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Improving Receiver Close-In Blocker Tolerance by Baseband Gm-C Notch Filtering

Abdulaziz, Mohammed LU ; Klumperink, Eric A.M.; Nauta, Bram and Sjoland, Henrik LU (2019) In IEEE Transactions on Circuits and Systems I: Regular Papers 66(3). p.885-896
Abstract

This paper presents a receiver front end with improved blocker handling implemented in a 65-nm CMOS technology. Since close-in blockers are challenging to reject at RF, the receiver features a baseband (BB) notch filter, which effectively sinks close-in blocker current directly from the output of an LNTA and passive mixer structure. The notch-filter frequency can be tuned to match the blocker offset frequency, and the measurements indicate a significant improvement in the overall front-end interference robustness, while sensitivity remains unaffected. To optimize notch performance, the BB impedance is analyzed in detail. The front-end RF range is 750 MHz-3 GHz with an RF channel bandwidth of 20 MHz corresponding to 10-MHz BB bandwidth.... (More)

This paper presents a receiver front end with improved blocker handling implemented in a 65-nm CMOS technology. Since close-in blockers are challenging to reject at RF, the receiver features a baseband (BB) notch filter, which effectively sinks close-in blocker current directly from the output of an LNTA and passive mixer structure. The notch-filter frequency can be tuned to match the blocker offset frequency, and the measurements indicate a significant improvement in the overall front-end interference robustness, while sensitivity remains unaffected. To optimize notch performance, the BB impedance is analyzed in detail. The front-end RF range is 750 MHz-3 GHz with an RF channel bandwidth of 20 MHz corresponding to 10-MHz BB bandwidth. The notch frequency is programmable from 16, which is less than one octave from the channel edge, up to 160 MHz. The gain-compression improvement is upto 9 dB, while IIP2 can be increased by more than 26 dB without calibration and IIP3 is 1 dBm. The current overhead for the notch function is between 7.5 and 30 mA, but it only exists under strong blocker conditions as the notch filter can be switched off if strong blockers are absent. The total front-end current consumption excluding the notch filter varies with LO frequency from 31 to 44 mA from a 1.2-V supply.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
blocker rejection, CMOS technology, compression point, Gm-C filter, Interference robustness, linearity, linearization., notch filter
in
IEEE Transactions on Circuits and Systems I: Regular Papers
volume
66
issue
3
pages
885 - 896
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85055019973
ISSN
1549-8328
DOI
10.1109/TCSI.2018.2872469
language
English
LU publication?
yes
id
32c131cb-a504-41e1-88a3-59cec26e3989
date added to LUP
2018-11-09 08:33:09
date last changed
2019-05-27 18:08:35
@article{32c131cb-a504-41e1-88a3-59cec26e3989,
  abstract     = {<p>This paper presents a receiver front end with improved blocker handling implemented in a 65-nm CMOS technology. Since close-in blockers are challenging to reject at RF, the receiver features a baseband (BB) notch filter, which effectively sinks close-in blocker current directly from the output of an LNTA and passive mixer structure. The notch-filter frequency can be tuned to match the blocker offset frequency, and the measurements indicate a significant improvement in the overall front-end interference robustness, while sensitivity remains unaffected. To optimize notch performance, the BB impedance is analyzed in detail. The front-end RF range is 750 MHz-3 GHz with an RF channel bandwidth of 20 MHz corresponding to 10-MHz BB bandwidth. The notch frequency is programmable from 16, which is less than one octave from the channel edge, up to 160 MHz. The gain-compression improvement is upto 9 dB, while IIP2 can be increased by more than 26 dB without calibration and IIP3 is 1 dBm. The current overhead for the notch function is between 7.5 and 30 mA, but it only exists under strong blocker conditions as the notch filter can be switched off if strong blockers are absent. The total front-end current consumption excluding the notch filter varies with LO frequency from 31 to 44 mA from a 1.2-V supply.</p>},
  author       = {Abdulaziz, Mohammed and Klumperink, Eric A.M. and Nauta, Bram and Sjoland, Henrik},
  issn         = {1549-8328},
  keyword      = {blocker rejection,CMOS technology,compression point,Gm-C filter,Interference robustness,linearity,linearization.,notch filter},
  language     = {eng},
  number       = {3},
  pages        = {885--896},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Circuits and Systems I: Regular Papers},
  title        = {Improving Receiver Close-In Blocker Tolerance by Baseband Gm-C Notch Filtering},
  url          = {http://dx.doi.org/10.1109/TCSI.2018.2872469},
  volume       = {66},
  year         = {2019},
}