A MMIC-based 75-110 GHz signal source

This paper describes the design, construction, and testing of a compact W-Band signal source module. The MMIC-based module is an active times-6 frequency multiplier, requiring a 12.5 to 18.5 GHz, 2 mW input signal, which can be provided by any microwave synthesizer or other readily available oscillators. The design Includes directional couplers with integrated millimeter-wave detectors on the output for power and reflection monitoring. Output power Is voltage-controllable over a 10 dB dynamic range. Test results show 10 dB conversion gain at the maximum output power of about 20 mW across the band

On the relation between rf noise and subthreshold swing in InP HEMTs for cryogenic LNAs

4 - 8 GHz low-noise amplifiers (LNAs) based on InP high electron mobility transistors (InP HEMTs) with different spacer thickness in the InAlAs-InGaAs heterostructure were fabricated and characterized at 5 K. A variation in the lowest average noise temperature of the LNA was observed with spacer thickness. We here report that the subthreshold swing (SS) at 5 K for the HEMT exhibited similar dependence with spacer thickness as the lowest average noise temperature of the LNA. This suggests that low-temperature characterization of SS for the HEMT can be used as a rapid assessment of anticipated noise performance in the cryogenic HEMT LNA

Influence of Spacer Thickness on the Noise Performance in InP HEMTs for Cryogenic LNAs

InP high electron mobility transistors (InP HEMTs) with different spacer thickness 1 to 7 nm in the InAlAs-InGaAs heterostructure have been fabricated and characterized at 5 K with respect to electrical dc and rf properties. The InP HEMT noise performance was extracted from gain and noise measurements of a hybrid low-noise amplifier (LNA) at 5 K equipped with discrete transistors. When biased for optimal noise operation, the LNA using 5 nm spacer thickness InP HEMTs achieved the lowest average noise temperature of 1.4 K at 4-8 GHz. The InP HEMT channel noise was estimated from the drain noise temperature which confirmed the minimum in noise temperature for the 5 nm spacer thickness InP HEMT. It is suggested that the spacer thickness acts to control the degree of real-space transfer of electrons from the channel to the barrier responsible for the observed noise variation in the cryogenic InP HEMTs

Full Ka-band High Performance InP MMIC LNA Module

A 0.1-µm InP HEMT Ka-band LNA with high and flat gain, very low noise figure and low VSWR has been developed. Across the entire Ka-band, of 26 GHz to 40 GHz, the MMIC LNA demonstrated associated gain of 21.9 plusmn 0.9 dB and an average noise figure of 1.5 dB with a minimum of 1.3 dB at 34 GHz. The LNA chip was cryogenically cooled to 12 K where it exhibited an associated gain of 23.0 ± 1.1 dB and an average noise temperature of 15.5 K, i.e. 0.23-dB noise figure. Two LNA chips were cascaded and assembled into a module. At room temperature, the module achieved an associated gain of 37.6 dB ± 1.8 dB and an average noise figure of 1.3 dB. At 15 K, the average noise temperature was improved to 11.4 K with 41.0 ± 2.4 dB associated gain

On the relation between rf noise and subthreshold swing in InP HEMTs for cryogenic LNAs

4 - 8 GHz low-noise amplifiers (LNAs) based on InP high electron mobility transistors (InP HEMTs) with different spacer thickness in the InAlAs-InGaAs heterostructure were fabricated and characterized at 5 K. A variation in the lowest average noise temperature of the LNA was observed with spacer thickness. We here report that the subthreshold swing (SS) at 5 K for the HEMT exhibited similar dependence with spacer thickness as the lowest average noise temperature of the LNA. This suggests that low-temperature characterization of SS for the HEMT can be used as a rapid assessment of anticipated noise performance in the cryogenic HEMT LNA

A MMIC-based 75-110 GHz signal source

This paper describes the design, construction, and testing of a compact W-Band signal source module. The MMIC-based module is an active times-6 frequency multiplier, requiring a 12.5 to 18.5 GHz, 2 mW input signal, which can be provided by any microwave synthesizer or other readily available oscillators. The design Includes directional couplers with integrated millimeter-wave detectors on the output for power and reflection monitoring. Output power Is voltage-controllable over a 10 dB dynamic range. Test results show 10 dB conversion gain at the maximum output power of about 20 mW across the band

Reduction of Noise Temperature in Cryogenic InP HEMT Low Noise Amplifiers with Increased Spacer Thickness in InAlAs-InGaAs-InP Heterostructures

The impact of InP HEMT spacer thickness on cryogenic performance in low noise amplifiers (LNAs) has been investigated. 100 nm gate-length InP HEMTs based on InAlAs-InGaAs-InP heterostructures with different spacer thickness (1 nm, 3 nm and 5 nm) were fabricated. The Hall measurements, simulated band structures and dc characteristics of InP HEMTs were compared for all the three different epitaxial structures at 5 K. The noise performance of the InP HEMT was studied using a three-stage 4–8 GHz hybrid LNA at 5 K. All LNAs yielded an average gain above 30 dB across the whole band. When biased for optimal low noise operation, the LNA with 5 nm spacer thickness InP HEMTs achieved an average noise temperature of 1.3 K. The LNAs with spacer thickness of 1 nm and 3 nm InP HEMTs exhibited a higher average noise temperature of 1.9 K and 1.7 K, respectively. The reduction in LNA noise temperature with increased spacer thickness was observed to correlate with a strongly enhanced electron mobility in the InP HEMT structure at 5 K

Full Ka-band High Performance InP MMIC LNA Module

A 0.1-µm InP HEMT Ka-band LNA with high and flat gain, very low noise figure and low VSWR has been developed. Across the entire Ka-band, of 26 GHz to 40 GHz, the MMIC LNA demonstrated associated gain of 21.9 plusmn 0.9 dB and an average noise figure of 1.5 dB with a minimum of 1.3 dB at 34 GHz. The LNA chip was cryogenically cooled to 12 K where it exhibited an associated gain of 23.0 ± 1.1 dB and an average noise temperature of 15.5 K, i.e. 0.23-dB noise figure. Two LNA chips were cascaded and assembled into a module. At room temperature, the module achieved an associated gain of 37.6 dB ± 1.8 dB and an average noise figure of 1.3 dB. At 15 K, the average noise temperature was improved to 11.4 K with 41.0 ± 2.4 dB associated gain

Low noise 874 GHz receivers for the international submillimetre airborne radiometer (ISMAR)

We report on the development of two 874 GHz receiver channels with orthogonal polarizations for the international submillimetre airborne radiometer. A spline horn antenna and dielectric lens, a Schottky diode mixer circuit, and an intermediate frequency (IF) low noise amplifier circuit were integrated in the same metallic split block housing. This resulted in a receiver mean double sideband (DSB) noise temperature of 3300 K (minimum 2770 K, maximum 3400 K), achieved at an operation temperature of 40 C and across a 10 GHz wide IF band. A minimum DSB noise temperature of 2260 K at 20 C was measured without the lens. Three different dielectric lens materials were tested and compared with respect to the radiation pattern and noise temperature. All three lenses were compliant in terms of radiation pattern, but one of the materials leads to a reduction in a noise temperature of approximately 200 K compared to the others. The loss in this lens was estimated to be 0.42 dB. The local oscillator chains have a power consumption of 24W and consist of custom-designed Schottky diode quadruplers (5% power efficiency in operation, 8%-9% peak), commercial heterostructure barrier varactor (HBV) triplers, and power amplifiers that are pumped by using a common dielectric resonator oscillator at 36.43 GHz. Measurements of the radiation pattern showed a symmetric main beam lobe with full width half maximum <5 and side lobe levels below 20 dB. The return loss of a prototype of the spline horn and lens was measured using a network analyzer and frequency extenders to be 750-1100 GHz. Time-domain analysis of the reflection coefficients shows that the reflections are below 25 dB and are dominated by the external waveguide interface