Obtaining temperature, pressure, and composition profiles along with wind velocities in the Earth’s
thermosphere/ionosphere system is a key NASA goal for understanding our planet. We report on the status of a
technology development effort to build an all-solid-state heterodyne receiver at 2.06 THz that will allow the
measurement of the 2.06 THz [OI] line for altitudes greater than 100 km. The receiver front end features low-parasitic
Schottky diode mixer chips that are driven by a local oscillator (LO) source using Schottky diode based multipliers. The
multiplier chain consists of a 38 GHz oscillator followed by a set of three cascaded triplers at 114 GHz, 343 GHz and
NASA and ESA are planning missions to Jupiter and its moons. There is strong interest in a submillimeter/Terahertz
spectroscopic heterodyne instrument covering the bands 520 to 600 GHz and 1100 to 1300 GHz. Therefore, we are
developing a prototype instrument incorporating unique features not previously developed for planetary instrumentation.
These include (1) extremely wide, rapid tunability. The Herschel/HIFI astronomical instrument, is also wideband, but far
larger. It incorporates a 3.5 meter telescope on a spacecraft massing over three tons orbiting near Earth, versus our 20 kg
Jupiter spectrometer. Hence, we have developed a wideband low-phase-noise synthesizer pumping two Schottky diode
LO multiplier chains outputting 520 to 600 and 550 to 650 GHz. Also based on Schottky diodes are (b) 550 and 1200
GHz room temperature mixers. The high frequency mixer is subharmonically pumped; the lower balanced fundamental.
To analyze the IF signals from the mixers, (c) ASIC based digital polyphase spectrometers consuming only a few Watts
each are being incorporated into the instrument. Finally, since signals for both receivers come from one telescope, we
include a new (d) compact dual band low-loss optical bench. It uses the fact that each receiver accepts one polarization,
making a polarizing beam splitter sufficient to split the beam with minimal loss.
Recent results from the Heterodyne Instrument for Far-Infrared (HIFI) on the Herschel Space Telescope have confirmed
the usefulness of high resolution spectroscopic data for a better understanding of our Universe. This paper will explore
the current status of tunable local oscillator sources beyond HIFI and provide demonstration of how power combining of
GaAs Schottky diodes can be used to increase both power and upper operating frequency for heterodyne receivers.
Availability of power levels greater than 1 watt in the W-band now makes it possible to design a 1900 GHz source with
more than 100 microwatts of expected output power.
A novel approach for submillimeter-wave heterodyne imaging arrays is presented in this paper. By utilizing diverse
technologies such as GaAs membrane based terahertz diodes, wafer bonding, bulk Si micromachining, micro-lens optics,
and CMOS 3-D chip architectures, a super-compact low-mass submillimeter-wave imaging array is envisioned. A fourwafer
based silicon block for a working W-band power amplifier MMIC is demonstrated. This module drastically
reduces mass and volume associated with metal block implementations without sacrificing performance. A path towards
super compact array receivers in the 500-600 GHz range is described in detail.
We report upon the development of a 190 GHz MMIC frequency doubler and 380 GHz sub-harmonic mixer using
foundry planar Schottky diodes. The devices have been fabricated by the company UMS using their BES process, and
post-processed afterwards to transfer the GaAs circuit membranes onto a quartz substrate. This novel substrate transfer
technique is presented. Preliminary measurements give a doubler output power over 3 mW in the frequency range 170-205 GHz.