Broadband Metamaterial Termination for Planar Superconducting Transmission Line Circuits

The power divider use Klopfenstein tapered transmission lines on each output branch of the junction impedance that is matched the input port. Thus, the output lines are well matched to the input, and a reflected power of 1% can be easily achieved. Resistors are distributed along the transmission lines to provide isolation between the two output ports which prevents power of one output port from coupling to the other output port. A large amount of the power is dissipated in the resistors rather than exiting through any other ports in the system. Due to the symmetry of the design, very little power is dissipated during normal operation. The resulting power divider is operable at high bandwidths as the tapered impedance match which have no upper frequency limitation. Additionally, the tapered lines eliminate many discontinuities in the layout which in turn reduce microwave junction effects. The power divider is capable of being manufactured using known methods and may be utilized in a compact microwave spectrometer.

Glenn's researchers originally created the MDC to improve the beacon sources for atmospheric propagation studies. These studies are typically conducted to test atmospheric conditions to determine the signal strength needed for satellite communications. A low-power transmitter (e.g., a beacon source) is attached to the satellite, and transmits a continuous waveform (CW) signal to a receiving station on Earth. However, when a separate frequency is desired, building a new beacon source for the transmitter on the satellite - especially one that will operate at higher frequencies - presents numerous challenges. For one, a single-frequency beacon source requires a temperature-stabilized oscillator for frequency generation separate from that provided by the spacecraft receiver. To solve such problems, Glenn's innovators fabricated the MDC from two sections of waveguide: a primary waveguide for the fundamental frequency (Ku-band), and a secondary waveguide for the harmonics (Ka-band). These sections are joined together so that precision-machined slots in the second waveguide selectively couple the harmonics, for amplification and transmission. The harmonics can then be used as an additional beacon source with very small power losses to the fundamental signal. Once the separation takes place, the second or higher harmonic can be amplified and transmitted to a station on Earth. The efficiency and performance of the MDC can be optimized through appropriate computer modeling software and currently available high-precision fabrication techniques. Without the complexity and expense involved in building separate traveling wave tube amplifiers to generate additional frequencies, Glenn's MDC enables satellites to produce multiple signals that can be received by multiple stations - a significant leap forward in satellite productivity.

The patch antenna consists of two radiating metal patch elements, a metal feed circuit, choke rings, several alignment spacers, a SMA connector, and a mounting lid giving the antenna a total diameter of 54 mm; small enough to fit in a coffee cup. The signal is carried between the lower patch and the circuit via a coaxial transmission structure, in which the probes are the inner conductor and the antenna structure is the outer conductor. The patch antenna is constructed entirely of metal, offering rugged physical durability while delivering superior performance. This advanced material not only enables the antenna to handle higher power loads (exceeding 10 watts) but also ensures exceptional stability under demanding conditions—outperforming standard patch antennas made with traditional dielectric materials. It is also not susceptible to the manufacturing variability incurred from using dielectrics. Ideally, this metallic design also allows for reentry and reuse across missions. The patch antenna is designed with integrated choke rings to effectively mitigate multipath signal interference, delivering an impressive front-to-back ratio of over 35 dB. Its integrated polarizer circuit enhances signal clarity and boosts overall efficiency, ensuring reliable communication in challenging environments. With support for both right- and left-handed circular polarization, the antenna achieves a co-polarization peak gain of 9 dBi and an axial ratio of less than 3 dB within a wide 50-degree orientation range. These advanced features provide superior signal performance and consistent clarity across diverse applications. Although designed for space and planetary exploration applications, the antenna may also be valuable for terrestrial use cases with rugged conditions. The X-band patch antenna is at technology readiness level (TRL) 5 (component and/or breadboard validation in relevant environment) and is available for patent licensing.

The electromagnetic properties of the material are engineered by optimizing its complex dielectric function through the volume filling fraction of its components. A low-index polymeric binder, such as thermal polymers and epoxies, serves as the host medium to minimize reflectance in the conductively loaded dielectric media. To ensure thermal compatibility with metal substrates in cryogenic environments, dielectric powders are incorporated to match thermal expansion. Additionally, alumina frit compensates for thermal contraction at cryogenic temperatures, while non-magnetic conductive particles such as bronze, carbon allotropes, and degenerately doped silicon help tailor the material’s dielectric response. To enhance performance, small-particle scatterers reduce heat capacity and limit resonant dispersion, while dirty alloys stabilize resistance under conductive loading. The formulation incorporates reststrahlen materials and supports applications across the microwave to terahertz range, making it suitable for baffles, Lyot stops, and optical terminations, or as a primer for enhancing near-infrared and visible black paints. This high-emissivity, non-magnetic coating is designed for microwave to far-infrared instrumentation in space and cryogenic systems. It also benefits industries producing absorptive epoxies, EMI/EMC shielding, and quantum sensing components. It has reached Technology Readiness Level (TRL) 5 (component validation in relevant environment) and is now available for patent licensing.

Initially developed for missions to Mars, Teletenna integrates RF and optical communication technologies to transmit data from deep space to Earth at extremely high speeds. The system combines a co-boresighted telescope and a Ka-band RF antenna to minimize system mass and enhance performance. Designed with an optimal focal length-to-diameter ratio, the apparatus features a classical Cassegrain geometry, including a sub-reflector in front of the RF feed which acts as a mirror for the optical signal while being transparent to the RF signal. The apparatus also mechanically and thermally isolates the RF reflector system from the optics to offer maximum stability. Teletenna was created to overcome two significant challenges to DSOC: 1) laser inefficiency due to poor alignment during spacecraft disturbances and 2) performance degradation due to lack of rigidity in vibrational environments (such as space). The first challenge is addressed by the telescope portion of this technology, which facilitates the acquisition and maintenance of the link with ease - even in less than ideal conditions. The second challenge is addressed by rigidly fixing the RF reflector to the spacecraft body and attaching the optical section to a vibration isolation platform. The result is a device that can point to within 0.5 degrees of the sun (traditional optical systems are limited to 3 degrees), allowing for approximately 20 extra days of contact time between Earth and Mars. By combining RF and optical communications, this breakthrough innovation has the power to transform communications as we know it. Glenn welcomes co-development opportunities.