RESEARCH ARTICLE
A switchable dual-mode fully-
differential common-source
low-noise amplifier in 0.18-μm
CMOS technology
Changchun Zhang
1
| Yongkai Wang
1
|
Shenjun Gao
1
| Lu Tang
2
|
Yi Zhang
1
| Sung Min Park
3
1
College of Electronic and Optical Engineering & College of
Microelectronics, Nanjing University of Posts and Telecommunications,
Nanjing, China
2
School of Information Science and Engineering, Southeast University,
Nanjing, China
3
Department of Electronic and Electrical Engineering, Ewha Womans
University, Seoul, Korea
Correspondence
Changchun Zhang, College of Electronic and Optical Engineering &
College of Microelectronics, Nanjing University of Posts and
Telecommunications, Nanjing 210023, China.
Email: zhangcc@njupt.edu.cn
Funding information
National Natural Science Foundation of China, Grant/Award Numbers:
61604082, 61674036; the 14th “Six Talent Peaks” Project of Jiangsu
Province, Grant/Award Number: XYDXX-080
Abstract
A highly-integrated switchable dual-mode low-noise
amplifier (LNA) is proposed and implemented in stan-
dard 0.18 μm complementary metal-oxide-semiconductor
(CMOS) technology for ultra-high frequency-radio-
frequency identification (UHF RFID) reader receivers.
This dual-mode LNA can be controlled to operate in two
different modes in order to meet the requirements for the
listen-before-talk mode and the normal mode of the UHF
RFID reader receiver, respectively. The fully-differential
common-source cascode topology with perfect input
impedance matching, capacitive cross-coupling, and
common-mode feedback techniques are employed to
improve its performance. Measurement results show that,
from a single power supply of 1.8 V, the LNA achieved
the power gain (S21) of 9.1 dB, the input power reflec-
tion (S11) of −20 dB, the minimum noise figure (NF) of
3.6 dB, and the P
1dB
of −5 dBm in high-gain mode. In
high-linearity mode, S21 of 3.2 dB, S11 of −17 dB, NF
of 5.2 dB, and P1dB of −1.3 dBm were obtained.
KEYWORDS
dual-mode, high gain, high linearity, LNA, UHF RFID
1 | INTRODUCTION
The ultra-high frequency (UHF) radio-frequency identification
(RFID) technology has many advantages such as high through-
put, long read-range, rewritable ability, and contactless non-
line-of-sight tag identification. Thus, it can find extensive
applications, for example, supply chain managements, airport
baggage handling, nonstop toll collection, antifraud systems.
1
For UHF RFID systems, the reader energizes the passive tags
and then exchanges information with them through far-field
electromagnetic waves.
According to the UHF RFID protocols, the reader operates
at two distinct operating modes: the listen-before-talk (LBT)
mode (or called the listen mode) and the normal mode (or called
the talk mode). Two different modes mandate the reader
receiver front-end two different requirements, that is, high sensi-
tivity in the LBT mode vs high linearity in the normal mode.
2-6
Several strategies have been presented in previously publi-
shed literatures. Low-noise amplifier (LNA) was removed in
order to improve linearity in the normal mode.
2,3
Yet, the reduced
sensitivity was incurred in the LBT mode. A switchable attenua-
tor controlled by the mode selection was added before LNA to
accommodate two operation modes.
4
However, the imperfect
nonidealities inevitably had adverse effects on both linearity and
sensitivity. Furthermore, a LNA (which could be bypassed) was
employed for the receiver front-end.
5,6
However, some flaws
unavoidably existed because of the imperfect bypass path.
In this paper, we present a switchable dual-mod e LNA,
which can operate in the high-gain mode and the high-
linearity mode, corresponding to the requirements for the
LBT mode and the normal mode in UHF RFID readers,
respectively. No additional blocks are introduced into the
signal path to achieve the mode switching and also to avoid
the introduction of non-idea l factors.
The circuit design and measurement results are given in
Section 2 and Section 3, respectively. Finally, conclusion is
followed in Section 4.
Received: 23 August 2019
DOI: 10.1002/mop.32169
Microw Opt Technol Lett. 2020;62:1163–1168. wileyonlinelibrary.com/journal/mop © 2019 Wiley Periodicals, Inc. 1163