A customizable, five-stage, intermediate frequency, low-noise amplifier and readout chain for the Astrophysics Stratospheric Telescope for High-spectral Resolution Observations at Submillimeter-wavelengths (ASTHROS)

Atmospheric interference, noise, and attenuation are a few limitations that arise when observing emissions of sub-millimeter wavelengths using ground-based telescopes. On-going research conducted on high-altitude balloons allow a new direction in observing these distributed emissions and eliminates all possible atmospheric interference. All sub-millimeter balloons and ground-based telescopes could benefit from a compact, re-configurable, high gain, programmable amplifier module to use in their receivers. We have designed, built, and tested an amplifier module for the Astrophysics Stratospheric Telescope for High Spectral Resolution Observations at Sub-millimeter wavelengths (ASTHROS), which is a high-altitude balloon mission that utilizes high-spectral resolution spectrometry to analyze stellar feedback by mapping ionized gas from the Milky Way galaxy and other neighboring galaxies. Using a five-stage Intermediate Frequency (IF) Low Noise Amplifier (LNA) added to a readout chain using commercial off-the-shelf components, the amplifier module yields 74 dB of gain up to 3.5 GHz with 31.75 dB of programmable attenuation with relatively linear gain flatness of ±1 dB, all while consuming 2.25 W per module (9 V at 250 mA).

While the amplification techniques and technology in this field are not new, achieving such high gain in systems usually require a significant amount of space to be allocated onboard. To alleviate this issue, this amplifier module has a unique form factor that combines the entire amplifier chain and bias system all in one module, saving space and weight on the system. The form factor design also allows the module to be stacked on top of one another to provide a higher range of gain in the system. Currently, the modules can be stacked up to eight times, and can be connected to allow for full control of the system with the use of a microcontroller. Sub-millimeter systems can have a set of 8 modules, all while saving space and reducing used weight.