the title of ‘Honorary Research Fellow’ (HRF, 2010-2011, 2011-2012) for this major scientific feat; the research and the honour became a WORLD NEWS.
  •     World’s third-largest radio telescope, JBT, UK: Prof. Pal’s second significant scientific contribution was to aid the astronomers of the Jodrell Bank Radio Telescope (JBT) (76M diameter) in UK, to help observe and understand the moon’s surface and its underneath - “Could the crater floors contain deposits of water ice or other frozen volatiles?”. Astronomers in JBT required a very sharp bandpass filter to cut off all the adjacent band radio signals from various applications interfering with the L band receiver front end, allowing only the 430 MHz signal with 25 MHz bandwidth to pass through.

To meet these objectives, Dr. Pal developed miniaturised, elliptic HTS bandpass filters for 430 MHz radio frequency signal with 25 MHz bandwidth and very sharp roll off at passband edges, all by himself, at the University of Birmingham. Measured results of the developed filters obtained during his honorary research fellowship visit, shown no losses added into the system and had very sharp filtering characteristics of 60 dB roll-off in comparison to expected 40 dB. Technical report and the developed filters are submitted to JBT in 2012. University of Birmingham conferred upon him further the title of ’Honorary Research Fellow’ (2012-2014) for his second major scientific contribution. This research and the following conferred honour news became GLOBAL NEWS through print and electronic media.

  •     World’s smallest planar UWB antenna: Professor Pal developed super compact planar UWB antenna for short-range high-speed communications with his PhD scholar Mrinmay Chakraborty in the laboratories of BIT Mesra. This antenna has wide scale applications in indoor, military, medical etc. Development of smallest planar UWB antenna from INDIA became a HOT NEWS in print and visual media. Global giant Samsung Inc. and Georgia Institute of Technology had approached for the design in 2013. Recently the patent, tilted AN ULTRA-WIDEBAND ANTENNA AND PROCESS OF FABRICATION OF THE ANTENNA” Srikanta Pal, Mrinmoy Chakraborty, BIT Mesra is granted. Patent: 409866, Date of Grant: 26/10/2022, Date of Filing: 09/07/2013, Patent ID: 814/KOL/2013.  The patent news on the button-size wireless antenna is remarked to be as the “revolution in wireless technology which has huge potentials to replace existing Bluetooth technology in many applications. The invention is lauded by about a million professionals and created front page headline stories in national dailies.
  •    World’s smallest planar Infinity (OAM) antenna: Professor Pal has conceptualized a new antenna, named infinity antenna using interesting electromagnetic properties of newly discovered special kind of light, possessing Orbital Angular Momentum, for enabling theoretically possible infinite communication channels which gathered significant interest and appreciation in IEEE APMC conference, Dec 2016, Delhi.  His guidance to a scholar of SNU, Dadri on development of a simple miniaturized planar antenna generating pure OAM mode waves led to the development of a single radiation patch fed by a complex Power Division Network (PDN) based novel OAM antenna, which is also the smallest in dimensions, is appreciated and published in the top journal of IEEE of this research area - IEEE Antennas and wave propagation letters journal, April 2020. This antenna has the potential of replacing MIMO antennas and just to mention that this specific complex research produces the first doctoral thesis in this country, in Oct 2021. Many academic stalwarts including AICTE Chairman – acknowledging this contribution as “significant breakthrough and the research is well ahead of time” news.
  •     High performance Filter software (synthesis): Developed a specialised software to design filters with multiple passbands and stopbands with arbitrary resonators network topology. Pal during his post-doctoral research at BU (2006-08) initiated this research development with an aim to aid designing of highly selective filters (brick-wall characteristics) to avoid any crosstalk or interference, which is generally common. Both bandpass and bandstop parts of the software is now completely developed in BIT through several UG and PG students research projects of BIT and Calcutta University. The software calculates transmission and reflection characteristics and generates complete coupling matrix with optimized number of resonators and transmission zeros, which is helpful to design extremely sharp (brick-wall frequency characteristics) filters with less volume, essential for future communication engineering. Integration of bandpass and bandstop filter parts is undergoing and will be developed soon.