UWB Radar Tutorial | UWB Radar System working Block diagram

This tutorial on UWB radar describes UWB radar system basics with UWB radar block diagram with transmitter and receiver part. It mentions benefits or advantages of UWB radar and drawbacks or disadvantages of UWB radar over conventional UWB radar system.

What is UWB ?

UWB is the short form of Ultra Wide Band. This technology uses wide bandwidth signal having low power level which is below noise level. It is defined in IEEE 802.15.4a specifications. UWB system operates at three frequency bands which include below 1 GHz, 3 to 5GHz and 6 to 10 GHz.

UWB signal is generated by using pulses having very shorter duration (approx. < 1 ns). As a result frequency spectrum of this UWB signal is very much wider compare to narrow band system.

UWB Radar working operation

The radar system which uses signal having UWB characteristics is known as UWB radar. The UWB signal occupies much wider frequency compare to conventional radar system. Moreover it uses very low power which is less than thermal noise signal power.

The figure depicts typical UWB transmitter and receiver block diagram. UWB transmitter converts information to be transmitted in the form of pulses before being amplified by amplifier. The amplified signal is transmitted using antenna as shown. At the receiver, zeros and ones are decoded from the pulse train received based on time interval between pulses.

Bits to symbol conversion is done with the help of modulation scheme. The UWB uses time based modulation scheme (i.e. PPM) and pulse shape based modulation schemes (i.e. PAM,OOK, Bi-phase, Orthogonal pulse modulation).

UWB has been used for various applications and domains such as asset tracking, military, healthcare, medicine, networking etc. Similarly UWB radars are used for various applications ranging from detecting concealed objects, geographical survey using airborne system, infrastructure mapping, snow thickness measurement etc.

UWB Radar system block diagram

The figure depicts typical block diagram of UWB radar system. As shown UWB transmitter part consists of waveform generator, RF filter, driver, power amplifier and transmit antenna. The UWB receiver consists of receiving antenna, RF filter (BPF type), LNA (Low Noise Amplifier), down converter (using mixer and LO circuit), IF amplifier (to amplify down converted IF signal), IF filter (BPF type) and ADC (Analog to Digital Converter). The digital output of ADC is acquired and processed to retrieve desired informations as per applications. Timing unit along with GPS helps in synchronization in order to provide start of frame.

Like other active radars, UWB radar transmits frequency modulated chirp signal in the 2 to 18 GHz range. The waveform generator shown can be used to produce this signal. The scattered or reflected signal from the target scene is captured using receiving antenna. The received RF signal is down converted to IF and processded to retrieve desired informations with the help of data acquisition system.

Advantages of UWB Radar

Following are the benefits or advantages of UWB radar system.
➤Due to broad operating bandwidth, UWB radars are capable of resolving closely spaced targets.
➤It uses low power and possess good noise immunity.
➤UWB radar uses UWB signals which can penetrate variery of materials easily. Hence it can be used for wide variety of applications.
➤It can be used in multipath fading environment due to its higher immunity against such fading type. Refer UWB channel models implementation in MATLAB >>.
➤Higher data rates (about 1 Gbps) can be achieved using UWB system.

Disadvantages of UWB Radar

Following are the drawbacks or disadvantages of UWB radar system.
➤UWB radar has longer signal acquisition time.
➤It has slow adoption rate.
➤UWB system has certain co-existence and interference related issues with other wireless technolies which uses similar bands.

RADAR Tutorial RELATED LINKS

Refer following radar tutorial related links which covers radar basics including its measurements, doppler radar, FMCW radar, radar bands, radar scope, weather radar, radar range and resolution, ground radar etc.
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