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We present a new strategy for the design of dual-band planar antennas based on metasurfaces (MTSs) in the microwave and millimeter-wave regimes. It is based on a double layer structure obtained by cascading two subwavelength patterned metallic claddings supported by a grounded dielectric slab. Each metallic layer is responsible for controlling radiation at one frequency, and it is engineered to be transparent at the other frequency. Hence, the two metallic layers can be designed independently using the well-established techniques for the design of single-layered MTS antennas. Layers decoupling is achieved by suitably exploiting Foster's reactance theorem, which regulates the frequency response of the impedance sheet modeling the metallic layer. By using the proposed strategy, a dual-band double-layered MTS antenna radiating a circularly polarized broadside beam in two popular frequency bands for climate science applications is designed and numerically verified.

The Cosmic Dark Ages represent the period in the early evolution of the Universe, starting immediately after the decoupling of CMB photons from matter, and ending with the formation of the first stars and galaxies. The HI signal from the neutral hydrogen atoms is the only mechanism for us to understand this crucial phase in the cosmological history of the Universe and answer fundamental questions about the validity of the standard cosmological model, dark matter physics, and inflation. Due to cosmological redshift, this signal is now only observable in the 3-30~MHz frequency band, which is blocked from reaching the surface of the Earth by the ionosphere. In this paper, we present the design of the Lunar Crater Radio Telescope that intends to carry out unprecedented measurements of this signal by deploying a kilometer-sized parabolic reflector mesh inside a lunar crater on the far side of the Moon and suspending a receiver at its focus.

We report on the development of a tunable antenna coupled intersubband terahertz (TACIT) detector based on GaAs/AlGaAs two dimensional electron gas. A successful device design and micro-fabrication process have been developed which maintain the high mobility (1.1x106 cm2/V-s at 10K) of a 2DEG channel in the presence of a highly conducting backgate. Gate voltage-controlled device resistance and direct THz sensing has been observed. The goal is to operate as a nearly quantum noise limited heterodyne sensor suitable for passively-cooled space platforms.

An all-metal circularly polarized UHF antenna element is presented. The patch antenna gives a wideband impedance and axial ratio bandwidth of 24% over the 0.3-0.38 GHz frequency band with 90% efficiency. The main advantage is the use of a single feed point to generate circular polarization (CP). The antenna can be used to set up a dual-band (0.3-0.32 GHz and 0.36-0.38 GHz) communication link, with an axial ratio better than 3 dB and a realized CP gain better than 8 dBiC and 10 dBiC, respectively. The interaction between the cavity walls and the patch element, results in near-field coupling and improves the impedance bandwidth as well as the axial ratio bandwidth of the antenna. Being a high gain, high aperture efficiency, low profile, light weight, and single feed point radiating element, this single patch antenna is an excellent candidate for future antenna array.

Distributed Aperture Radar Tomographic Sensors (DARTS)is a mission concept being studied at the NASA Jet PropulsionLaboratory in collaboration with the California Institute ofTechnology to enable global and repeated imaging of surfacetopography and three-dimensional vegetation structure usingsingle-pass tomographic SAR technique. The observing systemconsists of a distributed formation of multiple small syntheticaperture radar platforms deployed in space with variabledistances to achieve look angle diversity and sensitivityto the vertical distribution of vegetation components. Ourgoal is to identify the optimal system configuration startingfrom documented community needs and mature the criticaltechnologies that lead to a viable implementation of DARTS.Here, we provide an overview of DARTS and describe ourapproach for designing and demonstrating single-pass SARtomographic systems as part of an on-going funded NASA Instrument Incubator Program effort.

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In the past decade, CubeSats have undergone a revolution, moving from universityresearch projects to enabling industry opportunities and government missions. Six yearsago, the Jet Propulsion Laboratory, California Institute of Technology (JPL/Caltech)initiated a research and technology development effort to advance CubeSat communicationcapabilities, with one of the key thrusts being the Ka-band parabolic deployable antenna(KaPDA). This antenna started with the ambitious goal of fitting a 42 dB, 0.5 meter, 35 GHzantenna in a 1.5U canister. At that time, there had been very limited development in the areaof high gain CubeSat antennas which are critical for both high data rate communicationsand remote sensing science. A Ka-band high gain antenna would provide a 10,000 timesincrease in data communication rates over an X-band patch antenna and a 100 timesincrease over state-of-the-art S-band parabolic antennas. This paper discusses the process ofbuilding, integrating, and operating the flight antenna, its final performance and lessonslearned. KaPDA was an enabling technology for RainCube mission, the first Earth ScienceCubeSat to have an active instrument. RainCube was launched in May of 2018, makingKaPDA the second deployable parabolic antenna to fly on a CubeSat and the first of its kindto operate at Ka-band enabling a number of opportunities for high rate, deep space antennacommunications and remote sensing science.

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A new all-metal dual-frequency RHCP high gain antenna is under development at NASA’s Jet Propulsion Laboratory for a potential Europa Lander. The antenna is mainly made of metal so it could survive the harsh environment conditions (i.e. very low temperature and high radiation and ESD levels). The antenna is also flat to meet drastic volume constraints and has efficiencies higher than 80% at both the uplink and downlink X-band Deep Space frequency bands. This antenna is a key component for the potential mission enabling Direct Link to Earth (DTE) from and Direct-from-Earth (DFE) to the lander without any relay.

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