Single-stage MMIC Research Articles

Dual-Gate GaN MMICs for MM-Wave Operation

This letter describes the millimeter-wave operation of III-N dual-gate MMICs based on a complete mm-wave MMIC technology suitable for operation up to 110 GHz. The GaN HEMTs have a gate length of 100 nm, yield high maximum transconductance, and very low parasitic capacitances. The cutoff frequency fT is above 80 GHz at an operation bias of 15 V in a fully passivated device. Dual-gate devices were developed for high gain at high gate widths and for substantial improvements in gain per stage on MMIC level. Complete III-N MMICs in grounded coplanar passive technology were designed. A single-stage dual-gate MMIC at 60 GHz yields 150 mW (840 mW/mm) of output power. A second MMIC shows a linear gain of greater than 10 dB at 94 GHz. It further yields an output power of 22.8 dBm (190 mW or 520 mW/mm) in CW-operation to a 50 Ω load with a maximum PAE of 7% at 94 GHz. The letter demonstrates the advantage of GaN dual-gate devices in power gain over common-source devices while maintaining essential improvements in power density.

An optimized 25.5-76.5 GHz PHEMT-based coplanar frequency tripler

This letter presents an optimized single-stage MMIC tripler with W-band output frequency (76.5 GHz). The circuit is based on an 0.15 /spl mu/m gate-length AlGaAs/InGaAs/GaAs PHEMT. By using a class AB transistor bias point and carefully selecting its input and output terminations, a high conversion gain of -4.3 dB for an 8.5 dBm input signal and a saturated output power of 7 dBm have been obtained. To our knowledge, these results represent the best performance reported up to date for an active frequency tripler with W-band output frequency.

Fully passivated W-band InAlAs/InGaAs/InP monolithic low noise amplifiers

The development of W-band monolithic low noise amplifiers (LNAs) using a fully passivated 0.1 µm pseudomorphic InAlAs/InGaAs/InP low noise HEMT technology is presented. Both wafer passivation and stabilisation bakes have been introduced, for the first time, to the InP HEMT MMIC process to make it more suitable for production. A three-stage single-ended 94 GHz monolithic LNA shows a measured noise figure of 3.3 dB and 20 dB associated gain. A measured noise figure of 2.3 dB is achieved for a single-stage MMIC LNA at 94 GHz. These results represent state-of-the-art performance of HEMT MMIC LNAs at this frequency. The effects due to SiN passivation for both HEMT device and circuit performance are also addressed.

Cryogenically cooled performance of a monolithic 44-GHz InP-based HEMT low-noise amplifier

A monolithic 44-GHz low-noise amplifier using 0.1-μm pseudomorphic InAlAs/InGaAs/InP HEMT technology and its cryogenically cooled performance are reported. This single-stage MMIC amplifier has a measured noise figure of 2.5 dB with an associated gain of 8 dB at 44.5 GHz with 5-mW dc power consumption at room temperature. The noise temperature of this MMIC LNA decreases to 29 K (0.4-dB noise figure) and the associated gain increases to 10.3 dB when it is cooled down to 80 K under the same bias condition, which corresponds to an average noise temperature reduction slope of 0.9 and a gain increase slope of 0.01 dB//spl deg/K. To our knowledge, this is the first reported cryogenically cooled noise performance of a monolithic amplifier at this frequency.

V-band high-efficiency monolithic pseudomorphic HEMT power amplifiers

V-band monolithic power amplifiers have been developed and demonstrate state-of-the-art performance. For a single-stage MMIC amplifier employing a 200- mu m pseudomorphic HEMT, 151.4 mW (757 Mw/mm) output power with 26.4% power-added efficiency at 60 GHz is achieved. Maximum power-added efficiency of 30.6% at 130-mW output power is also obtained. A three-stage MMIC amplifier utilizing the same devices demonstrated 80-mW output power, 20.5% power-added efficiency, and 17-dB associated gain at 57 GHz. The linear gain of the amplifier was 21.5 dB. >

V-band GaAs MMIC low-noise and power amplifiers

GaAs MESFET amplifiers with on-chip DC-blocking and bias networks which were fabricated from both VPE and MBE materials, are reported. The low-noise designs resulted in a single-stage MMIC, low-noise amplifier achieving a 6.5-dB noise figure and a 4.1-dB gain at 59 GHz, as well as a cascaded six-stage amplifier exhibiting an 8-dB minimum noise figure and a 30-dB gain from 56.2 to 60 GHz. The single-stage power amplifier provides over 4.5 dB of gain from 57 to 60.5 GHz, with a maximum output power of 95 mW and a corresponding power-added efficiency at 11% at 58 GHz. Maximum power-added efficiency of 15.3% at 73 mW was also obtained. A cascaded four-stage amplifier demonstrated stable operation, achieving 17 dB of gain and 85 mW of output power. A two-stage balanced amplifier provided 136 mW of output power and 7.5 dB of linear gain from 56.6 to 61.5 GHz.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Monolithic 2–6 GHz limiting amplifier

A four-stage 2–6 GHz limiting amplifier has been developed based on a single-stage GaAs MMIC amplifier chip. The limiting amplifier is optimised for sharp linear-to-saturation power characteristics with less than 4 dB difference between minimum P1 dB (1 dB gain compression point) and maximum Psat (saturated output power) over frequency and temperature (−55°C to 85°C). The small-signal gain of the limiting amplifier at room temperature is 22.5 dB with gain flatness of ±0.5 dB, with less than 1.7:1 input and output VSWR over the band.

X-Band MMIC amplifier on GaAs/Si

A single-stage MMIC feedback amplifier fabricated on GaAs epitaxially grown on high-resistivity Si (6 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> Ω.cm) will be described. The GaAs active and buffer layers were grown on 4°-off-(100) high-resistivity Si substrate by organometallic chemical vapor deposition. The peakc arrier density was 1.7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> and the electron mobility was near 2900 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V·s. The amplifier had 5.5-dB maximum small-signal gain and a 3-dB bandwidth of 8.5-11.5 GHz. The performance was limited by the poor quality of the Schottky harrier on GaAs/Si. The thermal resistance of the MESFET in this MMIC was measured and found to be lower than that for a comparable unit on a semi-insulating GaAs substrate by 18°C mm/W.