Comparison of Fourth-harmonic and Combined Doubler/Subharmonic Mixer with integrated MMIC based Local Oscillator

Abstract

In this paper a comparison between a fourth harmonic mixer and a combined doubler/subharmonic mixer based on Schottky diodes working at 300 GHz with MMIC Local Oscillator (LO) integrated in a single enclosing is presented. Both configurations allow reducing the LO requirements, since a lower LO frequency is used. In addition, the integration of the MMIC Local Oscillator with the mixer in the same single metallic block is the main novelty and advantage of this work. Since only one block is used, flange connections are avoided. This way, misalignment errors are also prevented. Besides this advantage, the compactness of this solution is also remarkable, leading to a significant weight reduction.

A Millimeter-Wave 4th-Harmonic Schottky Diode Mixer with Integrated Local Oscillator

“…In this paper, we simplify this approach and evaluate the performance of a 4thharmonic mixer pumped with a similar MMIC-based LO source. The use of this type of configuration, for which RF = 4 × f OL ± IF [9][10][11], allows extending the frequency range of submillimeter-wave mixers without requiring the use of a high LO frequency or a frequency multiplier for the LO signal, such as that proposed in [8,12]. In return, the conversion loss (CL) and equivalent noise temperature (ENT) will be higher; however, we have the advantage of simplified LO generation and a high integration level, which produces a more compact solution, since the multiplier and its bias circuitry are not necessary, and entails a simplification in terms of design.…”