Niklas Rorsman

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A new large signal model for HEMT’s and MESFET’s, capable of ,modeling the current-voltage characteristic and its derivatives, including the characteristic transconductance peak, gate-source and gate-drain capacitances is described. Model parameter extraction is straightforward and is demonstrated for different submicron gate-length HEMT devices including(More)
This paper describes cryogenic broad-band amplifiers with very low power consumption and very low noise for the 4–8-GHz frequency range. At room temperature, the two-stage InP-based amplifier has a gain of 27 dB and a noise temperature of 31 K with a power consumption of 14.4 mW per stage, including bias circuitry. When cooled to 15 K, an input noise(More)
A theory for class-J microwave amplifier operation as a function of drive level and fundamental load impedance is derived. Calculations show that, under appropriate operating conditions, it is sufficient to modulate the transistor load reactance to enable high-efficiency operation (>;70%) over a large output power dynamic range (>;10 dB) with high(More)
This paper addresses the limitations and difficulties, in terms of DC-current density restrictions, and process limitations, associated with implementing impedance inverters with high characteristic impedance for monolithic microwave integrated circuit (MMIC) Doherty power amplifiers (DPAs). It is theoretically shown that impedance inverters with high(More)
This paper presents an X-band balanced Colpitts oscillator in GaN HEMT technology and a method to calculate its phase noise accurately. The method employs a low-frequency (LF) noise measurement and the oscillator waveforms from a harmonic-balance simulator. These data are post-calculated by Hajimiri's phase-noise model, in which the LF noise can be(More)
A monolithic microwave integrated circuit (MMIC) process based on an in-house SiC MESFET technology has been developed. The process uses microstrip technology, and a complete set of passive components, including MIM capacitors, spiral inductors, thin-film resistors, and via-holes, has been developed. The potential of the process is demonstrated by an 8-W(More)
The high-frequency noise performance of the GaN HEMT is studied for temperatures between 297-398 K. The access resistances R<sub>S</sub> and R<sub>D</sub> have a limiting effect on the noise performance, and in this paper, their temperature dependence is studied in detail for a 2 times 100 mum GaN HEMT. R<sub>S</sub> and R<sub>D</sub> show an increase of(More)
A MMIC process in AlGaN/GaN technology for advanced transceiver design has been developed. The process is based on microstrip technology with a complete model library of passive elements and AlGaN/GaN HEMTs. The transistor technology in this process is suitable for both power and low noise design, demonstrated with a power density of 5 W/mm, and an(More)
A broadband highly linear X-band mixer in AlGaN/GaN monolithic microwave integrated circuit technology has been designed, processed, and characterized. The design is based on a 4 times 100 mum AlGaN/GaN HEMT in a single-ended circuit topology. The mixer has an IF bandwidth of 2 GHz with a conversion loss (CL) of &lt; 8 dB across the X-band with a minimum CL(More)
SiC Schottky diode varactors have been fabricated for use in microwave power applications, specifically the dynamic load modulation (DLM) of power amplifiers (PAs). A custom doping profile has been employed to spread the C(V) over a large bias voltage range, thereby increasing the effective tuning range under large voltage swing conditions. The small-signal(More)