The introduction of the fifth-generation (5G) New Radio (NR) standard has imposed several challenges in the design of sub-6GHz receivers (RX). Firstly, the maximum channel bandwidth(2BW) increases to 100MHz, while a -15dBm continuous-wave (CW) blocker can be located only \Delta f=85MHz away from the desired band edge. Such a small \Delta f/BW(\sim2) places a stringent linearity requirement on an RX, thus demanding the use of higher-order filtering. Secondly, in-band (IB) linearity also becomes critical, since the band of interest may contain many signals resulting from carrier aggregation and digital beamforming 0peration. Finally, a sub-3dB noise Figure (NF) is required to achieve the highest possible link budget, which allows to maximize the spectral efficiency and data rate.

Packaged integrated low-pass quasi-load insensitive (QLI) class-E matching is proposed for the realization of energy-efficient wideband Doherty and outphasing transmitters. In view of this, a dedicated QLI class-E harmonic matching technique, suitable for in-package integration has been developed, optimized, and evaluated. As proof of concept, very compact, as well as easy to assemble, dual-input load-modulating transmitters have been realized. In this paper, we focus on a QLI class-E matched wideband Doherty that provides 71% peak efficiency (± 3%) at 48-dBm saturated output power and 49% (± 7%) efficiency at 6-dB power backoff, over a 1200-MHz frequency span (1.4-2.6 GHz), yielding 60% fractional bandwidth (BW). When tested with single-carrier long-term evolution (LTE) signals, having a 7-dB peak-to-average ratio, average efficiency remains close to 49% (± 3%) for the entire 60% fractional BW. The realized demonstrator shows excellent linearizability with adjacent channel power ratio and normalized mean square error levels below -50 dBc and -36 dB, respectively, even when operated in simultaneous dual-band LTE operation.