DecaWave ‘Performance of DW1000 Based Systems’ FAQs For Design Engineers Part 4

The DecaWave DW1000 IC provides a new approach to Real Time Location and Indoor Positioning Systems, Location Based Services, Wireless Sensor Networks and the Internet of Things by providing accurate location awareness and communication.

This series will share answers to some common DW1000 questions.

What is the power consumption of the DW1000 while transmitting /receiving?

There are various factors which influence the power consumption of the DW1000 during transmission and reception such as preamble length, data rate, number of data bytes and so on.

Is communications range or ranging accuracy impacted when a tag is kept close to the body?

The human body introduces approximately 30 dB of insertion loss so the transmitted signal from the tag will be heavily attenuated. Depending on the proximity of the tag antenna to the body the level of attenuation may be such that:

• no signal at all is received at the intended receiver or the direct path signal is heavily attenuated and only a reflected signal is received at the intended receiver thereby giving an incorrect distance measurement
• the direct path signal is heavily attenuated but is still received correctly at the intended receiver in which case the distance measurement will be correct.

Most monopole antennas are designed to operate in free space i.e. not in proximity to the body. Proximity to the body reduces antenna efficiency and fidelity factor. This could distort the UWB pulse and thereby give an incorrect range measurement. The solution here is to design an antenna which takes the body proximity in account. 

For additional DecaWave product information or technical support, contact Symmetry Electronics, an authorized distributor of industry leading wireless, audio/video and embedded chips, modules and dev/eval tools (877) 466-9722.