Advances In Microwave Engineering
Dr. Kushal R. TuckleyChairman and Director R&D AGV systems
What Do We Mean By Microwave?
• Common Man: Microwave oven!
• Radio frequency used in TV Satellite link
• The Radio Frequency Used by Radars
• Some range of Radio Frequency
So we quickly look into the spectrum
RF and Microwave Spectrum
Applications of Microwaves• Communication : Space, Terrestrial• Broadcasting : Satellite TV• Navigation :GPS• Remote sensing : Earth and Astronomical Study• Radars : Strategic, Atmospheric• Dielectric Heating : Cooking, Disinfection• Instrumentation :Sensors, Detectors, Security• Spectroscopy : Chemical Measurements • Linear Accelerator : Medical and X-ray Imaging
Clear Air Atmospheric Radars: Working Principle
Indian MST RADARThe Indian Mesospheric Stratospheric & Tropospheric radar (MST) was designed developed and commissioned by SAMEER at Gadanki near
Tirupati in Andhra Pradesh Location: 13.4o N, 79.17 oE
Wind Profiler RASS IMD, Pune
Wind profiler Antenna
Doppler Weather Radar
IONOSPHEREThe ionosphere is the partially ionized region of the atmosphere. It is present at heights of about 60 km to 450 Km. It is divided into different layers or regions; D, E, F1 and F2. These regions correspond to different altitude, composition and electron density levels. In the nighttime, there is no solar radiation to produce ionization, so recombination makes the D, E and F1 layers disappear. Typical daytime and nighttime profiles are shown in the figure.The F2 layer does not disappear at sunset, instead its density slowly decreases throughout the night.
Ionosonde for Earthquake Prediction?!
Antenna for vertical Ionospheric Sounding
Antenna’s for vertical Ionospheric Sounding are crucial element in the general design. The Following things are crucial for Tx and Rx antenna’s”The Tx and Rx antenna’s have to be wide band due to the wide frequency range.The main radiation lobe needs to be directed towards the zenith.
Ionosonde Transmit Antenna
Conventional Transmit Antenna
baluns
Co‐ax feed line to Tx & Rx
mast24m
Termination box
Insulated support,Two on each arm
Double Delta Transmit Antenna
Receive Antenna
Magnetic loop turnstile antenna
Arranged in orthogonal planes
Provides polarization of the received radiation
Antenna elements are arranged in 4 or 7 antenna patterns.
Configuration of Receive antennas
functional block Diagram of Ionosonde
PCI BUS
ADC
POLARIZATIONSWITCH
TX/RX SWITCH
BPF
LNA
POLARISATION SWITCH
TX/RX SWITCH
BPF
LNA
POLARISATION SWITCH
TX/RX SWITCH
BPF
LNA
POLARISATION SWITCH
TX/RX SWITCH
BPF
LNA
ADC ADC ADC
DDC DDC
FPGA
PCI BUS PCI BUS
FPGA
PCI BUS
POWER AMPLIFIER
BPF
SYNTHESIZER & CODE GENERATOR
REFERENCE CLOCK GENERATOR
SWITCH
Transmitter Receiver
The Ionogram studies
The Echoes from Ionosphere are Obtained by sweeping the Frequency 1MHz to 20MHzNormal Echoes are circularly polarized as the transmit wave. They indicate the layer boundaries. Whereas the extraordinary echoes are a circularly polarised in other direction.
IonosondeThese are HF radars for Ioniospheric Studies
Facilities in India
Over The Horizon Radar (SkyWave)These HF radars use Ionosphere as a mirror to detect the targets.They offer very large range and hence of strategically great importance
Working Principle
OTH Radar Working Principle
OTH Coverage USA
OTH Sea Wave Transmit Antenna Array
Bangor ANGB, ME,USA
Relocatable OTH Radar station(N/TPS‐71 ROTHR, Receiver array)
OTH (sea-wave) Radar1. Vertically Polarised EM wave
Propagates along the sea surface beyond the horizon
2. Detection of targets up to 300 Km is possible
HF antenna Array
Propagating Wave
Sea Surface
Earth
Relocatable OTH Radar station(US Navy)
Sea Monitoring Radars
Motivation
Operating Principle
Orthogonal Antennas for Direction Finding
Transmit antenna Receive Antenna
Antenna Pattern of Cross-polar Dipoles
BASEBANDAMP.
LPF
The spectrum analysis and oceanographic interpretation system
DIGITAL CONTROL
UNIT
SYSTEM CLOCK
OSCILLATOR
PC
CONTROL SIGNALS
HARMONIC FILTER
DDS
POWER AMP
SWITCHING CIRCUIT
TRANSMITTER ANTENNA
DC DC CONVERTOR to all the blocks
LIMITER FILTER
LNASWITCH
AGC AMP
RECEIVER ANTENNA
LIMITER FILTER
LNASWITCH
LNASWITCH
LIMITER FILTER
AGC AMP
AGC AMP
MIXER
ANALOG TO DIGITAL
CONVERSION
BLOCK DIAGRAM of SEA SONDE:
BASEBANDAMP.
LPF
BASEBANDAMP.
LPFMIXER
MIXER
DIGITALPROCESSOR & FPGA
Typical Doppler Spectrum of Seasonde
Spectrum ‘X’ channel Spectrum ‘Y’ Channel
SeaSonde Data Presentation
Single Seasonde
Combination of Two Seasonde
Coastal Ocean Dynamic Application Radars(Locations in the US)
C-Band TT&C Transponder – Receiver Bottom Deck-Microwave Subsystems 2
C-Band TT&C Transponder – Receiver Middle DeckDeck-Microwave Subsystems-1
Linear Accelerator for Cancer Treatment
Internal Structure of LINAC Arm
LINAC Structure
Internal Field Distribution
Linear particle Acceleration by Microwaves
Internal Structure of a Cavity
6 MeV Stack (Brazed)
4 & 15 MeV Linac
Magnetic Resonance Imaging
Processing for MRI Pictures
External Magnetic Field (B)(Increasing Magnitude)
Frequency Sweep RF Pulsed Transceiver
(Radar Principle)
Resonant Frequency Response of
Specific Tissues is Proportional to the Magnetic
Field
MRI Pictures
Research Areas in Microwave Engineering(Numerical method of Computation)
• Efficient methods for numerical computation of electromagnetic scattering and antenna radiation.
• FDTD (Finite Difference Time Domain) software development.
• Radar cross section design for wide band applications
• Planar Near‐field Antenna Measurements
• Microwave Holography
• Planar antennas and arrays, e.g. for automotive radar • Ultra‐wide‐band antennas• Integrated antennas and lenses• Electromagnetic Interference suppression• Planar Near‐field Antenna Measurements• Efficiency in the use of power, spectrum utilization, ability to integrate and being compatible with other technologies
• Phase Retrieval for antenna metrology. Terahertz near‐field measurements
• Fractal Antennas
Research Areas in Microwave EngineeringAntenna Design and Measurements
Research Areas in Microwave Engineeringcomponents and systems
• Photonic Band Gap filters and antennas
• Active Antenna arrays
• Microwave cavity design for high Power application
• Adaptive Array design
• Transmit‐Receive module for radars
• Wide Band Phase shifters
• Disinfection using microwaves
• Frequency agile wide band transmitter
• Microwave assisted chemical reactions
• Effects of microwave radiation on plants and animals
Thank You All !!