Sensitive, Compact 1x8 Array 530-600 GHz Receiver

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.

Glenn's revolutionary new multi-tone, high-frequency synthesizer can enable a major upgrade in the design of high data rate, wide-band satellite communications links, in addition to the study of atmospheric effects. Conventional single-frequency beacon transmitters have a major limitation: they must assume that atmospheric attenuation and group delay effects are constant at all frequencies across the band of interest. Glenn's synthesizer overcomes this limitation by enabling measurements to be made at multiple frequencies across the entire multi-GHz wide frequency, providing much more accurate and actionable readings. This novel synthesizer consists of a solid-state frequency comb or harmonic generator that uses step-recovery semiconductor diodes to generate a broad range of evenly spaced harmonic frequencies, which are coherent and tunable over a wide frequency range. These harmonics are then filtered by a tunable bandpass filter and amplified to the necessary power level by a tunable millimeter-wave power amplifier. Next, the amplified signals are transmitted as beacon signals from a satellite to a ground receiving station. By measuring the relative signal strength and phase at ground sites the atmospheric induced effects can be determined, enabling scientists to gather essential climate data on hurricanes and climate change. In addition, the synthesizer can serve as a wideband source in place of a satellite transponder, making it easier to downlink high volumes of collected data to the scientific community. Glenn's synthesizer enables a beacon transmitter that, from the economical CubeSat platform, offers simultaneous, fast, and more accurate wideband transmission from space through the Earth's atmosphere than has ever been possible before.

NASA Goddard Space Flight Center has developed a faster and widely-tunable monolithic optical parametric oscillator for use in laser spectrometers. This technology provides a continuously-tunable spectrum across any target, adding flexibility to the overall instrument. In addition, only 1 nonlinear crystal and oscillator pump source are used, greatly simplifying the spectrometer system.

The NDL uses homodyne detection to obtain changes in signal frequency caused by a target of interest. Frequency associated with each segment of the modulated waveform collected by the instrument is positive or negative, depending on the relative range and direction of motion between the NDL and the target. Homodyne detection offers a direct measurement of signal frequency changes however only the absolute values of the frequencies are measured, therefore additional information is necessary to determine positive or negative sign of the detected frequencies. The three segmented waveform, as opposed to conventional two-segmented ones, allows for resolving the frequency sign ambiguity. In a practical system, there are times when one or more of the three frequencies are not available during a measurement. For these cases, knowledge of the relative positions of the frequency sideband components is used to predict direction of the Doppler shift and sign, and thus make correct range and velocity measurements. This algorithm provides estimates to the sign of the intermediate frequencies. The instrument operates continuously in real time, producing independent range and velocity measurements by each line of sight used to take the measurement. In case of loss of one of the three frequencies, past measurements of range and velocity are used by the algorithm to provide estimates of the expected new range and velocity measurement. These estimates are obtained by applying an estimation filter to past measurements. These estimates are used during signal loss to reduce uncertainty in the sign of the frequencies measured once signals are re-established, and never to replace value of a measurement.

This instrument uses a variation of laser heterodyne radiometer (LHR) to measure the concentration of trace gases in the atmosphere by measuring their absorption of sunlight in the infrared. Each absorption signal is mixed with laser light (the local oscillator) at a near-by frequency in a fast photoreceiver. The resulting beat signal is sensitive to changes in absorption, and located at an easier-to-process RF frequency. By separating the signal into a RF filter bank, trace gas concentrations can be found as a function of altitude.