Advantages of FMCW Radar | disadvantages of FMCW Radar

This page covers advantages and disadvantages of FMCW Radar. It mentions FMCW Radar advantages or benefits and FMCW Radar disadvantages or drawbacks. It also describes FMCW radar basics.

What is FMCW Radar?

Introduction:
CW radar or doppler radar does not measure range or distance of the target. This limitation of CW radar is overcome by FMCW radar. FMCW radar detects, measures range and radial velocity of the object.

FMCW radar stands for Frequency Modulated Continuous Wave Radar. In the FMCW radar, transmitter frequency is continuously varied at known rate and reflected frequency signal is received by radar receiver and later compared with the transmitted frequency. Radar consists of both transmitter and receiver parts.

The FMCW radar uses following equation to determine range of the target.
R = Vo * Δt/2
Δt = [ T * { Δf/(f2-f1) } ]
Where,
Vo = Velocity of EM wave
T = Period of sweep from f1 to f2
f1 = Minimum frequency
f2 = Maximum frequency
Vo = Free space velocity of EM waves
Δf = difference between transmitted and received instantaneous frequencies.
Refer FMCW Radar System basics >>.

FMCW radar is used for following.
• Slant range of target
• Height of target
• Bearing and elevation angles of the target

Benefits or advantages of FMCW Radar

Following are the benefits or advantages of FMCW Radar:
➨FMCW radar is called altimeter. It is used in aircraft to measure height above the earth.
➨It uses low power for transmission. This can be supplied by many solid state devices such as magnetron, BWO, reflex klystron etc.
➨The super-heterodyne based architecture delivers good sensitivity and stability.
➨It offers higher bandwidth compare to CW radar.

Drawbacks or disadvantages of FMCW Radar

Following are the disadvantages of FMCW Radar:
➨They are used for targets at very short ranges. This is due to use of lower peak output power.
➨Due to use of lower transmit power, the signal gets attenuated and affected due to atmosphere and channel before it is received by the receiver.
➨It is more expensive compare to pulsed radar.
➨The transmissions from FMCW radar is interfered from other nearby radio systems due to use of large range of frequencies and low peak power for transmitter part.

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