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3078 IEEE JOURNAL OF SOLID-STAT E CIRCUITS, VOL. 56, NO. 10, OCTOBER 2021
an mm-wave front-end to cover this frequency band with suf-
ficient output power, excellent linearity, low-noise figure (NF),
compact size, robust package, and EVM requirement for the
IEEE 802.11aj requirement.
IEEE 802.11aj is devised for high data rate wireless personal
area network (WPAN) [24] and also for the portable device.
The system requires high linearity for the transmitter and low
NF for the receiver. For the system, it also requires low power
consumption, compact size, and wideband [11], [16], [25],
[26]. The direct-conversion topology has the advantage of the
system’s simplicity, compact size, and low-power consump-
tion. However, direct-conversion topology also suffers from
the local oscillator (LO) leakage and im age frequ e ncy signal.
Therefore, to achieve a direct-conversion system at 45 GHz
with 64 QAM, it is quite crucial to introduce LO leakage
suppression and image frequency signal suppression units.
In this work, we present a world-first IEEE 802.11aj
mm-wave I/Q transceiver front-end system targeted at support-
ing 64 QAM with Yagi-Uda antenna, operating from 42.3 to
48.4 GHz, in a 120-nm SiGe:C BiCMOS process. The pro-
posed system is comprised of a transmitter, a receiver, and two
onboard substrate integrated waveguide (SIW)-fed Yagi-Uda
antennas. The Yagi-Uda antennas are integrated with the trans-
mitter and receiver chips using broadband wire-bond intercon-
nections, which results in a low-cost solution. At mm-wave
frequency, the common-mode (CM) issue in a differential
system could degr ade the system linearity, system gain, and
introduce instability. In this work, the CM effect caused by
transformer-based balun is analyzed. Based on the analysis,
a fast impedance equalization with a passive component com-
pensation method is proposed to cope with this issue in a
short cycle, which effectively improves the linearity of the
transmitter. Also, a T -type second-order harmonic termination
method is applied at the output of the power amplifier (PA) to
further improve the linearity of the transmitter. Furthermore,
a self-mixing method is adopted to the power detector (PD)
of the tran smitter output to have closer monitoring on the
down-converted LO leakage term and image signal, which
is used for LO leakage and image signal calibration. With
all the proposed methods, the transmitter achieves an OP
1dB
of 14.6–16.4 dBm and a conversion gain (CG) of 24 dB
at the IEEE 802.11aj frequency band. The receiver achieves
3.8–4.1-dB NF and −18.7- to −22-dBm input 1-dB compres-
sion point, while the CG is 43.8 dB. In the wireless data
transmission test, the system delivers a measured transmitter-
to-receiver EVM with 64 QAM better than −28.5 dB at a
1-m distance over the IEEE 802.11aj frequency band. The
power consumption is 438 and 186 mW in the transmitter and
receiver modes, respectively.
This chipset is first reported in [27], and this article
presents a detailed design methodology. This article is orga-
nized as follows. Section II introduces the IEEE 802.11aj
direct-conversion transceiver architecture. Section III presents
the model to analyze the CM effect in transformer-based
balun and the proposed method. Section IV d escribes the
transceiver circuit design methodology, and the package design
methodology is provided in Section V. Section VI reports
the measurement results for the entire transceiver system.
Section VII draws conclusions.
TABLE I
B
ASIC LINK BUDGET PARAMETERS FOR SHORT-RANGE COMMUNI CATION
Fig. 1. Block diagram of the 45-GHz direct-conversion (a) transmitter and
(b) receiv er.
II. 45-GHz TRANSCEIVER SYSTEM ARCHITECTURE
Table I shows a short-range communication link budget
example of the 45-GHz transceiver. According to the IEEE
802.11aj standard [23], the receiver sensitivity of a typical
45-GHz receiver is −53 dBm for SC 64-QAM signals (modu-
lation and coding scheme index 7), and the minimum required
EVM is −26 dB at the receiver side. For a typical 45-GHz
transceiver shown in Table I, the received signal strength at
a 1-m distance is calculated to b e −47.5 dBm, which is
about a 5.5-dB margin from the receivers’ sensitivity. Besides,
the communication distance could be extended by using a high
gain antenna or multiantenna array configuration.
Fig. 1 shows the simplified block d iagram of this IEEE
802.11aj 45-GHz transceiver. A direct conversion architec-
ture is employed for both the transmitter and the receiver
for wide-bandwidth requirements [28] and low-power con-
sumption for the next step on phased array integration. The
transmitter, the receive r, and the antenna are implemented with
the system-on-board solution to improve transceiver isolation
and avoid signal coupling from the antenna switching unit.
The mixer-first topology is adopted for the transmitter to
obtain wideband gain characteristics with low-power con-
sumption [16]. The printed onboard Yagi-Uda antenna is
proposed to achieve a compact size. At the transmitter output,
the self-mixing m ethod is app lied to have a better LO leakage
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