Wideband, Subharmonic Mixer for Spectrometers

The novel mixer offers wideband and sub-harmonic conversion capabilities for enhanced signal processing across a broad frequency range. The mixer operates at 470-600 GHz and includes a LO waveguide to allow 265-300 GHz input signal and a radio frequency (RF) waveguide for the 470-600 GHz operation. The LO and RF signal multiply and down-convert the RF signal to an IF signal to a much lower frequencies for further digitization. The mixer is designed on a gold and quartz substrate for a lower dielectric constant. The filter design uses a triangular patch resonator-based low-pass filter to reduce the size of the mixer as well as isolates the LO signal and the wide IF signal. Additionally, an IF filter, RF filter, Schottky diode, LO, and RF probes are integrated into a single chip to further reduce the dimensions of the mixer. The invention also leverages an antiparallel diode orientation, where the LO frequency is half of the RF input. This LO signal is amplified and multiplied up to 265-300 GHz to provide an input power of 3-5 mW to pump the antiparallel mixer. The technology offers significant advantages in remote sensing and high-speed communications, enabling simultaneous detection of multiple molecular species and enhancing the efficiency of submillimeter-wave heterodyne spectrometers. The wideband functionality achieves high data rates required in emerging 6G networks and offers exceptional sensitivity, with prototype tests showing a conversion loss below 12 dB and noise temperatures under 4000 K at 470 GHz. The integration of components such as filters and diodes into a single chip reduces system size and complexity, contrasting with traditional multi-chip setups. The design is scalable across frequencies from 1 GHz-1 THz with minimal modifications, with the system's form factor inversely scaling with frequency. These features make the technology versatile for applications in environmental monitoring, planetary exploration, radar systems, and advanced communication systems. Heterodyne wave spectrometers include a receiver and are configured to analyze electromagnetic waves by mixing an incoming signal with a reference signal (local oscillator - LO) to produce a lower intermediate frequency (IF) for processing. Within the receiver, a mixer plays a crucial role by combining the incoming signal with a reference signal from a LO producing an IF signal, which retains the spectral information of the original signal but at a lower, more easily processed frequency. Thus, the mixer enables the receiver to convert high-frequency signals into a more manageable form for detailed analysis. Planetary observational spectrometers require a receiver with a wide IF bandwidth and low noise temperature to detect molecular species simultaneously in a desired frequency range. Existing mixers have a limited IF range, which may not be viable for future-state NASA remote-sensing applications. As a result, engineers and researchers at NASA have developed a novel compact mixer, achieving a wide IF bandwidth of approximately 70 GHz, a low noise temperature below 4,000 K, and a conversion loss under 12 dB at 470-600 GHz for space applications and may provide significant advantages to commercially-available spectrometers.