Gain bandwidth of NbN HEB mixers on GaN buffer layer operating at 2 THz local oscillator frequency
Paper i proceeding, 2017

In this paper, we present IF bandwidth measurement results of NbN HEB mixers, which are employing NbN thin films grown on a GaN buffer-layer. The HEB mixers were operated in the heterodyne regime at a bath temperature of approximately 4.5 K and with a local oscillator operating at a frequency of 2 THz. A quantum cascade laser served as the local oscillator and a reference synthesizer based on a BWO generator (130-160 GHz) and a semiconductor superlattice (SSL) frequency multiplier was used as a signal source. By changing the LO frequency it was possible to record the IF response or gain bandwidth of the HEB with a spectrum analyzer at the operation point, which yielded lowest noise temperature. The gain bandwidth that was recorded in the heterodyne regime at 2 THz amounts to approximately 5 GHz and coincides well with a measurement that has been performed at elevated bath temperatures and lower LO frequency of 140 GHz. These findings strongly support that by using a GaN buffer-layer the phonon escape time of NbN HEBs can be significantly lower as compared to e.g. Si substrate, thus, providing higher gain bandwidth.

Författare

Sergey Antipov

Andrey Trifonov

Sascha Krause

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Denis Meledin

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Vincent Desmaris

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Victor Belitsky

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Gregory Goltsman

28th International Symposium on Space Terahertz Technology, March 13-15, 2017

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Onsala rymdobservatorium

Nanotekniklaboratoriet

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Elektroteknik och elektronik

Nanoteknik

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