Dr. S. Raghavan
National Institute of Technology, India
Title: Microwave Integrated Circuit Components up to THz Design Made Easy
Abstract:
“It
was in the late 1940s and early 1950s, when the microwave technology was
beginning to emerge from the cocoon of war time secrecy that its applications
started encompassing the non-military fields as well Since then, the entire
field of microwaves has undergone tremendous revolution both in terms of
techniques and technologies” _Prof.Bharathi Bhat (International pioneer in
Microwave Integrated Circuits_M.I.C.s). The 1950s saw the entry of a new era of
microwave semiconductor technology. The availability of small size
semiconductor devices made it necessary to look for transmission media
compatible with these devices. The answer was given by “Planar transmission
line”. Skin depth at higher frequencies also found an indispensable need in the
usage of ‘Planar transmission lines’ which formed the backbones of Microwave
Integrated Circuits. M.I.C.s played an unparalleled technology when Waveguides
found lesser preference. The planar transmission lines include Stripline, Microstripline, Slot line, Coplanar waveguide
(CPW), Coplanar Strip(CPS), Finline and the variants of each transmission line
like “inverted’. ‘V-groove’, ‘suspended’ etc. Substrate Integrated Waveguide(S
I W) acts as the bridge between waveguide and planar transmission lines.
Frequency Selective Surfaces (F S S) too are the present hot field technology.
It will be shown that designing of M.I.C. components (Stub branch line couplers
Backward wave couplers, Hybrid ring, Equal and Unequal Power dividers and
Combiners etc.) up to THz are simply EASY as long as the Microwave Theory is
followed with thorough understanding. Transmission lines being distributed
network, initially the lumped equivalent of the corresponding stubs are
obtained. .Initially ‘S’ matrix is obtained from the effective chain parameters
and every stub is expressed in terms of the admittance and then Impedance. While
designing the M.I.C. components three dimensions length (l), Width (w) and
height (h) are to be determined. Out of three ‘h’ is
taken care of by the substrate manufacturers (default being 1/16 “). Length is
mostly in terms of guide wavelength (λg) which takes care of any
material (since €eff is used) and frequency .Guide wavelength does
miracles in the function of M.I.C.component design. There are infinite lambdas
from ‘0’ to “lambda”. Transmission line equation will make one know the
application of each length of a transmission line. The width ‘w’ is based on
the characteristic impedance or even mode and odd mode impedances. Suitable
nomograms are then used. Well defined closed form expressions are there .Matlab
or Python programming can be used for self-coding. The layout of the components
can be got with 100 % dimensional accuracy. Once the components are designed, systems
(E.g. Mixer, Antennae, all types of filters, transponders etc) can be
generated. When needed, even mode and odd mode analysis are taken for the
analysis. FINALLY LAYOUT DESIGN IS OBTAINED WHICH CAN DIRECTLY BE TRANSFERRED
FOR FABRICATION PROCESS.
Biography:
Dr. S. Raghavan Professor in Electronics and Communication Engineering
Department, National Institute of Technology (N.I.T.), Trichy has 35 years of teaching
and research experience. His interest includes Microwave Integrated Circuits, RF MEMS,
BioMEMS, Metamaterial and Microwave Engineering. A proud research scholar of Prof.
Bharathi Bhat and Prof. S K Koul, CARE, IIT Delhi, has established state of the art
Microwave Integrated Circuit and Microwave Laboratory in N.I.T., Trichy with the help of
Govt. of India funding. Won Best Teacher award twice and conferred with Honorary
Fellowship of Ancient Sciences and Archaeological Society of India, His first Research
Scholar obtained a Gold medal for the Best Thesis of the year. Short time visiting Fellow
in California State University, North Ridge, USA. Awarded to conduct Tutorial in APEMC
2010, Beijing, China. Organizing Chair of ‘Indian Antenna Week 2014’, Chandigarh.
Invited to be a session chair in PIERS 2013 symposium Taipei, Taiwan. Has to his credit
123 research papers in national and International Journals, 94 in IEEE Explore, 132
International conferences, 28 National conferences. Also, filed 3 patents. Guided 16 PhD
scholars. Senior Member/Fellow in more than 20 international and national Professional
Societies including IEEE, BES, IEI, IETE, CSI, TSI, ISTE, ISSS, NPC ISOI, ILA,
IELTS and ASI. Organized various workshops of national importance. Has contributed lot
in the development of state of the art Library (instrumental in the plan of the new
Multistoried Library building as the then Library Coordinator) and Hospital (changed a
clinical Dispensary into a 24 Hour hospital as the then Chairman of the Hospital
Modernization committee) in NIT-T. He is an Executive Member of TSI and also in the
Tamil Nadu Chapter of TSI. Also, the founding faculty advisor of IEEE MTT and APS
student branch Chapters NIT Trichy. S. Raghavan is the author of Microwave Integrated
Circuit Components Design through MATLAB. He Was the President of R.E.C., Trichy
Faculty association for 2 years. Made an impact in MICROWAVE ENGINEERING
EDUCATION among the student community at large.