Design ofGaN‐basedX‐band LNAsto achieve sub‐1.2 dBnoise figure

Abstract

GaAs and SiGe technologies take an edge over GaN-based devices in terms of better noise figure (NF). In this article, we present HEMT topologies and design techniques to achieve a sub-1.2 dB NF for a GaN-based X-band lownoise amplifier (LNA). This NF is comparable with state-of-the-art reported works in competitive GaAs and SiGe technologies. Moreover, this is the best reported NF in X-band using GaN technology to date. Two LNAs are fabricated using in-house 0.15 μm AlGaN/GaN on the SiC HEMT process. LNA-1 has inductive source degenerated (ISD) HEMTs at both stages, while LNA-2 has ISD HEMT at the first and common source at the second stage. The significance of ISD HEMT, for the first or subsequent stages in a multi-stage design, towards NF improvement is addressed. The criticality of stability networks towards NF contribution and its design is discussed in detail. Furthermore, even-mode stability of each HEMT after complete LNA design is assured using the S-probe method in Pathwave Advanced Design Systems.

Robustness of GaN on SiC low‐noise amplifiers in common source and cascode configurations for X‐band applications

“…An RRT of 30 ns is also reported in the literature for a gain compression level of around 8 dB 16 . Zafar et al have related the recovery times, from nanoseconds to milliseconds, to various P in levels ranging from 15 dBm to 30 dBm 10 . There is no reported work so far discussing RRT of LNAs based upon cascode HEMT configuration in the X ‐band to the best of authors' knowledge which highlights the novelty of this work.…”

“…16 Zafar et al have related the recovery times, from nanoseconds to milliseconds, to various P in levels ranging from 15 dBm to 30 dBm. 10 There is no reported work so far discussing RRT of LNAs based upon cascode HEMT configuration in the X-band to the best of authors' knowledge which highlights the novelty of this work. This work compares the robustness of LNAs based on cascode and common source configurations and facilitates the RF designers to choose appropriate HEMT configuration as per their application.…”

“…Some designs have used bigger periphery transistors at the first stage, improving survivability at the cost of NF 16 . On the other hand, the trap excitation phenomenon associated with GaN technology has its limitations in terms of RRT 10 . Increasing the input power (P in ) levels leads to high gain compressions and thus increases the RRT value.…”

“…The recent advances in GaN technology have resulted in the design and fabrication of low-noise amplifiers (LNAs) with promising noise figures (NFs) comparable to GaAs technology. 10 GaN technology has the advantage of built-in power handling capability to realize robust LNAs. 11 Robustness is defined by two figures of merits (FoMs): survivability and reverse recovery time (RRT).…”

“…16 On the other hand, the trap excitation phenomenon associated with GaN technology has its limitations in terms of RRT. 10 Increasing the input power (P in ) levels leads to high gain compressions and thus increases the RRT value. An RRT of 40 ms and 10 ms corresponding to gain compressions of 33 dB and 3 dB has been reported for corresponding P in levels of 36 dBm and 21 dBm, respectively.…”