Low noise 874 GHz receivers for the International Submillimetre Airborne Radiometer (ISMAR)

Abstract

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 led to a reduction in 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 24 W 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. Return loss of a prototype of the spline horn and lens was measured using a network analyzer and frequency extenders to 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.

The first global 883 GHz cloud ice survey: IceCube Level 1 data calibration, processing and analysis

“…So far the only other two passive sensors that carry a 874-883 GHz channel are ESA's airborne International SubMillimeter Airborne Radiometer (ISMAR) and NASA's airborne Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR). ISMAR only added the 874 GHz channel in recent flights, so data are not publicly available at this moment (Hammar et al, 2018;Fox, 2020). CoSSIR channel frequencies range from 183 ± 1, ±3, ±7 GHz (water vapor profiling), 220, 380±1, ±2, ±3, ±6 GHz (temperature profiling) and 640 GHz vertically polarized and horizontally polarized pairs to 874 GHz.…”

A Terahertz Monostatic Transceiver in 90-nm SiGe BiCMOS

“…Using silicon-integrated technologies at terahertz (THz) frequencies therefore becomes challenging due to the absence of practical transistor gain above f max /2, currently only demonstrated at 1 THz using a III-V InP high electron mobility transistor with f max of 1.5 THz [6]. Nevertheless, state-of-the-art terahertz designs are commonly implemented using bulky split-block designs incorporating III-V Schottky diodes which show excellent receiver noise temperatures of around 3000 K at 0.85 THz [7], 0.874 THz [8] and 1.134 THz [9]. Similarly, an output power of around 2 mW has been achieved using a Schottky diode frequency tripler at 1.03 THz [10].…”

Design and Measurement of a 0.67 THz Biased Sub-Harmonic Mixer

“…So, it is urgent to design biased sub-harmonic mixers to reduce the requirement for LO power. At present, biased sub-harmonic mixers working at 585 GHz [13], 874 GHz [14,15], 1.2 THz [16,17], and 1.2 THz [18] are designed and reported based on advanced GaAs membrane film process or frameless architecture. The biased mixers mentioned above are all based on monolithic integration technology, where the on-chip capacitor is required.…”