Advanced

Two Tunable Frequency Duplexer Architectures for Cellular Transceivers

ud Din, Imad ; Wernehag, Johan LU ; Andersson, Stefan and Sjöland, Henrik LU (2017) In IEEE Transactions on Circuits and Systems I: Regular Papers
Abstract
In this paper two architectures for tunable duplexers
are presented. The tuning is accomplished through variable
capacitance and resistance. The architectures are based on a
three element series-parallel resonator, with one pass and one
stop frequency. Both architectures rely on filtering as well as
cancellation for good Tx to Rx isolation while maintaining low
insertion loss. The first architecture, the Filtered Transformer
Balanced (FTB) isolator, has single ended transmit and antenna
ports and a differential receive port. The second architecture,
the Cross Coupled Filtering (CCF) isolator, is fully differential.
For a resonator Q of 50, the impedance ratio of the resonator at
pass and stop... (More)
In this paper two architectures for tunable duplexers
are presented. The tuning is accomplished through variable
capacitance and resistance. The architectures are based on a
three element series-parallel resonator, with one pass and one
stop frequency. Both architectures rely on filtering as well as
cancellation for good Tx to Rx isolation while maintaining low
insertion loss. The first architecture, the Filtered Transformer
Balanced (FTB) isolator, has single ended transmit and antenna
ports and a differential receive port. The second architecture,
the Cross Coupled Filtering (CCF) isolator, is fully differential.
For a resonator Q of 50, the impedance ratio of the resonator at
pass and stop frequencies is 18.5dB for 3GPP band-I. In the FTB
isolator this results in 1.65dB Tx and 2.14dB Rx insertion loss,
and 53 dB isolation for a 20 MHz channel bandwidth. In the CCF
isolator this results in 1.9dB Tx and 1.9dB Rx insertion loss, and
59dB isolation for a 20 MHz channel bandwidth. These figures
are obtained with a 20% resistive mismatch, showing feasibility of
good performance in an environment with changing impedance.
As the operating frequencies of cellular systems increase, these
structures will become fully integratable due to the reduced sizes
of inductors and transformers. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
IEEE Transactions on Circuits and Systems I: Regular Papers
pages
12 pages
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85020396584
ISSN
1549-8328
language
English
LU publication?
yes
id
8dda11fc-eb7a-4a5f-a462-724c25bebf8d
date added to LUP
2017-02-02 10:00:15
date last changed
2018-01-07 11:47:41
@article{8dda11fc-eb7a-4a5f-a462-724c25bebf8d,
  abstract     = {In this paper two architectures for tunable duplexers<br/>are presented. The tuning is accomplished through variable<br/>capacitance and resistance. The architectures are based on a<br/>three element series-parallel resonator, with one pass and one<br/>stop frequency. Both architectures rely on filtering as well as<br/>cancellation for good Tx to Rx isolation while maintaining low<br/>insertion loss. The first architecture, the Filtered Transformer<br/>Balanced (FTB) isolator, has single ended transmit and antenna<br/>ports and a differential receive port. The second architecture,<br/>the Cross Coupled Filtering (CCF) isolator, is fully differential.<br/>For a resonator Q of 50, the impedance ratio of the resonator at<br/>pass and stop frequencies is 18.5dB for 3GPP band-I. In the FTB<br/>isolator this results in 1.65dB Tx and 2.14dB Rx insertion loss,<br/>and 53 dB isolation for a 20 MHz channel bandwidth. In the CCF<br/>isolator this results in 1.9dB Tx and 1.9dB Rx insertion loss, and<br/>59dB isolation for a 20 MHz channel bandwidth. These figures<br/>are obtained with a 20% resistive mismatch, showing feasibility of<br/>good performance in an environment with changing impedance.<br/>As the operating frequencies of cellular systems increase, these<br/>structures will become fully integratable due to the reduced sizes<br/>of inductors and transformers.},
  author       = {ud Din, Imad  and Wernehag, Johan and Andersson, Stefan and Sjöland, Henrik},
  issn         = {1549-8328},
  language     = {eng},
  month        = {06},
  pages        = {12},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Circuits and Systems I: Regular Papers},
  title        = {Two Tunable Frequency Duplexer Architectures for Cellular Transceivers},
  year         = {2017},
}