Question 1(a) [3 marks]

List different microwave bands with their frequency range.

Answer:

Table: Microwave Frequency Bands

Band	Frequency Range	Wavelength
L Band	1-2 GHz	30-15 cm
S Band	2-4 GHz	15-7.5 cm
C Band	4-8 GHz	7.5-3.75 cm
X Band	8-12 GHz	3.75-2.5 cm
Ku Band	12-18 GHz	2.5-1.67 cm
K Band	18-27 GHz	1.67-1.11 cm
Ka Band	27-40 GHz	1.11-0.75 cm

Mnemonic: "Large Ships Can eXamine Kindly Using Knowledge Always"

Question 1(b) [4 marks]

Draw the general equivalent circuit of the transmission line. Write the equation for characteristic impedance for a lossless line.

Answer:

Transmission Line Equivalent Circuit:

    R      L
  ----▬▬▬▬----
 |             |
 |      C      | G
 |    -----    |
 |             |
  -------------
      dx

Circuit Elements:

R: Series resistance per unit length
L: Series inductance per unit length
C: Shunt capacitance per unit length
G: Shunt conductance per unit length

For Lossless Line (R = 0, G = 0):

Characteristic Impedance: Z₀ = √(L/C)

Key Points:

Lossless condition: No power loss during transmission
Impedance matching: Z₀ determines reflection behavior

Mnemonic: "Lossless Lines Love Constant Impedance"

Question 1(c) [7 marks]

Explain the impedance matching process using a single stub.

Answer:

Single Stub Matching Process:

graph LR
    A[Source] --> B[Main Line]
    B --> C[Stub Connection Point]
    C --> D[Load]
    C --> E[Short Stub]

Matching Steps:

Step	Process	Purpose
1	Calculate load admittance	Find Y_L = 1/Z_L
2	Move toward generator	Find point where G = G₀
3	Add stub susceptance	Cancel reactive part
4	Achieve matching	Y_total = Y₀

Design Equations:

Distance to stub: d = (λ/2π) × tan⁻¹(√(R_L/R₀))
Stub length: l = (λ/2π) × tan⁻¹(B_stub/Y₀)

Applications:

Antenna matching
Amplifier input/output
Filter design

Mnemonic: "Single Stubs Stop Standing Waves Successfully"

Question 1(c) OR [7 marks]

Compare rectangular and circular waveguides.

Answer:

Comparison Table:

Parameter	Rectangular Waveguide	Circular Waveguide
Shape	Rectangular cross-section	Circular cross-section
Dominant Mode	TE₁₀	TE₁₁
Cutoff Frequency	fc = c/(2a) for TE₁₀	fc = 1.841c/(2πa) for TE₁₁
Power Handling	Lower	Higher
Manufacturing	Easy	Difficult
Mode Separation	Good	Poor
Applications	Radar, microwave ovens	Satellite communication

Key Advantages:

Rectangular: Better mode control, easier fabrication
Circular: Higher power capacity, rotating polarization

Mnemonic: "Rectangular is Regular, Circular Carries Current"

Question 2(a) [3 marks]

Define group velocity and phase velocity in relation to them.

Answer:

Velocity Definitions:

Velocity Type	Formula	Physical Meaning
Phase Velocity	vₚ = ω/β = c/√(1-(fc/f)²)	Speed of constant phase
Group Velocity	vₘ = dω/dβ = c√(1-(fc/f)²)	Speed of signal energy

Relationship: vₚ × vₘ = c²

Key Points:

Phase velocity: Always > c (speed of light)
Group velocity: Always < c
Signal travels: At group velocity

Mnemonic: "Phase is Fast, Group Carries Message"

Question 2(b) [4 marks]

Describe the principles and workings of the Directional coupler.

Answer:

Directional Coupler Principle:

graph TD
    A[Port 1 - Input] --> B[Main Line]
    B --> C[Port 2 - Through]
    B --> D[Port 3 - Coupled]
    E[Port 4 - Isolated] --> F[Terminated]

Working Principle:

Electromagnetic coupling between two transmission lines
Power division based on coupling factor
Directional sensitivity to wave direction

Key Parameters:

Coupling Factor: C = 10 log(P₁/P₃) dB
Directivity: D = 10 log(P₃/P₄) dB
Insertion Loss: IL = 10 log(P₁/P₂) dB

Mnemonic: "Directional Couplers Divide Power Precisely"

Question 2(c) [7 marks]

Explain Magic TEE with construction, operation and application.

Answer:

Magic TEE Construction:

         E-Arm (Port 3)
              |
              |
    Port 1----+----Port 2
              |
              |
         H-Arm (Port 4)

Operating Principles:

Port	Function	Field Pattern
Port 1 & 2	Collinear ports	Symmetric
Port 3 (E-Arm)	E-plane port	Electric field coupling
Port 4 (H-Arm)	H-plane port	Magnetic field coupling

Scattering Properties:

Isolation: Port 3 ↔ Port 4
Power division: Equal split when matched
Phase relationships: 0° and 180°

Applications:

Mixers and modulators
Power combiners
Impedance bridges
Antenna feeds

Mnemonic: "Magic TEE Creates Perfect Isolation"

Question 2(a) OR [3 marks]

Draw TE₁₀, TE₂₀ modes for rectangular waveguide.

Answer:

TE₁₀ Mode (Dominant Mode):

  a
┌─────────────┐
│      ↑      │ b
│   E  ↑  E   │
│      ↑      │
└─────────────┘
  Field Lines

TE₂₀ Mode:

  a
┌─────────────┐
│  ↑     ↓    │ b
│  ↑  E  ↓  E │
│  ↑     ↓    │
└─────────────┘
  Two Half-Waves

Mode Characteristics:

TE₁₀: One half-wave variation in x-direction
TE₂₀: Two half-wave variations in x-direction
Field patterns: Electric field perpendicular to propagation

Mnemonic: "TE modes have Electric Transverse"

Question 2(b) OR [4 marks]

Describe the Hybrid Ring with a necessary sketch.

Answer:

Hybrid Ring Structure:

graph TD
    A[Port 1] --- B[Ring Structure]
    C[Port 2] --- B
    D[Port 3] --- B
    E[Port 4] --- B
    B --- F[3λ/2 circumference]

Operating Principle:

Ring circumference: 3λ/2
Port spacing: λ/4 apart
Power division: Equal split between adjacent ports

Key Features:

Isolation: Between opposite ports
Phase relationships: 0° and 180°
Impedance: Matched at all ports

Mnemonic: "Hybrid Rings Handle Half-wavelengths"

Question 2(c) OR [7 marks]

Explain the Isolator with principles, construction and operation.

Answer:

Isolator Principle:

graph LR
    A[Input] --> B[Ferrite Material]
    B --> C[Output]
    C -.->|Blocked| B
    D[Magnetic Field] --> B

Construction Elements:

Component	Function	Material
Ferrite	Non-reciprocal medium	Yttrium Iron Garnet
Magnet	Bias field	Permanent magnet
Resistive Load	Absorb reverse power	Carbon/ceramic

Operating Principle:

Faraday rotation in magnetized ferrite
Non-reciprocal phase shift
Forward transmission: Low loss
Reverse transmission: High attenuation

Applications:

Amplifier protection
Oscillator isolation
Antenna systems

Specifications:

Isolation: 20-30 dB typical
Insertion Loss: < 0.5 dB

Mnemonic: "Isolators Ignore Reverse Reflections"

Question 3(a) [3 marks]

Draw a Traveling wave tube amplifier.

Answer:

TWT Amplifier Structure:

Electron Gun    Helix Structure    Collector
     |               |                |
     v               v                v
    [|]---> ~~~~~~~~~~~~~~~~~~~~~~~~ -->|
         Electron    RF Input         RF Output
         Beam        Coupler          Coupler
                        |
                   Attenuator

Key Components:

Electron gun: Produces electron beam
Helix: Slow-wave structure
Couplers: Input/output RF connections
Collector: Collects spent electrons

Mnemonic: "TWT Transfers Wave Through Helix"

Question 3(b) [4 marks]

Describes various types of hazards due to microwave radiation.

Answer:

Microwave Radiation Hazards:

Hazard Type	Effects	Safety Limit
HERP (Personnel)	Tissue heating, burns	10 mW/cm²
HERO (Ordnance)	Explosive detonation	Variable
HERF (Fuel)	Fuel ignition	5 mW/cm²

Biological Effects:

Thermal effects: Tissue heating above 41°C
Non-thermal effects: Cellular damage
Sensitive organs: Eyes, reproductive organs

Protection Measures:

Shielding: Conductive enclosures
Distance: Power density ∝ 1/r²
Time limits: Exposure duration control
Warning systems: Radiation detectors

Mnemonic: "Heat Energy Requires Proper Protection"

Question 3(c) [7 marks]

Explain two cavity klystrons construction and operation with an Applegate diagram.

Answer:

Two-Cavity Klystron Structure:

graph LR
    A[Cathode] --> B[Input Cavity]
    B --> C[Drift Space]
    C --> D[Output Cavity]
    D --> E[Collector]
    F[RF Input] --> B
    D --> G[RF Output]

Applegate Diagram:

Velocity
   ^
   |    Bunched    Bunched
   |   /      \   /      \
v₀ +--+        \-/        \--
   |   \        /\        /
   |    Bunched    Bunched
   |
   +-------------------------> Distance
   Input   Drift    Output
   Cavity  Space    Cavity

Operation Principle:

Stage	Process	Result
Velocity Modulation	RF input varies electron speed	Speed variation
Bunching	Fast electrons catch slow ones	Current bunches
Energy Extraction	Bunches interact with output cavity	RF amplification

Key Parameters:

Transit time: Critical for bunching
Drift space length: Optimized for maximum bunching
Cavity tuning: Resonant frequency matching

Applications:

Radar transmitters
Satellite communications
Linear accelerators

Mnemonic: "Klystrons Create Bunches Through Velocity Variation"

Question 3(a) OR [3 marks]

Draw the block diagram of the attenuation measurement method for microwave frequency.

Answer:

Attenuation Measurement Setup:

graph LR
    A[Signal Generator] --> B[Directional Coupler]
    B --> C[Device Under Test]
    C --> D[Power Meter]
    B --> E[Reference Power Meter]
    F[Display Unit] --> G[Attenuation Reading]
    D --> F
    E --> F

Measurement Process:

Reference measurement: Without DUT
Insertion measurement: With DUT
Attenuation calculation: A = P₁ - P₂ (dB)

Mnemonic: "Attenuation Appears After Accurate Assessment"

Question 3(b) OR [4 marks]

Describe the limitation of vacuum tubes at microwave range.

Answer:

Vacuum Tube Limitations:

Limitation	Cause	Effect
Transit Time	Finite electron travel time	Reduced gain at high frequency
Lead Inductance	Connecting wire inductance	Poor impedance matching
Inter-electrode Capacitance	Plate-cathode capacitance	Feedback and instability
Skin Effect	High-frequency current distribution	Increased resistance

Frequency-Related Problems:

Input impedance: Becomes reactive
Gain-bandwidth: Product limitation
Noise figure: Increases with frequency
Power handling: Decreases

Solutions:

Special tube designs: Lighthouse tubes
Cavity resonators: Replace tuned circuits
Short leads: Minimize inductance

Mnemonic: "Vacuum Tubes Fail Fast at High Frequencies"

Question 3(c) OR [7 marks]

Explain the Principle, construction, effect of the electric and magnetic field and operation of the magnetron in detail.

Answer:

Magnetron Construction:

        Anode Vanes
    ╭─────┬─────┬─────╮
   ╱   1  │  2  │  3   ╲
  ╱       │     │       ╲
 ╱    8   │  C  │   4    ╲
│         │     │         │
│    7    │  +  │    5    │
 ╲        │     │        ╱
  ╲   6   │     │       ╱
   ╲─────┴─────┴─────╱
        Cathode (C)

Operating Principle:

Field	Direction	Effect
Electric Field	Radial (cathode to anode)	Accelerates electrons
Magnetic Field	Axial (perpendicular to page)	Deflects electrons
Combined Effect	Cycloid motion	Phase synchronization

Operation Stages:

Electron Emission: Heated cathode emits electrons
Cycloid Motion: E×B fields create spiral paths
Synchronization: Electrons synchronize with RF field
Energy Transfer: Kinetic energy → RF energy
Output Coupling: RF extracted through waveguide

Key Parameters:

Magnetic flux density: B = 2πmf/e
Hull cutoff voltage: VH = (eB²R²)/(8m)
Frequency: f = eB/(2πm) × (anode modes)

Applications:

Microwave ovens (2.45 GHz)
Radar transmitters
Industrial heating

Mnemonic: "Magnetrons Make Microwaves Through Magnetic Motion"

Question 4(a) [3 marks]

Explain the working principle of a varactor diode using a graph.

Answer:

Varactor Diode Characteristics:

Capacitance (pF)
      ^
      |     
   100|╲    
      | ╲   
    50|  ╲  
      |   ╲ 
    10|    ╲
      |     ╲_____
      +─────────────> Reverse Voltage (V)
      0   5   10   15

Working Principle:

Reverse bias operation: Diode operated in reverse
Depletion layer: Acts as dielectric
Variable capacitance: C ∝ 1/√VR
Voltage tuning: Capacitance controlled by voltage

Applications:

Voltage-controlled oscillators
Frequency multipliers
Parametric amplifiers

Mnemonic: "Varactors Vary Capacitance Via Voltage"

Question 4(b) [4 marks]

Explain the Gunn Effect and negative resistance for Gunn diode.

Answer:

Gunn Effect Mechanism:

Parameter	Lower Valley	Upper Valley
Energy Level	Lower	Higher
Electron Mobility	High (μ₁)	Low (μ₂)
Effective Mass	Light	Heavy

Transfer Characteristic:

Current (mA)
      ^
      |   ╱╲
      |  ╱  ╲ Negative
      | ╱    ╲ Resistance
      |╱      ╲ Region
      +────────╲──> Voltage (V)
             Threshold

Negative Resistance:

Threshold voltage: Electrons transfer to upper valley
Current decrease: Due to reduced mobility
Oscillation: Negative resistance enables
Domain formation: High-field domains propagate

Key Points:

Materials: GaAs, InP
Frequency range: 1-100 GHz
Efficiency: 5-20%

Mnemonic: "Gunn diodes Generate oscillations through Negative resistance"

Question 4(c) [7 marks]

Explain frequency measurement method for microwave frequency.

Answer:

Direct Frequency Measurement:

graph LR
    A[Unknown Signal] --> B[Frequency Counter]
    B --> C[Display]
    D[Reference Oscillator] --> B

Indirect Methods:

Method	Principle	Accuracy
Wavemeter	Cavity resonance	±0.1%
Beat Frequency	Heterodyne mixing	±0.01%
Standing Wave	λ/2 measurement	±0.5%

Cavity Wavemeter Setup:

   Waveguide
  ┌─────────────┐
  │    ┌───┐    │
──┤    │ C │    ├── Output
  │    └───┘    │
  └─────────────┘
   Tuning Screw

Measurement Procedure:

Coupling: Weakly couple to signal line
Tuning: Adjust cavity for resonance
Indication: Monitor output for minimum/maximum
Calibration: Read frequency from calibrated scale

Beat Frequency Method:

Local oscillator: Known reference frequency
Mixer: Generates beat frequency
Measurement: fbeat = |fsignal - fLO|

Mnemonic: "Frequency Found through Careful Cavity Calibration"

Question 4(a) OR [3 marks]

Explain the working of a PIN diode as a switch.

Answer:

PIN Diode Structure:

P+ Region | Intrinsic | N+ Region
    │         │           │
    ├─────────┼───────────┤
   Holes   No Carriers  Electrons

Switching Operation:

Bias Condition	Intrinsic Region	RF Impedance	Switch State
Forward Bias	Flooded with carriers	Low (~1Ω)	ON (Closed)
Reverse Bias	Depleted	High (~10kΩ)	OFF (Open)
Zero Bias	Few carriers	Medium	Variable

Key Advantages:

Fast switching: Nanosecond response
Low insertion loss: When ON
High isolation: When OFF
Wide frequency range: DC to microwave

Applications:

RF switches
Modulators
Attenuators
Phase shifters

Mnemonic: "PIN diodes Perform Perfect switching"

Question 4(b) OR [4 marks]

Explain stripeline and Microstrip circuits.

Answer:

Stripline Configuration:

  Ground Plane
 ───────────────
     Dielectric
 ─────┬─────────  ← Signal Conductor
     Dielectric
 ───────────────
  Ground Plane

Microstrip Configuration:

  Signal Conductor
 ─────┬─────────
    Dielectric
 ───────────────
   Ground Plane

Comparison Table:

Parameter	Stripline	Microstrip
Ground Planes	Two (sandwich)	One (bottom)
Shielding	Complete	Partial
Dispersion	Lower	Higher
Manufacturing	Complex	Simple
Cost	Higher	Lower

Applications:

Stripline: High-performance systems
Microstrip: PCB circuits, antennas

Design Equations:

Characteristic impedance: Function of w/h ratio
Effective permittivity: εeff = (εr + 1)/2

Mnemonic: "Striplines are Sandwiched, Microstrips are Mounted"

Question 4(c) OR [7 marks]

Explain the principles and process of amplification for a Parametric amplifier.

Answer:

Parametric Amplifier Principle:

graph LR
    A[Signal fs] --> B[Nonlinear Reactance]
    C[Pump fp] --> B
    B --> D[Idler fi]
    B --> E[Amplified Signal]
    F[Energy Flow: Pump → Signal]

Frequency Relationships:

Parameter	Relationship	Typical Values
Pump Frequency	fp = fs + fi	10 GHz
Signal Frequency	fs (input)	1 GHz
Idler Frequency	fi = fp - fs	9 GHz

Amplification Process:

Nonlinear Element: Varactor diode provides time-varying capacitance
Pump Power: High-frequency pump supplies energy
Frequency Mixing: Three-frequency interaction
Energy Transfer: Pump energy → Signal energy
Impedance Matching: Optimize power transfer

Circuit Configuration:

Signal ──┬── Varactor ──┬── Amplified
Input   │    Diode     │    Output
        │              │
       ┌┴┐            ┌┴┐
       │C│            │L│ Idler
       │ │            │ │ Circuit
       └─┘            └─┘
        │              │
      Pump ────────────┘
      Input

Key Advantages:

Low noise figure: Near quantum limit
High gain: 10-20 dB typical
Wide bandwidth: Limited by pump circuit

Applications:

Satellite receivers
Radio astronomy
Low-noise amplifiers

Design Considerations:

Pump power: Sufficient for nonlinear operation
Impedance matching: All three frequencies
Stability: Prevent oscillation

Mnemonic: "Parametric amplifiers Pump Power into signal Perfectly"

Question 5(a) [3 marks]

Compare RADAR and SONAR.

Answer:

RADAR vs SONAR Comparison:

Parameter	RADAR	SONAR
Wave Type	Electromagnetic	Acoustic
Medium	Air/Vacuum	Water
Frequency	300 MHz - 30 GHz	1 kHz - 1 MHz
Speed	3×10⁸ m/s	1500 m/s (water)
Range	Up to 1000 km	Up to 100 km
Applications	Aircraft, weather	Submarines, fishing

Common Principles:

Echo ranging: Measure time-of-flight
Doppler effect: Detect moving targets
Beam forming: Directional transmission

Key Differences:

Propagation: EM waves vs sound waves
Attenuation: Different loss mechanisms
Resolution: Frequency dependent

Mnemonic: "RADAR sees Radio waves, SONAR hears Sound waves"

Question 5(b) [4 marks]

Write the name of RADAR display method and explain anyone.

Answer:

RADAR Display Methods:

Display Type	Description	Application
A-Scope	Range vs amplitude	Target detection
B-Scope	Range vs azimuth	2D position
C-Scope	Azimuth vs elevation	3D tracking
PPI	Plan Position Indicator	Air traffic control
RHI	Range Height Indicator	Weather radar

PPI Display Explanation:

graph TD
    A[Center - Radar Position] --> B[Sweep Line - Antenna Direction]
    B --> C[Target Blips - Range & Bearing]
    D[Circular Pattern] --> E[360° Coverage]

PPI Features:

Polar coordinates: Range and bearing
Rotating sweep: Follows antenna rotation
Persistence: Targets remain visible
Scale selection: Adjustable range

Display Process:

Sweep generation: Synchronized with antenna
Target plotting: Distance and direction
Intensity modulation: Target strength
Map overlay: Geographic reference

Mnemonic: "PPI Provides Perfect Position Information"

Question 5(c) [7 marks]

Explain the basic pulse radar system with a block diagram.

Answer:

Pulse Radar Block Diagram:

graph LR
    A[Master Oscillator] --> B[Modulator]
    B --> C[Power Amplifier]
    C --> D[Duplexer]
    D --> E[Antenna]
    E --> F[Target]
    F --> E
    E --> D
    D --> G[Receiver]
    G --> H[Signal Processor]
    H --> I[Display]
    J[Timer] --> A
    J --> I

System Components:

Component	Function	Key Parameters
Master Oscillator	Generate RF signal	Frequency stability
Modulator	Create pulse train	Pulse width, PRF
Power Amplifier	Boost transmit power	Peak power, efficiency
Duplexer	Switch Tx/Rx	Isolation, switching time
Antenna	Radiate/receive	Gain, beamwidth
Receiver	Amplify echo signals	Sensitivity, bandwidth

Operating Sequence:

Transmission Phase:
- Master oscillator generates RF
- Modulator creates pulses
- Power amplifier boosts signal
- Duplexer routes to antenna
Reception Phase:
- Antenna receives echoes
- Duplexer routes to receiver
- Signal processing extracts information
- Display shows target data

Key Equations:

Range: R = ct/2 (where t = round-trip time)
Maximum range: Rmax = cPRT/2
Range resolution: ΔR = cτ/2

Performance Parameters:

PRF: Pulse Repetition Frequency
Duty cycle: τ × PRF
Average power: Peak power × duty cycle

Mnemonic: "Pulse Radar Properly Processes Reflected signals"

Question 5(a) OR [3 marks]

List the application of microwave frequency.

Answer:

Microwave Applications:

Application Category	Specific Uses	Frequency Band
Communication	Satellite, cellular, WiFi	1-40 GHz
Radar Systems	Weather, air traffic, military	1-35 GHz
Industrial	Heating, drying, medical	0.9-5.8 GHz
Navigation	GPS, aircraft landing	1-15 GHz
Scientific	Radio astronomy, research	1-300 GHz
Medical	Diathermy, cancer treatment	0.9-2.45 GHz
Domestic	Microwave ovens	2.45 GHz

Key Points:

ISM bands (Industrial, Scientific, Medical): License-free
Penetration ability: Depends on frequency and material
Atmospheric absorption: Increases with frequency

Mnemonic: "Microwaves Serve Many Applications Perfectly"

Question 5(b) OR [4 marks]

Compare PULSED RADAR and CW RADAR.

Answer:

PULSED vs CW RADAR Comparison:

Parameter	Pulsed RADAR	CW RADAR
Transmission	Pulse train	Continuous wave
Range Measurement	Time-of-flight	Frequency shift
Velocity Measurement	Doppler in pulses	Direct Doppler
Antenna	Single (duplexer)	Separate Tx/Rx
Power	High peak, low average	Low continuous
Range Resolution	Pulse width limited	Poor
Velocity Resolution	Limited	Excellent
Complexity	High	Low
Cost	Higher	Lower

Operational Differences:

Pulsed RADAR:

Range equation: R = ct/2
Maximum range: Limited by PRF
Blind ranges: Multiple of cPRT/2
Applications: Long-range detection

CW RADAR:

Doppler equation: fd = 2vr/λ
Range measurement: Requires FM modulation
No blind ranges: Continuous operation
Applications: Speed measurement, proximity

Key Advantages:

Pulsed: Better range capability, target separation
CW: Better velocity accuracy, simpler design

Mnemonic: "Pulsed measures Range, CW measures Velocity"

Question 5(c) OR [7 marks]

Explain MTI Radar with the block diagram.

Answer:

MTI RADAR Block Diagram:

graph LR
    A[Transmitter] --> B[Duplexer]
    B --> C[Antenna]
    C --> D[Target]
    D --> C
    C --> B
    B --> E[Receiver]
    E --> F[Phase Detector]
    G[STALO] --> H[Mixer]
    H --> F
    I[COHO] --> F
    F --> J[MTI Filter]
    J --> K[Display]
    G --> L[Frequency Multiplier]
    L --> A

MTI System Components:

Component	Full Form	Function
STALO	Stable Local Oscillator	Reference frequency
COHO	Coherent Oscillator	Phase reference
MTI Filter	Moving Target Indicator	Clutter suppression
Phase Detector	-	Compare signal phases

MTI Operating Principle:

Pulse-to-Pulse Comparison:

Signal Amplitude
       ^
       |    Fixed Target (Clutter)
       |    ________________
       |   |                |
       |   |                |
       |   |                |
   ____+___|________________|____
       |                        
       |    Moving Target
       |     /\      /\
       |    /  \    /  \
       |   /    \  /    \
   ____+__/______\/______\______
       |
       +-------------------------> Time
           Pulse 1    Pulse 2

MTI Process:

Coherent transmission: Maintain phase relationships
Echo reception: Preserve phase information
Phase comparison: Compare successive pulses
Clutter cancellation: Subtract stationary returns
Moving target detection: Enhance moving targets

Key Equations:

Doppler frequency: fd = 2vr cos(θ)/λ
Phase change: Δφ = 4πvr/λ × PRT
Blind speeds: vb = nλ/(2PRT)

MTI Improvement Factor:

Definition: Ratio of clutter power before/after MTI
Typical values: 20-40 dB
Factors affecting: System stability, clutter characteristics

Limitations:

Blind speeds: Targets invisible at certain velocities
Tangential targets: Radial velocity component needed
Weather effects: Atmospheric fluctuations

Applications:

Air traffic control: Separate aircraft from ground clutter
Weather radar: Distinguish precipitation from terrain
Military radar: Detect moving vehicles/aircraft

Mnemonic: "MTI Makes Targets Identifiable by Movement"