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Description
Fifth-Generation (5G) New Radio (NR) connectivity will launch in the year 2020. Although initially set to be a non-standalone radio system, it will not serve as another patch to current-existing 4G LTE (Long-Term Evolution) communication, but instead present a new wireless entity of its own. Superseding its predecessor, 5G NR seeks to address a major issue seen in mobile technology today, frequency congestion, due to the continuous increase in wireless traffic. Frequency band n79 is new, spans from 4.4 GHz to 5 GHz, and is set for mobile cellular usage. The need to support a large bandwidth stimulates the investigation of radio components—in this case, a Low Noise Amplifier (LNA)—that exhibit broadband performance. An LNA integrated circuit (IC) that exploits the theory of noise cancellation (NC) for 5G’s enhanced Mobile Broadband (eMBB) is discussed. Constructed using pSemi Corporation’s UltraCMOS 65 nm technology process, the LNA IC uses a cascode amplifier with an LC-tank and resistive feedback as a matching amplifier to achieve a high gain and large operational bandwidth. The resistive feedback in the circuit serves instrumental for simultaneously breaking the tie between an input match for maximum power transfer and one for noise figure, and NC of the input transistor. Both the input and output impedances of the amplifier depend on the intrinsic transconductance of a metal-oxide semiconductor field- effect transistor (MOSFET), which varies little with frequency. The voltage-sensing amplifier is made up of a common-source (CS) configuration loaded by a diode connected MOSFET, which is shown to limit the LNA’s performance. Both a prototype and revision IC are presented. This work provides 360 degrees of scope on the circuit design through theoretical analysis of operation using conventional MOSFET models, feasibility by simulation with industry-wide Cadence tools, practicality and implementation through design and fabrication of silicon, and verification through on-wafer measurements. The IC design is considered customized since it uses digital control circuitry for tunable capability, input and output bias-tees, and coplanar return path. Low supply voltage, low current consumption, and limited IC die area accompany the design. A discrepancy analysis between simulated and measured results is also presented.
