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An adaptive impedance tuning CMOS circuit for ISM 2.4-GHz band

Sjöblom, Peter LU and Sjöland, Henrik LU (2005) In IEEE Transactions on Circuits and Systems Part 1: Fundamental Theory and Applications 52(6). p.1115-1124
Abstract
The difficulties encountered in matching an antenna to its optimal impedance are reduced with an adaptive 0.35-mu m CMOS circuit based on several switched shunt capacitors arranged in capacitor banks and on a few external series inductors. As high-quality inductors are difficult to obtain in CMOS, the inductors are placed either in an low-temperature cofired ceramic (LTCC) substrate or is a lumped component outside the core circuit. The circuits, presented here through a range of simulations, are optimized to function within the ISM 2.4-GHz band, but the general approach employed to improve matching can be used for other frequency bands as well. The circuits discussed provide a VSWR <= 2 match for every impedance with VSWR <= 5.... (More)
The difficulties encountered in matching an antenna to its optimal impedance are reduced with an adaptive 0.35-mu m CMOS circuit based on several switched shunt capacitors arranged in capacitor banks and on a few external series inductors. As high-quality inductors are difficult to obtain in CMOS, the inductors are placed either in an low-temperature cofired ceramic (LTCC) substrate or is a lumped component outside the core circuit. The circuits, presented here through a range of simulations, are optimized to function within the ISM 2.4-GHz band, but the general approach employed to improve matching can be used for other frequency bands as well. The circuits discussed provide a VSWR <= 2 match for every impedance with VSWR <= 5. There is a 1-dB power loss for a perfect 50 Omega -> 50 Omega transformation, a break-even point at VSWR = 1.5, and a 3-dB increase in delivered power for VSWR = 4.3. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CMOS, antenna tuning unit (ATU), impedance matching, impedance tuning, reconfigurable matching, unit (ITU), ISM, capacitor, bank, switched capacitor
in
IEEE Transactions on Circuits and Systems Part 1: Fundamental Theory and Applications
volume
52
issue
6
pages
1115 - 1124
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • wos:000229818800009
  • scopus:22144488501
ISSN
1057-7122
DOI
10.1109/TCSI.2005.849116
language
English
LU publication?
yes
id
cf512eef-16a9-4bff-8d1b-b007763b0982 (old id 236170)
date added to LUP
2007-08-06 09:21:41
date last changed
2017-04-02 04:07:25
@article{cf512eef-16a9-4bff-8d1b-b007763b0982,
  abstract     = {The difficulties encountered in matching an antenna to its optimal impedance are reduced with an adaptive 0.35-mu m CMOS circuit based on several switched shunt capacitors arranged in capacitor banks and on a few external series inductors. As high-quality inductors are difficult to obtain in CMOS, the inductors are placed either in an low-temperature cofired ceramic (LTCC) substrate or is a lumped component outside the core circuit. The circuits, presented here through a range of simulations, are optimized to function within the ISM 2.4-GHz band, but the general approach employed to improve matching can be used for other frequency bands as well. The circuits discussed provide a VSWR &lt;= 2 match for every impedance with VSWR &lt;= 5. There is a 1-dB power loss for a perfect 50 Omega -&gt; 50 Omega transformation, a break-even point at VSWR = 1.5, and a 3-dB increase in delivered power for VSWR = 4.3.},
  author       = {Sjöblom, Peter and Sjöland, Henrik},
  issn         = {1057-7122},
  keyword      = {CMOS,antenna tuning unit (ATU),impedance matching,impedance tuning,reconfigurable matching,unit (ITU),ISM,capacitor,bank,switched capacitor},
  language     = {eng},
  number       = {6},
  pages        = {1115--1124},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Circuits and Systems Part 1: Fundamental Theory and Applications},
  title        = {An adaptive impedance tuning CMOS circuit for ISM 2.4-GHz band},
  url          = {http://dx.doi.org/10.1109/TCSI.2005.849116},
  volume       = {52},
  year         = {2005},
}