Design Example: Small Loop Antenna Matching
Printed loop antennas are inexpensive and can easily be adapted for printed circuit board (PCB) applications such as wireless car keys. Typically, the 433 MHz band is used and the antenna loop diameter is about 2-3 cm. This makes the antenna small compared to the 70 cm wavelength and thus the antenna must be carefully matched with low loss matching components. The matched small loop antenna exhibits an interesting but undesirable feature: it magnifies the small changes in the antenna impedance caused by environmental factors.
This video discusses how to analyze and minimize this phenomenon using NI AWR Design Environment, specifically Microwave Office circuit design software and Optenni Lab matching circuit design software, to emulate loop antenna impedance variations and seek matching circuit topologies that minimize the corresponding variation of the matched impedance.