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Moreover, the added circuit increases the conversion gain of the mixer.
The proposed mixer uses a cascoded complementary switching pair to improve port-to-port isolation.
This paper presents a novel fourth harmonic mixer with new structure.
With the advantage of charge-injection, the mixer achieves a high conversion gain with low dc consumption.
This is the first demonstration of a monolithic HEMT mixer with conversion gain at W-band.
Finally, we propose a method to use integrated inductors to suppress the currents which flow when two mixer switches are on at the same time, alleviating this loss mechanism.
The conversion gain of the mixer, controlled by the voltage of the diodes, could be applied to meet gain compensation requirements in communication systems.
Our theoretical and experimental studies carried out over Ka-band show that the new mixer has a conversion loss comparable to the conventional balanced fundamental harmonic mixer.
Journal ArticleDOI
01 Dec 1946
31 Citations
The noise of triode and multigrid mixer stages is shown to be reducible to the value for a comparable triode amplifier stage by the application of proper feedback.
It is shown that an approach like the mapping method is a prerequisite in order to obtain meaningful results after a number of mixer elements.

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What are the potential applications of HEMT terahertz transistors in various industries?
5 answers
HEMT terahertz transistors offer promising applications across various industries. They enable wide spectrum detection, improved sensitivity, and scanning imaging capabilities in wireless communication, non-destructive imaging, and spectrum inspection fields. GaN-based HEMT structures show potential for filling the THz technology gap in medical, biological, industrial imaging, communication, and radar applications. Additionally, novel recessed gate AlGaN/AlN/GaN Nano-HEMT devices on β-Ga2O3 substrates exhibit superior terahertz frequency characteristics, paving the way for high-frequency devices in the future. Furthermore, In0.8Ga0.2As quantum-well HEMTs demonstrate scaling behavior for terahertz devices, achieving drain-induced-barrier-lowering, high-frequency characteristics, and maximum oscillation frequencies suitable for terahertz applications. These advancements highlight the diverse industrial applications of HEMT terahertz transistors in fields like imaging, communication, and high-frequency technology.
Is the heterostructure is good ?
4 answers
The heterostructures discussed in the provided contexts demonstrate their significance in various applications. From the development of compound semiconductor-based high-speed devices like MESFETs, MODFETs, and HEMTs, to the utilization of heterostructures in optoelectronic devices through sacrificial layers and additional processing, and the design of heterostructures for high electron mobility transistors (HEMTs) with specific material compositions and layer thicknesses, it is evident that heterostructures play a crucial role in enhancing device performance and functionality. The detailed descriptions of heterostructures in these contexts highlight their importance in achieving desired properties such as high electron mobility, low interface state density, and crack-free active layers, making them essential components in advanced semiconductor devices.
In Ti/Al/Ni/Au would Ni and Au increase worsen the contact resistance?
5 answers
The inclusion of Ni and Au in the Ti/Al/Ni/Au ohmic contact scheme can actually improve the contact resistance performance. Research on ultrawide bandgap AlN barrier heterostructures demonstrated that the addition of Au in the metal stack aids in reducing contact resistance by assisting in the formation of more conducting inter-metallic phases during annealing. Additionally, the study on self-heating effects in AlGaN/GaN heterostructures highlighted that the Au layer insertion can lead to a drastic improvement in surface quality, resulting in lower contact resistance values. Therefore, the presence of Ni and Au in the Ti/Al/Ni/Au ohmic contact configuration can actually contribute to reducing contact resistance and improving the overall performance of the contacts.
What is flexible dc grid system?
5 answers
A flexible DC grid system refers to a system that can efficiently adapt to internal and external uncertainties by utilizing resources that provide regulation capabilities. These systems often involve key components like DC/DC converters, such as a GaN HEMT-based LLC resonant converter, known for high frequency, high efficiency, and miniaturization capabilities. Additionally, Voltage Source Converter (VSC) based multi-terminal HVDC systems play a crucial role in flexible collector systems for interconnected AC/DC hybrid grids with renewable energy sources, emphasizing the need for cooperative regulation and secure operation. Furthermore, the evolution towards meshed HVDC supergrids involves combining shunt connected AC-DC converters with flexible DC-DC converters to control power flows, voltages, and provide various services for enhanced grid stability and control.
Doherty power amplifier 3.3 - 3,8 GHz
5 answers
A Doherty power amplifier (DPA) operating in the 3.3 - 3.8 GHz range is not explicitly discussed in the provided contexts. However, the contexts do provide valuable insights into DPAs operating at higher frequencies. For instance, a 2.4 GHz DPA based on voltage combining in 22 nm CMOS achieved high efficiency and linearity, with a peak power added efficiency (PAE) of 42.5% and a PAE of 25.2% at 6 dB back-off power. Additionally, a millimeter-wave (mmWave) three-way Doherty output network was implemented at 38 GHz for 5G applications, achieving power-added efficiency (PAE) of 13.7%/11.0% at 9.5-/11.5-dB back-off. While specific details for 3.3 - 3.8 GHz are not provided, these examples showcase the efficiency and performance optimization strategies that can be applied to DPAs in different frequency ranges.
How GaN Field-Plate dielectric affect the TDDB?
5 answers
The presence of a field plate in GaN devices significantly impacts Time-Dependent Dielectric Breakdown (TDDB). Field plates enhance breakdown voltage, as evidenced by a GaN HEMT with a field plate exhibiting a breakdown voltage of 292V compared to 98V without a field plate. Additionally, the use of a field plate in GaN MIS-FETs contributes to robust forward gate TDDB stability, allowing for an extrapolated operating gate voltage of 7V or 8.8V after 10 years with 1% failure rate. However, the introduction of a field plate can lead to reduced frequency performance, with field-plated GaN HEMTs showing lower cut-off and maximum frequencies compared to those without field plates. Understanding the impact of field plates on TDDB is crucial for optimizing the reliability and performance of GaN devices.
How field-plate dielectric affect the TDDB of GaN-HEMTs?
5 answers
Field plates in GaN-HEMTs play a crucial role in enhancing breakdown voltage and reducing parasitic effects. Different field plate techniques, such as gate, source, and gate-source field plates, have been studied to optimize device performance. Optimized field plate structures like T-gate HEMTs with dual discrete field plates (DDFP-HEMT) and single discrete field-plate (SDFP-HEMT) have shown improved breakdown characteristics and current collapse suppression, leading to higher off-state breakdown voltages and reliability enhancement. Additionally, utilizing artificial neural networks (ANN) and particle swarm optimization (PSO) algorithms can efficiently optimize field plate structures like gate-source dual field plates to predict breakdown voltage and improve breakdown performance with high accuracy. These advancements in field plate technology contribute significantly to enhancing the reliability and performance of GaN-HEMTs under electrical stress.
What's the key characteristics of field-plate dielectric that affect the TDDB of GaN-HEMTs?
5 answers
The key characteristics of the field-plate dielectric that significantly impact the Time-Dependent Dielectric Breakdown (TDDB) of GaN-HEMTs include the stress level and composition of the dielectric film. Stress variations in the SiN field-plate dielectric film, ranging from compressive to tensile, influence isolation leakage and gate leakage current in AlGaN/GaN HEMTs. Additionally, the incorporation of a SiO2 pocket around the field plate edge in GaN-HEMTs results in a substantial reduction in electric field intensity, carrier temperature, and self-heating, leading to improved device performance and reliability. Furthermore, optimized field plate structures, such as T-gate AlGaN/GaN HEMTs with dual discrete field plates, demonstrate enhanced breakdown characteristics and current collapse suppression, contributing to improved TDDB behavior in GaN-HEMTs.
What are the applications where WHAs are prefereed over pure W ?
5 answers
Tungsten Heavy Alloys (WHAs) are preferred over pure tungsten in applications where a balance of properties like high density, machinability, and improved mechanical strength is required. WHAs are particularly suitable for fusion diverter components due to their enhanced properties. Additionally, in circuit combining networks, WHAs can be advantageous for low-loss interconnecting transmission lines, offering reduced excess loss and improved characteristic impedance maintenance. Moreover, the use of WHAs can enhance the performance of oil extractors by providing a suitable balance between weight and strength, as seen in the W-towing oil extractor application. Therefore, WHAs find favor in various applications where a combination of properties is essential for optimal performance.
Can GaN HEMTs be used to improve the radiation tolerance of high-speed electronic circuits in space applications?
5 answers
Gallium Nitride (GaN) High-Electron-Mobility Transistors (HEMTs) can indeed enhance the radiation tolerance of high-speed electronic circuits in space applications. GaN transistors offer superior radiation hardness compared to silicon transistors, making them ideal for use in space where radiation-induced failures are common. By implementing GaN HEMTs in circuits like Latching Current Limiters (LCLs), which are crucial for protecting payloads in satellites, the radiation tolerance can be significantly improved. Studies have shown that GaN devices can withstand short-circuit events caused by radiation, and setups have been developed to characterize failure mechanisms and degradation indicators of GaN HEMTs under such conditions. Additionally, GaN devices have demonstrated efficiency and power density improvements over traditional MOSFET technology in space-rated power conversion applications, further highlighting their potential for enhancing radiation tolerance in high-speed electronic circuits for space missions.
How to acheive flat gain gan hemt LNA?
4 answers
To achieve a flat gain in GaN HEMT LNAs, various techniques and designs have been proposed in the literature. One approach involves utilizing a defective ground bias (DGB) technique, which incorporates gate and drain biasing topologies to achieve dual-band operation. Another method includes employing a series inductive source degeneration and an R-C feedback network in a Common-Source topology. Additionally, a multi-stage noise matching approach with series inductive degeneration common source has been suggested for maintaining high flat gain while achieving a low noise figure over a wide frequency spectrum. These techniques help optimize the LNA's performance, ensuring a consistent and flat gain response across the desired frequency bands.