Gallium Nitride is becoming an interesting solution for low-noise applications in the lower part of the millimetre-wave spectrum and is gaining increasing attention in the space community for ...microwave receiver functionalities. Lately, its maturity level has increased and its performance in terms of noise figure and operating frequency is reaching other advanced III-V technologies such as Gallium Arsenide and Indium Phoshpide. Moreover, Gallium Nitride features higher power handling capability in comparison to the previously mentioned III-V technologies. In this context, we have designed and characterized two demonstrator circuits of critical microwave receiver functionalities: a Low-Noise Amplifier and a Low-Distortion Amplifier operating at Ka-band. It is shown that GaN circuits compare well in terms of noise figure, gain, and operating frequency with respect to other advanced III-V technologies, and most of all exhibit superior linearity in terms of intermodulation distortion. The designed Low-Noise Amplifier exhibits state-of-the-art 1.2 dB Noise Figure in the 27-31 GHz bandwidth thanks to a profitable combination of 60- and 100-nm gate length transistors on the same MMIC. On the other hand, the Low-Distortion Amplifier features state-of-the-art +30 dBm Output Third Order Intercept point in the same operating bandwidth while requiring only 216 mW dc power. The presented electrical performances are validated by comparing these designs to others available in open literature through figures of merit that normalize trade-offs by transistor length (therefore a fair comparison) aiming to highlight the merits of the proposed design methodologies.
A fundamental step in the design of electronic circuits is the verification that they are stable at least on a given set of external terminations, in order to avoid that the solution found be not ...observable in practice. This is especially true at microwave and millimeter-wave circuits, which are typically analyzed in the frequency domain rather than in the time domain. As a consequence, both in the linear and large-signal case, unstable solutions may be found instead of an observable one. Unfortunately, as compared to the linear case, the stability analysis of large-signal solutions is significantly more cumbersome. In particular, although it is possible to translate the small-signal tests based on the Nyquist principle to large-signal equivalents, the price to pay is a significant increase in matrix size. In the case of the Ohtomo test, which has only recently been applied to large-signal solutions, it is however possible to exploit the structure of the problem to significantly reduce the complexity and, therefore, simulation time. A real-world balanced amplifier is selected to validate the proposed method and illustrate its practical usage. The application of the method to a realistic monolithic circuit with a large number of devices is also presented.
In this paper, an analysis of gate-source and gate-drain scaling effects in MESFETs fabricated on hydrogen-terminated single-crystal diamond films is reported. The experimental results show that a ...decrease in gate-source spacing can improve the device performance by increasing the device output current density and its transconductance. On the contrary, the gate-drain distance produces less pronounced effects on device performance. Breakdown voltage, knee voltage, and threshold voltage variations due to changes in gate-source and drain-source distances have also been investigated. The obtained results can be used as a design guideline for the layout optimization of H-terminated diamond-based MESFETs.
Abstract
The first realizations of S-band hybrid amplifiers based on hydrogenated-diamond (H-diamond) FETs are reported. As test vehicles of the adopted H-diamond technology at microwave frequencies, ...two designs are proposed: one, oriented to low-noise amplification, the other, oriented to high-power operation. The two amplifying stages are so devised as to be cascaded into a two-stage amplifier. The activities performed, from the technological steps to characterization, modelling, design and realization are illustrated. Measured performance demonstrates, for the low-noise stage, a noise figure between 7 and 8 dB in the 2–2.5 GHz bandwidth, associated with a transducer gain between 5 and 8 dB. The OIP3 at 2 GHz is 21 dBm. As to the power-oriented stage, its transducer gain is 5–6 dB in the 2–2.5 GHz bandwidth. The 1-dB output compression point at 2 GHz is 20 dBm whereas the OIP3 is 33 dBm. Cascading the measured S-parameters of the two stages yields a transducer gain of 15 ± 1.2 dB in the 2–3 GHz bandwidth.
In this paper a GaN-on-Si MMIC Low-Noise Amplifier (LNA) working in the Ka-band is shown. The chosen technology for the design is a 100 nm gate length HEMT provided by OMMIC foundry. Both ...small-signal and noise models had been previously extracted by the means of an extensive measurement campaign, and were then employed in the design of the presented LNA. The amplifier presents an average noise figure of 2.4 dB, a 30 dB average gain value, and input/output matching higher than 10 dB in the whole 34–37.5 Ghz design band, while non-linear measurements testify a minimum output 1 dB compression point of 23 dBm in the specific 35–36.5 GHz target band. This shows the suitability of the chosen technology for low-noise applications.
This paper is focused on the extraction of the noise parameters of a linear active device by exploiting both forward and reverse noise power measurements associated with different terminations. In ...order for load-pull measurements to yield a significant marginal improvement (as compared to forward measurements only) it is expected that the device under test should appreciably deviate from unidirectionality. For this reason, the source/load-pull technique is applied to frequencies at which the considered devices are still usable but their reverse noise factor exhibits a measurable dependence on the output terminations. Details on the test bench set up to the purpose, covering the 20–40 GHz frequency range, are provided. A characterization campaign on a 60 nm gate length, 4×35 µm GaN-on-Si HEMT fabricated by OMMIC is illustrated.
Available techniques for stability analysis of DC solutions, such as the popular Ohtomo test, make the task quite a straightforward one. Such tests are based on the assumption that the active ...subcircuit is inherently stable, which is reasonably easy to enforce in practice since the active devices themselves are typically inherently stable. However, besides this empirical observation, there is an unfortunate lack of techniques to verify the proviso itself before proceeding to the stability test of the whole circuit. This contribution presents a quick-and-easy technique for identifying a single, technology-dependent parameter and choosing the test section appropriately. Examples are also given of active devices that, quite unusually, were found to be non-inherently stable. It is shown that, due to the nature of the instability in the considered cases, the proviso cannot be checked without accessing the intrinsic circuit on a single-finger basis, which, in turn, calls for the availability of a multi-finger model. The devices illustrated in this contribution are based on a 250-nm GaN HEMT technology provided by the UMS foundry and are featured by standard and customized geometries, only the latter presented unstable behavior.
GaN-Based Robust Low-Noise Amplifiers Colangeli, Sergio; Bentini, Andrea; Ciccognani, Walter ...
I.E.E.E. transactions on electron devices/IEEE transactions on electron devices,
10/2013, Volume:
60, Issue:
10
Journal Article
Peer reviewed
Open access
In this paper, an overview of recently reported low-noise amplifiers (LNAs), designed, and fabricated in GaN technology is provided, highlighting their noise performance together with high-linearity ...and high-robustness capabilities. Several SELEX-ES GaN monolithic technologies are detailed, providing the results of the noise characterization and modeling on sample devices. An in-depth review of three LNAs based on the 0.25- μm GaN HEMT process, marginally described in previous publications, is then presented. In particular, two robust and broadband 2-18-GHz monolithic microwave integrated circuit (MMIC) LNAs are designed, fabricated, and tested, exhibiting robustness to over 40-dBm input power levels; an X-band MMIC LNA, suitable for synthetic aperture radar systems, is also designed and realized, for which measurement results show a noise figure ~ 2.2 dB with an associated gain and robustness up to 41-dBm input power level.
A geometrical test for the unconditional stability of three-port networks is presented. The derivation is presented in full detail, starting from the concept of input mapping region as an indicator ...of unconditional stability. A novel set of (equivalent) parameters is then defined, which can serve to rapidly check the unconditional stability of a three-port network under test. Although the derivation is rather lengthy, the final part of the contribution shows that the practical application of the test is actually straightforward.
A theoretical analysis is carried out of the problem of checking the unconditional stability of a linear <inline-formula> <tex-math notation="LaTeX">N </tex-math></inline-formula>-port with arbitrary ...<inline-formula> <tex-math notation="LaTeX">N </tex-math></inline-formula>, explaining at length its inherent difficulties. To overcome the algebraic roadblock, an optimization-based method is proposed; the main novelty is that notwithstanding the use of optimization, the problem formulation is specifically chosen so as to guarantee convergence to the global minimum. In particular, recent advancements in the field of convex optimization, mostly unknown to the high-frequency engineering community, are exploited to that end. The result is a method suitable for checking the unconditional stability of linear <inline-formula> <tex-math notation="LaTeX">N </tex-math></inline-formula>-ports with <inline-formula> <tex-math notation="LaTeX">N </tex-math></inline-formula> up to 4. Higher numbers of ports, although allowed in principle, are not viable with the current combination of hardware resources and software implementation. Several examples of applications are provided, both purely illustrative and from actual circuit designs.
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