300-GHz integrated heterodyne receiver with carrier lock-in Costas loop

Abstract

A carrier signal lock-in experiment using a 300-GHz integrated heterodyne circuit is presented. The circuit contains a single voltage-controlled oscillator with a single set of quadrature mixers that are fabricated using 250-nm InP double hetero-junction bipolar transistor technology. An external feedback loop containing packaged baseband components such as amplifiers, a phase discriminator, and a filter is connected to the integrated circuit to form a complete receiver system. For a -25 dBm of input RF signal with 3.5-GHz single-tone carrier-suppressed modulation, the receiver system responds with successful lock-in range of 110 MHz centred around 311 GHz.