Open AccessEfficient RF voltage transformer with bandpass filter characteristics
Author(s) -
Moreira M.,
Bjurström J.,
Katardjiev I.,
Yantchev V.
Publication year - 2013
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2012.3982
Subject(s) - band pass filter , transformer , electronic engineering , voltage , radio frequency , electrical engineering , materials science , engineering
A microwave bandpass filter with a large ratio between the output and the input impedance has been designed and fabricated. Consequently, it functions both as a voltage transformer and a bandpass filter, or transfilter for brevity. It represents a two‐port micro‐acoustic resonator employing Lamb waves in a thin piezoelectric AlN film grown onto a Si carrier substrate with a centre frequency of around 887 MHz. The transfilter has a transformer ratio of 10 and a voltage efficiency of over 80%. The component has a small size (< 0.5 mm 2 ) and is shown to sustain power levels of 250 mW. It can be used in a variety of cases where both voltage amplification and frequency filtering are required. Examples include: charge pumps in RFID tags, energy scavenging, remotely triggered switches, wake‐up radios in wireless networks, stand‐by units in home electronics etc.