## 1 Introduction  
The fifth-generation (5G) wireless network is one of the most attractive research hotspots in recent years. To obtain wider bandwidth and higher communication rates, the frequency of 5G applications is increased gradually towards millimeter-wave bands. To save the time to market as much as possible, the circuits should cover multiple frequency bands to avoid repeated design when new applications appear, which brings greater design challenges to improve performance at the same time. Some broadband receivers covering multiple frequency bands have been proposed for 5G new radio (NR) frequency bands, including 24.5, 28, 37, 39, and 43 GHz [1, 2]. In the receiver of a heterodyne structure, the down-conversion mixer is located between LNA and VGA, in the second stage. Parameters such as conversion gain (CG), 1 dB compression point, noise figure (NF), and isolation cannot be ignored and seriously affect the system's overall performance. Moreover, the data rate of several Gbps is highly expected, which requires the mixer's intermediate frequency (IF) to be higher and have a wide IF bandwidth. For passive mixers, resistive ring mixers [3] and drain-driven mixers [4] all have a significant loss at millimeter-wave frequencies, which requires additional power consumption to compensate, and higher local oscillator power requirements make the system more complicated. Various active implementations have been proposed under silicon-basedprocesses, for example, gate-/base-driven [5], source-driven [6; 7], bulk-driven [8], drain-driven and gate-driven [9], switching stage only [10], half Gilbert-cell [11], and switching stage with single-ended transconductance stage [12]. They all have strengths in terms of gain, linearity, bandwidth, and so on, but they cannot be improved simultaneously. The Gilbert-cell is widely used due to its double-balanced characteristics and moderate gain capability. Nevertheless, due to the limitation of its stacked structure and low voltage, its linearity is far inferior to passive mixers. The multiple-gate transistor (MGTR) method is applied to mixers [13; 14; 15], which improves the input third-order intercept point (IIIP3) effectively without significantly increasing power consumption and sacrificing CG. However, it is voltage-sensitive, and the boosting effect is weakened rapidly when a large signal is input and the input-referred 1 dB compression point (IP1 dB) has not been raised. Source/emitter degradation is also a widely used linearization method [16], but the output-referred 1 dB compression point (OP1 dB) has not been improved effectively due to the expense of conversion gain. In [17], Gilbert-cell's transconductance stage and switching stage are separated through a transformer; the linearity is improved through independent voltage bias. However, the introduction of large-area passive structures leads to higher costs and more complicated designs. Therefore, a more efficient method is needed to improve the linearity of the active mixers while sacrificing other performance less. This paper proposes a new and more efficient linearization method to increase the IP1 dB and OP1 dB of Gilbert-cell-based active mixers by analyzing the phenomenon of \"reverse uplift\". Compared to other works where linearity is concerned [4; 6; 16; 18; 19; 20; 21; 22; 23], no extra components are added except a pair of phase-adjusting inductors, the linearity is greatly improved by using the energy of harmonics, and the IP1 dB reaches +7.2\(\sim\)+10.1 dBm. At the same time, the CG and the gain flatness remain appropriate, so the excellent OP1 dB performance is realized simultaneously, with an average of +5.4 dBm, which is the state-of-the-art OP1 dB performance in mixers under a silicon-based process, whether active or passive. Furthermore, the input radio frequency (RF) band covers the n257, n258, and n261 bands of 5G NR frequency bands. The use of a low-Q Marchand balun ensures that the IF covers 3-11 GHz and the relative IF bandwidth up to 114%. This paper is organized as follows.