Broadband MgB2 Hot-Electron Bolometer THz Mixers Operating up to 20 K

We discuss performance of submicron size hot-electron bolometer mixers made from thin MgB
₂
superconducting films. With a superconducting transition temperature of ~30 K, such terahertz (THz) mixers can operate with high sensitivity at temperatures up to 20 K. Due to very small dimensions local oscillator power requirements are rather low. In the intermediate frequency band of 1-3 GHz, the double sideband receiver noise temperature is 1600 K at 10 K operation temperature, 2000 K at 15 K, 2500-3000 K at 20 K. The gain bandwidth of such devices is 6 GHz and the noise bandwidth is estimated to be 6-8 GHz.